Dental instrument with heating system and method of use thereof

Abstract

Dental instruments having a heating system and methods of using such dental instruments are provided. The dental instrument includes a head portion and a handle portion. The head portion includes a housing, a reflective layer coupled to a top part of the housing and a heating system comprising a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer. The heating system can further include a power PCB comprising a connection pin, and the resistive heating circuit layer can be provided as a heating PCB comprising a connection point configured to be in electrical communication with the connection pin.

Description

DENTAL INSTRUMENT WITH HEATING SYSTEM AND METHOD OF USE THEREOFTECHNICAL FIELD

[0001] The technical field generally relates to dental instruments, and more particularly relates to dental instruments, such as dental mirrors, that include a heating system.BACKGROUND

[0002] It may be challenging for a health care provider, such as a dentist or a dental hygienist, to have a direct line of sight into a patient’s mouth to perform a dental exam or other dental procedures. Intraoral mirrors, also known as dental mirrors, are frequently used by such health care providers to facilitate the viewing of biological structures that are located inside the oral cavity of the patient’s mouth, such as teeth and gums, by enabling the observation of reflections of the biological structure of interest onto the reflective surface of the dental mirror.

[0003] Nonetheless, the oral cavity of a patient’s mouth is typically a humid and warm environment, due to the patient’s saliva and body temperature. This type of environment can make it difficult to properly view the biological structure of interest on the reflective surface of the dental mirror because water vapor can condense onto the reflective surface of the dental mirror. Thus, in order to improve the visibility within the interior of the oral cavity of the patient’s mouth using a dental mirror, an external device configured to spray fluid, such as water, can be directed toward the dental mirror to remove condensed water droplets from the reflective surface and provide a cleaner and clearer viewing surface. Alternatively, the health care provider can choose to frequently wipe the reflective surface of the mirror.

[0004] However, these approaches to remove condensed water droplets from the reflective surface of the mirror can have various drawbacks, such as requiring additional manipulations by the health care provider, or a nearby assistant, thereby increasing the time during which the health care provider is providing treatment to the patient. In addition, wiping the reflective surface of the mirror frequently can lead to damage to the reflective surface and can thus result in having to change the dental mirror frequently, which in turn can translate into significant costs and waste. Accordingly, there remains several challenges with respect to dental instruments.SUMMARY

[0005] In accordance with an aspect, there is provided a dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: a housing having a bottom part and a top part together defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the top part of the housing and having a bottom surface facing the housing cavity and a top surface, opposite the bottom surface; and a heating system comprising: a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer.

[0006] In some implementations, the resistive heating circuit layer is in direct thermal contact with the reflective layer.

[0007] In some implementations, the bottom surface of the reflective layer is substantially flat, and the resistive heating circuit layer and the reflective layer are in contact with each other in a flat configuration.

[0008] In some implementations, the resistive heating circuit layer is in indirect thermal contact with the reflective layer.

[0009] In some implementations, a superposition of the resistive heating circuit layer and the reflective layer defines an interlayer space therebetween, the interlayer space being at least partially filled with a filler.

[0010] In some implementations, the heat generated by the resistive heating circuit layer is transferrable to the reflective surface at least via conduction heat transfer.

[0011] In some implementations, the resistive heating circuit layer is flexible or rigid.

[0012] In some implementations, the resistive heating circuit layer is electrically connectable to the power source via an electrical connection.

[0013] In some implementations, the resistive heating circuit layer comprises a heating printed circuit board (PCB).

[0014] In some implementations, the electrical connection comprises a power PCB.

[0015] In some implementations, the resistive heating circuit layer is configured to be in electrical communication with the power PCB via a connection assembly.

[0016] In some implementations, the connection assembly comprises at least one connection pin and at least one connector point configured to be electrically engageable with each other.

[0017] In some implementations, the power PCB comprises the at least one connection pin, and the resistive heating circuit layer comprises the at least one connector point.

[0018] In some implementations, the power PCB comprises the at least one connector point, and the resistive heating circuit layer comprises the at least one connecting pin.

[0019] In some implementations, the at least one connection pin comprises a pogo-pin.

[0020] In some implementations, the dental instrument further comprises an intermediate layer provided between the resistive heating circuit layer and the power PCB, the intermediate layer defining a connection pin aperture through which the at least one connection pin extends.

[0021] In some implementations, the dental instrument further comprises an intermediate layer provided between the resistive heating circuit layer and the power PCB, the intermediate layer defining a corresponding connection pin aperture through which each connection pin of the at least one connection pin extends.

[0022] In some implementations, the intermediate layer is directly connected to the bottom part via a mechanical fastener.

[0023] In some implementations, the intermediate layer comprises a recessed portion defining a heating layer receiving surface configured to receive the resistive heating circuit layer thereon.

[0024] In some implementations, the intermediate layer further comprises an elevated annular edge provided around the recessed portion.

[0025] In some implementations, the intermediate layer further comprises a housing indexing feature and the resistive heating circuit layer further comprises a heating layer indexing feature, the heating layer indexing feature being engageable with the housing indexing feature to enable positioning the resistive heating circuit layer in a predetermined position relative to the intermediate layer.

[0026] In some implementations, the resistive heating circuit layer comprises an optical sensor window alignable with an optical sensor provided in the housing cavity.

[0027] In some implementations, the resistive heating circuit layer and the reflective layer are coupled to each other as a sub-assembly, and the reflective layer comprises a reflective layer window aligned with the optical sensor window.

[0028] In some implementations, the resistive heating circuit layer and the reflective layer are coupled to each other via an adhesive.

[0029] In some implementations, the sub-assembly further comprises a gasket adhered to the bottom surface of the reflective layer.

[0030] In some implementations, the gasket is superposable to the elevated annular edge of the intermediate layer.

[0031] In some implementations, the housing indexing feature comprises a shoulder having an internal edge partly defining an outer periphery of the heating layer receiving surface and being offset in an upward direction relative to the heating layer receiving surface, and the heating layer indexing feature comprises a cutoff edge, the internal edge and the cutoff edge having a complementary shape.

[0032] In some implementations, the resistive heating circuit layer extends over at least 50% of a surface area of the bottom surface of the reflective layer.

[0033] In some implementations, the resistive heating circuit layer extends over at least 75% of a surface area of the bottom surface of the reflective layer.

[0034] In some implementations, the resistive heating circuit layer extends over at least 95% of a surface area of the bottom surface of the reflective layer.

[0035] In some implementations, the resistive heating circuit layer and the reflective layer have substantially the same surface area.

[0036] In some implementations, the top part of the housing comprises a ring-shaped body defining a housing opening, the reflective layer and the resistive heating circuit layer being positioned within the housing opening.

[0037] In some implementations, the ring-shaped comprises an annular protrusion extending inwardly toward a center of the reflective layer, and the bottom part defines an annular recess, the annular recess being configured to receive the annular protrusion therein to engage the top part and the bottom part together in a snap-fit.

[0038] In some implementations, the top surface of the reflective layer is flush with a top edge of the ring-shaped body.

[0039] In some implementations, the reflective surface of the reflective layer is spaced apart from a top edge of the ring-shaped body.

[0040] In some implementations, the resistive heating circuit layer has a heating layer thickness between about 2 and about 20 times thinner than a reflective layer thickness of the reflective layer.

[0041] In some implementations, the resistive heating circuit layer has a heating layer thickness between about 0.5 mm and about 1.2 mm, between about 0.6 mm and about 1 mm, or between about 0.7 mm and about 0.9 mm.

[0042] In some implementations, the power source comprises a battery provided in the handle portion.

[0043] In accordance with another aspect, there is provided a dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: a housing having a bottom part and a top part together defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the top part of the housing and having a bottom surface facing the cavity and a top surface, opposite the bottom surface; a heating system comprising: a heating layer positioned underneath the reflective layer and in thermal contact therewith, the heating layer being complementarily-shaped relative to the reflective layer and operable to heat the reflective layer and impede formation of condensation on the top surface of the reflective layer.

[0044] In some implementations, the heating layer is in direct thermal contact with the reflective layer.

[0045] In some implementations, the bottom surface of the reflective layer is substantially flat, and the heating layer and the reflective layer are in contact with each other in a flat configuration.

[0046] In some implementations, the heating layer is in indirect thermal contact with the reflective layer.

[0047] In some implementations, a superposition of the heating layer and the reflective layer defines an interlayer space therebetween, the interlayer space being at least partially filled with a filler.

[0048] In some implementations, the heating layer extends over at least 50% of a surface area of the bottom surface of the reflective layer.

[0049] In some implementations, the heating layer extends over at least 75% of a surface area of the bottom surface of the reflective layer.

[0050] In some implementations, the heating layer extends over at least 95% of a surface area of the bottom surface of the reflective layer.

[0051] In some implementations, the heating layer and the reflective layer have substantially the same surface area.

[0052] In accordance with another aspect, there is provided a dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: an open-top housing defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the open-top housing and having a bottom surface facing the housing cavity and a top surface, opposite the bottom surface; and a heating system comprising: a power PCB received within the housing cavity, underneath the reflective layer, and comprising a connection pin extending upwardly, the power PCB being electrically connectable to a power source; and a heating PCB provided between the reflective layer and the power PCB, the heating PCB comprising a connection point configured to be in electrical communication with the connection pin to generate heat transferrable to the reflective surface to impede formation of condensation on the top surface of the reflective layer.

[0053] In some implementations, the heating PCB is in direct thermal contact with the reflective layer.

[0054] In some implementations, the bottom surface of the reflective layer is substantially flat, and the heating PCB and the reflective layer are in contact with each other in a flat configuration.

[0055] In some implementations, the heating PCB is in indirect thermal contact with the reflective layer.

[0056] In some implementations, a superposition of the heating PCB and the reflective layer defines an interlayer space therebetween, the interlayer space being at least partially filled with a filler.

[0057] In some implementations, the heat generated by the heating PCB is transferrable to the reflective surface at least via conduction heat transfer.

[0058] In some implementations, the connection pin comprises a pogo-pin.

[0059] In some implementations, the heating PCB is a flexible heating PCB.

[0060] In some implementations, the heating PCB is a rigid heating PCB.

[0061] In some implementations, the dental instrument further comprises an intermediate layer provided between the heating PCB and the power PCB, the intermediate layer defining a connection pin aperture through which the connection pin extends.

[0062] In some implementations, the heating PCB extends over at least 50% of a surface area of the bottom surface of the reflective layer.

[0063] In some implementations, the heating PCB extends over at least 75% of a surface area of the bottom surface of the reflective layer.

[0064] In some implementations, the heating PCB extends over at least 95% of a surface area of the bottom surface of the reflective layer.

[0065] In some implementations, the heating PCB and the reflective layer have substantially the same surface area.

[0066] In some implementations, the heating PCB has a heating layer thickness between about 2 and about 20 times thinner than a reflective layer thickness of the reflective layer.

[0067] In some implementations, the heating PCB has a heating layer thickness between about 0.5 mm and about 1.2 mm, between about 0.6 mm and about 1 mm, or between about 0.7 mm and about 0.9 mm.

[0068] In some implementations, the power source comprises a battery provided in the handle portion.

[0069] In accordance with another aspect, there is provided a replaceable sub-assembly for use as a component of a head portion of a dental instrument, the replaceable subassembly comprising: a reflective layer provided with a reflective surface and being removably engageable with a top part of the head portion, the reflective layer having a bottom surface configured for orientation toward a bottom part of the head portion, and a top surface, opposite the bottom surface; and a resistive heating circuit layer positioned underneath the reflective layer, the resistive heating circuit layer being configured to be in thermal contact with the reflective layer and be electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer; wherein the reflective layer and the resistive heating circuit layer are coupled together to form the sub-assembly.

[0070] In some implementations, the reflective layer and the resistive heating circuit layer are coupled together via an adhesive.

[0071] In some implementations, the replaceable sub-assembly further comprises a gasket coupled to the bottom surface of the reflective layer, around the resistive heating circuit layer.

[0072] In some implementations, the gasket and the reflective layer are coupled together via an adhesive.

[0073] In accordance with another aspect, there is provided a method for heating a reflective layer of a dental instrument, the method comprising: detecting a position of the dental instrument relative to a mouth of a patient to obtain a dental instrument detected position, wherein the dental instrument detected position is an in-mouth position or an out-of-mouth position; controlling a heating output of a heating system comprising a resistive heating circuit layer positioned underneath the reflective layer upon receipt of a control signal determined in accordance with the dental instrument detected position, wherein the controlling comprises: supplying electric current to the resistive heating circuit layer when the dental instrument detected position is the in-mouth position to heat the reflective layer to a controlled temperature and impede formation of condensation on a reflective surface of the reflective layer.

[0074] In some implementations, the out-of-mouth position comprises a resting position and a hand-held position.

[0075] In some implementations, the controlling further comprises supplying electric current to the resistive heating circuit layer when the dental instrument detected position in the hand-held position.

[0076] In some implementations, the controlling further comprises preventing electric current supply to the resistive heating circuit layer when the dental instrument detected position is the resting position.

[0077] In some implementations, supplying electric current to the resistive heating circuit layer is performed during a heating event having a predetermined duration.

[0078] In some implementations, supplying electric current to the resistive heating circuit layer is performed until a predetermined temperature upper threshold is reached.

[0079] In some implementations, when the predetermined temperature upper threshold is reached, electric current is prevented from being supplied to the resistive heating circuit layer irrespective of the dental instrument detected position.

[0080] In some implementations, preventing electric current supply to the resistive heating circuit layer is performed until a predetermined temperature lower threshold is reached.

[0081] In some implementations, when the predetermined temperature lower threshold is reached, electric current is supplied to the resistive heating circuit layer if the dental instrument detected position is one of the in-mouth position or the hand-held position.

[0082] In some implementations, controlling the heating output of the resistive heating circuit layer comprises toggling the resistive heating circuit layer between an on configuration and an off configuration.

[0083] In some implementations, operating of the resistive heating circuit layer between the on configuration and the off configuration is performed to maintain a substantially constant temperature of the reflective layer when the dental instrument detected position is the in-mouth position.

[0084] In some implementations, detecting the position of the dental instrument relative to the mouth of the patient is performed using a motion sensor integrated in the dental instrument.

[0085] In accordance with another aspect, there is provided a dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: an open-top housing defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the open-top housing and having a bottom surface facing the housing cavity and a top surface, opposite the bottom surface;a heating system comprising: a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer; a motion sensor integrated in the dental instrument; and a controller operatively connected to the heating system and the motion sensor, the controller being configured to receive an input signal from the motion sensor and process the input signal to determine a position of the dental instrument with respect to a mouth of a patient, and to send a control signal to the heating system to control a heating output of the resistive heating circuit layer based on the determined position.

[0086] In some implementations, the motion sensor comprises an accelerometer and / or a gyroscope.

[0087] In some implementations, the motion sensor is integrated into the head portion of the dental instrument.

[0088] In some implementations, the motion sensor is integrated into the handle portion of the dental instrument.

[0089] In some implementations, the determined position is an in-mouth position or an out-of-mouth position.

[0090] In some implementations, the out-of-mouth position comprises a resting position and a hand-held position.

[0091] In some implementations, when the determined position of the dental instrument is the in-mouth position, the controller is configured to send a control signal to turn the heating system on until a predetermined temperature upper threshold is reached.

[0092] In some implementations, when the determined position of the dental instrument is the hand-held position, the controller is configured to send a control signal to turn the heating system on until a predetermined temperature upper threshold is reached.

[0093] In some implementations, when the determined position of the dental instrument is the resting position, the controller is configured to send a control signal to turn the heating system off until a predetermined temperature lower threshold is reached.

[0094] In accordance with another aspect, there is provided a dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: an open-top housing defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the open-top housing and having a bottom surface facing the housing cavity and a top surface opposite the bottom surface; a heating system comprising: a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer; a temperature sensor provided in close proximity of the reflective layer; and a controller operatively connected to the heating system and to the temperature sensor, the controller being configured to receive an input signal from the temperature sensor and process the input signal to determine a temperature of the reflective layer, and to send a control signal to the heating system to control a heating output of the resistive heating circuit layer based on the determined temperature.

[0095] In some implementations, when the determined temperature of the reflective layer is determined to be below a predetermined temperature upper threshold, the controller is configured to send a control signal to the heating system to turn the heating system on.

[0096] In some implementations, when the predetermined temperature upper threshold is reached, the controller is configured to send a control signal to the heating system to turn the heating system off.

[0097] In some implementations, when the temperature of the reflective layer is determined to be below a predetermined temperature lower threshold, the controller is configured to send a control signal to the heating system to turn the heating system on.

[0098] In accordance with another aspect, there is provided a replaceable sub-assembly for use as a component of a head portion of a dental instrument, the replaceable subassembly comprising: a frustoconical reflective layer comprising a top surface, a bottom surface opposite the top surface, and a peripheral wall defining an outwardly extending slope; and a resistive heating circuit layer coupled to the bottom surface of the reflective layer; wherein the peripheral wall of the reflective layer is configured to abut a reflective layer engaging surface of a ring-shaped body of the head portion ring removably engageable with a bottom portion of the head portion, the reflective layer engaging surface and the outwardly extending slope having complimentary angles.

[0099] In some implementations, the resistive heating circuit layer comprises an optical sensor window alignable with an optical sensor provided in the housing cavity.

[0100] In some implementations, the reflective layer comprises a reflective layer window aligned with the optical sensor window.

[0101] In some implementations, the replaceable sub-assembly further comprises a gasket coupled to the bottom surface of the reflective layer and configured to seal a remainder of the components of the head portion when a downward pressure is applied to the reflective layer.

[0102] In some implementations, the gasket is a compressible gasket.

[0103] In some implementations, the gasket is coupled to the bottom surface of the reflective layer via an adhesive.

[0104] In some implementations, the resistive heating circuit layer is coupled to the bottom surface of the reflective layer via an adhesive.

[0105] In accordance with another aspect, there is provided a replaceable sub-assembly for use as a component of a head portion of a dental instrument, the replaceable subassembly comprising: a reflective layer a top surface, a bottom surface opposite the top surface, and a peripheral wall; and a resistive heating circuit layer coupled to the bottom surface of the reflective layer, the resistive heating circuit layer comprising: a heating layer indexing feature engageable with a housing indexing feature of an intermediate layer provided in the head portion to mount the resistive heating circuit layer onto the intermediate layer in a predetermined position.

[0106] In some implementations, the heating layer indexing feature comprises a cutoff edge engageable with the housing indexing feature in a single orientation corresponding to the predetermined position.

[0107] In some implementations, the resistive heating circuit layer is generally circular, and the cutoff edge extends along a chord of the resistive heating circuit layer.

[0108] In some implementations, the heating layer indexing feature comprises a shoulder engageable with the housing indexing feature in a single orientation corresponding to the predetermined position.

[0109] In some implementations, the resistive heating circuit layer is generally circular, and the shoulder comprises an internal edge extending along a chord of the resistive heating circuit layer.

[0110] In some implementations, the heating layer indexing feature is defined within the outer periphery of the heating layer to define a housing indexing feature receiving opening configured to receive the housing indexing feature therein.

[0111] In some implementations, the resistive heating circuit layer comprises an optical sensor window alignable with an optical sensor provided in a housing cavity of the head portion.

[0112] In some implementations, the reflective layer comprises a reflective layer window aligned with the optical sensor window.

[0113] In some implementations, the resistive heating circuit layer and the reflective layer are coupled to each other via an adhesive.

[0114] In some implementations, the replaceable sub-assembly further comprises a gasket adhered to the bottom surface of the reflective layer.

[0115] In accordance with another aspect, there is provided a dental instrument, comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle, the head portion comprising: a housing comprising a housing having a bottom part and a top part connectable to each other and together defining a housing cavity, the top part comprising: a ring-shaped body connectable to the bottom part and defining a housing opening defining a reflective layer receiving opening; a reflective layer including a reflective surface and having a bottom surface and a top surface, opposite the bottom surface, the reflective layer being received in the reflective layer receiving opening; an intermediate layer provided within the housing cavity, underneath the reflective layer, and having a heating layer receiving surface;a heating system comprising a heating layer configured for placement onto the heating layer receiving surface of the intermediate layer in a predetermined position, the heating layer being adhered to the bottom surface of the reflective layer and operable to generate heat to impede formation of condensation on the top surface of the reflective layer.

[0116] In some implementations, the dental instrument further comprises one or more features as defined herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0117] Figure 1 is a perspective view of a dental instrument according to an implementation, showing a handle and a head portion coupled together.

[0118] Figure 2 is a side view of the dental instrument shown in Figure 1 , showing a neck portion extending between the handle and the head portion, according to an implementation.

[0119] Figure 3A is a cross-sectional side view of the dental instrument shown in Figure 2, showing a battery housed within the handle, according to an implementation.

[0120] Figure 3B is an enlarged view of the head portion shown in Figure 3A, showing a reflective layer positioned on a top part of a housing of the head portion, according to an implementation.

[0121] Figure 4 is an enlarged perspective view of the head portion shown in Figure 3B, showing components of a heating system installed within the housing, according to an implementation.

[0122] Figure 5 is an exploded view of the head portion shown in Figure 4, showing a resistive heating circuit layer provided above an intermediate portion of the housing, according to an implementation.

[0123] Figure 6 is an exploded view of the head portion shown in Figure 4, showing portions of the housing and of the heating system adapted to cooperate with one another, according to an implementation.

[0124] Figure 7 is a side view of the head portion shown in Figure 6, showing the connection pins extending from a power PCB provided below the intermediate portion of the housing, according to an implementation.

[0125] Figure 8 is a cross-sectional view of the head portion shown in Figure 2, showing the connection pins extending through the intermediate portion for engaging with a resistive heating circuit layer, according to an implementation.

[0126] Figure 9 is a bottom exploded perspective view of the head portion shown in Figure 6, showing connector points on the resistive heating circuit layer for engagement with the connection pins, according to an implementation.

[0127] Figure 10 is a perspective view of an alternative implementation of the head portion of the dental instrument shown in Figure 1.

[0128] Figure 11 is a cross-sectional view of the head portion shown in Figure 10, showing the housing having a top part including a ring-shaped body engaged with a bottom part, according to an implementation.

[0129] Figure 12 is a perspective exploded view of the head portion shown in Figure 11 , showing complementing components for indexing a resistive heating circuit layer relative to an intermediate layer, according to an implementation.

[0130] Figure 13 is a bottom view of a reflective layer and a resistive heating circuit layer, showing heating layer indexing features on opposite sides of the resistive heating circuit layer, according to an implementation.

[0131] Figure 14 is a perspective exploded view of the head portion shown in Figure 10, showing portions of the housing and of the heating system adapted to cooperate with one another, according to an implementation.

[0132] Figure 15 is a side exploded view of the head portion shown in Figure 14, showing connection pins extending from a power PCB provided below the intermediate layer of the housing, according to an implementation.

[0133] Figure 16 is an exploded bottom view of a reflective layer, a resistive heating circuit layer and a gasket intended to be combined together as a sub-assembly, theresistive heating circuit layer being shown adhered to the reflective layer.

[0134] Figure 17 is a perspective view of the sub-assembly of Figure 16, with the gasket being further adhered to the reflective layer.

[0135] Figure 18 is an exploded perspective view of a reflective layer, a resistive heating circuit layer and an intermediate layer showing an alignment of a reflective layer window of the reflective layer, an optical sensor window of the resistive heating circuit layer, and a slot of the intermediate layer, the reflective layer being shown as transparent.DETAILED DESCRIPTION

[0136] As will be explained below in relation to various implementations, the present disclosure describes devices, systems and methods for assisting health care providers, such as dentists and dental hygienists, to perform various procedures.

[0137] In some implementations, the present disclosure describes dental instruments, such as a dental mirror, provided with an integrated heating system configured to heat a reflective layer of the dental mirror to impede formation of condensation onto the reflective layer of the dental mirror, thereby contributing to keeping a top surface of the reflective layer substantially free of condensed water droplets and thus keeping the reflective layer substantially clear during operation of the dental mirror (e.g., during dental procedures performed by the dentist / dental hygienist).

[0138] The dental mirror can be manipulated by the health care provider, with a portion thereof, typically the head portion, being configured to be introduced into the oral cavity of the patient’s mouth. The dental mirror can include an elongated handle portion enabling the dental instrument to be grasped, with the head portion being positioned at a distal end of the handle portion. The head portion can include an open-top housing defining an internal housing cavity. The head portion includes a reflective layer provided with a reflective surface ( / .e., a mirror) and a heating system. The heating system is configured to generate heat that can be transferred to the reflective layer via various heat transfer mechanisms, for instance depending on the placement of components of the heating system relative to the reflective layer. The heating system includes a heating layer, which can be a resistive heating circuit layer, positioned underneath the reflective layer, the resistive heating circuit layer being electrically connectable to a power source. The powersource can be for instance a battery housed within the handle portion of the dental instrument. The resistive heating circuit layer is configured to heat the reflective layer to a controlled temperature that is selected to impede formation of condensation on the top surface of the reflective layer while avoiding burning the mucous membranes within the patient’s mouth. In some implementations, the resistive heating circuit layer can be configured as a heating printed circuit board (PCB). In some implementations, the electrical connection between the resistive heating circuit layer and the power source can be provided by a power PCB positioned underneath the resistive heating circuit layer and in electrical communication therewith via a connection assembly. When the power source is provided by a power PCB, the connection assembly can include for instance one or more connection pins extending upwardly from the power PCB to contact corresponding connection points defined on the resistive heating circuit layer to establish electrical communication between the power PCB and the resistive heating circuit layer.

[0139] Various implementations and features of the dental instrument and associated methods will now be described in greater detail in the following paragraphs.General description of dental instrument

[0140] With reference to Figures 1 and 2 examples of a dental instrument 10 is shown. In the illustrated implementation, the dental instrument 10 corresponds to a dental mirror 12, although other dental instruments or types of tools can be used and are within the scope of the present description. The dental instrument 10 includes a handle portion 14 enabling the dental instrument 10 to be grasped and handled by a user (e.g., a dentist), and a head portion 18 coupled to or at least proximate to a distal end 15 of the handle portion 14. The head portion 18 typically includes the functional part of the dental instrument 10, such as sickles, scalers, dental picks, probes, cleaners, scrapers, mirrors, etc. As will be described below, in the illustrated implementation, the head portion 18 includes a mirror, generally referred to as a mouth mirror, configured to assist the user in viewing the interior of the patient’s mouth during certain procedures.

[0141] More specifically, and with reference to Figures 1 to 4, 10 to 12, 14 and 15, the head portion 18 includes a housing 20 (which can also be referred to as a casing) having a top part 22 and a bottom part 24 defining a housing cavity 25. The top part 22 and the bottom part 24 can be connectable to each other or can form an integral structure. Thetop and bottom parts 22, 24 of the housing 20 are thus adapted to define a hollow interior of the head portion 18, referred to as the housing cavity 25. In the illustrated implementations, the head portion 18 includes a reflective layer 26 provided with a reflective surface 27 (e.g., the mirror). It is therefore noted that, when the dental instrument 10 includes the reflective layer 26, the user (e.g., the dentist) can manipulate the dental instrument via the handle portion 14 to selectively position the head portion 18, for instance, within a mouth of a patient in order to use the reflective surface 27 and indirectly view a given area within the mouth. In some implementations, the reflective layer 26 can be omitted, and can be replaced by another structure or component, such as a component which does not include a reflective surface, for example.

[0142] In the illustrated implementations, the reflective layer 26 has a generally diskshaped configuration, with a bottom surface 28 facing the housing cavity 25, and a top surface 29, opposite the bottom surface 28, the reflective layer 26 being provided with the reflective surface 27. The reflective surface 27 thus faces away from the housing cavity 25, and away from the housing 20 in general. It is to be noted that the reflective surface 27 can be provided adjacent to the bottom surface 28 of the reflective layer 26 (i.e. , the reflective layer 26 can be a rear surface mirror), or the reflective surface 27 can be provided adjacent to the top surface 29 of the reflective layer 26 (i.e., the reflective layer 26 can be a front surface mirror). It is further noted that in the illustrated implementations, the bottom and top surfaces 28, 29 are substantially flat and parallel relative to each other, although other configurations are possible. As will be described further below, in some implementations, the reflective layer 26 is coupled to the top part 22 of the housing 20 in a manner such that the reflective surface 27 is generally unobstructed and faces away from the housing cavity 25.

[0143] With reference to Figures 4 to 6, and 12 to 18, the dental instrument 10 includes a heating system 30 provided within the head portion 18 and operable to generate heat transferrable to the reflective layer 26 in a controlled manner to impede formation of condensation on the reflective layer 26. The heating system 30 includes a heating layer, exemplified as a resistive heating circuit layer 34, provided underneath the reflective layer 26 and capable of generating heat, such as via resistive heating. In some implementations, the resistive heating circuit layer 34 can be configured as a heating PCB, such as a flexible heating PCB, a flex heating PCB, or a rigid heating PCB. It is to be understood that in the context of the present description, the heating PCB is given as anexample of resistive heating circuit layer 34, and the expression “heating PCB” is thus sometimes be used to designate the resistive heating circuit layer 34. It is to be understood however that in such instances, the description of the heating PCB can be extrapolated to other types of resistive heating circuit layers 34, and thus should therefore not be given a restrictive interpretation.

[0144] The resistive heating circuit layer 34 is in electrical communication with a power source 5, which is exemplified as a battery (shown in Figure 3A). When subjected to an electrical current, i.e., when an electric current flows through the electric circuits of the resistive heating circuit layer 34, the resistive heating circuit layer 34 generates power loss in the form of heat, typically expressed in Joules.

[0145] In the implementations shown in Figures 1 to 18, the electrical communication between the resistive heating circuit layer 34 and the power source 5 is provided by an electrical connection that includes a power PCB 32. The power PCB 32 is in electrical communication with the power source 5, and the resistive heating circuit layer 34 is thus in electrical communication with the power source via the power PCB 32. Accordingly, the resistive heating circuit layer 34 can be supplied with electrical energy that will be converted to resistive heating by the resistive heating circuit layer 34 to provide heat to the reflective layer 26. As mentioned above, in the illustrated implementation, the power source 5 includes a battery in electrical communication with the resistive heating circuit layer 34 via the power PCB. The battery 5 is provided in the handle portion 14, and the dental instrument 10 includes an internal PCB assembly enabling the electrical coupling of the battery 5 to the power PCB. It is to be understood that the internal PCB assembly can have a different configuration than the illustrated one. In other implementations, the power source can be provided as an external power source, for example. In some implementations, the battery can be rechargeable or disposable, for instance depending on the configuration of the dental instrument and its intended use.

[0146] The resistive heating circuit layer 34 is adapted to be in thermal contact with the reflective layer 26. In the context of the present description, when describing the resistive heating circuit layer 34 being in thermal contact with the reflective layer 26, it is intended to mean that the resistive heating circuit layer 34 is placed in sufficiently close proximity to the reflective layer 26 to enable at least a portion of the heat generated by the resistive heating circuit layer 34 to be transferred to the reflective layer 26 via heat transfermechanisms such as conduction, convection and / or radiation. In order to do so, the resistive heating circuit layer 34 can be placed underneath the reflective layer 26 or, alternatively, along the sidewall of the reflective layer 26. In addition, the expression “sufficiently close proximity” is intended to mean that the resistive heating circuit layer 34 can be positioned in either direct contact with the reflective layer 26 or in indirect contact with the reflective layer 26. Thus, as used herein, the expression “thermal contact” generally means that heat conduction occurs directly or indirectly between the resistive heating circuit layer 34 and the reflective layer 26, whether the resistive heating circuit layer 34 and the reflective layer 26 are in direct contact with each other or a substantially solid material or a fluid such a gas having sufficient thermal conduction is provided between them.

[0147] When the resistive heating circuit layer 34 is positioned in indirect contact with the reflective layer, this configuration can result in an interlayer space being defined between the bottom surface 28 of the reflective layer 26 and the top surface 36 (or reflective layer facing side) of the resistive heating circuit layer 34. In some implementations, this interlayer space can be filled with a filler such as gas (e.g., air), or a substance or material can be provided to at least partially fill this interlayer space. The substance or material can be chosen for instance to modify the heat transfer from the resistive heating circuit layer 34 to the reflective layer 26. For instance, in some implementations, the filler can be chosen to enhance the heat transfer from the resistive heating circuit layer 34 to the reflective layer 26, while in other implementations, the filler can be chosen to reduce the heat transfer from the resistive heating circuit layer 34 to the reflective layer 26. When the resistive heating circuit layer 34 is positioned in indirect contact with the reflective layer 26 and the interlayer space defined between the bottom surface 28 of the reflective layer 26 and the top surface 36 of the resistive heating circuit layer 34 is filled with a fluid such as air, the heat generated by the resistive heating circuit layer 34 can be transferrable to the reflective layer 26 via convection heat transfer and radiation heat transfer, for instance. When the interlayer space defined between the bottom surface 28 of the reflective layer 26 and the top surface 36 of the resistive heating circuit layer 34 is filled with a material that is substantially solid, this material can be chosen according to its thermal conductivity, and the heat generated by the resistive heating circuit layer 34 can be transferrable to the reflective layer 26 for instance via conduction heat transfer.

[0148] When the resistive heating circuit layer 34 is positioned in direct contact with the reflective layer 26, the resistive heating circuit layer 34 can be positioned immediately adjacent to the reflective layer 26, such that substantially no space is defined between the bottom surface 28 of the reflective layer 26 and the top surface 36 of the resistive heating circuit layer 34. In such implementations, the heat generated by the resistive heating circuit layer 34 can be transferrable to the reflective layer 26 for instance via conduction heat transfer.

[0149] In some implementations, the resistive heating circuit layer 34 can be configured such that one or more selected portions of the top surface 36 of the resistive heating circuit layer 34 are in direct contact with the bottom surface 28 of the reflective layer 26, while other portions of the resistive heating circuit layer 34 are not in contact with the bottom surface 28 of the reflective layer 26. In such implementations, various mechanisms can be involved in the heat transfer from the resistive heating circuit layer 34 to the reflective layer 26, such as convection, conduction and / or radiation.

[0150] Thus, it is to be understood that various heat transfer mechanisms can be involved in the transfer of heat from the resistive heating circuit layer 34 to the reflective layer 26, depending on the configuration of the resistive heating circuit layer 34 and the reflective layer 26.

[0151] In the implementations illustrated in Figures 4, 8, 11 , 13, 16 and 17, the resistive heating circuit layer 34 is shown positioned within the housing cavity 25, underneath the reflective layer 26, in proximity of the bottom surface 28 of the reflective layer 26 and in thermal contact therewith, the top surface 36 of the resistive heating circuit layer 34 being placed in direct contact with the bottom surface 28 of the reflective layer 26.

[0152] In some implementations, the shape and the dimensions of the resistive heating circuit layer 34 can be chosen to facilitate cooperation with the reflective layer 26. For instance, when the resistive heating circuit layer 34 is intended to be placed in direct contact with the bottom surface 28 of the reflective layer 26, the resistive heating circuit layer, and more particularly the top surface of the resistive heating circuit layer can have a shape complementary to the shape of the bottom surface of the reflective layer.

[0153] In the illustrated implementation, the top surface 36 of the resistive heating circuit layer 34 is exemplified as being substantially flat. Given that the bottom surface 28 of thereflective layer 26 is also substantially flat, the top surface 36 of the resistive heating circuit layer 34 and the bottom surface 28 of the reflective layer 26 can be placed directly against each other, in what can be referred to as a flat configuration. In some implementations, this configuration can facilitate providing a substantially uniform distribution of heat over the reflective layer 26.

[0154] In other implementations, the top surface 36 of the resistive heating circuit layer 34 can include ridges and the bottom surface 28 of the reflective layer 26 can include corresponding furrows, or vice versa, which can facilitate engagement of the resistive heating circuit layer 34 with the reflective layer. In some implementations, the spatial distribution of the furrows and ridges can enable providing selected area(s) of the reflective layer with a chosen degree of heat. For instance, in some implementations, selected areas of the reflective layer can be provided with an enhance degree of heat, while other selected areas of the reflective layer can be provided with a reduced degree of heat.

[0155] In some implementations, the resistive heating circuit layer 34 and the reflective layer 26 can be positioned so as to be substantially parallel to each other, such as shown in Figures 4, 8, 11 , 13, 16 and 17. This configuration can facilitate avoiding colder areas on the reflective layer at locations where the resistive heating circuit layer would be located further away from the resistive heating circuit layer, for instance if the resistive heating circuit layer was angled relative to the reflective layer.

[0156] In some implementations, the relative size between the reflective layer 26 and the resistive heating circuit layer 34 can be such that the resistive heating circuit layer 34 extends over at least 50% of a surface area of the bottom surface 28 of the reflective layer 26 to facilitate transferring heat to a majority of the surface area of the reflective layer 26. In some implementations, the resistive heating circuit layer 34 can extend over at least 75% of a surface area of the bottom surface 28 of the reflective layer 26. In some implementations, the resistive heating circuit layer 34 can extend over at least 95% of a surface area of the bottom surface 28 of the reflective layer 26. Given that the heat transferred to the reflective layer 26 by the resistive heating circuit layer 34 can also dissipate within the reflective layer 26 via conduction, the surface area of the resistive heating circuit layer 34 is not required to match the surface area of the reflective layer 26. In other words, the surface area of the resistive heating circuit layer 34 can be smaller than the surface area of the reflective layer 26. Thus, in some implementations, theresistive heating circuit layer can be sized to contact less than 100% of the surface area of the bottom surface 28 of the reflective layer 26, for example, because of the presence of additional components of the dental instrument 10 within and / or around the housing 20. In some implementations, the shape of the resistive heating circuit layer 34 can match the shape of the reflective layer 26. For instance, if the cross-section of the reflective layer is circular, the cross-section of the resistive heating circuit layer 34 can be circular as well. Alternatively, the shape of the resistive heating circuit layer 34 can be different than the shape of the reflective layer 26. For instance, the cross-section of the reflective layer can be circular, and the cross-section of the resistive heating circuit layer can be square, annular, or shaped as a wheel with spokes, etc.

[0157] It is to be noted that the resistive heating circuit layer 34 is configured to heat the reflective layer 26 to a controlled temperature that is selected to impede formation of condensation on the top surface 29 of the reflective layer 26, regardless of the location of the reflective surface 27. In other words, the resistive heating circuit layer 34 is configured to heat the reflective layer 26 to a controlled temperature that is selected to impede formation of condensation on the top surface 29 of the reflective layer 26 when the reflective surface 27 is provided adjacent to the top surface 29 of the reflective layer 26, or when the reflective surface 27 is provided adjacent to the bottom surface 28 of the reflective layer 26.

[0158] Referring to Figures 4 to 7, 11 , 12, 14 and 15, the top part 22 of the housing 20 includes a body 40, 110 having a generally ring-shaped configuration. The ring-shaped body 40, 110 defines a housing opening 42 therethrough, which communicates with the housing cavity 25 of the housing 20 to enable cooperation between different components of the dental instrument 10. For example, the resistive heating circuit layer 34 and at least a portion of the reflective layer can be shaped and adapted to be positioned within the housing opening 42 and coupled to the top part 22. As such, a housing cavity facing side 35 of the resistive heating circuit layer 34 is oriented toward the housing cavity 25 and can thus be selectively placed in physical contact with given components housed within the housed cavity 25. This aspect will be discussed in further detail below. In some implementations, the reflective layer 26 and the resistive heating circuit layer 34 can be coupled to the top part 22 of the housing 20 via an interference fit, an adhesive (e.g., glue) or any other suitable means or combination thereof.

[0159] In some implementations, the ring-shaped body 40, 110 can be configured as an optical diffusing layer. The optical diffusing layer can be configured to diffuse light emitted by light sources distributed underneath the optical diffusing layer. This aspect is detailed in PCT Applications Nos. PCT / CA2023 / 051642 and PCT / CA2024 / 050186, which are incorporated herein in their entirety.

[0160] As shown in Figures 5 and 6, in some implementations, the ring-shaped body 40 can include an annular edge 44 extending inwardly toward a center region of the housing and defining a heating layer receiving surface. More specifically, the annular edge 44 can extend circumferentially from an inner sidewall of the ring-shaped body 40. In the implementation shown, the annular edge 44 extends circumferentially around the entire opening (e.g., the annular edge extends 360 degrees), although it is appreciated that the annular edge 44 can include a plurality of edge portions spaced apart from one another about the housing opening 42. In the implementation shown, the annular edge 44 is lower than a top edge 45 of the ring-shaped body 40, i.e., spaced apart from the top edge 45 of the ring-shaped body 40 in a downward direction relative to the top edge 45, thereby defining a rabbet or rabbeted edge.

[0161] In the implementation shown in Figures 5 and 6, the reflective layer 26 and the resistive heating circuit layer 34 are shaped and sized to be received within the housing opening 42 and sit on the annular edge 44, i.e., on the heating layer receiving surface, of the rabbeted edge. In other words, the top part 22 of the housing 20 can include a depression or pocket configured to receive the reflective layer 26 and the resistive heating circuit layer 34. As shown in Figure 4, when the resistive heating circuit layer 34 sits on the annular edge 44, i.e., on the heating layer receiving surface, the resistive heating circuit layer 34 can be completely contained within the opening 42 such that a reflective layer facing side 36 (shown in Figure 7) of the resistive heating circuit layer 34 is spaced apart from the top edge 45 of the ring-shaped body 40, i.e., is provided below the top edge 45 of the ring-shaped body 40. This positioning of the resistive heating circuit layer 34 relative to the ring-shaped body 40 and more particularly to the top edge 45 of the ringshaped body 40 defines a remaining space in the housing opening 42 that can receive at least a portion of the reflective layer 26 therein. In some implementations, the reflective layer 26 can be contained within the housing opening 42 in a manner such that the top surface 29 of the reflective layer 26 is offset inwardly relative to the top edge 45. Alternatively, the reflective layer 26 can be partially contained within the housing opening42 such that the top surface 29 is offset outwardly and thus above the top edge 45 of the ring-shaped body 40. In another implementation, the top surface 29 of the reflective layer 26 can be substantially flush (e.g., coplanar) with the top edge 45 of the ring-shaped body 40, 110.

[0162] Referring to Figures 4 to 9, 11 , 12, 14 and 15, the housing 20 of the dental instrument 10 can further include an intermediate layer 50 positioned within the housing cavity 25. In some implementations, the intermediate layer 50 can be connected to at least one of the top and bottom parts 22, 24. In some implementations, the intermediate layer 50 can contribute to increasing the structural integrity of the head portion 18 and assist in positioning other components within the housing cavity 25. For instance, in the implementations shown in Figures 4 to 9, 11 , 12, 14 and 15, the power PCB 32 and the resistive heating circuit layer 34 are provided on respective sides of the intermediate layer 50. More specifically, the power PCB 32 is positioned within the housing cavity 25 below the intermediate layer 50, whereas the resistive heating circuit layer 34 is positioned above the intermediate layer 50. In the implementation shown in Figures 11 , 12, 14 and 15, the resistive heating circuit layer 34 is deposited directly onto the intermediate layer 50, as will be described in further detail below.

[0163] The intermediate layer 50 can include a portion that is part of an optical diffusing assembly configured to diffuse light emitted by a light source housed within the housing 20. Alternatively, or additionally, the intermediate layer 50 can define a through-hole configured to receive an optical sensor 52, which can be operatively connected to the power PCB 32. For example, and as shown in Figures 4, 5, 12 and 14, the intermediate layer 50 can include a slot 54 through which the optical sensor 52 can extend in order to capture optical signals from a surrounding environment. These features ( / .e., the light diffusing and optical sensor features) are further discussed in PCT Applications Nos. PCT / CA2023 / 051642 and PCT / CA2024 / 050186, which are incorporated herein by reference in their entirety.

[0164] In some implementations, the top part 22, the bottom part 24 and the intermediate layer 50 can be adapted to be connected to one another to form the housing 20. Each part of the housing 20 can be connected to each one of the other parts, although other configurations are possible and may be used. In the implementation shown in Figures 4 and 5, the intermediate layer 50 is connectable to the bottom part 24, and the top part 22is connectable to the intermediate layer 50 such that the top part 22 is indirectly coupled to the bottom part 24. For example, the intermediate layer 50 can be securable to the bottom part 24 via a mechanical fastener 55, such as a screw or a bolt. With reference to Figures 6 to 9, the top part 22 is configured to engage the intermediate layer 50 to be removably connected therewith. In order to do so, the top part 22 of the ring-shaped body 40 can include one or more resilient elements 56 extending downwardly and configured to engage with a corresponding feature of the intermediate layer 50. For instance, in some implementations, the resilient elements 56 can be configured as hooks or clips, as shown in Figures 6 to 9. In some implementations, the intermediate layer 50 can include slots, alcoves or recesses 58 shaped and configured to receive respective resilient elements 56.

[0165] Referring more specifically to Figure 8, in the implementation shown, the resilient elements 56 include a hook 57 exemplified as being substantially L-shaped, and the recesses 58 can be complementarily-shaped relative to at least a portion of the hook 57. For instance, the recesses 58 can be defined by an inverted L-shaped catch 59 onto which the hook 57 can connect. Therefore, the resilient elements 56 can engage the recesses 58 in order to have the hooks 57 clip onto respective catches 59. The cooperation between the resilient elements 56 and the recesses 58 can thus enable the connection between the top part 22 and the intermediate layer 50. In one implementation, in order to connect the top part 22 and the intermediate layer 50 together, the resilient elements 56 can be inserted into respective recesses 58, and the ring-shaped body 40 can be pressed down to have the hooks 57 clip onto the catches 59.

[0166] In the implementation shown in Fig 8, the top part includes four (4) resilient elements 56 and hooks 57 and the intermediate layer 50 includes four (4) recesses 58 and catches 59. However, it is appreciated that any other suitable number of these components can be used. The removable connection between the top part 22 and the intermediate layer 50 and thus indirectly the rest of the housing 20, can enable the top part 22 to be removed together with the resistive heating circuit layer 34 and the reflective layer 26 when deemed necessary by the user of the dental instrument 10. For instance, when it is determined that the reflective surface 27 and / or the top surface 29 of the reflective layer 26 no longer offers a satisfactory performance, the top part 22, the resistive heating circuit layer 34 and the reflective layer 26 can be removed, e.g., unclipped, from the remainder of the housing 20 as a single unit to be replaced by a new unit comprising a new top part 22, a new resistive heating circuit layer and a new reflective layer. Thisfunctionality of the dental instrument can be particularly beneficial to enable long-term use of the remaining components of the dental instrument other than the top part 22, the resistive heating circuit layer and the reflective layer, thus avoiding the need to replace the entire dental instrument when only the reflective layer would need replacement.

[0167] With reference to Figures 4 to 9, 11 , 12, 14 and 15, the power PCB 32 is in electrical communication with the resistive heating circuit layer 34 via an electrical connection assembly. For example, the electrical connection assembly can include a connection pin 60 extending upwardly from the power PCB 32, and the resistive heating circuit layer 34 can include a corresponding connector point 62 configured to engage the connector point 62 to enable establishing electrical communication between the power PCB 32 and the operation of the resistive heating circuit layer 34. In the implementations shown, the electrical connection assembly includes a pair of connection pins 60 and a corresponding pair of connector points 62. When the intermediate layer 50 is present, the intermediate layer 50 defines an aperture 65 shaped and sized to enable the connection pin 60 to extend upwardly from the power PCB, through the thickness of the intermediate layer 50 (e.g., through the aperture 65) and contact the connector point 62. In some implementations, the power PCB can include two or more connection pins 60, and the resistive heating circuit layer can include a corresponding number of connector points 62. As shown in Figure 5, the aperture 65 can be adapted to enable both of the connection pins 60 to extend therethrough. In other words, the connection pins 60 can extend through a common aperture 65 defined through the intermediate layer 50. However, it is appreciated that other configurations are possible, such as having each connection pin 60 extend through a corresponding aperture, for example, as shown in Figure 12. In alternative implementations, the connection pins 60 and the connector points 62 can be provided in a reverse configuration, with the connection pins 60 extending downwardly from the housing cavity facing side 35 of the resistive heating circuit layer to engage connector points 62 provided on top surface of the power PCB 32.

[0168] In some implementations, each connection pin 60 includes a pogo-pin 66 provided with a spring-loaded pin head 68 to facilitate establishing electrical communication between the power PCB and the resistive heating circuit layer 34. The spring-loaded pin head 68 can thus remain in contact with the connector point 62 on the resistive heating circuit layer 34 during handling of the dental instrument 10. In some implementations, the resistive heating circuit layer 34 is exemplified as a flex heating PCBor a rigid heating PCB having connector points 62. The connector points 62 are exemplified as being substantially flat on the housing cavity facing side 35 of the resistive heating circuit layer 34. The connection points 62 can be printed onto the housing cavity facing side 35 of the resistive heating circuit layer 34. In other implementations, the connector points 62 can be any suitable type of connector point, such as a socket or receptacle, configured to enable connection with a PCB connection pin. Similarly, the connection pin 60 can be any suitable connection pin.

[0169] The use of a resistive heating circuit layer 34 as described herein, and for example of a flex heating PCB, can enable providing a component of the heating system that is sufficiently thin to fit within the casing of the head portion and that can enable providing a heat source that can be substantially uniformly distributed over the surface area of the reflective layer. In the implementations shown, the heating PCB 70 has a thickness that is smaller than a thickness of the reflective layer, thereby facilitating placement in proximity of, or against, the bottom surface 28 of the reflective layer 26. In some implementations, the thickness of the resistive heating circuit layer 34 can depend on its configuration, for instance whether it is a flex heating PCB, another type of PCB such as a rigid heating PCB, or simply another type of layer enabling resistive heating to occur. For instance, in some implementations, the resistive heating circuit layer 34 can be a rigid heating PCB having a heating layer thickness that is sufficient to enable indexing the reflective layer 26 in a predetermined position relative to the optical sensor 52 via an interaction with corresponding indexing features provided by the intermediate layer 50. This aspect will be described in further detail below.

[0170] In some implementations, the resistive heating circuit layer 34 can have a heating layer thickness that is between about 2 and about 20 times thinner than a reflective layer thickness of the reflective layer 26. This ratio can of course change depending on the reflective layer thickness, but nonetheless illustrates the miniaturization of this component of the heating system that enables it to be present in a casing of a head portion of a dental mirror having substantially standard dimensions. This configuration of the resistive heating circuit layer 34 can thus contribute to facilitating placement thereof within the head portion 18 of the dental instrument 10 in a desired position to increase efficiency of the heat transfer to the reflective layer 26. In the implementation shown in Figures 4 to 9, the resistive heating circuit layer 34 exemplified as a flex heating PCB shown positionedunderneath the reflective layer 26, and “sandwiched” between the annular edge 44 of the ring-shaped body 40 and the reflective layer 26.

[0171] Additional details regarding the implementation shown in Figures 10 to 18 will now be provided. The dental instrument 10 includes the reflective layer 26 provided with the reflective surface 27 and the resistive heating circuit layer 34. The resistive heating circuit layer 34 is coupled to an underside of the reflective layer 26 and is operable to generate and transfer heat to the reflective layer 26 as described above. Similar to previously described implementations, the resistive heating circuit layer 34 can be coupled to the reflective layer 26 via an adhesive or via any other suitable manner or combination thereof.

[0172] The housing 20 includes the top part 22, the bottom part 24 and the intermediate layer 50 shaped and sized to cooperate with one another. In the implementation shown in Figures 10 to 18 and as mentioned above, the intermediate layer 50 includes a portion that is part of an optical diffusing assembly configured to diffuse light emitted by light sources 31 (shown in Figure 14) housed within the housing 20. In the implementation shown in Figures 10 to 18, the portion of the intermediate layer 50 that corresponds to an optical diffusing assembly is generally annular and thus extends circumferentially to provide diffused light circumferentially around the reflective layer 26.

[0173] As shown in Figures 11 and 12, the intermediate layer 50 can be connected to the bottom part 24 using a mechanical fastener 55, such as a screw or a bolt. In the illustrated implementation, the top part 24 includes a ring-shaped body 110 configured to be connected to the bottom part 24. IN some implementations, the ring-shaped body 110 can include an annular protrusion 112 proximate a bottom edge thereof, the annular protrusion 112 extending inwardly, i.e., toward a center region of the head portion 18. The bottom part 24 can include a complementarily-shaped annular recess 114 configured to receive the annular protrusion 112 therein. The annular protrusion 112 of the ring-shaped body 110 is thus configured to engage the annular recess 114 of the bottom part 24 to removably engage the top part 22 with the bottom part 24. In the illustrated implementation, the ring-shaped body 110 can be clipped onto the bottom part 24, as a snap-fit, thereby enclosing the various components of the heating system 30 within the housing cavity 25. It is to be understood that other types of engagements between the top part 22 and the bottom part 24 are also possible, such as having the top and bottom parts22, 24 be provided with threads to enable screwing / fastening to one another, among other possibilities. In some implementations, the ring-shaped body 110 can be made of a metal, such as titanium, for instance to provide sufficient durability characteristics to the ringshaped body 110.

[0174] In the implementation illustrated in Figures 10 to 18, the resistive heating circuit layer 34 is mounted to the intermediate layer 50 in a predetermined configuration. In order to do so, the resistive heating circuit layer 34 and the intermediate layer 50 can be provided with complementing components allowing the resistive heating circuit layer 34 to be indexed relative to the intermediate layer 50, thereby positioning the resistive heating circuit layer 34 in a predetermined position (e.g., in the predetermined configuration) relative to other components of the head portion 18. In some implementations, the installation of the resistive heating circuit layer 34 in the predetermined position can contribute to facilitating and / or ensuring that the connection points 62 provided on the resistive heating circuit layer 34 are in alignment with the connection pins 60 of the power PCB 32. In other words, indexing the resistive heating circuit layer 34 relative to the intermediate layer 50 can facilitate an electrical connection of the resistive heating circuit layer 34. Indexing the resistive heating circuit layer 34 relative to the intermediate layer 50 can facilitate an alignment of various other components of the head portion 18 with one another. For instance, given that the resistive heating circuit layer 34 is mounted to the reflective layer 26, for instance with an adhesive, indexing the resistive heating circuit layer 34 relative to the intermediate layer 50 can thus also enable providing the reflective layer 26 in a predetermined position relative the optical sensor 52. In such implementations, the indexing of the combined resistive heating circuit layer 34 and reflective layer 26 can enable aligning the optical sensor 52 extending through the slot 54 of the intermediate layer 50 with a corresponding optical sensor window 53 defined in the resistive heating circuit layer 34 and a reflective layer window 51 defined in the reflective surface 27 such that the optical sensor 52 can capture images through the resistive heating circuit layer 34 and the reflective layer 26 without the resistive heating circuit layer 34 and / or the reflective surface 27 being mistakenly placed in front of the optical sensor 52. Accordingly, by providing the resistive heating circuit layer 34 and the reflective layer 26 engaged together in a predetermined orientation and indexing the combination of the resistive heating circuit layer 34 and the reflective layer 26 relative to the intermediate payer 50, both the optical sensor window 53 defined in the resistive heating circuit layer 34 and the reflective layerwindow 51 defined in the reflective surface 27 can be aligned with the optical sensor 52 via the indexing with the intermediate layer 50.

[0175] In Figures 12 to 14 and 18, the intermediate layer 50 defines the heating layer receiving surface 126 and includes housing indexing features 120. In turn, the resistive heating circuit layer 34 includes heating layer indexing features 124 having a complementary shape relative to the housing indexing features 120 to enable the resistive heating circuit layer 34 to be placed onto the intermediate layer 50 in a predetermined position. In the illustrated implementation, the resistive heating circuit layer 34 has a generally circular shape and the intermediate layer 50 has an elevated annular edge 125 defining an internal depression corresponding to the heating layer receiving surface 126 shaped and sized to receive the resistive heating circuit layer 34 therein. In other words, the intermediate layer 50 includes a recessed portion corresponding to the heating layer receiving surface 126, and a remainder of the intermediate layer 50 is defined by the elevated annular edge 125 encircling the depressed portion. In such implementations, the housing indexing features 120 can include one or more shoulders 128 partly defining the outer periphery of the heating layer receiving surface 126 and being offset from the heating layer receiving surface 126 in an upward direction, the one or more shoulders 128 comprising respective internal edges 130. In some implementations, the trajectory of the shoulders 128 can correspond to respective chords cutting across a circle, thereby defining a relatively straight section along the perimeter of the internal depression 126. The shoulder 128 can thus have a semi-circular shape, with a straight edge corresponding to the internal edge 130 described above.

[0176] Still with reference to Figures 12 to 14 and 18, the heating layer indexing features 124 can include cutoff edges 132 of the resistive heating circuit layer 34 configured to match with the edges 130 defined by the shoulders 128 of the intermediate layer 50. In the illustrated implementation, the housing indexing feature 120 includes a pair of shoulders 128 extending opposite and parallel to one another such that the internal edges 130 are similarly provided opposite and parallel to one another. As shown in Figure 13, the resistive heating circuit layer 34 is provided with a pair of cutoff edges 132 opposite and parallel to one another to allow the resistive heating circuit layer 34 to “match” the internal edges 130 of the intermediate layer 50 and be engaged therewith so that theresistive heating circuit layer 34 can fit into the internal depression 126 in a single orientation corresponding to the predetermined position.

[0177] In some implementations, in order for the resistive heating circuit layer 34 to be adapted to provide heating layer indexing features 124 as described above, the resistive heating circuit layer 34 can have a heating layer thickness that is sufficient to enable matching with the housing indexing feature 120. In other words, the resistive heating circuit layer 34 can have a heating layer thickness that is sufficient to define a cutoff edge 132 that can abut the internal edge 130 of the intermediate layer 50, without risking an undesired overlap between the resistive heating circuit layer 34 and the shoulder 128 of the intermediate layer 50. In such implementations, the resistive heating circuit layer 34 can be for instance a rigid-flex heating PCB or a rigid heating PCB. The heating layer thickness of the resistive heating circuit layer 34 can range for instance between about 0.5 mm and about 1 .2 mm, or between about 0.6 mm and about 1 mm, or between about 0.7 mm and about 0.9 mm.

[0178] It is thus understood that the resistive heating circuit layer 34 can be indexed (e.g., installed in the predetermined position) onto the intermediate layer 50, as two pieces of puzzles fitting together in a single possible orientation. It should be noted that other configurations of housing indexing feature 120 and heating layer indexing feature 124 are possible and may be implemented to enable indexing the resistive heating circuit layer 34 relative to a component of the housing 20, such as the intermediate layer 50. For instance, in some implementations, the housing indexing feature 120 and heating layer indexing feature 124 can include additional indexing features, non-parallel indexing features, a combination of different indexing features (e.g., edges and protrusions), etc.

[0179] For instance, in some implementations, the housing indexing feature of the intermediate layer 50 can include an outwardly extending feature and the resistive heating circuit layer 34 can include a housing indexing feature receiving opening configured to receive the housing indexing feature therein, thereby positioning the resistive heating circuit layer 34 in the predetermined position. In other implementations, a reverse configuration of the implementation shown in Figures 12 to 18 can be implemented, with the resistive heating circuit layer 34 including a shoulder and the intermediate layer 50 including a cutoff edge having a complementary shape relative to the shoulder. In addition, although Figures 12 to 18 illustrate the resistive heating circuit layer 34 having a pair ofcutoff edges 132 and the intermediate layer 50 having a pair of shoulders 128, it is to be understood that in alternative implementations, a single cutoff edge 132 and a single shoulder 128 can be sufficient to enable indexing the resistive heating circuit layer 34 in the predetermined position relative to the intermediate layer 50.

[0180] In the implementation shown in Figures 10 to 18, the resistive heating circuit layer 34 can be engaged with the reflective layer 26. For instance, in some implementations, the resistive heating circuit layer 34 can be adhered, i.e. , glued, to the bottom surface 28 (the bottom surface) of the reflective layer 26. In such implementations, the positioning of the resistive heating circuit layer 34 on the intermediate layer 50 therefore also enables the positioning of the reflective layer 26 relative to the intermediate layer 50 and thus the optical sensor 52. Accordingly, as mentioned above, providing the resistive heating circuit layer 34 and the reflective layer 26 engaged together in a predetermined orientation and indexing the combination of the resistive heating circuit layer 34 and the reflective layer 26 relative to the intermediate payer 50, can enable both the optical sensor window 53 defined in the resistive heating circuit layer 34 and the reflective layer window 51 defined in the reflective surface 27 to be aligned with the optical sensor 52 via the indexing with the intermediate layer 50. Thus, once the combination of the resistive heating circuit layer 34 and the reflective layer 26 is placed onto the intermediate layer 50 and the optical sensor window 53 and the reflective layer window 51 are in alignment with the optical sensor 52, the top part 22 of the housing 20 can be removably engaged with the bottom part 24 of the housing 20, thereby placing the head portion 18 in an operable configuration.

[0181] In some implementations, the top part 22 of the housing 20, and more particularly the ring-shaped body 110, can be shaped and configured to engage a peripheral wall 71 of the reflective layer 26 such that connecting the top and bottom parts 22, 24 together can immobilize the combination of the resistive heating circuit layer 34 and reflective layer 26 onto the intermediate layer 50. In some implementations and as shown in Figures 11 , 12, 17 and 18, the peripheral wall of the reflective layer 26 can be tapered to enable a complementary tapered edge of the top part 22 (e.g., the top edge of the ring-shaped body 110) to extend over a largest outer perimeter of the reflective layer 26 without extending over and / or across the reflective surface 27. The complementary tapered edges thus cooperate to prevent disengagement of the reflective layer 26 from the housing 20 uponconnecting the top and bottom parts 22, 24 together. This aspect is further described below.

[0182] The reflective layer 26 can thus be removably engageable with the remainder of the components of the head portion 18 of the dental instrument 10. Referring more particularly to Figures 11 , 12, 17 and 18, the removable engagement of the reflective layer 26 with the remainder of the components of the head portion 18 of the dental instrument 10 can be done via the ring-shaped body 110. As mentioned above, the ring-shaped body 110 can be engaged with the bottom part 24 via a snap-fit or a press fit. The diameter of the ring-shaped body 110 can vary along a height thereof, the diameter of the ring-shaped body 110 being larger in proximity of the bottom part 24 compared to the top of the ringshaped body 110. In turn, the reflective layer 26 can be shaped as a truncated cone, i.e., the reflective layer 26 can be a frustoconical reflective layer, having an outwardly extending slope 73 having an angle that is complementary to the angle of the reflective layer engaging surface 75 of the ring-shaped body 110 such that the outwardly extending slope 73 can abut the reflective layer engaging surface 75 of the ring-shaped body 110. Thus, the peripheral wall 71 of the reflective layer 26 can be configured to abut the reflective layer engaging surface 75 of the ring-shaped body 110 that is removably engageable with the bottom part 24, the reflective layer engaging surface 75 and the outwardly extending slope 73 having complimentary angles.

[0183] When the combination of the reflective layer 26 and the resistive heating circuit layer 34 is placed over the intermediate layer 50, the ring-shaped body 110 can be superposed thereto and via a rotational motion, or a downward pressure if the bottom part 24 is removably engageable with the ring-shaped body 110 via a snap-fit or a press-fit, the ring-shaped body 110 will eventually exert a downward pressure onto the outwardly extending slope 71 of the reflective layer 26. This engagement of the ring-shaped body 110 and the combination of the reflective layer 26 and the resistive heating circuit layer 34 can facilitate locking the combination of the reflective layer 26 and the resistive heating circuit layer 34 in place onto the intermediate layer 50 and with the remainder of the components of the head portion 18.

[0184] Although in the illustrated implementation, the interaction of the peripheral wall 71 of the reflective layer 26 with the reflective layer engaging surface 75 is achieved with the complementary angles of the outwardly extending slope 73 and the reflective layerengaging surface 75, it is to be understood that other types of interaction that enables securing the combination of the reflective layer 26 and the resistive heating circuit layer 34 with the top art 22 and the bottom part 24 can also be suitable.

[0185] In the illustrated implementation, a gasket 92, such as a compressible gasket that can be made for instance of silicone, can be provided on the intermediate layer 50 such that when the ring-shaped body 110 is engaged with the bottom part 24, the reflective layer 26 can press downwardly onto the gasket 92, thereby sealing the components of the dental instrument 10 provided in the head portion 18. In other words, the gasket 92 can be compressible such that when subjected to a downward force as the ring-shaped body 110 is being engaged with the bottom part 24, the components of the dental instrument 10 provided in the head portion 18 can be sealed within the head portion 18. The gasket 92 can thus provide a waterproof and moisture-proof seal to prevent the components of the head portion 18 to be damaged, for instance during steam sterilization. Once again, depending on the interaction between the ring-shaped body 110 and the reflective layer 26, other alternatives enabling the water and moisture proofing of the components of the dental instrument 10 provided in the head portion 18 can also be envisioned. In some implementations, the gasket 92 can be coupled with the reflective layer 26, for instance via an adhesive. This aspect will be described in more detail below.

[0186] With reference to Figures 16 and 17, the combination of the reflective layer 26 and the resistive heating circuit layer 34 can be referred to as a sub-assembly of the head portion 18. When it is determined that the reflective layer 26 is damaged, or if the performance of the resistive heating circuit layer 34 is no longer satisfactory, replacement of the sub-assembly can be achieved by disengaging the ring-shaped body 110 from the bottom part 24, and the sub-assembly can be discarded. A replacement sub-assembly comprising a new reflective layer 26 and resistive heating circuit layer 34 can then be used and placed onto the intermediate layer 50 and the ring-shaped body 110 can subsequently be re-engaged with the bottom part 24. In some implementations, it may be desirable to change the gasket 92 as well if needed, which can be done concomitantly with the change of the sub-assembly. When the sub-assembly includes a reflective layer 26, a resistive heating circuit layer 34, and a gasket 92, the resistive heating circuit layer 34 and the gasket 92 can both be coupled to the reflective layer 26 via an adhesive, the disengagement of the sub-assembly from the bottom part 24 of the housing 20 can enable removing the reflective layer 26, the resistive heating circuit layer 34 and the gasket 92 asa single piece. Removing the gasket 92 in addition to the reflective layer 26 and the resistive heating circuit layer 34 can advantageously enable replacing the gasket 92 without any additional step having to be performed, such that a new gasket 92 can be used to ensure maintaining the sealing performance of the gasket 92 to protect the components received in the housing cavity 25 of the head portion 18 from moisture, for instance.

[0187] With such a configuration of the ring-shaped body 110, the sub-assembly comprising the reflective layer 26, the resistive heating circuit layer 34 and optionally the gasket 92, the head portion 18 of the dental instrument 10, as well as other portions of the dental instrument 10 not discussed in further detail herein, can be subjected to steam sterilization, for instance in an autoclave, without moisture and water infiltrating within the housing cavity 25 and without pressurized steam damaging the components of the head portion 18.Temperature control of the resistive heating circuit layer

[0188] As mentioned above, the resistive heating circuit layer can be configured to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer. In some implementations, the control of the temperature can be obtained via operation of one or more motion sensors and / or temperature sensors integrated in the dental instrument and an associated controller.

[0189] The motion sensor can enable operation of the heating according to given parameters. For instance, the motion sensor can be used to indicate to the heating system via the controller when to provide power, i.e., supply electric current, to the resistive heating circuit layer and when to cease the supply of electric current resistive heating circuit layer, and can also be used to indicate to the heating system via the controller to supply electric current to the resistive heating circuit layer for a given duration of a heating event.

[0190] The motion sensor can be configured to detect a movement of the dental instrument 10 in 3D space. The motion sensor can, for example, detect movement in the form of a translation and / or change in orientation of the dental instrument 10, and generate a signal indicative such movement. Such signals can subsequently be processed to determine whether the dental instrument is in motion, for example being indicative that thedental instrument is hand-held or being otherwise manipulated by a dental professional, or whether the dental instrument is stationary, for example being indicative that the dental instrument is resting on a table or in a dental handpiece holder.

[0191] The motion sensor can include one or more accelerometers and / or one or more gyroscopes. The one or more accelerometers can be adapted to measure a rate of change of velocity of the dental instrument 10. The one or more accelerometers can include triaxial accelerometers adapted to detect the movement of the dental instrument 10 along three orthogonal axes. The one or more gyroscopes can be adapted to detect the orientation and / or angular velocity of the dental instrument 10 about three orthogonal axes, such as pitch, roll and yaw.

[0192] In some implementations, the motion sensor can include accelerometers and / or gyroscopes integrated in the handle of the dental instrument, for example to detect a position and / or orientation of the handle portion 14 of the dental instrument 10. In some implementations, the motion sensor can include accelerometers and / or gyroscopes integrated into the head portion 18 of the dental instrument, for example to detect a position and / or orientation of the head portion 18 of the dental instrument.

[0193] The motion sensor can thus be used to determine a position of the dental instrument relative to the patient’s mouth. In some implementations, determining the position of the dental instrument can include detecting whether the dental instrument is inside the patient's mouth (in-mouth position) or outside the patient's mouth (out-of-mouth position). In some implementations, the determination of the in-mouth position or the out- of-mouth position can be done in cooperation with a camera, as described in PCT Application No. PCT / CA2024 / 050186, which is incorporated herein in its entirety.

[0194] The in-mouth position can correspond to the dental instrument being at least partially inside the patient’s mouth. At least partially inside the patient mouth can include the head portion of the dental instrument (such as the head portion 18 of the abovedescribed dental instrument 10) being at least partially inserted into the patient’s mouth.

[0195] The out-of-mouth position can correspond to the dental instrument being outside of the patient’s mouth. For example, the out-of-mouth position can include the dental instrument resting on a table or a dental handpiece holder, or being hand-held by thedental professional while the head portion of the dental instrument is outside the patient’s mouth.

[0196] Once the position of the dental instrument with respect to the patient’s mouth has been determined, electronic components of the dental instrument can be operated based on the determined position to control the heating output of the resistive heating circuit layer. Controlling the heating output can include modulating the heating output of the resistive heating circuit layer, such as by turning on and / or turning off the electric current supplied to the resistive heating circuit layer.

[0197] For instance, the controller can be operatively connected to the motion sensor and the heating system and be configured to receive an input signal from the motion sensor, process the input signal, and send a signal, such as a control signal, to control the heating output of the resistive heating circuit layer based on the input signal, i.e., upon determination that the dental instrument has transitioned from one position to another. In some implementations, sending the control signal can involve the controller providing an instruction each time the heat output of the resistive heating circuit layer is to be changed. For example, the controller can transmit an on / off instruction that toggles the resistive heating circuit layer depending on its current state. For instance, when the resistive heating circuit layer is initially supplied with electric current, i.e., turned on, the instruction sent by the controller can turn off the electric current. Similarly, when the resistive heating circuit layer is initially not supplied with electric current, i.e., turned off, the instruction sent by the controller can enable supplying electric current to the resistive heating circuit layer. In some implementations, transmitting a signal can involve the controller continuously providing a signal to the resistive heating circuit layer to maintain the supply of electric current thereto, and ceasing the signal when the resistive heating circuit layer is to be turned off.

[0198] The determination of the moment when the heating system, and more particularly the resistive heating circuit layer, is to be turned on or off can thus be performed according to the positioning of the dental instrument relative to the patient’s mouth or the movement of the dental instrument. For instance, when the dental instrument is picked up or handled by the user or when the dental instrument is introduced into the patent’s mouth, the heating system can be turned on in prevision of the reflective layer being subjected to a warm and moist environment. Similarly, when the dental instrument is taken out of the patent’s mouthor placed in a resting position, the heating system can be turned off to avoid draining the power source unnecessarily.

[0199] In addition, when the heating system is turned on, for instance because the dental instrument is in use within the patient’s mouth, the controller can be configured to send a signal to the heating system to turn it off when a predetermined temperature upper threshold is reached. Similarly, when the heating system is turned off while the dental instrument is still in the patient’s mouth, the controller can be configured to send a signal to the heating system to turn it back on when a predetermined temperature lower threshold is reached. The predetermined temperature upper threshold can be determined as corresponding to a temperature sufficient to impede formation of condensation on the top surface of the reflective layer while avoiding burning the mucous membranes within the patient’s mouth. The predetermined temperature lower threshold can be determined as corresponding to a temperature that remains sufficiently high such that the next heating event enables reaching the predetermined temperature upper threshold in an acceptable period of time without draining a significant amount of energy from the power source. For instance, in some implementation, the difference between the predetermined temperature upper threshold and the predetermined temperature lower threshold can be between about 1 °C to about 10°C. In some implementations, the predetermined temperature upper threshold can be between about 28°C and about 37°C, for instance. In some implementations, the predetermined temperature lower threshold can be between about 25°C and about 28°C, for instance.

[0200] Thus, even when the dental instrument is located within the patient's mouth, which generally would result in the heating system being turned on, the controller can modulate the operation of the heating system between an “on configuration” and an “off configuration” to maintain a desired temperature of the reflective surface of the reflective layer. In some implementations, the controller can modulate the operation of the heating system between an on configuration and an off configuration to maintain a substantially constant temperature of the reflective surface of the reflective layer during use in the patient’s mouth.

[0201] In order to determine a temperature of the reflective layer, a temperature sensor can be provided in close proximity of the reflective layer and be configured to gather temperature data representative of the temperature of the reflective layer. A controller canbe operatively connected to the heating system and to the temperature sensor. The controller can be configured to receive an input signal from the temperature sensor and determine a temperature of the reflective layer, and to send a control signal to the heating system to control a heating output of the resistive heating circuit layer based on the determined temperature. For instance and as mentioned above, if the temperature of the reflective layer is determined to be below a predetermined temperature upper threshold, the controller can be configured to send a control signal to the heating system to turn the heating system on. If the predetermined temperature upper threshold is reached, the controller can be configured to send a control signal to the heating system to turn the heating system off. If the temperature of the reflective layer is determined to be below a predetermined temperature lower threshold, the controller can also be configured to send a control signal to the heating system to turn the heating system on. It is to be noted that these examples of control strategies can vary depending on the configuration of the heating system and dental instrument, and can be adapted depending on the intended use of the dental instrument.

[0202] In some implementations, the controller can include a processor, a microprocessor, a microcontroller, a circuit, a circuit element (e.g., transistor, resistor, capacitor, inductor, etc.), an integrated circuit, an application specific integrated circuit (ASIC), a programmable logic device (PLD), a digital signal processor (DSP), a field programmable gate array (FPGA), a logic gate, a register, a semiconductor device, a chip, a microchip, a chip set, and so forth, or a combination thereof.

[0203] This temperature control of the resistive heating circuit layer can advantageously contribute to reduce the power consumption from the power source, e.g., the battery, when the dental instrument is not in use or when the reflective layer has reached a desired temperature, which can be one that impedes formation of condensation on the top surface of the reflective layer.Additional features of the dental instrument

[0204] Referring broadly to Figures 1 to 15, the head portion 18 of the dental instrument 10 can include a neck portion 80 extending therefrom and configured to connect with the distal end 15 of the handle portion 14. The neck portion 80 can extend from the bottom part 24 of the housing 20 and, in some implementations, be integrally formed therewith asa single piece. In some implementations, the neck portion 80 can be adapted to increase the structural integrity of the head portion 18 relative to the handle portion 14 by providing a rigid structure. In some implementations, the bottom part 24 of the housing 20 can be shaped like a cup or a saucer, and is adapted to house various components therein, such as the electrical connection between the resistive heating circuit layer and the power source, the intermediate layer 50, etc. The head portion 18 can also be provided with a sealing assembly 90 configured to seal at least some interstices defined between the different parts of the housing 20. For example, the sealing assembly 90 can include a seal or gasket 92 provided between any of the top, bottom and intermediate parts 22, 24, 50, the seal or gasket 92 being annular. In some implementations, the gasket 92 can be placed about an outer periphery of the cup-shaped bottom part 24 such that, when the top part 22 is pressed and clipped onto the intermediate layer 50, the top part 22 can be simultaneously pressed onto the gasket 92, thereby creating a seal between the top and bottom parts 22, 24. In the implementation shown in Figures 12 and 14, the gasket 92 is optionally further connected to the reflective layer 26 using a gasket adhesive 93, although other configurations are possible. The components of the sealing assembly 90 (e.g., the gasket 92) can assist in maintaining the cavity 25 substantially watertight, or waterproof, to protect the components housed therein.

[0205] In some implementations, the head portion 18 can include additional features such as optical diffusing layers 100 received within diffusing layer openings 102 defined in the wall of the bottom part 24. This aspect is further discussed in PCT Applications Nos. PCT / CA2023 / 051642 and PCT / CA2024 / 050186, which are incorporated herein in their entirety. Other examples of features can include spacers and / or holders shaped and configured to assist in positioning surrounding components within the housing 20.

[0206] It should thus be noted that bottommost structural components of the head portion 18 can be considered to define a housing bottom wall 106 of the casing, and that additional components can be layered on top of the housing bottom wall to build up the internal structure of the head portion 18. For example, the power PCB 32 can be shaped and adapted for placement over the housing bottom wall 106, followed by the intermediate layer 50 which can be layered on top of the power PCB 32, then the gasket 92, the top part 22 (e.g., the ring-shaped body 40), while the resistive heating circuit layer and the reflective layer 26 are placed within the pocket of the top part 22 (e.g., placed on theannular edge 44 within the housing opening 42). However, it is appreciated that other configurations are possible and may be used.

[0207] In the implementation shown in Figure 11 , the housing bottom wall 106 can correspond to a back glass 140 coupled to the bottom part 24 of the housing. The back glass 140 can be selected for aesthetic purposes or can be an additional mirror having an additional reflective surface in addition to the reflective surface 27 of the reflective layer 26. As shown more particularly in Figures 11 and 14, the back glass 140 can be held in place and connected to the bottom part 24 via a fastening ring 142. In some implementations, the fastening ring 142 can be screwed on the bottom part 24, or engaged with the bottom part 24 with a snap-fit, for instance. In such implementations, the fastening ring 142 and the back glass 140 can also be referred to as a sub-assembly comprising the back glass 140 and optionally the fastening ring 142. In some implementations, the sealing assembly 90 can further include a bottom seal 94, or bottom gasket 94, configured to seal interstices between the back glass 140, the fastening ring 142 and / or other components of the housing 20.

[0208] It should be appreciated from the present disclosure that the various implementations of the dental instrument and related components can increase the performance of the dental instrument by including a heating system operable to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer, and thus prevent, or at least reduce the accumulation of water droplets onto the reflective surface thereof. The structure of the head portion and of the components housed therein can enable layering these components within the casing. As described herein, the head portion can include a reflective layer (e.g., the reflective layer / mirror), a heating layer (e.g., a resistive heating circuit layer such as a heating PCB), an intermediate layer, one or more structural components, an electrical connection that can include a power PCB), etc. The top part of the casing can be shaped and sized to define and separate an upper compartment of the cavity and a lower compartment of the cavity. External components, that is, components configured to cooperate with a surrounding environment, such as the mirror, can be placed in the t compartment, while internal components, such as the resistive heating circuit layer and associated connection assembly, can be housed in the lower compartment.

[0209] It is to be noted that while the systems, devices and methods described herein are presented in the context of dental instruments that can be used during dental procedures typically performed on humans, it will be appreciated that the systems, devices and methods can alternatively be used in the context of veterinary treatments. In addition, the systems, devices and methods described herein can also be used in other contexts when formation of condensation on a given surface can be an issue.

[0210] It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the example implementations described herein. However, it will be understood by those of ordinary skill in the art that the example implementations described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the example implementations described herein. Also, the description is not to be considered as limiting the scope of the example implementations described herein.

[0211] As used herein, the wording “and / or” is intended to represent an inclusive - or. That is, “X and / or Y” is intended to mean X or Y or both, for example. As a further example, “X, Y, and / or Z” is intended to mean X or Y or Z or any combination thereof.

[0212] As used herein, the terms “coupled”, “coupling”, “attached”, ’’connected” or variants thereof as used herein can have several different meanings depending in the context in which these terms are used. For example, the terms coupled, coupling, connected or attached can have a mechanical or electrical connotation. For example, as used herein, the terms coupled, coupling or attached can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via a mechanical element depending on the particular context.

[0213] Similarly, in the context of the present disclosure, the expressions “unit”, “assembly”, “assemblage”, “sub-assembly”, “subsystem”, “mechanism”, “apparatus”, “component”, as well as any other equivalent expression(s) and / or compound word(s) thereof known in the art can be used interchangeably, as apparent to a person skilled inthe art. This applies also for any other mutually equivalent expressions, such as, for example: "fastening", "securing", "locking", "restraining", "affixing", "holding", "adjusting", "coupling", etc.

[0214] It is to be understood that terms such as “upper”, “top”, “bottom”, “lower”, “inwardly”, “downwardly” as used herein are to be interpreted in the context of the figures and should not be interpreted in a restrictive sense.

[0215] While the above description describes features of example implementations, it will be appreciated that some features and / or functions of the described implementations are susceptible to modification without departing from the spirit and principles of operation of the described implementations. For example, the various characteristics which are described by means of the represented implementations or examples may be selectively combined with each other. Accordingly, what has been described above is intended to be illustrative of the claimed concept and non-limiting. It will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. The scope of the claims should not be limited by the preferred implementations and examples, but should be given the broadest interpretation consistent with the description as a whole.

[0216] In the present disclosure, an implementation is an example or implementation of the described features. The various appearances of “one implementation,” “an implementation” or “some implementations” do not necessarily all refer to the same implementations. Although various features may be described in the context of a single implementation, the features may also be provided separately or in any suitable combination. Conversely, although the dental instrument and / or the associated components may be described herein in the context of separate implementations for clarity, it may also be embodied in a single implementation. Reference in the specification to “some implementations”, “an implementation”, “one implementation”, or “other implementations”, means that a particular feature, structure, or characteristic described in connection with the implementations is included in at least some implementations, but not necessarily in all implementations.

[0217] In addition, although the optional configurations as illustrated in the accompanying figures comprises various components and although the optionalconfigurations of the tool as shown may consist of certain geometrical configurations as explained and illustrated herein, not all of these components and geometries are essential and thus should not be taken in their restrictive sense, i.e., should not be taken as to limit the scope of the present disclosure. It is to be understood that other suitable components and cooperations thereinbetween, as well as other suitable geometrical configurations may be used for the implementation and use of the system, and corresponding parts, as briefly explained and as can be easily inferred herefrom, without departing from the scope of the disclosure.

Claims

CLAIMS1 . A dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: a housing having a bottom part and a top part together defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the top part of the housing and having a bottom surface facing the housing cavity and a top surface, opposite the bottom surface; and a heating system comprising: a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer.

2. The dental instrument of claim 1 , wherein the resistive heating circuit layer is in direct thermal contact with the reflective layer.

3. The dental instrument of claim 2, wherein the bottom surface of the reflective layer is substantially flat, and the resistive heating circuit layer and the reflective layer are in contact with each other in a flat configuration.

4. The dental instrument of claim 1 , wherein the resistive heating circuit layer is in indirect thermal contact with the reflective layer.

5. The dental instrument of claim 4, wherein a superposition of the resistive heating circuit layer and the reflective layer defines an interlayer space therebetween, the interlayer space being at least partially filled with a filler.

6. The dental instrument of any one of claims 1 to 5, wherein the heat generated by the resistive heating circuit layer is transferrable to the reflective surface at least via conduction heat transfer.

7. The dental instrument of any one of claims 1 to 6, wherein the resistive heating circuit layer is flexible or rigid.

8. The dental instrument of any one of claims 1 to 7, wherein the resistive heating circuit layer is electrically connectable to the power source via an electrical connection.

9. The dental instrument of claim 7, wherein the resistive heating circuit layer comprises a heating printed circuit board (PCB).

10. The dental instrument of claim 8 or 9, wherein the electrical connection comprises a power PCB.

11. The dental instrument of claim 10, wherein the resistive heating circuit layer is configured to be in electrical communication with the power PCB via a connection assembly.

12. The dental instrument of claim 11 , wherein the connection assembly comprises at least one connection pin and at least one connector point configured to be electrically engageable with each other.

13. The dental instrument of claim 12, wherein the power PCB comprises the at least one connection pin, and the resistive heating circuit layer comprises the at least one connector point.

14. The dental instrument of claim 12, wherein the power PCB comprises the at least one connector point, and the resistive heating circuit layer comprises the at least one connecting pin.

15. The dental instrument of any one of claims 12 to 14, wherein the at least one connection pin comprises a pogo-pin.

16. The dental instrument of any one of claims 12 to 15, further comprising an intermediate layer provided between the resistive heating circuit layer and the powerPCB, the intermediate layer defining a connection pin aperture through which the at least one connection pin extends.

17. The dental instrument of any one of claims 12 to 15, further comprising an intermediate layer provided between the resistive heating circuit layer and the power PCB, the intermediate layer defining a corresponding connection pin aperture through which each connection pin of the at least one connection pin extends.

18. The dental instrument of claim 16 or 17, wherein the intermediate layer is directly connected to the bottom part via a mechanical fastener.

19. The dental instrument of any one of claims 16 to 18, wherein the intermediate layer comprises a recessed portion defining a heating layer receiving surface configured to receive the resistive heating circuit layer thereon.

20. The dental instrument of claim 19, wherein the intermediate layer further comprises an elevated annular edge provided around the recessed portion.21 . The dental instrument of claim 20, wherein the intermediate layer further comprises a housing indexing feature and the resistive heating circuit layer further comprises a heating layer indexing feature, the heating layer indexing feature being engageable with the housing indexing feature to enable positioning the resistive heating circuit layer in a predetermined position relative to the intermediate layer.

22. The dental instrument of claim 21 , wherein the resistive heating circuit layer comprises an optical sensor window alignable with an optical sensor provided in the housing cavity.

23. The dental instrument of claim 22, wherein the resistive heating circuit layer and the reflective layer are coupled to each other as a sub-assembly, and the reflective layer comprises a reflective layer window aligned with the optical sensor window.

24. The dental instrument of claim 23, wherein the resistive heating circuit layer and the reflective layer are coupled to each other via an adhesive.

25. The dental instrument of claim 23 or 24, wherein the sub-assembly further comprises a gasket adhered to the bottom surface of the reflective layer.

26. The dental instrument of claim 25, wherein the gasket is superposable to the elevated annular edge of the intermediate layer.

27. The dental instrument of any one of claims 21 to 26, wherein the housing indexing feature comprises a shoulder having an internal edge partly defining an outer periphery of the heating layer receiving surface and being offset in an upward direction relative to the heating layer receiving surface, and the heating layer indexing feature comprises a cutoff edge, the internal edge and the cutoff edge having a complementary shape.

28. The dental instrument of any one of claims 1 to 27, wherein the resistive heating circuit layer extends over at least 50% of a surface area of the bottom surface of the reflective layer.

29. The dental instrument of any one of claims 1 to 27, wherein the resistive heating circuit layer extends over at least 75% of a surface area of the bottom surface of the reflective layer.

30. The dental instrument of any one of claims 1 to 27, wherein the resistive heating circuit layer extends over at least 95% of a surface area of the bottom surface of the reflective layer.

31. The dental instrument of any one of claims 1 to 27, wherein the resistive heating circuit layer and the reflective layer have substantially the same surface area.

32. The dental instrument of any one of claims 1 to 31 , wherein the top part of the housing comprises a ring-shaped body defining a housing opening, the reflective layer and the resistive heating circuit layer being positioned within the housing opening.

33. The dental instrument of claim 32, wherein the ring-shaped comprises an annular protrusion extending inwardly toward a center region of the reflective layer, and the bottom part defines an annular recess, the annular recess being configured to receive the annular protrusion therein to engage the top part and the bottom part together in a snap-fit.

34. The dental instrument of claim 32 or 33, wherein the top surface of the reflective layer is flush with a top edge of the ring-shaped body.

35. The dental instrument of claim 32 or 33, wherein the reflective surface of the reflective layer is spaced apart from a top edge of the ring-shaped body.

36. The dental instrument of any one of claims 1 to 35, wherein the resistive heating circuit layer has a heating layer thickness between about 2 and about 20 times thinner than a reflective layer thickness of the reflective layer.

37. The dental instrument of any one of claims 1 to 35, wherein the resistive heating circuit layer has a heating layer thickness between about 0.5 mm and about 1 .2 mm, between about 0.6 mm and about 1 mm, or between about 0.7 mm and about 0.9 mm.

38. The dental instrument of any one of claims 1 to 37, wherein the power source comprises a battery provided in the handle portion.

39. A dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: a housing having a bottom part and a top part together defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the top part of the housing and having a bottom surface facing the cavity and a top surface, opposite the bottom surface; a heating system comprising: a heating layer positioned underneath the reflective layer and in thermal contact therewith, the heating layer being complementarily-shaped relative to the reflective layer and operable to heat the reflective layer and impede formation of condensation on the top surface of the reflective layer.

40. The dental instrument of claim 39, wherein the heating layer is in direct thermal contact with the reflective layer.

41. The dental instrument of claim 40, wherein the bottom surface of the reflective layer is substantially flat, and the heating layer and the reflective layer are in contact with each other in a flat configuration.

42. The dental instrument of claim 39, wherein the heating layer is in indirect thermal contact with the reflective layer.

43. The dental instrument of claim 42, wherein a superposition of the heating layer and the reflective layer defines an interlayer space therebetween, the interlayer space being at least partially filled with a filler.

44. The dental instrument of any one of claims 39 to 43, wherein the heating layer extends over at least 50% of a surface area of the bottom surface of the reflective layer.

45. The dental instrument of any one of claims 39 to 43, wherein the heating layer extends over at least 75% of a surface area of the bottom surface of the reflective layer.

46. The dental instrument of any one of claims 39 to 43, wherein the heating layer extends over at least 95% of a surface area of the bottom surface of the reflective layer.

47. The dental instrument of any one of claims 39 to 43, wherein the heating layer and the reflective layer have substantially the same surface area.

48. A dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: an open-top housing defining a housing cavity;a reflective layer provided with a reflective surface, the reflective layer being coupled to the open-top housing and having a bottom surface facing the housing cavity and a top surface, opposite the bottom surface; and a heating system comprising: a power PCB received within the housing cavity, underneath the reflective layer, and comprising a connection pin extending upwardly, the power PCB being electrically connectable to a power source; and a heating PCB provided between the reflective layer and the power PCB, the heating PCB comprising a connection point configured to be in electrical communication with the connection pin to generate heat transferrable to the reflective surface to impede formation of condensation on the top surface of the reflective layer.

49. The dental instrument of claim 48, wherein the heating PCB is in direct thermal contact with the reflective layer.

50. The dental instrument of claim 48, wherein the bottom surface of the reflective layer is substantially flat, and the heating PCB and the reflective layer are in contact with each other in a flat configuration.

51. The dental instrument of claim 48, wherein the heating PCB is in indirect thermal contact with the reflective layer.

52. The dental instrument of claim 51 , wherein a superposition of the heating PCB and the reflective layer defines an interlayer space therebetween, the interlayer space being at least partially filled with a filler.

53. The dental instrument of any one of claims 48 to 52, wherein the heat generated by the heating PCB is transferrable to the reflective surface at least via conduction heat transfer.

54. The dental instrument of any one of claims 48 to 53, wherein the connection pin comprises a pogo-pin.

55. The dental instrument of any one of claims 48 to 54, wherein the heating PCB is a flexible heating PCB.

56. The dental instrument of any one of claims 48 to 54, wherein the heating PCB is a rigid heating PCB.

57. The dental instrument of any one of claims 48 to 56, further comprising an intermediate layer provided between the heating PCB and the power PCB, the intermediate layer defining a connection pin aperture through which the connection pin extends.

58. The dental instrument of any one of claims 48 to 57, wherein the heating PCB extends over at least 50% of a surface area of the bottom surface of the reflective layer.

59. The dental instrument of any one of claims 48 to 57, wherein the heating PCB extends over at least 75% of a surface area of the bottom surface of the reflective layer.

60. The dental instrument of any one of claims 48 to 57, wherein the heating PCB extends over at least 95% of a surface area of the bottom surface of the reflective layer.61 . The dental instrument of any one of claims 48 to 57, wherein the heating PCB and the reflective layer have substantially the same surface area.

62. The dental instrument of any one of claims 48 to 61 , wherein the heating PCB has a heating layer thickness between about 2 and about 20 times thinner than a reflective layer thickness of the reflective layer.

63. The dental instrument of any one of claims 48 to 61 , wherein the heating PCB has a heating layer thickness between about 0.5 mm and about 1.2 mm, between about 0.6 mm and about 1 mm, or between about 0.7 mm and about 0.9 mm.

64. The dental instrument of any one of claims 48 to 63, wherein the power source comprises a battery provided in the handle portion.

65. A replaceable sub-assembly for use as a component of a head portion of a dental instrument, the replaceable sub-assembly comprising: a reflective layer provided with a reflective surface and being removably engageable with a top part of the head portion, the reflective layer having a bottom surface configured for orientation toward a bottom part of the head portion, and a top surface, opposite the bottom surface; and a resistive heating circuit layer positioned underneath the reflective layer, the resistive heating circuit layer being configured to be in thermal contact with the reflective layer and be electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer; wherein the reflective layer and the resistive heating circuit layer are coupled together to form the sub-assembly.

66. The replaceable sub-assembly of claim 65, wherein the reflective layer and the resistive heating circuit layer are coupled together via an adhesive.

67. The replaceable sub-assembly of claim 65 or 66, further comprising a gasket coupled to the bottom surface of the reflective layer, around the resistive heating circuit layer.

68. The replaceable sub-assembly of claim 65, wherein the gasket and the reflective layer are coupled together via an adhesive.

69. A method for heating a reflective layer of a dental instrument, the method comprising: detecting a position of the dental instrument relative to a mouth of a patient to obtain a dental instrument detected position, wherein the dental instrument detected position is an in-mouth position or an out-of-mouth position; controlling a heating output of a heating system comprising a resistive heating circuit layer positioned underneath the reflective layer upon receipt of a controlsignal determined in accordance with the dental instrument detected position, wherein the controlling comprises: supplying electric current to the resistive heating circuit layer when the dental instrument detected position is the in-mouth position to heat the reflective layer to a controlled temperature and impede formation of condensation on a reflective surface of the reflective layer.

70. The method of claim 69, wherein the out-of-mouth position comprises a resting position and a hand-held position.

71. The method of claim 70, wherein the controlling further comprises supplying electric current to the resistive heating circuit layer when the dental instrument detected position in the hand-held position.

72. The method of claim 71 , wherein the controlling further comprises preventing electric current supply to the resistive heating circuit layer when the dental instrument detected position is the resting position.

73. The method of any one of claim 69 to 72, wherein supplying electric current to the resistive heating circuit layer is performed during a heating event having a predetermined duration.

74. The method of any one of claims 69 to 72, wherein supplying electric current to the resistive heating circuit layer is performed until a predetermined temperature upper threshold is reached.

75. The method of claim 74, wherein when the predetermined temperature upper threshold is reached, electric current is prevented from being supplied to the resistive heating circuit layer irrespective of the dental instrument detected position.

76. The method of any one of claims 69 to 75, wherein preventing electric current supply to the resistive heating circuit layer is performed until a predetermined temperature lower threshold is reached.

77. The method of claim 76, wherein when the predetermined temperature lower threshold is reached, electric current is supplied to the resistive heating circuit layerif the dental instrument detected position is one of the in-mouth position or the handheld position.

78. The method of any one of claims 69 to 77, wherein controlling the heating output of the resistive heating circuit layer comprises toggling the resistive heating circuit layer between an on configuration and an off configuration.

79. The method of claim 78, wherein operating of the resistive heating circuit layer between the on configuration and the off configuration is performed to maintain a substantially constant temperature of the reflective layer when the dental instrument detected position is the in-mouth position.

80. The method of any one of claims 69 to 79, wherein detecting the position of the dental instrument relative to the mouth of the patient is performed using a motion sensor integrated in the dental instrument.81 . A dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: an open-top housing defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the open-top housing and having a bottom surface facing the housing cavity and a top surface, opposite the bottom surface; a heating system comprising: a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer; a motion sensor integrated in the dental instrument; anda controller operatively connected to the heating system and the motion sensor, the controller being configured to receive an input signal from the motion sensor and process the input signal to determine a position of the dental instrument with respect to a mouth of a patient, and to send a control signal to the heating system to control a heating output of the resistive heating circuit layer based on the determined position.

82. The dental instrument of claim 81 , wherein the motion sensor comprises an accelerometer and / or a gyroscope.

83. The dental instrument of claim 81 or 82, wherein the motion sensor is integrated into the head portion of the dental instrument.

84. The dental instrument of claim 81 or 82, wherein the motion sensor is integrated into the handle portion of the dental instrument.

85. The dental instrument of any one of claim 81 to 84, wherein the determined position is an in-mouth position or an out-of-mouth position.

86. The dental instrument of claim 85, wherein the out-of-mouth position comprises a resting position and a hand-held position.

87. The dental instrument of any one of claim 81 to 86, wherein when the determined position of the dental instrument is the in-mouth position, the controller is configured to send a control signal to turn the heating system on until a predetermined temperature upper threshold is reached.

88. The dental instrument of claim 86, wherein when the determined position of the dental instrument is the hand-held position, the controller is configured to send a control signal to turn the heating system on until a predetermined temperature upper threshold is reached.

89. The dental instrument of claim 86, wherein when the determined position of the dental instrument is the resting position, the controller is configured to send a control signal to turn the heating system off until a predetermined temperature lower threshold is reached.

90. A dental instrument comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle portion, the head portion comprising: an open-top housing defining a housing cavity; a reflective layer provided with a reflective surface, the reflective layer being coupled to the open-top housing and having a bottom surface facing the housing cavity and a top surface opposite the bottom surface; a heating system comprising: a resistive heating circuit layer positioned underneath the reflective layer and in thermal contact therewith, the resistive heating circuit layer being electrically connectable to a power source to heat the reflective layer to a controlled temperature and impede formation of condensation on the top surface of the reflective layer; a temperature sensor provided in close proximity of the reflective layer; and a controller operatively connected to the heating system and to the temperature sensor, the controller being configured to receive an input signal from the temperature sensor and process the input signal to determine a temperature of the reflective layer, and to send a control signal to the heating system to control a heating output of the resistive heating circuit layer based on the determined temperature.91 . The dental instrument of claim 90, wherein when the determined temperature of the reflective layer is determined to be below a predetermined temperature upper threshold, the controller is configured to send a control signal to the heating system to turn the heating system on.

92. The dental instrument of claim 91 , wherein when the predetermined temperature upper threshold is reached, the controller is configured to send a control signal to the heating system to turn the heating system off.

93. The dental instrument of any one of claims 90 to 92, wherein when the temperature of the reflective layer is determined to be below a predetermined temperature lower threshold, the controller is configured to send a control signal to the heating system to turn the heating system on.

94. A replaceable sub-assembly for use as a component of a head portion of a dental instrument, the replaceable sub-assembly comprising: a frustoconical reflective layer comprising a top surface, a bottom surface opposite the top surface, and a peripheral wall defining an outwardly extending slope; and a resistive heating circuit layer coupled to the bottom surface of the reflective layer; wherein the peripheral wall of the reflective layer is configured to abut a reflective layer engaging surface of a ring-shaped body of the head portion ring removably engageable with a bottom portion of the head portion, the reflective layer engaging surface and the outwardly extending slope having complimentary angles.

95. The replaceable sub-assembly of claim 94, wherein the resistive heating circuit layer comprises an optical sensor window alignable with an optical sensor provided in the housing cavity.

96. The replaceable sub-assembly of claim 95, wherein the reflective layer comprises a reflective layer window aligned with the optical sensor window.

97. The replaceable sub-assembly of claim 94 or 95, further comprising a gasket coupled to the bottom surface of the reflective layer and configured to seal a remainder of the components of the head portion when a downward pressure is applied to the reflective layer.

98. The replaceable sub-assembly of claim 96, wherein the gasket is a compressible gasket.

99. The replaceable sub-assembly of claim 96 or 97, wherein the gasket is coupled to the bottom surface of the reflective layer via an adhesive.

100. The replaceable sub-assembly of any one of claims 94 to 99, wherein the resistive heating circuit layer is coupled to the bottom surface of the reflective layer via an adhesive.

101. A replaceable sub-assembly for use as a component of a head portion of a dental instrument, the replaceable sub-assembly comprising: a reflective layer a top surface, a bottom surface opposite the top surface, and a peripheral wall; and a resistive heating circuit layer coupled to the bottom surface of the reflective layer, the resistive heating circuit layer comprising: a heating layer indexing feature engageable with a housing indexing feature of an intermediate layer provided in the head portion to mount the resistive heating circuit layer onto the intermediate layer in a predetermined position.

102. The replaceable sub-assembly of claim 101 , wherein the heating layer indexing feature comprises a cutoff edge engageable with the housing indexing feature in a single orientation corresponding to the predetermined position.

103. The replaceable sub-assembly of claim 102, wherein the resistive heating circuit layer is generally circular, and the cutoff edge extends along a chord of the resistive heating circuit layer.

104. The replaceable sub-assembly of claim 101 , wherein the heating layer indexing feature comprises a shoulder engageable with the housing indexing feature in a single orientation corresponding to the predetermined position.

105. The replaceable sub-assembly of claim 104, wherein the resistive heating circuit layer is generally circular, and the shoulder comprises an internal edge extending along a chord of the resistive heating circuit layer.

106. The replaceable sub-assembly of claim 101 , wherein the heating layer indexing feature is defined within the outer periphery of the heating layer to define a housingindexing feature receiving opening configured to receive the housing indexing feature therein.

107. The replaceable sub-assembly of any one of claims 101 to 106, wherein the resistive heating circuit layer comprises an optical sensor window alignable with an optical sensor provided in a housing cavity of the head portion.

108. The replaceable sub-assembly of claim 107, wherein the reflective layer comprises a reflective layer window aligned with the optical sensor window.

109. The replaceable sub-assembly of any one of claims 101 to 108, wherein the resistive heating circuit layer and the reflective layer are coupled to each other via an adhesive.

110. The replaceable sub-assembly of any one of claims 101 to 109, further comprising a gasket adhered to the bottom surface of the reflective layer.

111. A dental instrument, comprising: a handle portion having a distal end and a proximal end; a head portion coupled to the distal end of the handle, the head portion comprising: a housing comprising a housing having a bottom part and a top part connectable to each other and together defining a housing cavity, the top part comprising: a ring-shaped body connectable to the bottom part and defining a housing opening defining a reflective layer receiving opening; a reflective layer including a reflective surface and having a bottom surface and a top surface, opposite the bottom surface, the reflective layer being received in the reflective layer receiving opening; an intermediate layer provided within the housing cavity, underneath the reflective layer, and having a heating layer receiving surface;a heating system comprising a heating layer configured for placement onto the heating layer receiving surface of the intermediate layer in a predetermined position, the heating layer being adhered to the bottom surface of the reflective layer and operable to generate heat to impede formation of condensation on the top surface of the reflective layer.

112. The dental instrument of claim 111 , further comprising one or more features as defined in any one of claims 1 to 109.

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