Dental needle for dental syringe for dispensing media and manufacturing method for a dental needle

Description

[0001] The present invention relates to a dental cannula intended for the delivery of fluid media such as air and / or water. The cannula according to the invention is intended for use with so-called dental syringe handpieces. The medical cannula according to the invention is considered an attachment for a so-called dental syringe handpiece, serving as a dental syringe attachment.

[0002] So-called spray handpieces or multifunctional handpieces are frequently used in the dental field and serve to support dental examinations or treatments. These spray handpieces are used to deliver air, water, or an air-water mixture in the form of a spray onto the area to be examined or treated in order to clean and, if necessary, dry the area. This ensures good visibility of the area to be examined or treated at all times, which is why regular use of these spray handpieces is essential.

[0003] Typically, spray handpieces of the type described above are connected via a supply hose to, for example, a so-called dental unit, which supplies the media delivered by the handpiece—i.e., compressed air and water. Using corresponding push buttons on the handpiece, the user can then select which medium is delivered by the handpiece.

[0004] The actual outlet of the media occurs at the front end of a cannula located at the front end of the handpiece. Typically, the cannula is interchangeably coupled to the handpiece in such a way that it can be rotated relative to the handpiece around a rotational axis, at least within a certain angular range. In the coupling area, the media is then transferred from the handpiece to lines running inside the cannula. These lead to the front end of the cannula, where a nozzle-like taper in the line cross-section is usually provided, ensuring that the media exits at high speed. This improves the cleaning effect of the air or water emitted by the spray handpiece.

[0005] For hygienic reasons, the cannula must be cleaned and sterilized after use. The need for such reprocessing is limited to the cannula only if its length ensures that the actual injection handpiece is sufficiently spaced from the front end of the cannula, thus ensuring that the handpiece does not come into contact with the patient. Corresponding standards stipulate that the cannula should have a length of at least 80 mm.

[0006] Various approaches to implementing such cannulas are known from the prior art. These are often reusable components comprising an elongated, conically tapered sleeve-like base body. The sleeve has a coupling area at its rear end for connection to a dental handpiece and is provided with nozzle-like media outlets at its front end. The media lines then extend within this sleeve in the form of hoses or tubes. Corresponding light guides, via which the area to be treated is illuminated, can also run through the hollow space of the sleeve. Such a cannula is known, for example, from EP 2 124 812 B1.

[0007] WO 86 / 04247 A1 and US 4519385 A describe surgical handpieces designed for surgical irrigating and suction applications. The handpieces disclosed herein have media lines formed at least partially by flexible channels, each of which can be closed by a trigger mechanism. Furthermore, the handpieces each have an area for media delivery and for liquid suction. However, these attachments are not intended for use with dental syringe handpieces and are also not suitable for dispensing multiple media.

[0008] InIn the dental cases described above, the cannulas are relatively complex components that require a relatively high level of effort to manufacture and assemble. A further disadvantage arises from the fact that the sleeve-like outer casing forms a hollow space through which the cables and, if applicable, a light guide run in a protected manner. However, it also creates additional unused cavities that are difficult to clean and / or sterilize during reprocessing.

[0009] Accordingly, there are also alternative approaches to implementing such cannulas as cost-effective plastic components that can then possibly be used once as disposable products. Two solutions for this are shown, for example, in US 9,814,551 and DE 691 06 138 T2. Both of these are plastic injection-molded parts that can be manufactured easily and inexpensively. However, these known disposable cannulas have the problem that, due to manufacturing difficulties, they can only be implemented with straight media lines. However, it would be preferable for the cannula to be angled at its front end, as this improves visibility during use of the injection handpiece.Furthermore, the disposable cannulas known from the prior art can only be manufactured in relatively short lengths, making the aforementioned minimum length of 80 mm difficult to achieve. Finally, the injection-molding process of manufacturing these cannulas only allows for a limited design of the front end areas of the media lines in a nozzle-like manner to enable high-speed media delivery. Accordingly, while these known disposable cannulas are cost-effective to manufacture, they also have numerous disadvantages.

[0010] An improvement over these known solutions is presented in US 2020 / 0290066 A1. It shows a cannula intended for detachable coupling to the front end of a dental syringe handpiece, whereby pressurized fluids such as air or water are conveyed via the cannula. The cannula is formed by two plastic bodies, each having corresponding flat contact surfaces, to which the two plastic bodies are welded together. During this manufacturing process, media channels extending along the cannula are formed. This procedure increases the design options for the media channels compared to the manufacturing process according to US 9,814,551 or DE 691 06 138 T2.

[0011] The object of the present invention is to provide a further improved possibility of producing such cannulas for dispensing fluid media in a simple and cost-effective manner, while nevertheless avoiding the problems and disadvantages known from and existing in the prior art.

[0012] The invention is achieved by a dental cannula for dispensing media having the features of claim 1 and by a method for producing a cannula having the features of claim 13. Advantageous developments of the invention are the subject of the dependent claims.

[0013] The solution according to the invention is again based on the idea of ​​forming the cannula in the form of a cost-effectively producible plastic body, wherein, analogous to the approach of US 2020 / 0290066 A1, the media lines are formed, at least in sections, by channels extending through the plastic body. In contrast to the disposable cannulas of US 9,814,551 or DE 691 06 138 T2, the plastic body is therefore initially not provided as a one-piece injection-molded component, but rather consists of two one-piece plastic sub-bodies that are sealed together along a connecting plane in which the channels run.

[0014] It is further provided that two media lines are brought together in the front end area of ​​the cannula in a so-called mixing chamber and open into a common outlet opening, wherein a nozzle for mixing the media transmitted through the two media lines is provided in the area of ​​the mixing chamber and wherein this nozzle is formed by a separate insert.

[0015] According to the present invention, a dental cannula for delivering fluid media such as air and / or water is proposed, wherein the cannula is to be understood as an attachment for a dental syringe and comprises: a rear coupling region designed for coupling to a medical handpiece that provides the media, a front end region with at least one outlet opening for dispensing the media, and at least two elongated media lines extending from the coupling region to the front end region, which serve to guide the media from the rear coupling region to the outlet opening at the front end region of the cannula.

[0016] According to the invention, it is provided that the media lines are formed at least in sections by channels in a plastic body which consists of two one-piece plastic part bodies which are sealed together along a connecting plane in which the channels run, and that the two media lines are brought together in a mixing chamber in the front end region of the cannula and open into a common outlet opening, wherein a nozzle for mixing the media transmitted through the two media lines is arranged in the region of the mixing chamber and is formed by a separate insert.

[0017] According to the present invention, a method for producing a dental cannula for dispensing fluid media such as air and / or water is also proposed, wherein the cannula is to be understood as an attachment piece for a dental syringe and comprises: a rear coupling region designed for coupling to a medical handpiece that provides the media, a front end region with at least one outlet opening for dispensing the media, and at least two elongated media lines extending from the coupling region to the front end region, which serve to guide the media from the rear coupling region to the outlet opening at the front end region of the cannula.

[0018] The manufacturing process involves producing two one-piece plastic parts in a first step, which are then sealed together along a connecting plane in a subsequent manufacturing step. When assembled, channels that form the media lines run along the connecting plane in the resulting plastic body. The two media lines are joined in a mixing chamber in the front end region of the cannula and open into a common outlet opening. A nozzle for mixing the media conveyed by the two media lines is arranged in the region of the mixing chamber and is formed by a separate insert.

[0019] By manufacturing the cannula not as a one-piece plastic injection-molded body, but in the manner according to the invention, numerous advantages can be achieved. These arise in particular from the fact that the grooves or recesses in the plastic parts that ultimately form the channels are freely accessible before they are connected. Therefore, if the plastic parts are again manufactured using an injection molding process, for example, no problems arise during the demolding of these plastic parts compared to the prior art solutions, which ultimately opens up the possibility of designing the channels that form the lines with great freedom and, at the same time, high precision. This not only means that the ultimately formed cannula can easily achieve the above-mentioned minimum length of 80 mm, but also leads to the advantage that an angled design of the channels can be easily realized.A tapering of the channels in the front end area of ​​the cannula, which is necessary for optimized delivery of the media, can also be easily realized in this way, so that although the manufacturing effort is slightly increased compared to the disposable cannulas of the state of the art, numerous advantages are achieved at the same time.

[0020] The two plastic partial bodies preferably each form half-shells, in particular two half-shells that are symmetrical with respect to the connecting plane.

[0021] As already mentioned, it is particularly preferred to form the two plastic partial bodies by injection-moulding elements, which represents a particularly simple method of production.

[0022] The sealed connection between the two plastic parts is preferably achieved by bonding them together. A first option, for example, would be to glue the two plastic parts together. However, they are particularly preferably welded together, with laser welding being particularly suitable. However, another welding method, such as ultrasonic welding, could also be used.

[0023] According to a preferred embodiment, it is further provided that at least one of the media lines is tapered in the front end region of the cannula. As explained, this can be achieved without major problems using the inventive method for implementing the cannula. A tapered design of the media lines then leads to an accelerated release of the media in the form of a nozzle, which results in an improved cleaning effect when using the spray handpiece.

[0024] An improvement in handling and visibility of the area to be treated is preferably achieved by the cannula being angled in a front section.

[0025] The at least two media lines extending along the cannula are preferably provided for the delivery of air on the one hand and water on the other. However, according to a particularly preferred embodiment, a third media line can also be provided along the cannula. This third media line is also provided for the transmission of air, with one of the two air media lines then serving, if necessary, together with the media line for water, to deliver a so-called spray. The additional, separate media line for air is then provided exclusively for the delivery of air, which has the advantage that, if necessary, pure air without any water residue can be delivered immediately.

[0026] As already mentioned, the invention provides for two media lines to be combined in a so-called mixing chamber at the front end of the cannula and to open into a common outlet opening. This can be particularly useful for media lines intended to deliver a mixture of air and water in the form of a spray.

[0027] A further preferred embodiment of the cannula according to the invention consists in that it has a light guide which extends from the coupling region to a front region of the cannula for emitting light, wherein the light guide is then preferably formed by a separate component which is inserted into a further channel of the plastic part. This is also very easy to implement in terms of manufacturing technology, since during production of the plastic part bodies only measures have to be taken to create a further channel, wherein the light guide is then inserted into this channel and fixed within the cannula as part of the connection of the two plastic part bodies to one another. In this case, it can be provided that an end of the light guide intended for emitting light is arranged in the region of the at least one outlet opening for dispensing the media.Alternatively, however, the end of the light guide intended for emitting light can also be arranged on an outer peripheral region of the plastic body and aligned in such a way that light is directed to a location which is arranged in front of the at least one exit opening.

[0028] The coupling area provided for coupling to the handpiece preferably has a substantially hollow-cylindrical receiving area for receiving a coupling pin of the handpiece. Particularly preferably, annular channels are formed on the inner wall of the receiving area, each of which is in fluid communication with a channel forming a media line. This configuration of the coupling area allows the cannula to rotate or at least partially twist around a rotational axis relative to the handpiece, which ultimately facilitates handling of the injection handpiece.

[0029] According to a first, particularly preferred variant, it can be provided that the coupling region is formed by the two interconnected plastic partial bodies and is thus a component of the plastic body. Apart from the optionally provided insert for the nozzle and / or the inserted optical fiber, the cannula according to the invention in this case consists exclusively of the two interconnected plastic partial bodies. Alternatively, however, it would also be conceivable for the two interconnected plastic partial bodies to form an approximately hollow cylindrical region on their rear side, in which an insert forming the receiving region for receiving the coupling pin is arranged. This can be a correspondingly designed sleeve made of metal, which is then responsible for the actual media transfer.Finally, it would also be conceivable to form the coupling area by a separate component, which is then arranged on the back of the plastic body forming the media lines and connected to it.

[0030] The invention will be explained in more detail below with reference to the accompanying drawings. They show: Figures 1a to 1d Views of a first example of a cannula not falling within the scope of the claims to illustrate the method of manufacture; Figures 2a to 2e Views of a first embodiment of a cannula according to the invention; Figures 3a to 3e Views of a second embodiment of a cannula according to the invention; Figures 4a to 4e Views of a third embodiment of a cannula according to the invention; Figures 5a to 5d Views of a second example of a cannula not falling within the scope of the claims; Figures 6a to 6dViews of a third example of a cannula not falling within the scope of the claims.

[0031] Based on the Figures 1a - 1d First, a first example of a cannula will be explained in detail. The variants shown in the subsequent figures differ primarily in terms of the number of media lines running along the cannula and the design of the areas for media delivery and coupling to a medical handpiece.

[0032] The basic design of the cannula, designated by reference numeral 100 in the figures, is Figures 1a and 1b which show two perspective views of the cannula 100. Figure 1c then shows a section through the cannula 100 along the connection plane, while Figure 1d shows the two plastic parts before they are joined together to form the cannula 100.

[0033] As already explained, the cannula 100 is intended for coupling to a dental handpiece (not shown in the figures), which provides the media to be delivered using the cannula 100. These media are typically air and water, which can optionally be delivered together in the form of a spray. In principle, however, the cannula 100 according to the invention could also be used to deliver other liquid or gaseous media, or generally to deliver fluid media.

[0034] The rear portion of the cannula 100 is formed by a coupling portion 80, which is designed for connection to a dental handpiece. This coupling portion 80 has a greater width or thickness than the front portion of the cannula 100 and simultaneously serves as a gripping portion for the cannula 100, which is why two opposing indentations 89 (see FIG. Fig. 1b ) are provided, which facilitate gripping of the cannula 100.

[0035] From this coupling area 80, the design of which will be described in more detail below, a tube-like area extends towards the front, which is angled in the front third and opens into the front end area 70 for the discharge of the media. Figures 1a - 1dIn the variant shown, the release of air and water is provided via two separate lines 11, 12, which is why the front end region 70 in this case has two separate outlet openings 71 and 72, each for one of the two media. Both outlet openings 71 and 72 can be aligned parallel to one another or designed and aligned such that the released media meet or cross at a certain distance in front of the cannula 100, so that a spray is created when air and water are released simultaneously. However, as the other variants show, the release of a spray can also be realized in other ways.

[0036] The main function of the coupling area 80 is to receive the media provided by the handpiece. For this purpose, the handpiece has a correspondingly designed, approximately cylindrical coupling pin, which dips into a hollow cylindrical receiving area 85 of the coupling area 80 and releases air and / or water there depending on the actuation of the handpiece by the user. Accordingly, annular circumferential channels 81 and 82 are provided on the inner wall of the receiving area 85 of the cannula 100, which interact with discharge openings of the coupling pin and, due to their annular shape, prevent the cannula 100 from being rotated by an angle defined in Figure 1cindicated axis I. In particular, it is ensured that the media can be transferred in any rotational position of the cannula 100. While a rear annular channel 82 is formed by a circumferential groove approximately halfway up the cylindrical receiving area 85, a front annular channel 81 is formed by the correspondingly stepped design of the receiving area 85.

[0037] These annular channels 81 and 82 are then connected to media lines 11 and 12 extending in the longitudinal direction of the cannula 100 and leading to the outlet openings 71 and 72. In particular, it can be provided that the media lines 11 and 12 have a reduced cross-section in the front end region 70 near the outlet openings 71 and 72 or are continuously tapered. Both measures result in the exit velocity of the corresponding medium being further increased, thereby achieving a better cleaning effect.

[0038] The solution according to the invention now consists, among other things, in the question of how the cannula 100 with the media lines 11 and 12 extending therein is realized. According to the invention, the cannula 100 is formed by a plastic body 50 in which channels 51 and 52 corresponding to the lines 11 and 12 extend. In contrast to the prior art discussed at the beginning, the lines 11 and 12 are not formed by hoses or tubes to be laid separately in a hollow space, but by longitudinal channels in a plastic body 50. This measure has the consequence, among other things, that apart from the media lines 11 and 12 and the receiving area 85 of the coupling area 80, the cannula 100 has no further hollow spaces or the like in which liquids and / or bacteria could accumulate.This is a great advantage, particularly if the cannula 100 is to be reused and cleaned accordingly, as there are no cavities that are difficult to access and therefore difficult to clean.

[0039] However, the realization of the channels 51 and 52 forming the media lines 11 and 12 in the form shown - angled, tapered, of suitable length, etc. - is only possible within the framework of a special measure according to the invention, which will be explained in more detail below.

[0040] Due to the design and the course of the channels 51 and 52, it is not possible to realize the cannula 100 in the form of a one-piece injection-molded part. Instead, according to the present invention, two Figure 1d to form the plastic partial bodies 60a and 60b shown, which are sealed together in a subsequent work step.

[0041] The design of the plastic part bodies 60a and 60b is in accordance with the illustrations of the Figures 1c and 1d such that there are two half-shells which are ideally designed symmetrically to one another, each of which forms half of the receiving area 85 with the circumferential channels 81 and 82 and in particular also the channels 51 and 52 extending from the receiving area 85 to the front side. This means that each plastic part body 60a and 60b has a partial groove which is open towards the connecting plane - for example with a semicircular cross-section - which corresponds to a corresponding partial groove of the other plastic part body 60a, 60b and, when the two plastic part bodies 60a and 60b are assembled, then forms the actual channel 51 or 52 which is preferably circular in cross-section.

[0042] With regard to channels 51 and 52, it would also be conceivable, in principle, to design one of the plastic sub-bodies flat in the connection area and to provide the corresponding groove exclusively in the second plastic sub-body. However, a symmetrical design of the plastic sub-bodies 60a and 60b, in which both plastic sub-bodies 60a, 60b together form the channels 51, 52 and the other components of the cannula 100, is preferred.

[0043] It is essential that both plastic partial bodies 60a and 60b are actually tightly connected to one another when joined to form the plastic body 50, so that the channels 51 and 52 created in this process can then actually smoothly transfer the media from the coupling region 80 to the front end region 70 of the cannula 100. Preferably, a material-to-material connection is provided between the two plastic partial bodies 60a and 60b, whereby a first variant could consist of correspondingly gluing the two plastic partial bodies 60a and 60b to one another. However, it is particularly preferred for the two plastic partial bodies 60a and 60b to be welded to one another, in particular using a laser welding process. Ultimately, the measures described result in the two plastic partial bodies 60a and 60b being inseparably connected to one another in order to then form the cannula 100 shown in the figures.

[0044] The described procedure leads to numerous advantages over the solutions known from the prior art, in particular over disposable cannulas realized in the form of one-piece plastic bodies. Thus, in contrast to the prior art, the proposed measure allows the realization of the angled, i.e., non-rectilinear design of the cannula 100 shown. The tapered design of the media lines 11 and 12 in the front end region can also be realized in a particularly simple manner with the aid of the measures according to the invention. Finally, the proposed procedure for manufacturing the cannula 100 also imposes no restrictions on the dimensions of the cannula 100.This means that the distance from the rear coupling area 80 to the front end area 70 with the discharge openings 71 and 72 can always be selected such that the dimensions required by hygiene regulations can be achieved. In particular, this means that the cannula 100 can have a length that reaches or exceeds the above-mentioned 80 mm.

[0045] Appendix of the Figures 2 - 6 Variants of the cannula according to the invention will now be explained. These are based on the same basic principle as it is based on the Figures 1a to 1d In all cases, the media lines are formed, at least in sections, by channels in a plastic body, which is formed by sealingly connecting two one-piece plastic parts. Identical components of the cannulas discussed below are accordingly provided with the same reference numerals.

[0046] In the Figures 2a - 2e The illustrated embodiment is in comparison to the example of Figures 1a - 1d A third media line 13 is provided, which in turn extends from the coupling region 80 to the front end of the cannula. On the inner wall of the receiving region 85, a corresponding further annular channel 83 is formed for the third media line 13, which is connected to an additional, longitudinally extending third channel 53. As already mentioned, all channels 51, 52, 53 run in the connecting plane of the two plastic partial bodies 60a, 60b and thus parallel to one another.

[0047] While the cannula Figures 1a - 1dWhile the two discharge openings 71 and 72 were each connected to one of the two media lines 11 and 12, the embodiment according to the invention provides for two media lines 11 and 12 to be brought together before the actual outlet opening 74. Strictly speaking, both corresponding channels 51 and 52 open into a small, approximately cylindrical mixing chamber 20, in which the supplied media are mixed with one another before their actual discharge. Accordingly, it is preferably provided here to conduct, for example, air via one of the two media lines 11 and water via the other media line 12, with air and water then being mixed with one another in the mixing chamber 20 and discharged in the form of a spray via the opening 74.The mixing of air and water is optimized by an additional part 25 forming a nozzle, which is inserted into the chamber 20 as an insert and fixed there during the assembly of the two plastic parts 60a and 60b. Grooves formed on the outer circumference of this insert 25 achieve a better distribution of one of the two media, so that it can then be more evenly mixed with the second medium to form the spray discharged via the opening 74.

[0048] The additional third media line 13 with the associated outlet opening 72 can in turn be used to conduct air. While the air-water mixture is discharged in the form of a spray via the outlet opening 74, pure air is discharged via the opening 72. The use of a separate line 13 exclusively for air discharge offers the advantage that when the air discharge is activated, it does not initially contain small amounts of residual liquid, but instead immediately provides dry air to blow away particles or other contaminants.

[0049] The Figures 3a - 3e The variant of the cannula 100 according to the invention shown corresponds to the transfer and forwarding of the media in the Figures 2a - 2eshown variant. In this case, too, three media lines 11 - 13 are provided, through which either pure air or spray can be delivered to the front of the cannula 100.

[0050] Additionally, this third embodiment provides for a light guide 30 extending parallel to the lines 11-13, which in turn leads from the rear coupling region 80 to the front end region 70 of the cannula 100. Light provided at the front end of the coupling pin (not shown) of the handpiece is then coupled into the rear of the light guide 30 and emitted at the front end region of the cannula 100, just like the other media. The orientation of the front end 31 of the light guide 30, intended for light emission, is such that it is aligned parallel to the orientation of the emission openings 72, 74, so that the light emitted by the light guide 30 is directed to the same area as the other media.

[0051] Preferably, the light guide 30 is formed by a separate component, which is inserted into a corresponding longitudinal channel 55 of the plastic body 50. Analogous to the media lines 11-13, the plastic partial bodies 60a and 60b are designed such that they additionally have corresponding partial grooves facing one another, which, when the two plastic partial bodies 60a, 60b are joined together, form an elongated, angled channel in which the light guide 30 is laid. The light guide 30, like the insert 25 forming the nozzle, is inserted into one of the two plastic partial bodies 60a or 60b before it is firmly bonded to the other plastic partial body 60a, 60b. This measure also ensures secure fixation of the light guide 30 in the cannula 100.

[0052] Also in the Figures 4a - 4eIn the variant according to the invention shown, the use of a light guide 30 is provided. However, this now ends in a peripheral region of the longitudinally extending cannula 100 and is thus set back compared to the discharge openings 72, 74 for the further media. In this case too, however, the orientation of the light guide 30 at the front end 31 is such that the light emitted by it is directed towards the area to which the media is also discharged. Since the light guide 30 now does not extend to the front end 70 of the cannula 100, this can be compared to the variant according to the Figures 3a - 3d be designed to be somewhat more compact, which may lead to better visibility of the area to be examined or treated.

[0053] It should be noted that the use of a light guide as shown in the Figures 3 and 4 Of course, also explains in Figure 1cannula shown could be intended.

[0054] In the previously discussed examples of the Figures 1 - 4 The coupling area 80 was also formed using the two plastic parts 60a and 60b. Accordingly, the half-shells 60a, 60b also have the annular channels 81 to 83 provided for media transfer, or form them when joined together.

[0055] However, it would also be conceivable to design this coupling area 80 differently, whereby the Figures 5a - 5dFirst, we will show a first example of this, in which the coupling area is formed by a separate component 95, which is cylindrical and intended for the actual coupling to the medical handpiece. In this case, too, the separate component 95 has a cylindrical receiving area 85 with corresponding annular channels 81, 82, which is designed for coupling to the coupling pin of the handpiece. The channels formed in the separate component 95, which can be realized, for example, as a turned part, then lead at the front end of this component 95 to corresponding discharge openings 91, 92, which are connected to the actual channels 51, 52 in the plastic body 50 of the cannula 100. The plastic body 50 itself is firmly connected with its circular end to the component 95 forming the coupling area 80, which can again be done, for example, by gluing or other suitable measures.

[0056] With regard to the implementation of the longitudinally extending channels 51 and 52, this example is similar to the previously described embodiments. Again, two half-shells 60a, 60b are provided, which, when joined together, form the media lines 11, 12 in the form of elongated channels 51, 52. This variant can also be implemented analogously to the variants of Figures 1 - 4 with different numbers of channels and, if necessary, with a light guide and the insert part 25.

[0057] Figure 6Finally, FIG. 1 shows a sixth variant, which again differs with regard to the design of the coupling region 80. In this case, the plastic body 50 again extends over the entire length of the cannula 100, although the region intended for the actual coupling to the dental handpiece is now realized by an insert 90, which is inserted into a purely cylindrical receptacle of the rear plastic part 50 and fixed there, for example, by means of adhesive bonding or the like. The advantage of this variant is that it allows for even more precise machining of the areas of the cannula 100 required for the actual coupling to the handpiece, so that, if necessary, a better and more reliable media transfer can be realized. Despite everything, the embodiments of the Figures 1 - 4 to be preferred, since these can be realized with the help of the smallest possible number of components.

[0058] Depending on the material chosen, the cannula can be designed as either a disposable or reusable product. For a disposable product, PE (polyethylene) could be used, for example. However, if the cannula is to be reused and thus sterilized, a more durable plastic material would be recommended. PA (polyamide), PEEK (polyetheretherketone), or PSU (polysulfone) would be particularly suitable in this case.

[0059] Overall, the present invention provides a cannula for delivering media that can be implemented in a simple manner and yet avoids the disadvantages known from the prior art. Furthermore, as explained above, there are various possibilities for easily adapting the design of the cannula to the number of media to be delivered.

Claims

1. Dental cannula (100), which forms an attachment piece for a dental syringe for dispensing fluid media, wherein the cannula (100) has: • a rear coupling region (80), which is designed for coupling to a dental handpiece that provides the media, • a front end region (70) with at least one outlet opening (71, 72, 74) for dispensing the fluid media, and • at least two elongate media lines (11, 12) extending from the coupling region (80) to the front end region (70), for guiding the media from the rear coupling region to the outlet opening at the front end region of the cannula, wherein the media lines (11, 12) are formed, at least in some sections, by channels (51, 52) in a plastic body (50) which consists of two one-piece plastic parts (60a, 60b), which are sealingly connected to each other along a connection plane in which the channels (51, 52) run, wherein the two media lines (11, 12, 13) are brought together, in the front end region of the cannula (100), in a mixing chamber (20) and open into a common outlet opening (43), characterized in that, in the region of the mixing chamber (20), a nozzle (25), formed by a separate insert part, is arranged for mixing the media transferred through the two media lines.

2. Dental cannula according to Claim 1, characterized in that the two plastic parts (60a, 60b) are formed by half-shells, preferably by two half-shells that are symmetrical with respect to the connection plane.

3. Dental cannula according to Claim 1 or 2, characterized in that the two plastic parts (60a, 60b) are formed by injection moulding elements.

4. Dental cannula according to any one of the preceding claims, characterized in that the two plastic parts (60a, 60b) are cohesively connected to each other, in particular bonded or welded to each other, in particular connected to each other by laser welding.

5. Dental cannula according to any one of the preceding claims, characterized in that the cannula (100) is angled in a front section.

6. Dental cannula according to any one of the preceding claims, characterized in that three media lines (11, 12, 13) extend along the cannula (100).

7. Dental cannula according to any one of the preceding claims, characterized in that the cannula (100) has a light guide (30), which extends from the coupling region (70) to a front region of the cannula (100) for light emission, wherein the light guide (30) is preferably formed by a separate component which is inserted into a further channel (55) of the plastic part.

8. Dental cannula according to Claim 7, characterized in that a light-emitting end (31) of the light guide (30) is arranged in the region of the at least one outlet opening (71, 72, 74) for dispensing the media.

9. Dental cannula according to Claim 7, characterized in that a light-emitting end (31) of the light guide (30) is arranged on an outer circumferential region of the plastic body (50) and is oriented in such a way that light is directed to a location which is in front of the at least one outlet opening (71, 72, 74).

10. Dental cannula according to any one of the preceding claims, characterized in that the coupling region (80) has a substantially hollow-cylindrical receiving region (85) for receiving a coupling pin of the handpiece that provides the media, wherein ring-like channels (81, 82, 83) are preferably formed on the inner wall of the receiving region (85), which channels are each fluidically connected to a channel (51, 52, 53) forming a media line (11, 12, 13).

11. Dental cannula according to any one of the preceding claims, characterized in that the coupling region (80) is formed by the two interconnected plastic parts (60a, 60b) and is thus a constituent part of the plastic body (50).

12. Dental cannula according to any one of Claims 1 to 10, characterized in that the coupling region (80) is formed by a separate component (95), which is arranged on and connected to a rear face of the plastic body (50) forming the media lines (11, 12, 13).

13. Method for producing a dental cannula (100) which forms an attachment piece for a dental syringe for dispensing fluid media, wherein the cannula (100) has: • a rear coupling region (80), which is designed for coupling to a dental handpiece that provides the media, • a front end region (70) with at least one outlet opening (71, 72, 74) for dispensing the fluid media, and • at least two elongate media lines (11, 12) extending from the coupling region (80) to the front end region (70), for guiding the media from the rear coupling region to the outlet opening at the front end region of the cannula, wherein the method has the following steps: producing two single-piece plastic parts (60a, 60b); connecting the two plastic parts (60a, 60b) along a connection plane to form a plastic body (50), wherein, in the assembled state, channels (51, 52) run in the plastic body (50) along the connection plane and form the media lines (11, 12), wherein the two media lines (11, 12, 13) are brought together, in the front end region of the cannula (100), in a mixing chamber (20) and open into a common outlet opening (43), characterized in that, in the region of the mixing chamber (20), a nozzle (25), formed by a separate insert part, is arranged for mixing the media transferred through the two media lines.

14. Method according to Claim 13, characterized in that the two plastic parts (60a, 60b) are produced by injection moulding.

15. Method according to Claim 13 or 14, characterized in that the two plastic parts (60a, 60b) are cohesively connected to each other, in particular bonded or welded to each other, in particular connected to each other by laser welding.