Electrofluidic control of dental delivery systems

Abstract

The cooling water circuit of a dental unit comprises a plurality of predetermined dental device locations to which dental devices using cooling water can be connected, and a cooling water valve connected to the plurality of dental device locations and also connectable to a pressurized cooling water source. The cooling water valve is operable by pulse width modulation (PWM) and can be selectively controlled to simultaneously supply cooling water from the cooling water source to at least one of the plurality of dental device locations. The cooling water valve used for the plurality of dental device locations may have a water holdback valve associated with each dental device location. A novel cooling air proportional valve is described.

Description

Background Art

[0001] A dental delivery system provides a physical connection for delivering air, water, electricity, and / or data to dental devices used by a clinician for dental treatment of a patient. Dental devices used with the delivery system (which may also be commonly referred to as “handpieces”) include dental air / water syringes, air-driven rotary dental handpieces (high speed / low speed), electric rotary dental handpieces, ultrasonic scaling handpieces, air / water friction polishing handpieces, dental lasers, and other devices that are typically held by the clinician and receive supply from the delivery system. The control head of a dental delivery system has at least one dental device location, but more typically a plurality of dental device locations, each of which is designed to accommodate a dental device. Since normal treatment procedures involve the use of two or more dental devices, control heads having a plurality of dental device locations are common. At least some of the dental device locations have connections to sources of pressurized fluid (usually air and treated water) that are used, among other purposes, for cooling the treatment site, supplying driving force to a certain type of dental device, irrigation, drying, and / or removal of materials.

[0002] Dental devices that use water have tubes (sometimes referred to as water lines) that carry water from the control head to the dental device. Similarly, dental devices that use air have tubes that carry air from the control head to the dental device. Some dental devices that use both air and water have both air tubes and water tubes, which, among other capabilities, can mix air and water to generate a desired spray, for example, inside an internal chamber or outside the dental device.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Current methods involve complex designs that can increase initial costs and maintenance expenses, so there is room for improvement in the fluid control of dental delivery systems. At the same time, practitioners are seeking more flexible control over the use of dental devices and access to advanced functions that were previously unavailable. [Means for solving the problem]

[0004] The following describes a novel apparatus and method that addresses the challenges of current approaches to fluid control in dental delivery systems.

[0005] According to the first embodiment, the cooling water circuit of the dental unit includes a plurality of predetermined dental device positions to which dental devices using cooling water can be connected, and a cooling water valve connected to the plurality of dental device positions and also connectable to a pressurized cooling water source. The cooling water valve is operable by pulse width modulation (PWM) and can be selectively controlled to simultaneously supply cooling water from the cooling water source to at least one of the plurality of dental device positions.

[0006] According to one embodiment of the method, the supply of dental cooling water in a dental delivery system includes the steps of: providing a single cooling water valve connected to a plurality of dental device locations defined on a control head; connecting the single cooling water valve to a pressurized dental cooling water source; and operating the cooling water valve by electronic pulse width modulation (PWM) to selectively control the flow of dental cooling water from the single cooling water valve to at least one selected of the plurality of dental device locations.

[0007] According to another embodiment, a cooling water holdback valve for use in a dental unit comprises a valve body having a valve inlet and a valve outlet for cooling water, and a flexible diaphragm positioned on the valve body between the valve inlet and the valve outlet. The flexible diaphragm can be selectively controlled to allow cooling water to flow in from the valve inlet and out through the valve outlet, and to block the inflow of cooling water. The cooling water holdback valve can be connected in a dental unit downstream of a cooling water source and upstream of a dental device location to which a dental device can be connected.

[0008] According to another embodiment, a pneumatic proportional valve for supplying cooling air in a dental unit comprises a valve inlet connected to a pressurized air source, a valve outlet selectively connectable to one of a plurality of dental device assignment positions to which each of a plurality of dental devices can be connected, and an electrical control circuit for receiving a signal and selectively controlling the supply of cooling air to at least one of the selected dental device assignment positions.

[0009] The above and other purposes, features, and advantages will become clearer from the following detailed description, which will proceed with reference to the attached drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram of a dental delivery system comprising a control head, an air / dental water supply source, user controls, a dental device used during treatment to supply air and / or dental water, and a control circuit. [Figure 2] This is a circuit diagram of a new cooling water solenoid valve that supplies dental cooling water to multiple dental devices, such as the first dental device schematically shown in Figure 2, using periodic operation (e.g., pulse width modulation or PWM). [Figure 3A] Figure 2 is a circuit diagram of a new cooling water solenoid valve, although according to the second embodiment, a second dental device is also connected to this single cooling water solenoid valve. [Figure 3B]This is a schematic cross-sectional view of a new cooling water solenoid valve in a closed state according to one embodiment. [Figure 3C] This is a schematic cross-sectional view of a new cooling water solenoid valve in an open state, according to one embodiment. [Figure 4] This is a circuit diagram of a conventional cooling water needle valve connected to a single dental device to supply cooling water for dental use. [Figure 5] This is a circuit diagram of a conventional cooling water needle valve connected to each dental device. [Figure 6] Figure 2 shows a circuit diagram of a new cooling water valve combined with a dental device selection solenoid valve and a cooling air proportional valve, for use with a single dental device. [Figure 7] This circuit diagram is similar to Figure 6, except that it shows a single cooling water valve and a single cooling air proportional valve used with two dental devices. [Figure 8] This is a schematic diagram showing valve diaphragms in different states. [Figure 9] This is a schematic diagram showing valve diaphragms in different states. [Figure 10] Figure 10A is a schematic diagram showing valve diaphragms in different states. Figure 10B is a schematic diagram showing valve diaphragms according to an alternative embodiment. [Figure 11] This graph shows the operation of the cooling water valve and the resulting cooling water flow rate and pressure for the dental device when the valve is operated according to the selected frequency and duty cycle. [Figure 12] This graph shows the effect of two levels of system capacitance when smoothing the PWM-generated flow passing through a dental device (handpiece). [Figure 13] This graph shows the effect of two different PWM duty cycle rates when controlling the average flow rate through a dental device (handpiece). [Figure 14]Figure 14A is a graph of pressure fluctuations measured at the cooling water valve outlet and the dental device (handpiece) inlet at four different PWM frequencies. Figure 14B is a graph of pressure fluctuations measured at the cooling water valve outlet and the dental device (handpiece) inlet at four different PWM frequencies. Figure 14C is a graph of pressure fluctuations measured at the cooling water valve outlet and the dental device (handpiece) inlet at four different PWM frequencies. Figure 14D is a graph of pressure fluctuations measured at the cooling water valve outlet and the dental device (handpiece) inlet at four different PWM frequencies. [Modes for carrying out the invention]

[0011] Embodiments of electrofluidic control used in connection with dental delivery systems and methods thereof are described below.

[0012] Figure 1 is a schematic block diagram of a dental delivery system 100 with electrofluidic control according to one embodiment. The dental delivery system typically has a control head 102 connected to receive one or more fluid inputs 104. The fluids of the dental delivery system typically include dental water and pressurized air, as will be described in more detail below. Thus, there is a dental water source 106 that supplies water at the desired pressure(s), temperature(s), and state(s)(s) during treatment. The dental water source 106 may be a direct connection to the building's water supply or an independent bottled water supply system (sometimes referred to as a self-contained water supply system). There is also a dental air source 108 for supplying air at the desired pressure(s).

[0013] A dental delivery system includes a user control 109 that is typically used by a dentist or other operator to initiate and control the delivery of one or more fluids during a patient's treatment. The user control 109 can include, as three examples, one or more of a foot control 112, a user control 114 (hand control, user-worn control, or other type of user-actuated control), and a touch screen 116. In addition to serving as a user control, the touch screen 116 (or other display device) can serve as an output device that displays information regarding the operation of the system.

[0014] Also as shown in FIG. 1, there are various fluid outputs 120 from a control head 102 that uses an available fluid source. Typically, the fluid is used (or consumed) through one or more dental devices 130a - 130f. The dental devices 130a - 130f are connected to the control head 102 via respective tubes at each dental device location 128a - 128f, and fluid is supplied through each tube. The illustrated embodiment can be interpreted as referring to physical dental device locations, but the same concept also applies to alternative embodiments that are logical assignments where the dental device "location" may or may not have a given physical location (singular or plural) relative to the control head 102.

[0015] Representative types of dental devices are dental syringes, air-driven dental devices (high speed, low speed), electric dental devices, surgical dental devices, hygienic dental devices, ultrasonic dental devices, and the like.

[0016] Some dental devices supply dental water as a coolant to lower the temperature of the treatment site in the oral cavity. Some dental devices may mix air with dental water to obtain a desired spray. Air is also used to dry surfaces and remove debris. Additionally, air may be supplied as an energy source ("drive air") for pneumatically actuated dental devices. It would also be possible to use air as a coolant.

[0017] The control head 102 houses an electronic fluid control element (e.g., a valve), along with the connections between the fluid input 104, the user control 109, and the various fluid outputs 120 via the dental device, for controlling the method of supplying fluid. The control head can include other elements used for patient care, and such elements are preferably housed within or on the control head 102, but are not shown or described as they are not primarily relevant to the fluid uses described herein.

[0018] The control head 102 includes an electronic control circuit that includes one or more controllers 140, a memory 150, one or more optional sensors 160, and connections to the system 170. A portion of the control circuit can be housed within the control head 102 or can be distributed to other locations within the overall dental treatment system.

[0019] A representative control head, also referred to as a dental unit, is described in U.S. Patent No. 11,185,389 by the assignee, which is hereby incorporated by reference herein.

[0020] New cooling water circuit According to some embodiments, the new cooling water circuit 200 includes a single central cooling water valve corresponding to multiple dental devices (instead of requiring one valve per dental device), and other new components described below. First, FIG. 2 is a circuit diagram showing a single cooling water valve 202 connected to a first dental device 130a for supplying pressurized dental water. The cooling water valve 202 is connected to a dental water source 106. In this example, the dental water source 106 supplies dental water at a pressure of 35 psi to 40 psi. In other embodiments, for example, a low pressure of 25 psi to 40 psi is used.

[0021] The cooling water valve 202 operates to supply water to the rest of the cooling water circuit 200 by pulse width modulation (PWM). In the example in Figure 2, the cooling water valve 202 is a two-position servo-controlled valve that accepts frequency and pulse width inputs as operating parameters, as will be described in more detail below.

[0022] The cooling water valve 202 is connected to a first cooling water holdback valve 204a associated with the first dental device 130a. The first cooling water holdback valve 204a is a normally closed valve in two positions, preventing (or "restricting") the flow to the rest of the circuit until it is moved to the open position. When the first cooling water holdback valve 204a is in the open position, cooling water is supplied to the first dental device 130a via the first line 206a, following the left side of the circuit, and released as a coolant at the distal end 208 to cool the treatment site. The same concept applies to dental devices that have an internal mixing chamber that mixes the mixture internally before releasing it. For example, water can be used to cool a dental bur 132 and / or the associated tooth T of the treatment site actuated by the first dental device 130a.

[0023] In the example in Figure 2, the first coolant holdback valve 204a is connected to the first dental device selection valve 212a to receive a signal indicating that the associated first dental device 130a is ready for use, and this signal moves the first coolant holdback valve 204a to the open position. In the example in Figure 2, the first dental device selection valve 212a sends an air signal to the first coolant holdback valve 204a to open it, allowing coolant to flow into the first line 206a.

[0024] In some embodiments, the dental device selection valve (sometimes referred to as the "holder valve") is a two-position mechanical three-way valve that detects when each dental device is removed from its holder or when the whip arm holding the dental device is moved from its stowed position. As shown in Figure 2, the first is connected to a dental air source 108 that supplies pressurized air. In this example, the dental air source 108 supplies pressurized air at 90 psi to 125 psi.

[0025] When dental devices are positioned in their respective holders, a mechanical lever is activated, and the inlet is connected to the outlet pilot signal. When the dental device is removed from the holder, the valve lever is not activated, so the outlet pilot signal is released and the inlet is closed.

[0026] While the dental appliance is removed from its holder, the user can activate a controller (e.g., foot control, hand control, or other control) to start the flow of cooling water through the dental appliance.

[0027] When the first dental device 130a is positioned in its holder, the presence of a pilot air signal from the first dental device selection valve 212a closes the first cooling air holdback valve 214a associated with the first dental device 130a. The first cooling air holdback valve 214a prevents (or "suppresses") air from the cooling air needle valve 216. In the illustrated embodiment, the first cooling air holdback valve 214a is a two-position, two-way pilot-operated air valve. When the first dental device 130a is removed from its holder, the pilot air signal is released, and when the foot control is activated, the first cooling air holdback valve 214a opens to supply dental cooling air.

[0028] Next, the pilot signal of the holdback valve is repressurized. Before repressurization, the amount of water in the first cooling air holdback valve 214a is pushed out of the port(s) of the first dental device 130a. Generally, the user first removes their foot from the foot control disc / lever to stop the cooling water flowing through the cooling water valve 202. This water flow should be quickly "interrupted" and not drip thereafter. Optimization of the holdback valve concerns ensuring that the amount of water remaining in the holdback valve volume is not pushed out of the handpiece coolant port when the holdback pilot pressure returns after the first dental device 130a has been closed off.

[0029] The cooling air needle valve 216 is connected to a dental cooling air source, such as a dental air source 110. In this example, the dental air source 110 supplies pressurized air at 70 psi to 80 psi.

[0030] The cooling air needle valve 216 is a mechanical needle valve having an inlet, an outlet, and a needle that forms a variable-size orifice between the inlet and the outlet. The cooling air needle valve 216 is user-adjustable within a certain range. For example, if the dental air at the inlet is 70 psi to 80 psi, the cooling air needle valve 216 can be adjusted to produce cooling air at the outlet within a pressure range of 5 psi to 60 psi.

[0031] As schematically shown in Figure 2, when the first cooling air holdback valve 214a opens, dental air from the cooling air needle valve 216 flows through line 218a to the first dental device 130a and is released at the distal end 220. The cooling air is usually combined with cooling water inside or outside the dental device to generate a spray as desired. In other embodiments, it may be possible to use cooling air alone.

[0032] As explained, the cooling water valve 202 is a single valve used to supply dental coolant to multiple dental devices. While dental devices are usually used one at a time, they may be controlled to operate simultaneously during flushing operations, as will be explained in more detail below.

[0033] Figure 3A shows a circuit 240 in which a cooling water valve 202 is connected to multiple dental devices, such as a first dental device 130a and a second dental device 130b. In circuit 240, the connection between the cooling water valve 202 and the first dental device 130a is the same as in Figure 2. Similarly, in the branch circuit for the second dental device 130b shown on the right, there is a first cooling water holdback valve 204b, a second line 206b, a second dental device selection valve 212b, a second cooling air holdback valve 214b, and a second line 218b. Thus, there is a single cooling water valve, and for each connected dental device, there is a cooling water holdback valve, a dental device selection valve, and a cooling air holdback valve.

[0034] Single cooling water valve Figures 3B and 3C are schematic cross-sectional views of a typical cooling water valve 202 that can be used as a single valve to supply cooling water to multiple dental devices. Figure 3B shows the cooling water valve 202 in the closed position. Figure 3C shows the cooling water valve in the open position.

[0035] The cooling water valve 202 comprises a body 262, an armature 264, a coil 266, and a coil spring 267. When the coil 266 is energized, the armature 164 reciprocates, moving the diaphragm seal 268, which causes the fluid to flow in through the inlet 270 and out through the outlet 272. In the illustrated embodiment, the cooling water valve 202 is an isolation valve designed so that only a minimum number of components come into contact with the fluid due to the sealing action of the diaphragm seal 268. The simplified flow path shown in the illustration helps prevent biofilm growth by minimizing corners and dead ends where fluid, especially water, can accumulate. Furthermore, the valve components may be made of inert materials.

[0036] There are commercially available PWM valves that can enable the basic operation and / or proof of concept of the cooling water valve embodiments described herein. However, commercially available PWM valves as currently understood do not meet at least some design requirements, and therefore an improved valve is needed.

[0037] As described, the cooling water valve 202 in some embodiments is a special high-speed, two-position, two-way normally closed on / off solenoid valve used for multiple purposes in dental water circuits. It has a simple, robust, and low-cost design. It can deliver very low flow rates but can also handle high flow rates, such as during full flush functions. In some embodiments, valves with orifice nominal diameters of approximately 0.030 inches to approximately 0.039 inches can meet this dual need. In some embodiments, the target orifice nominal diameter is 0.035 inches. This corresponds to a stroke of approximately 0.008 inches, so the orifice with the poppet open will have this same orifice area.

[0038] The cooling water valve 202 also offers an isolation-type valve design, which is desirable for addressing common dental water quality issues, including biofilm reduction. Furthermore, it provides a long lifespan and consistent operation. Its relatively small size and low moving weight enable fast, robust, and quiet operation. The cooling water valve 202 addresses the dripping problems of current needle valves by having a poppet stroke that retracts during each cycle and flush.

[0039] As will be explained in more detail below, coolant pulses occur at a speed imperceptible to the user.

[0040] While electrically operated or other similar motor-driven or actuator-driven needle valves or flow control valves can be used, these valves tend to be more expensive, complex, and less robust. These valves may also require additional on / off valves to fully meet application requirements.

[0041] While proportional solenoid valves (or equivalent devices) can be used, the small orifices required for low-flow cooling water are prone to clogging, and easily meeting the needs of high-flow flushing inevitably requires additional components and complexity.

[0042] The cooling water valve 202 allows for the use of programmable cooling water flow capabilities via a user interface, enabling the cooling water and / or flush flow to be specified for each user, dental device, and / or procedure. Custom settings are also available. Extended functions, such as cooling water flow management, can be programmed to enhance visibility and optimize tooth / tool ​​cooling in high-performance systems. In some cases, signals from electronic measuring instruments such as tool load sensors, microphones, and temperature sensors can be used as additional inputs for optimal cooling and visibility. It is also possible to control the supply of a minimal flow that is effective for cooling while providing excellent visibility (avoiding situations where so much coolant is supplied that the practitioner cannot see).

[0043] The cooling water valve 202 allows for manual, semi-automatic (timed), or fully automatic flushing of the dental device. Existing mechanical foot controls can be continued, with the addition of a foot control water switching sensor if necessary. Electronic foot controls (wired or wireless) can be easily integrated.

[0044] The cooling water valve 202 is considered to have a fail-safe design due to its spring-loaded normally closed configuration, so that the system is protected from excessive water leakage in the event of a loss of power or system pressure.

[0045] If it is desired to improve flow consistency over time, closed-loop control can be incorporated.

[0046] During operation, when the dental device is removed from its holder, the cooling water valve 202 is turned on and off using the foot control. In some embodiments, when the pressure transducer detects that the drive air pressure due to the foot control operation has increased beyond 8 psi to 12 psi, the cooling water valve 202 begins to flow water. When the foot control is close to a completely deactivated state (i.e., the user removes their foot from the foot control and deactivates it) and the drive air pressure falls below approximately 5 psi, the cooling water valve 202 stops the water flow.

[0047] In other embodiments, in addition to foot control activation, one or more other parameters are used to control the timing of the cooling water flow initiation.

[0048] The user interface and related software can be programmed to correlate the water flow with the movement of the foot control (e.g., the percentage of foot control movement) and / or the driving air pressure. The water flow in the cooling water valve 202 can also be associated with external sensors (pressure, temperature, flow rate, sound, etc.), and in some cases, this can be linked to the foot control operation rate to optimize the water spray (i.e., mixed cooling water and cooling air) to obtain optimal tooth cooling and optimal operator visibility.

[0049] The driving air, cooling air, and cooling water can all be synchronized with foot control operation and / or external sensors to enhance the operator's visibility within the work area and optimize the cooling of teeth and dental instrument tools / burs. Adjustments and pre-programming via the user interface can also optimize the operator's vision and tooth / tool ​​cooling in conjunction with foot control operation and / or external sensors.

[0050] Coolant hold-back valve A new coolant holdback valve is used to direct coolant to the desired dental device. For example, a first coolant holdback valve 204a is used to direct coolant to the first dental device 130a. Such holdback valves are not currently used. Coolant valve 202 provides a fail-safe design that protects against power or pressure loss, so a simpler and less expensive coolant holdback valve can be used for the circuit selection function. The coolant holdback valve also prevents backflow of water from the dental device and the formation of water droplets on the dental device after the dental device has been returned to the holder. The components and geometric shape of the coolant holdback valve are optimized to reliably function to control the coolant flow while avoiding backflow and droplet formation problems.

[0051] Figures 8, 9, 10A, and 10B are schematic cross-sectional views of the first coolant holdback valve 204a, each showing a different state. Two ports 402 and 404 are shown. The two ports 402 and 404 have an optimized shape and position so that the diaphragm 406 does not deform toward the input and / or output openings when the pilot signal P is applied, thereby preventing droplets from adhering to the dental device when the dental device is returned to its holder. The female cavity is also sized and shaped to provide an orifice with minimal restriction when the coolant flows when open, while minimizing diaphragm elongation.

[0052] Figure 8 shows that no dental appliances are selected, so the pilot signal P is ON and the cooling water valve is OFF (i.e., the foot control is not pressed). Figure 9 shows that the cooling water valve is ON (i.e., the foot control is activated) and the dental appliance has been removed from its holder. Figure 10A shows that the dental appliance remains removed from its holder, but the cooling water valve is OFF (i.e., the foot control is not pressed). Figure 10A also shows the expected degree of elongation of the diaphragm 406 over time. Figure 10B shows an alternative configuration with an additional spring or similar device 408 to hold the diaphragm 406 in place when there is no pilot signal pressure or cooling water valve pressure. The spring or similar device 408 reduces the formation of water droplets from the water volume under the elongated diaphragm when the dental appliance is eventually returned to its holder and the pilot signal is repressurized.

[0053] Considerations for pulse width modulation valve operation Figure 11 is a graph showing the operation of the cooling water valve 202 as it rapidly changes state between the ON and OFF positions according to the selected frequency and duty cycle (lower line extending along the horizontal axis), and the resulting cooling water flow rate (upper line) and cooling water pressure (middle line) of the dental device. Figure 11 also shows the pressure and flow rate response fluctuations and transient rise response resulting from repeated cycles of the cooling water valve 202. In the example in Figure 11, after achieving steady-state operation, the cooling water valve 202 provides a flow rate of 10 ml / min to 12 ml / min and a pressure of 4 psig to 6 psig in the dental device.

[0054] As described above, the cooling water valve 202 can be selectively controlled to supply cooling water to at least one connected dental device at one of the dental device locations, and since the flow rate pulsation is not visually discernible to the user, the cooling water will be perceived as flowing continuously (sometimes referred to herein as "semi-continuous" flow).

[0055] In some embodiments, an optional compliance member may be provided downstream of the cooling water valve. The compliance member may help to reduce pulsation in the cooling water flow from the cooling water valve. For example, in some embodiments, sufficient compliance can be achieved by a compliance member that includes a flexible tube through which the cooling water flows. The compliance member may be part of a standard tube or an additional section of tube.

[0056] In other embodiments, compliance is provided by a compliance member in the form of a flexible diaphragm of the valve member. Different types of compliance members (e.g., flexible tubes, flexible diaphragms, and / or other types of compliance members) may be used in combination.

[0057] The use of compliance is one technique for obtaining the fluid capacitance effect, which tends to result in quasi-continuous flow in dental devices. For further illustration, Figure 12 is a graph showing the effect of two levels of system capacitance on smoothing the PWM-generated flow as it is discharged from the cooling water valve 202 through the dental device. When the capacitance is at a very low level (short dashed line), the flow pulses in the handpiece are noticeable and therefore easily detected by the user. Conversely, when the capacitance is at a sufficient level ("good capacitance") (long dashed line), the flow pulses in the handpiece are very small. At sufficiently high or good capacitance, the flow in the handpiece appears smooth and continuous, and the flow pulses are generally not noticeable to the user during normal use.

[0058] Figure 13 is a graph showing the effect of the PWM duty cycle of the cooling water valve 202 at two different rates when controlling the average flow rate through the dental device (handpiece), with capacitance and PWM frequency kept constant for the two different rates. Figure 13 also shows the valve state (i.e., open or closed) at low and high duty cycle rates. As shown in Figure 13, the effect of changes in the duty cycle of the cooling water valve 202 does not correlate well with flow rate fluctuations in the dental device (handpiece).

[0059] In some embodiments, the desired quasi-continuous flow can be obtained in the PWM frequency range of 15Hz to 25Hz or 10Hz to 30Hz. In some embodiments, the desired quasi-continuous flow can be obtained at a PWM frequency of at least 15Hz. More continuous flow can be obtained at frequencies above 15Hz, but frequencies above 25Hz (and the resulting very short operating times) are difficult to achieve with some current valves. Furthermore, higher frequency operation means that the valve must withstand more cycles, resulting in reduced reliability and increased upfront costs and replacement / maintenance costs during its service life.

[0060] For example, Figures 14A to 14D are graphs showing the pressure measured at the outlet of the cooling water valve and the inlet to the dental device (handpiece) at PWM frequencies of 10 Hz, 15 Hz, 20 Hz, and 25 Hz, respectively. At low frequencies of 10 Hz and 15 Hz, as shown in Figures 14A and 14B, the pressure fluctuations in the dental device are more pronounced. At high frequencies such as 20 Hz and 25 Hz, as shown in Figures 14C and 14D, the pressure fluctuations in the dental device are reduced to the point where the resulting flow rate fluctuations are not noticeable to the user (the flow appears continuous to the user and is therefore referred to as "semi-continuous" flow in this specification).

[0061] In some embodiments, the cooling water valve 202 is operated at a select speed sufficient to provide the desired water flow rate and to produce a semi-continuous flow. In other words, the semi-continuous flow contains a flow component substantially different from the average flow rate, but the deviation is imperceptible to the user.

[0062] Certain types of dental devices are prone to exhibiting pulses during operation, which is at least partly due to differences in the operating range of back pressure. Dental devices in which cooling water and cooling air are pre-mixed in an internal chamber and then ejected as a mist tolerate less flow rate fluctuation than dental devices in which air and water combine to form a mist outside the device.

[0063] A simple, inexpensive, and robust electrical circuit that allows for quick on / off times is desirable for the cooling water valve 202. Furthermore, a special circuit can be used that generates an open-circuit voltage spike, followed by a voltage drop after the shift to save power and reduce heat gain. The operating voltage can be 4.3 volts, 24 volts, or some other reliable VDC. Lowering the dental water supply pressure (conventionally 35 psi to 40 psi) to 25 psi to 40 psi allows for a longer "on time" of PWM operation, enabling precise achievement of the desired flow rate.

[0064] The cooling water valve 202 may have a base-mounted design that accommodates 1 / 8-inch outer diameter and 1 / 16-inch inner diameter tubing on both the inlet and outlet sides. A manifold-mounted design may be used in some cases.

[0065] Various cooling aqueous solutions containing a 3% hydrogen peroxide solution can be used. Similarly, various aqueous shock treatment solutions containing A-dec ICX Renew shock treatment solution can be used.

[0066] In some embodiments, the audible level of the valve should be a maximum of 50 dB at a distance of 1 meter in all directions from the valve. Desired flow rate variability with a 20 Hz PWM on / off time may include: 3 msec on / 47 msec off, 4 msec on / 46 msec off, 5 msec on / 45 msec off, etc. It is important to fully shift the poppet for flow rate consistency over its lifetime / hours during the fastest on / off time required for low flow rate coolant (e.g., approximately 3 msec on / 47 msec off for a coolant flow rate of 5 ml / min).

[0067] At 35 psi with a 0.035-inch diameter orifice, a total flush flow rate of over 500 ml / min is expected. Therefore, in a system of six dental devices using manual flushing, there is sufficient flow to flush all six dental device tubes simultaneously if desired. If the stroke length of the cooling water valve is shortened from 0.008 inches to a shorter stroke length (e.g., 0.005-0.007 inches) to ensure that the poppet always shifts completely during rapid PWM signals, the flush flow rate should still be sufficient to flush multiple dental device tubes simultaneously (at least fewer than all of them).

[0068] In some embodiments, the cooling water valve 202 should allow flow rates as low as 5 ml / min. While consistency between valves is not critical, individual valves should be adjustable to 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, 25 ml / min, 30 ml / min, 40 ml / min, and 50 ml / min by adjusting the PWM on-time at a constant 20 Hz frequency (i.e., a speed at which the user's eye cannot perceive the pulse). The flow rates should match approximately 25,000,000 cycles to ±30% at 5 ml / min, ±20% at 10 ml / min to 30 ml / min, and ±10% at 40 ml / min or 50 ml / min. Readjustment of low flow rates is possible by changing settings in the user interface, etc.

[0069] The average lifespan may be 500,000,000 cycles, with cleaning / reassembly required at 125,000,000 cycles, and / or the valve assembly may be easily and economically readjusted with a reassembly kit at 250,000,000 cycles.

[0070] Conventional water and dental air circuits For comparison, Figure 4 is a schematic circuit diagram showing the dental water and dental air connections in a conventional circuit 300 for a single dental device, for example, a first dental device 130a. Similarly, Figure 5 is a schematic circuit diagram showing the dental water and dental air connections in a conventional circuit having multiple dental devices, namely a first dental device 130a, a second dental device 130b, and a third dental device 130c.

[0071] As shown in the figure, the dental water source 106 supplies dental water at 35 psi to 40 psi to the first water cartridge valve 322a associated with the first dental device 130a. The first water cartridge valve 322a is a two-position, two-way normally closed, pilot-operated water valve. The pilot signal is an air signal from the first water signal holdback valve 324a, which will be described later. If power or system air pressure is lost, the spring of the first water cartridge valve 322a closes the valve, reducing leakage and / or overflow.

[0072] When the first water cartridge valve 322a is opened, water is supplied to the first cooling water needle valve 325a and the first dental device 130a, where it is discharged from the distal end 309. The first cooling water needle valve 325a is a mechanical needle valve having an inlet, an outlet, and a needle that forms a variable-size orifice between the inlet and the outlet. In the illustrated embodiment, the first cooling water needle valve 325a is user-adjustable and has an adjustment range that can generate a cooling water pressure of 5 psi to 30 psi at the outlet based on a dental water pressure of 35 psi to 40 psi at the inlet.

[0073] The first water signal holdback valve 324a, connected to the first water cartridge valve 322a, is a two-position, two-way pilot-operated air signal valve. As best shown in Figure 5, the first water signal holdback valve 324a is connected to a cooling water signal solenoid valve 330 (for cooling water) or a flash signal toggle valve 328 (for flushing), which are further connected to a dental air source supplying dental air at 70 psi to 80 psi.

[0074] The first water signal holdback valve 324a is also connected to the first dental device selection valve 312a. A pilot signal from the first dental device selection valve 312a closes the first water signal holdback valve 324a if the pilot signal is present / pressurized (i.e., the first dental device 130a is in its holder). The first dental device selection valve 312a is connected to a dental air source 308 that supplies dental air at 90 psi to 125 psi.

[0075] When the first dental device 130a is removed from its holder, the pilot signal is released at the first handpiece selection valve 312a, and the first water signal holdback valve 324a opens, allowing the dental water-air signal to flow when the foot control is activated or the flush toggle is activated. When the first dental device selection valve 312a opens, air is also supplied to the first cooling air holdback valve 314a associated with the first dental device 130a. The first cooling air holdback valve 314a prevents (or "suppresses") air from the cooling air needle valve 316. The cooling air needle valve 316 is connected to a dental cooling air source, such as the dental air source 110. In this example, the dental air source 110 supplies pressurized air at 70 psi to 80 psi.

[0076] When the cooling air holdback valve opens, cooling air is supplied to the first dental device 130a via the first line 318a and released at the distal end 320.

[0077] In the embodiment shown in Figure 14, the flash mode can be selectively activated to flash one or more dental devices. A flash signal toggle valve 328 is connected to a first water flash hold-back valve 326a associated with a first dental device 130a, which is further connected to a first cooling water needle valve 325a. The flash signal toggle valve 328 is a two-position, four-way normally open mechanical toggle valve with an inlet connected to a dental air source of 70 psi to 80 psi. The inlet is normally connected to one of the outlet ports, from which a pilot signal is supplied to the first water flash hold-back valve 326a. When the flash signal toggle valve 328 is activated (e.g., manually), the pilot air signal is released.

[0078] The first water flush hold-back valve 326a is a two-position, two-way pilot-operated water valve. A pilot air signal from the flush signal toggle valve 328 closes the first water flush hold-back valve 326a when the pilot air signal is present / pressurized (i.e., the toggle is not activated). When the toggle of the flush signal toggle valve 328 is activated, the pilot air signal is released, and the first water flush hold-back valve 326a remains open, allowing the flow of dental water flush to proceed.

[0079] Figure 5 is similar to Figure 4, but also shows the branch lines for the circuits of the second dental device 130b and the third dental device 130c. Therefore, there are corresponding components, including the second dental device selection valve 312b, the second cooling air holdback valve 314b, the second line 318b, the second water cartridge valve 322b, the third dental device selection valve 312c, the third cooling air holdback valve 314c, the third line 318c, and the third water cartridge valve 322c. Furthermore, there is an optional cooling air solenoid valve 334 that can be activated to disable the air supply to the cooling air needle valve 316. The cooling air solenoid valve 334 is activated electronically from a touchscreen user interface or another electronic control, etc.

[0080] As shown in Figure 5, some embodiments have an optional coolant signal solenoid valve 330. The coolant signal solenoid valve 330 is an electronically controlled valve that can be activated from a user interface or another electronic control to disable the coolant circuit.

[0081] As explained, the following components of the conventional circuit can be eliminated: (1) Multiple manual coolant needle valves (1 to 6 or more) are replaced by a single coolant valve 202. (2) The operating knobs and illumination indicators of the manual coolant needle valves are not required. (3) The water flush holdback valve is not required (unwanted low flow paths are also eliminated). (4) The flush signal toggle valve is not required (its dual purpose of turning the water valve on / off and transmitting a flush air signal is eliminated). (5) Multiple water cartridge valves are not required due to the new coolant valve (water on / off) and the new coolant holdback valve (water delivery to the desired dental device position). (6) The shuttle valve is not required. (7) The optional coolant signal solenoid valve is not required.

[0082] New cooling water / cooling air circuit Figure 6 is a schematic diagram of circuit 280, which has the single cooling water valve 202 described above in relation to Figures 2 and 3, and a dental device selection solenoid valve instead of a mechanical dental device selection valve. Furthermore, circuit 280 has a new cooling air proportional valve that supplies cooling air to all dental device positions instead of a cooling air needle valve required for each dental device position. Figure 7 is a schematic diagram similar to Figure 6, but differs in that it shows components for multiple dental devices, including the first dental device 130a and the second dental device 130b.

[0083] The cooling water valve 202, the first cooling water holdback valve 204a for the first dental device 130a, and the first line 206a are the same as those described above in relation to Figure 2. Instead of the mechanical valve, the first dental device selection valve 212a, there is an electronic first dental device selection valve 380a.

[0084] The first coolant holdback valve 204a is connected to receive a pilot signal from the first dental device selection valve 380a. When the pilot signal is present / pressurized (i.e., the first dental device 130a is in its holder), the first coolant holdback valve 204a is closed. The first dental device selection valve 380a is connected to a dental air source 108 that supplies dental air at 90 psi to 125 psi.

[0085] When the first dental device 130a is removed from its holder, the pilot signal is released, and the first coolant holdback valve 204a opens, allowing the coolant to flow.

[0086] Furthermore, when the first dental device 130a is positioned within its holder, the presence of a pilot air signal from the first dental device selection valve 280a causes the first cooling air holdback valve 214a associated with the first dental device 130a to close. When the first dental device 130a is removed from its holder, the pilot air signal is released, the first cooling air holdback valve 214a opens, and dental cooling air is supplied from the cooling air proportional valve.

[0087] The presence of the cooling air proportional valve 382 eliminates the need for the cooling air solenoid valve 334. The cooling air proportional valve allows for pre-programming of different cooling air flow rates and / or pressures for each dental device position. It is also possible to release cooling air once from the cooling air proportional valve each time the foot control is released (this is desirable as it helps remove cooling water droplets from the dental device). Furthermore, tip air can be supplied through the cooling air proportional valve 382. The elimination of the cooling air needle valve, and thus the mechanical adjustment knob required for this valve, reduces the number of required parts and connections, making system cleaning easier and more effective. Existing mechanical foot controls can still be used, and electronic foot controls and other electronic devices (such as head-up displays) can be easily integrated. Closed-loop control can be added if desired.

[0088] Furthermore, extended functions such as coolant flow rate management can be implemented to enhance visibility and / or improve cooling. User preferences regarding flow rate (for example, to achieve sufficient cooling without generating excessive mist) can be accommodated. Signal inputs such as tool load sensing, cooling, and visual signals can be detected and used to set coolant flow rate parameters.

[0089] Additional design considerations Dental water is supplied by a dental unit to various dental devices (also referred to as dental appliances and / or instruments) used during patient treatment to cool instruments and tooth tissues, and to assist in rinsing debris and rinsing the mouth. Because dental unit water comes into contact with oral tissues and may be accidentally ingested, it must have acceptable chemical and microbiological properties. Bacterial biofilm formation within dental unit water lines is a particular challenge to maintaining acceptable dental unit water quality. Adding medications to the dental unit water used during treatment, and regularly injecting cleaning / disinfecting solutions into the dental unit water system when the dental unit is not being used to treat patients, are common strategies for controlling biofilm formation. Dead ends, crevices, and other areas within the dental unit water system where water may not circulate well can become breeding grounds for bacterial biofilm, potentially becoming sources of bacterial contamination of the dental unit water. The aforementioned circuits and components are designed to ensure appropriate microbiological quality of dental unit water by reducing bacterial biofilm in the dental unit.

[0090] Dental unit water is not intended to be consumed as drinking water. However, drinking water standards are often cited as reference standards for dental unit water quality, and some dental infection control organizations incorporate drinking water requirements into their dental unit water guidelines or requirements. The maximum concentration of heterotrophic bacteria in drinking water, as defined by the EPA, the American Public Health Association (APHA), and the American Water Works Association (AWWA), is 500 CFU / mL.

[0091] Maintaining consistently acceptable microbiological water quality requires the implementation of appropriate infection prevention measures. Furthermore, the quality of water delivered by dental units should be regularly monitored to ensure compliance with standards. Industry standards such as ISO 7494-1 and ISO 7494-2 specify requirements for dental units, and these are recognized by regulatory authorities in many countries. These requirements include ensuring that dental water systems conform to manufacturers' recommendations regarding dental waterline treatment.

[0092] As described above, dental air is compressed air supplied by a dental unit to various instruments used during patient treatment, mixed with cooling water to create a water spray that cools the cutting bur and tooth tissue. Compressed air is also used to power certain instruments (referred to as "driving air"). Compressed air is also used to assist in debris removal (referred to as "tip air"), to dry tooth surfaces, and to evaluate tooth temperature sensation. Therefore, proper control of the chemical and microbiological quality of the air in the dental unit is desirable.

[0093] Industry standards such as ISO 22052, ISO 8573, ISO 7494-1, and ISO 7494-2 specify requirements for dental air quality, and these are recognized by regulatory authorities in many countries. Air cleanliness classes are defined according to ISO 8573-1. Dental air quality is specified in ISO 22052. Flow rate, pressure, filtering, humidity, and oil content should meet specific usage requirements.

[0094] In view of the many possible embodiments to which the principles of the invention disclosed herein may be applied, it should be recognized that the embodiments described are merely preferred examples of the invention and should not be considered to limit the scope of the invention. In practice, the scope of the invention is defined in the appended claims. Accordingly, everything within the scope and spirit of these claims is claimed to be the invention.

Claims

1. A cooling water circuit for a dental unit, Multiple predetermined dental device positions to which dental devices using cooling water can be connected, A cooling water valve connected to a plurality of dental device locations and connectable to a pressurized cooling water source, which is operable by pulse width modulation (PWM) and can be selectively controlled to simultaneously supply the cooling water from the cooling water source to at least one of the plurality of dental device locations, and A cooling water circuit equipped with a cooling water circuit.

2. A cooling water circuit according to claim 1, wherein the cooling water valve operates at a frequency of approximately 10 Hz to 30 Hz.

3. A cooling water circuit according to claim 1, wherein the cooling water valve operates at a frequency of 15 Hz to 25 Hz.

4. A cooling water circuit according to claim 1, wherein the cooling valve is operable at a duty cycle of 1% to 25% to supply the cooling water to at least one of the plurality of dental device positions.

5. A cooling water circuit according to claim 1, wherein the cooling water valve is operable at a 100% duty cycle to supply the cooling water to at least one of the plurality of dental devices for flushing in a flash mode.

6. A cooling water circuit according to claim 1, wherein the cooling water valve is a normally closed valve with two positions.

7. A cooling water circuit according to claim 1, wherein the cooling water valve has an isolation valve design.

8. A cooling water circuit according to claim 1, wherein the cooling water valve is operable to supply the cooling water at a flow rate of 3 mL to 50 mL per minute.

9. A cooling water circuit according to claim 1, wherein the cooling water valve is operable to supply the cooling water at a flow rate of 5 mL to 150 mL per minute.

10. The cooling water circuit according to claim 1, wherein the plurality of dental device positions include at least one dental device position that receives pressurized air in addition to cooling water.

11. The cooling water circuit according to claim 1, further comprising at least one connected dental device connected to one of the dental devices, wherein the cooling water valve is selectively controllable to supply cooling water through the connected dental device at a semi-continuous flow rate.

12. The cooling water circuit according to claim 1, further comprising a compliance member positioned downstream of the cooling water valve, wherein the compliance member attenuates the pulsation of the cooling water flow from the cooling water valve.

13. The cooling water circuit according to claim 12, wherein the compliance member includes a flexible tube through which the cooling water flows.

14. A cooling water circuit according to claim 12, wherein the compliance member includes a flexible diaphragm of a valve member.

15. A cooling water circuit according to claim 1, wherein the cooling water valve is operable to supply cooling water simultaneously to one or more dental device positions in a flash mode.

16. The cooling water circuit according to claim 15, wherein in the flash mode, substantially all of the flash flow rate is directed through the cooling water valve for simultaneous flashing of the dental device at one or more of the dental device positions.

17. A cooling water circuit according to claim 1, wherein the cooling water valve is connectable to a power source, and the water cooling valve remains in the off state and the cooling water flow is interrupted in response to the power being turned off or a loss of power supplied to the cooling water valve.

18. A method for supplying dental cooling water in a dental delivery system, The steps include providing a single cooling water valve connected to multiple dental device positions defined on the control head, The steps include connecting the single cooling water valve to a pressurized dental cooling water source, The steps include: operating the cooling water valve by electronic pulse width modulation (PWM) to selectively control the flow of dental cooling water from the single cooling water valve to at least one of the multiple dental device locations; Methods that include...

19. A cooling water hold-back valve used in dental units, A valve body having a valve inlet and a valve outlet for cooling water, A flexible diaphragm positioned on the valve body between the valve inlet and the valve outlet, which can be selectively controlled to allow cooling water to flow in from the valve inlet and out through the valve outlet, and to block the flow of cooling water. A cooling water hold-back valve, comprising the above, which can be connected downstream of the cooling water source and upstream of the dental device location where a dental device can be connected within the dental unit.

20. A coolant holdback valve according to claim 19, further comprising a pilot control input, wherein a pilot control off signal causes the flexible diaphragm to move to an off position that prevents coolant flow.

21. A coolant holdback valve according to claim 19, wherein the pilot control input is an air pressure signal.

22. A cooling water holdback valve according to claim 19, wherein the pilot control input is a signal from a holder valve operably connected to a dental device holder, and the pilot control input is configured to change from a closed signal to an open signal when the holder valve switches over and the dental device is removed from the dental device holder.

23. A cooling water hold-back valve according to claim 19, wherein the cooling water hold-back valve is configured to prevent dripping from the dental device when the dental device returns to the dental device holder.

24. A cooling water hold-back valve according to claim 19, wherein the cooling water hold-back valve is configured to prevent the formation of water droplets at the outlet of the dental device.

25. A cooling water hold-back valve according to claim 19, further comprising at least one biasing member configured to bias the diaphragm to the closed position.

26. In the coolant holdback valve according to claim 19, the diaphragm is pilot-controlled by a pilot-on or pilot-off signal, and the coolant holdback valve is In the first OFF state, the pilot signal is ON and no cooling water is flowing into the valve inlet. The pilot signal is ON and cooling water is flowing into the valve inlet, in the second OFF state. The pilot signal is off, and cooling water flows in at the valve inlet and out at the valve outlet, in the third ON state. The pilot signal is off, and no cooling water is flowing into the valve inlet, representing the fourth OFF state. A cooling water hold-back valve, which includes the following four operating states.

27. A coolant holdback valve according to claim 19, wherein the diaphragm is pilot-controlled by an air signal in the range of 70 psi to 125 psi.

28. A pneumatic proportional valve for supplying cooling air in a dental unit, A valve inlet connected to a pressurized air source, A valve outlet that can be selectively connected to one of several dental device assignment positions, each capable of connecting to multiple dental devices, An electrical control circuit for receiving a signal from a pneumatic proportional valve and selectively controlling the supply of cooling air to at least one selected dental device assignment position, A pneumatically proportional valve equipped with a pneumatic valve.

29. A proportional air pressure valve according to claim 28, wherein the electrical control circuit receives a cooling air supply signal corresponding to one of the selected dental device positions and specifies a flow rate and / or pressure for supplying cooling air to one of the selected dental device positions.

30. A cooling air proportional valve according to claim 29, wherein the cooling air supply signals for the plurality of dental device assignment positions are stored in memory.

31. A cooling air proportional valve according to claim 29, wherein the cooling air supply signal corresponding to one of the selected dental device positions is set by the user using a touch interface connected to the dental unit.

32. A cooling air proportional valve according to claim 28, wherein the dental unit is connected to one or more sensing devices selected from a tool load sensor, a microphone, a light sensor, or a temperature sensor, and the signals received by the electrical control circuit are modified by the signals from the one or more sensing devices.

Images