Foil panel element

Description

[0001] The invention relates to a film tensioning element, according to the preamble of claim 1.

[0002] These types of film tensioning elements have been used successfully for decades under the name OPTRAGATE. They consist of a lip ring and a vestibular ring, between which a film extends. The resulting shape is essentially ring-shaped and allows the patient's lip area to be covered, thus enabling hygienically sound access to the patient's oral cavity.

[0003] To avoid allergic reactions, the film is typically latex-free.

[0004] An example of such a film tensioning element can be found in EP 3 708 112 A1 and EP 3 666 221 A1. The film must be able to adapt to the quite different anatomical requirements. To avoid having to stock a large number of different shapes of film tensioning elements, a highly elastic elastomer is typically used for the film. This is typically injection-molded onto the two aforementioned rings. With this solution, it is possible, for example, to manage with only two sizes of film tensioning element: one size for adults and one size for children. This reduces inventory to the necessary minimum. Elastomers (TPE) show significantly fewer allergic reactions than latex. However, since at least 15% of the population is prone to allergies, allergies to these synthetic plastics also exist.

[0005] Another problem with using TPE for the film is its high coefficient of friction. When the dentist inserts an instrument into the patient's mouth and the instrument shaft comes into contact with the film, the film often sticks to the shaft. This leads to the so-called slip-stick effect. When scanning the vestibular space, this causes the scan to be interrupted or distorted and may need to be repeated.

[0006] Therefore, it has been suggested that the film be coated with a lubricant on the oral side and with an allergy-proof coating on the lip side.

[0007] Such coatings increase the cost of manufacturing the film tensioning element and also make the disposal of this single-use product more problematic, as a total of four different materials (rings, film, inner coating, outer coating) are then used.

[0008] Therefore, the invention is based on the objective of creating a film tensioning element, according to the preamble of claim 1, which is inexpensive to manufacture and easy to handle.

[0009] This problem is solved according to the invention by claim 1.

[0010] Advantageous further training opportunities arise from the sub-requirements.

[0011] According to the invention, the film is to be manufactured from a tough, rigid plastic with a modulus of elasticity between 1 and 2 kilonewtons per square millimeter. Polypropylene or, optionally, polyamide can be used as such a plastic. Neither of these plastics is known to be allergenic. According to the invention, the film consists of only a single material, namely the tough, rigid plastic, and has no coatings.

[0012] According to the invention, it is particularly advantageous that, due to the suitable dimensions of the film tensioning element, only two sizes need to be used despite the use of a tough plastic for the films.

[0013] Investigations carried out in connection with the invention have shown that even when using only one adult size and one child size, no complaints regarding the fit were raised. The uniform application of pressure or deformation of soft tissue is by no means perceived as unpleasant by patients, at least not in comparison to the machining of hard dental tissue required for the placement of dental restorations.

[0014] According to the invention, when using polypropylene and polyamide for the film, no slip-stick effect is observed. Therefore, it is ensured that a scan of the vestibular space can be performed without problems, thus reducing the overall treatment time compared to the prior art, which is convenient for both the dentist and the patient.

[0015] The scan can also be performed at a more precise height. To do this, the dentist deliberately places the shaft of the intraoral scanner against the foil, for example, the foil resting on the patient's lower lip, and guides the scan head along the entire vestibular space at a constant height. According to the invention, this also improves the scan quality.

[0016] According to the invention, the film tensioning element is used as a support for the movement of the scan head.

[0017] According to the invention, the film tensioning element can also be manufactured in a particularly simple and efficient manner: For the production of the film, a mold with a male and a female die is used. The mold is initially open, and a shaped film extends under slight tension between the male and female dies.

[0018] Before, during, and / or after closing the mold, a vacuum is applied to the male die, causing the film to be drawn into it. Alternatively or additionally, a vacuum or positive pressure can also be applied to the female die to improve the film's adhesion to the mold.

[0019] At the points where the rings are to be formed, ring-shaped cavities are provided, each with the shape of a ring. The material for the rings is injected into these cavities via injection molding nozzles and molded onto the film.

[0020] A particularly advantageous aspect is that the same material can surprisingly be used for both the rings and the foil. The difference in material thickness of 0.1 mm to 1 mm is sufficient to ensure the desired strength distribution.

[0021] Both the rings and the film are preferably made of polypropylene. The film has a constant thickness along its length, and the rings have an oval or circular, but in any case rounded, cross-section.

[0022] In a modified embodiment, the rings are designed to taper towards the film. This avoids a sudden change in stiffness, and the film can have a reduced thickness without risk of tearing at that point.

[0023] Instead of polypropylene, a polyamide fabric can also be used for the film and polyamide for the rings, or a fabric made of polyolefin.

[0024] Preferably, a ring-shaped cavity is formed at the base of the male part and another at the head of the male part. The first cavity is used for injecting the lip ring, and the second for injecting the vestibular ring.

[0025] Using a suitable punching tool, the foil is now punched out on the head side of the male die, immediately adjacent to the vestibular ring.

[0026] The punching can also be done while the injection molds are closing, by using a ring-shaped cutting blade to cut away the film adjacent to the cavity for the vestibular ring.

[0027] In any case, this results in a frustoconical foil tensioning element that is particularly well suited for the scanning process in the patient's mouth.

[0028] Further advantages, details and features will become apparent from the following description of an embodiment of the invention with reference to the drawing.

[0029] They show: Fig. 1 shows a schematic section through a mold for manufacturing a film tensioning element according to the invention in one embodiment, in the open state; Fig. 2 shows the representation according to Fig. 1 , however, in a partially closed state of the mold; Fig. 3 the mold according to the Figure 1 and 2 in closed state, ready for injection of the rings; Fig. 4 the mold according to the Figures 1 to 3 in the open state, after removal of the die; and Fig. 5 a film tensioning element produced according to the invention, before and after punching out the end face.

[0030] In Fig. 1 A mold 10 for the production of a film tensioning element 12 according to the invention is shown. Basically, the mold 10 consists of a male die 14 and a female die 16. These can be moved towards each other in a manner known per se to close the mold.

[0031] A film web 18 is wound on a supply roll 20 and is passed as film 22 between the male die 14 and the female die 16.

[0032] The film has a modulus of elasticity of less than 2 kN / mm². It is made of a tough, rigid plastic with a modulus of elasticity greater than 1 kN / mm². It can be made of polypropylene, polyamide, or polyolefin and have a thickness suitable for the film tensioning element. This thickness can be, for example, between 0.08 mm and 0.4 mm.

[0033] When the mold 10 closes, the film 22 extends between the male die 14 and the female die 16 in such a way that they are separated by the film 22. The male die 14 essentially has a truncated cone shape, with a truncated cone 24 and an end face 26. In the illustrated embodiment, the end face 26 is convexly pre-curved.

[0034] Outside the path of the film web 18, the die 16 and the male die 14 are abutting each other. This closes the mold 10. A gap is provided between the male die 14 and the die 16 at the point where the film web 18 runs. The gap is adapted to the thickness of the film web and has, for example, a thickness of 0.1 mm.

[0035] When form 10 is closed, the foil web 18 fills form 10.

[0036] In addition, two annular spaces 28 and 30 are formed in the die 16. When the die 10 is closed, the annular space 28 extends at the base of the truncated cone 24 of the male die 14, i.e., at the male-side end of the die 16.

[0037] The annular space 30 extends, in the closed form 10, at the transition of the truncated cone 24 to the end face 26, thus at the transition of the wall 32 of the matrix 16 to its base surface 34.

[0038] Both annular spaces 28 and 30 have an essentially circular cross-section of about one millimeter and extend along the course of the foil web 18.

[0039] The annular space 28 is intended for the formation of the lip ring of the film tensioning element 12, and the annular space 30 for the formation of the vestibular ring of the tensioning element 12.

[0040] Two injection molding channels, 36 and 38, extend towards the annular space 28. Alternatively, it is also possible to implement only one of the injection molding channels 36 and 38, as the annular space 28 will still be filled with injection molding material. It is also possible to use injection molding channel 36 as such and allow the air displaced by the injection molding process to escape via channel 38.

[0041] In contrast, the annular space 30 is intended for the formation of the vestibular ring of the film tensioning element 12. Channels 40 and 42 extend towards the annular space 30. Here, too, it is possible to use only one of the channels 40 and 42 for injection molding and the other for the escape of the displaced air.

[0042] From the comparison of Figure 1 and 2 It follows that in an intermediate position between the open form 10 according to Fig. 1 and the closed form 10 according to Fig. 3 The film web 18 extends over the male die 14 and into the female die 16. A cavity 50 remains between the male die 14 and the female die 16, in which the film web 18 runs loosely and unguided.

[0043] The male die 14 has suction channels 52, 54, and 56 that terminate at the end face 26, which are connected to a vacuum source 60. When the vacuum is applied, the end face 26 draws in the film web 18, causing it to adhere to it. As the mold 10 closes, the film web 18 therefore lies smoothly and without creases in the gap between the male die 14 and the female die 16. In addition, the film web 18 is held under a certain, but slight, tension. This tension can be adjusted within a wide range to suit the requirements. It can range from 0.1 Newtons to 10 Newtons.

[0044] Out of Fig. 3The closed form 10 is shown. Here, as in the other figures, identical reference numerals correspond to identical or similar parts. The annular spaces 28 and 30 extend along the film web 18. Thus, during injection molding of the annular spaces 18 and 20, the injection molding material is injected directly onto the film 22.

[0045] The injection molding material can be the same material as the film material. The film tensioning element is produced in a single injection molding process together with the tensioning rings.

[0046] After injection molding in the position according to Fig. 3 Once this has occurred, mold 10 is cooled until the injection molding material has solidified. Cooling channels (not shown) may be incorporated into mold 10 to enable cooling within a few seconds.

[0047] This is followed by demolding. This is in Fig. 4The die 16 has already been removed, and the fully formed film tensioning element 16 is exposed. Due to the frustoconical shape of the male die 14, the film tensioning element 12 can be easily removed. This is preferably done mechanically.

[0048] Out of Fig. 5 The foil tensioning element 12 with the vestibular ring 62 and the lip ring 64 is visible above. The foil is still present on its front face 66, but this is no longer needed for application.

[0049] Furthermore, an excess of film 68 remained adjacent to the lip ring 64 from the injection molding process.

[0050] These two excess pieces are punched out and discarded.

[0051] This results in the Fig. 5 The shape of the foil tensioning element 12 according to the invention is shown below.

[0052] The entire manufacturing process of the foil tensioning element according to the invention can easily be carried out mechanically and automatically.

Claims

1. A film tensioning element (12) for dental applications, having a film (22) which extends between tensioning rings (62, 64), the film having a modulus of elasticity of less than 2 KN / mm2, characterized in that the film (22) consists of a plastic, in particular a tough plastic, having a modulus of elasticity of more than 1 KN / mm2, and the film tensioning element (12) is produced together with the tensioning rings (62, 64).

2. The film tensioning element (12) according to claim 1, characterized in that the tensioning rings (62, 64) consist of the same tough plastic as the film (22) and are in particular integral with the latter.

3. The film tensioning element (12) according to one of the preceding claims, characterized in that it is produced by the mold labelling or mold coating method.

4. The film tensioning element (12) according to one of the preceding claims, characterized in that the film tensioning element (12) is free of a coating and / or is hydrophobic.