Lip retractor and system comprising an intraoral scanner and a lip retractor

Abstract

The invention relates to a lip-buccal retractor, which is particularly suitable for use with an intraoral scanner, having a membrane made of an elastomer, a lip ring and a vestibular ring, the membrane extending between the lip ring and the vestibular ring, being held open by the lip ring and the vestibular ring and forming a hose-like section between the lip ring and the vestibular ring. It is provided here that the membrane (20) is prefabricated with a sliding element (36) on the inner side (32) of its hose-like section, which is fixedly connected to the membrane (20), in particular changes the surface of the membrane (20) here, is produced by surface treatment, has a sliding friction coefficient μ of less than 1.5, preferably less than 1 G .

Description

Technical Field

[0001] This invention relates to a lip and cheek retractor and a system comprising an intraoral scanner and a lip and cheek retractor. Background Technology

[0002] The lip and cheek retractor has long been known and marketed under the trademark "Optragate" by Ivoclar Vivadent AG.

[0003] This lip-cheek retractor has a lip ring and a vestibular ring. The lip ring fits the lips and extends around the patient's mouth, while the vestibular ring extends substantially circumferentially in the patient's vestibule. The lip ring and vestibular ring are interconnected by an elastic membrane.

[0004] The patient's lips are thus covered and supported. The dentist can perform necessary procedures in the patient's mouth without the risk of cross-infection due to contact with the mucous membranes.

[0005] During the procedure, the dentist typically introduces instruments into the mouth. Most of these instruments come into contact with the membrane of the labial / buccal retractor, both during insertion and sometimes during removal. These instruments usually have a metal handle and slide along the membrane with that handle.

[0006] The suction tube of the saliva aspirator is suspended over the lips and thus over the membrane of the lip and cheek retractor, and remains in constant contact with them.

[0007] Sometimes, patients may attempt to swallow during the procedure and unconsciously close their mouths at this time. This causes the handle of the instrument to adhere to the lower and upper lip, specifically to the thin films on the upper and lower lip, respectively. Of course, even under this pressure, the films should maintain their function and, in particular, should not adhere to the handle of the instrument.

[0008] Therefore, it is known from DE 10 2005 015 406 B4 that a thin film with particularly good slipability is used. However, in experiments using such a thin film, a so-called "stick-slip effect" occurs, which distorts the scanning results.

[0009] Using a membrane with exceptionally good gliding properties is a compromise. On the one hand, this membrane should be as thin as possible to conform smoothly to the patient's mouth. On the other hand, this membrane should be tear-resistant.

[0010] The material chosen for this type of membrane is typically an elastomer. This elastomer is highly elastic but has rubbery properties. When an intraoral scanner, which usually has a plastic handle, is inserted into a patient's mouth, a so-called stick-slip effect can easily occur. This effect causes the scanner to briefly adhere to the membrane and only detach from it again as the scanner's movement continues.

[0011] To obtain a 3D image of a patient's dental arch, it is essential to guide the scanner around the arch at a constant speed. If the scanner adheres to the diaphragm, this movement is interrupted, and the scanning process may become intermittent. The dentist's attention is also diverted from actually examining the 3D image. To get the scanner back into motion, the guiding force must be increased. This often results in a jittery motion.

[0012] This problem is exacerbated when the patient tries to close their mouth due to the foreign body effect, because the pressure between the handle and the membrane increases at this time.

[0013] Dentists can handle this by applying lubricant to the membrane and / or handle. However, this approach negates the advantages of using a labial retractor, which offers an easy-to-use and simple accessory without the need for additional preparation. Summary of the Invention

[0014] In contrast, the object of the present invention is to provide a lip-cheek retractor and a system including an intraoral scanner and a lip-cheek retractor, wherein the lip-cheek retractor is better suited to achieve an uninterrupted working process in dental practice.

[0015] Thus, according to the present invention, the film of the lip and cheek retractor is provided with sliding elements at least at the relevant locations, i.e., at the locations where it may come into contact with the handle, by processing the relevant surfaces of the film.

[0016] Therefore, the film does not become thicker, or at least not significantly thicker, thus maintaining its flexibility. The sliding element can be a coating produced by atomic deposition or a surface-modified structure. This sliding element has a sliding friction coefficient significantly lower than that of common rubber-like elastomers. This sliding friction coefficient can be, for example, 1.5 or 1.0.

[0017] Compared to the rest of the film body, the sliding element is significantly stiffer and correspondingly more brittle. Surprisingly, testing has confirmed that, in practice, the lip-cheek retractor's film still exhibits at least the same level of tear resistance reliability. This is likely due to the reliable avoidance of stick-slip effects and thus a significant reduction in the forces acting on the film during operation.

[0018] This is particularly applicable to the cheek area of ​​the lip-cheek retractor. The handle of the lip-cheek retractor typically adheres to the membrane on three sides, and therefore the adhesion pressure is greatest here. However, according to the invention, uniform sliding motion is still ensured here.

[0019] The sliding element can also be produced by a combination of atomic deposition and surface modification, or by atomic deposition alone. For surface coatings using silica, surface modification can also be achieved simultaneously.

[0020] According to the present invention, there are no loose materials, as in lubricant coatings. A sterile working environment is always ensured.

[0021] The invention provides an exceptionally low coefficient of sliding friction compared to all handle materials used in practice. Dental endoscopes, as dental instruments, typically have metal handles. Intraoral scanners typically have replaceable scanning heads. These heads may be made of, for example, polyurethane or, more preferably, autoclaved polysulfone. According to the invention, the coefficient of sliding friction is less than 2 compared to these materials.

[0022] In an advantageous design, the sliding element according to the invention extends only on the inner side of the buccal retractor, which is essentially a tube in its initial state. The inner side may have the sliding element entirely provided, or only in the middle region of the inner side, i.e., the region spaced apart from the two rings and abutting against the lip junction leading to the oral cavity. The advantage of this solution is that no adhesion occurs between the sliding element and the patient's mucosa, even in the vestibule, because the membrane does not have a sliding element adjacent to the vestibular rings. Alternatively, the sliding element may be omitted only adjacent to the vestibular rings, i.e., for example, only for 20% or 30% of the length of the buccal retractor adjacent to the vestibular rings. Attached Figure Description

[0023] Other advantages, details and features will become apparent from the following description of several embodiments of the invention with reference to the accompanying drawings.

[0024] in:

[0025] Figure 1 A schematic diagram of a system including an intraoral scanner and a lip-cheek retractor according to a first embodiment of the invention is shown.

[0026] Figure 2 Showing according to Figure 1 An enlarged view of the implementation method;

[0027] Figure 3 Show Figure 2 This is a partial enlarged view of a detail, but it illustrates another embodiment of the invention.

[0028] Figure 4 Showing according to Figure 3 The illustration shows a third embodiment of the invention according to the invention; and

[0029] Figure 5 Showing according to Figure 3 The illustration shows a fourth embodiment of the invention according to the invention. Detailed Implementation

[0030] exist Figure 1 The diagram shows an intraoral scanner 10 and a labial / buccal retractor 12. The intraoral scanner 10 has an operating handle 14 and a shank 16. The shank 16 can be removed along with the scanning head 18 and can be releasably secured to the operating handle 14. The diameter of the shank 16 is 20 mm in the illustrated embodiment. The intraoral scanner 10 is guided along the dental arch for scanning. The intraoral scanner is inserted into the vestibule 26. For this, the upper lip 30 must be pressed in, and for the relevant scan, the lower lip 28 must also be pressed in so that the scanning head 18 reaches the height of the relevant dental arch. This causes a corresponding compressive force.

[0031] The lip-cheek retractor 12 according to the invention includes a membrane 20, a lip ring 22, and a vestibular ring 24. The membrane 20 extends between the lip ring 22 and the vestibular ring 24. Thus, the membrane 20 forms a tubular segment between the lip ring and the vestibular ring. The vestibular ring 24 has a diameter slightly smaller than that of the lip ring 22 and is designed for insertion into the vestibule 26 of a patient. In the open state, the lip-cheek retractor 12 has a necked portion between the lip ring 22 and the vestibular ring 24.

[0032] The film 20 covers the patient's lower lip 28 and upper lip 30 in a manner known per se, and the film prevents direct contact between the lips 28 and 30 and the handle 16, and prevents contact even when the patient closes their lips around the handle 16.

[0033] The film 20 has an inner side 32 and an outer side 34. The inner side 32 is the side facing the handle 16, while the outer side 34 is the side facing the lips 28 and 30.

[0034] According to the present invention, a sliding element 36 is provided on the inner side 32 of the thin film 20. The sliding element 36 is generated by surface treatment of the thin film 20, specifically surface treatment of the inner side 32 of the thin film, and the sliding element has a low coefficient of sliding friction of 1.

[0035] The sliding element 36 extends only within the region of the necked portion, i.e., spaced apart from the lip ring and vestibular ring, on the inner side 32 of the tubular section of the membrane 20.

[0036] The thin film 20 has a thickness of 0.2 mm in the illustrated embodiment. The sliding element 36 has a thickness in the atomic range or slightly above the atomic range. The sliding element 36 is manufactured such that it is firmly anchored to the thin film. According to... Figure 1 and 2 In the illustrated embodiment, the sliding element is composed of silicon dioxide particles that are at least partially embedded in the surface of the film 20. This particular type of surface coating ensures that the elements of the sliding element 36 do not detach from the film 20, even under high shear loads.

[0037] Depend on Figure 2 It can be seen that the sliding element 36 and the handle 16 are in accordance with Figure 1 A slightly enlarged view of the mating area at the circled location. The film 20 with the sliding element 36 is flattened by mating it to the handle 16, and the lip 30 is deformed accordingly. Figure 2 The thickness of the sliding element 36 is exaggerated in the figure, which is necessary to show the sliding element 36. Even in the presence of common compressive forces of 1 to 10 Newtons, relative movement between the intraoral scanner 10 and the lips 30 can be achieved with very little force according to the present invention.

[0038] The sliding element 36 according to the invention ensures that no stick-slip effect occurs; instead, uniform sliding is achieved between the handle 16 and the lip / cheek retractor 12 during movement in the direction 40. The difference between static friction and sliding friction is correspondingly smaller.

[0039] exist Figure 3 The middle corresponds to in Figure 2 The circles shown indicate enlarged views of specific areas. According to... Figure 3 In one embodiment, another sliding element 36 according to the invention is used. The thin film 20, according to... Figure 3 In this embodiment, a p-xylene coating is used. This also involves atomic deposition. The surface of the p-xylene coating is uniform and smooth, and provides a low coefficient of sliding friction relative to the handle 16 made of polysulfone.

[0040] The coefficient of sliding friction fluctuates to a certain extent, averaging between 0.9 and 1.2.

[0041] Depend on Figure 4 A further modified embodiment of the lip and cheek retractor 12 according to the invention can be seen. In this embodiment, microstructures are formed on or within the elastomer of the film 20. The microstructures consist of peaks 42 and valleys 44, which alternate with each other. The peaks 42 protrude toward the stem 16 and the valleys 44 retract away from the stem.

[0042] Only the peaks form contact areas 46. The contact areas 46 of the sliding element 36 remain unchanged or substantially unchanged as the film 20 stretches, that is, more than 80% remain unchanged, and this stretching increases the spacing between the contact areas 46.

[0043] The peaks 42 are uniformly distributed on the surface of the sliding element 36. The size of the peaks 42, that is, the thickness of the microstructure 48, can be selected in any suitable manner, for example, in the range from the atomic level to a few micrometers. The microstructure 48 can be machined as a negative form into the surface of the injection mold, and then the microstructure 48 of the sliding element 36 is automatically formed by injection molding.

[0044] Depend on Figure 5 A further modification of the lip and cheek retractor 12 according to the invention can be seen. In this embodiment, the microstructure 48 is constructed in the form of a pyramid. This pyramid has sharp peaks 42 and valleys 44, which converge sharply. However, the configuration of the valleys is not important in terms of the static friction coefficient.

[0045] This design scheme is based on... Figure 4 Compared to the design scheme with convex spherical peak 42, a lower coefficient of friction is obtained.

[0046] Static and sliding friction tests were conducted with polysulfone as the friction counterpart. Polysulfone was chosen because the shank 16 of the intraoral scanner 10 is typically made of polysulfone. The extrusion pressure varied between 1 and 5 N. In the sliding friction measurement, the movement speed was approximately 6 mm / s.

[0047] Furthermore, the microstructure size was varied between grid sizes of 50 µm to 200 µm and between pyramid heights of 24 µm to 87 µm.

[0048] Depending on the specific extrusion pressure, the coefficient of friction is reduced by 22% to 25% compared to the elastomer strip, or by 37% in another test setup, and this was measured at the maximum microstructure size tested.

[0049] A significantly larger range of fluctuations was observed in comparative measurements with the siloxane coating of alternative microstructure 48. In this case, the reduction in the coefficient of friction fluctuated between 21% and 49%, depending on the specific extrusion pressure.

[0050] Importantly, the difference between the static friction coefficient and the sliding friction coefficient is smaller in the various designs according to the invention than in the case of uncoated and untreated elastomer films.

[0051] This effect is sufficient to prevent stick-slip effects. The embodiments of the invention have a particular advantage: a small difference exists between the static friction coefficient and the sliding friction coefficient, respectively.

[0052] Measurements have confirmed that uncoated and untreated elastomer films, such as standard Optragate, have a static coefficient of friction of about 3.5 to 4 and a sliding coefficient of friction of about 2.5.

Claims

1. A lip-cheek retractor, the lip-cheek retractor having a thin film made of an elastomer, a lip ring, and a vestibular ring, the thin film extending between the lip ring and the vestibular ring, held open by the lip ring and the vestibular ring, and forming a flexible tube-like segment between the lip ring and the vestibular ring, characterized in that, The film (20) has a sliding element (36) prefabricated on the inner side (32) of its tubular section, which is produced by surface treatment and fixedly connected to the film (20). The sliding element has a sliding friction coefficient µ of less than 1.

5. G .

2. The lip and cheek retractor according to claim 1, characterized in that, The sliding element (36) changes the surface of the film (20) on the inner side (32).

3. The lip and cheek retractor according to claim 1, characterized in that, The sliding element has a sliding friction coefficient µ of less than 1. G .

4. The lip and cheek retractor according to claim 1, characterized in that, The sliding friction coefficient µ of the sliding element (36) G The numerical descriptions pertain to the following material pairs: film / shape-stabilized plastic or film / metal.

5. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) has a SiO2 coating that is fixedly connected to the thin film (20) in order to provide the sliding friction coefficient.

6. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) is produced by a combination of atomic deposition and surface modification or surface structuring.

7. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) has a coating made of p-xylene that is fixedly connected to the film (20) in order to provide the sliding friction coefficient.

8. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) has a microstructure (48) produced by injection molding in order to provide the sliding friction coefficient, the microstructure having peaks (42) and valleys (44).

9. The lip and cheek retractor according to claim 8, characterized in that, The peak (42) of the microstructure (48) is harder than the elastomer of the film (20).

10. The lip and cheek retractor according to claim 9, characterized in that, The peak (42) of the microstructure (48) occupies less than 30% of the area of ​​the sliding element (36).

11. The lip and cheek retractor according to claim 8, characterized in that, The sliding element (36) has contact areas (46) having dimensions ranging from atomic level to several µm and being uniformly distributed on the sliding element (36).

12. The lip and cheek retractor according to claim 11, characterized in that, The peaks (42), protruding regions, or convex regions of the microstructure (48) form the contact region (46).

13. The lip and cheek retractor according to claim 11 or 12, characterized in that, The contact area (46) of the sliding element remains unchanged or substantially unchanged, i.e., more than 80%, when the film (20) stretches, and this stretching increases the spacing between the contact areas (46).

14. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) extends over the entire inner side (32) of the tubular section of the film (20).

15. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The film (20) has a necked portion between the lip ring and the vestibular ring in the open state, and the sliding element extends only in the area of ​​the necked portion, i.e., on the inside of the tubular section of the film, spaced apart from the lip ring and the vestibular ring.

16. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) has a thickness between 2µm and 200µm.

17. The lip and cheek retractor according to claim 16, characterized in that, The sliding element (36) has a thickness between 5µm and 150µm.

18. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) is applied to the film (20) and fixedly connected to the film.

19. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) has less elasticity than the elastomer of the film (20) and is harder than the elastomer of the film.

20. The lip and cheek retractor according to any one of claims 1 to 4, characterized in that, The sliding element (36) is configured to be hydrophobic.

21. A system comprising an intraoral scanner and a buccal retractor, the intraoral scanner having a housing made of plastic and / or metal and the buccal retractor having a membrane, a lip ring, and a vestibular ring made of an elastomer, the membrane extending between the lip ring and the vestibular ring, held open by the lip ring and the vestibular ring, and forming a tubular segment between the lip ring and the vestibular ring, characterized in that, The film (20) is prefabricated with a sliding element (36) formed by surface treatment on the inner side (32) of its tubular section, which is fixedly connected to the film (20). The sliding element has a sliding friction coefficient of less than 1.5 µ relative to the handle (16) of the intraoral scanner (10). G .

22. The system according to claim 21, characterized in that, The sliding element (36) changes the surface of the film (20) on the inner side (32).

23. The system according to claim 21 or 22, characterized in that, The sliding element has a sliding friction coefficient of less than 1 µ relative to the handle (16) of the intraoral scanner (10). G .

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