Device for trimming dental splints

Abstract

A device for trimming dental splints (1) is described, comprising a spatially displaceable holder (2) for the dental splint (1), a suction device (3), a laser (4) and a computing unit (5). In order to configure the device mentioned at the beginning in such a way that, despite the use of conventional components, precise trimming of the dental splint is possible with minimal control effort and preparation for the user, it is proposed that the laser (4) is in a fixed position, a camera (6) is provided for determining the position of the dental splint (1) and the holder (2) has an at least partially thermostable platform (7) and a stopper (8) for receiving the dental splint (1) released from the deep-drawing mold in a force-connected manner and without play.

Description

[Technical field]

[0001] The invention relates to a device for trimming dental splints, comprising a spatially displaceable holder for a dental splint, a suction device, a laser and a computing unit. [Background technology]

[0002] Dental splints are known from the prior art, which are produced from a deep-drawing sheet by means of a deep-drawing process, where the dental splint has to be trimmed after the deep-drawing sheet has been drawn over a model of the dentition, whereby the exposed free deep-drawing edges, i.e. the parts of the deep-drawing sheet that are not shaped by the model and do not form part of the dental splint, are separated from the dental splint and deburred at the resulting cut lines.

[0003] EP 2101674 discloses a device in which a dental splint is supported on three posts located on a spatially movable platform, where the dental splint is fixed to the posts using negative pressure, so that the dental splint can be subsequently trimmed with a laser, whereby a computing unit calculates the required cut line of the laser based on a CAD model of the dental splint and controls the platform and the movable laser so that the laser follows the cut line.

[0004] However, according to the disadvantages of the prior art, in order to trim the dental splint, a corresponding CAD model must always be created and loaded into the computing unit. In addition, both the laser variables, such as the intensity or spatial direction of the beam, and the position of the dental splint must be precisely known and precisely adjusted to each other. In addition, the problem arises that the part of the deep-drawn edge that has already been cut off by the cutting process suddenly sags, which can cause the dental splint to slip off. This results in cutting errors, since the actual position of the dental splint differs from the target position determined in the CAD model.

[0005] It has already been proposed to accommodate the dental splint on a platform, so that it rests over a large area with a free deep-drawn edge and is supported by the dentition model (EP 2 760 624), but this still requires a complex dynamic control of the laser intensity, since the intensity must be constantly adjusted to the local thickness of the deep-drawn sheet and thus the dentition model will not be welded to the deep-drawn sheet due to an incorrectly set laser intensity or the device will be damaged by the laser. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 2101674 [Patent Document 2] European Patent No. 2760624 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem underlying the present invention is therefore to provide a device which, despite the use of conventional parts, allows precise trimming of dental splints with minimal control effort and preparation for the user. [Means for solving the problem]

[0008] The invention solves the set problem in that the laser is in a fixed position, a camera is provided for determining the position of the dental splint, and the holder has an at least partially heat-stable platform and a stop for receiving the dental splint released from the deep-drawing mold in a force-locked manner and without play. The dental splint separated from the dentition model is received on the platform before trimming, so that the free deep-drawn edge rests approximately flat on the platform. The stop fixes the dental splint in a force-locked manner and without play over its free deep-drawn edge, so that a relative movement between the dental splint and the platform is prevented despite the displacement of the holder. The camera captures the position and shape of the dental splint received on the platform and the boundary area in the space between the dental splint and the free deep-drawn edge. From such spatial data, a computing unit determines a cut line for separating the dental splint from the free deep-drawn edge and accordingly determines how the holder must be displaced in order for the laser beam to follow the cut line. In this case, the determination of the cut line can be repeated again, including a new acquisition of position data by the camera at all times during trimming, so that an adapted cut line can be determined. Additionally, the use of a camera eliminates the position marking on the dental splint, which is required in the prior art. Since the laser is in a fixed position, it is only necessary to displace the holder to allow the laser to follow the cut line. This reduces positional inaccuracies and makes control easier. The laser intensity can be kept uncontrolled during trimming, since the excess energy of the laser is absorbed by the thermally stable platform. The laser intensity and the material of the platform can be adjusted to each other in the factory, so that the laser intensity is sufficient to trim a normal dental splint, but is too low to damage the platform. Since the required cut line of the dental splint essentially always extends only over the same part of the platform, the platform only needs to be configured to be thermally stable in this partial area.The dental splint is trimmed without a model of the dentition, so that the laser intensity does not have to be adapted to protect the model. In this case, it has unexpectedly turned out that even if the free deep-drawn edge is completely separated from the dental splint, the dental splint is still stably accommodated by a frictional connection to the separated free deep-drawn edge. In a preferred embodiment, the platform is not only thermally stable but also thermally conductive, so that excess laser energy can be conducted away from the dental splint and no heat reservoirs are formed in the platform that heat up the dental splint. To this end, the platform can be made, for example, of anodized aluminum. To determine the position of the dental splint and the required cutting lines from the camera data, the computing unit can implement a self-learning algorithm or a neural network. The computing unit can be trained in particular to only acquire the spatial orientation of the dental splint, the free deep-drawn edge and the boundary area between them, and not to process other detailed image information. To determine the position, the holder together with the dental splint can be displaced to an acquisition position where the camera records an image of the dental splint. The acquisition position is selected such that, with respect to the relative position of the holder with respect to the camera, the camera used can record a high-quality image of the dental splint and the surrounding deep-drawn edge, as far as possible without autofocus or other technical aids, so that the image can be easily processed by the computing unit. The dental splint may thus be oriented, for example, approximately transversely to the optical axis of the camera at the acquisition position. The processing steps of the image by the computing unit may include fragmentation, normalization and segmentation, so that the computing unit can determine the course of the required cut line from the processed image. After the image has been normalized at the acquisition position, the surrounding deep-drawn edge is recognized by the computing unit via its pixel values ​​and is differentiated from the dental splint, so that the required cut line can be determined. Optionally, the computing unit may compare the acquired and processed image with a computer model of the dental splint. A reference point may be determined at the detection position, based on which the relative position of the dental splint can still be recognized even after a displacement of the holder.

[0009] If the camera is located in the area of ​​the laser, the computational effort for determining the required cut line is reduced and the control of the holder is facilitated. The closer the camera is located to the laser, the closer the optical path of the laser and the optical path of the camera are, so that the computing unit does not have to carry out complex conversion steps to convert the camera data into instructions for displacing the holder. When the computing unit uses a neural network, this also facilitates the training of the computing unit itself, since the training images also do not require complex conversion steps, which reduces the training time. In a preferred embodiment, the camera is an RGB camera, since the image quality of such a camera is high enough to generate reliable image data for further processing in the computing unit, despite its low cost.

[0010] If the platform has at least one through-hole, which is in fluid communication with the inlet of a suction device mounted on the platform on the side opposite the laser, the dental splint can be fixed even more firmly on the platform without further measures. Based on these measures, the suction device not only sucks particles and / or vapors occurring during trimming, but also applies negative pressure to the dental splint via the at least one through-hole. The negative pressure promotes the attachment of the dental splint on the platform. Since the required cut line of the dental splint essentially always extends only over the same partial area of ​​the platform, in a preferred embodiment, a number of through-holes are arranged in this partial area, so that particles and / or vapors are sucked in where they occur and the dental splint is additionally fixed by the negative pressure at its cut edge. Since the laser beam can also pass through the through-hole of the platform and impinge on the part of the holder located below it, thermally unstable parts of the holder must be arranged outside the beam path and / or parts reachable by the laser beam must also be designed to be thermally stable. The platform may take up various relative positions to the laser based on its displaceability, but in the context of the invention, the side of the platform facing away from the laser when processing the dental splint is intended. In addition to high local precision during trimming, it is also proposed that the platform is at least partially displaceable in five spatial directions in order to simplify the deburring of the dental splint. Thus, in addition to the three translational movements, the holder and thus the dental splint can also rotate about two axes, which allows the cutting angle of the laser to be changed. This allows the cutting edge of the dental splint to be post-processed or removed, and thus allows for better deburring of the dental splint.

[0011] During deep drawing, the free deep-drawn edge of the dental splint may be deformed, which may make it difficult to fix the dental splint on the platform. The dental splint would then not be able to be accommodated on the platform in a force-connected manner in all directions, since the dental splint would transmit the deformation of the free deep-drawn edge to the dental splint during the establishment of the force connection, which would result in the formation of an incorrect cut line. In order to allow an accurate determination of the cut line despite such deformations, the stopper may be annular and, together with the platform, form a receiving section for the free deep-drawn edge of the dental splint. As a result of this measure, a force connection is formed along the entire free deep-drawn edge, which is optionally supplemented by a form connection. That is to say, the dental splint can be accommodated on the platform regardless of the orientation of the dental splint over the free deep-drawn sheet, if the free deep-drawn sheet rests flat on the platform. This allows the wavy deformations that often occur on the free deep-drawn edge to be pressed flat. In one preferred form, the stopper is connected to the holder via a hinge so that it can be pivoted downward and locked prior to trimming.

[0012] If the holder has a cross slide, the holder can be easily and precisely displaced. Due to its simple operating principle, the cross slide can be easily operated via an adjustment spindle and does not require calibration. Furthermore, the holder can also be rotated via one or more guides of the cross slide guide.

[0013] To produce a compact configuration, the holder has a rotating platform to which an at least partially thermostable platform is assigned, so that the dental splint can be displaced together with the platform in a simple and space-saving manner without restricting access to the laser. A particularly favorable configuration is obtained if the rotating platform is arranged on the cross slide.

[0014] The drawings illustrate the subject matter of the invention. [Brief description of the drawings]

[0015] [Figure 1] 1 shows a front view of the device according to the invention; [Diagram 2] FIG. 2 shows a cross-sectional view taken along line II-II in FIG. [Diagram 3] 3 shows a plan view of a holder of a device according to the invention on a further enlarged scale. [Figure 4] 4 shows a cross-sectional view taken along line IV-IV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The device according to the invention for trimming a dental splint 1 (shown only diagrammatically) comprises a displaceable holder 2 for the dental splint 1 and a suction device 3 mounted on the holder 2 for aspirating particles and vapors resulting from the trimming process. The device further comprises a laser 4, a computing unit 5, which in the illustrated embodiment is mounted on the housing of the laser 4, and a camera 6. The holder 2 has an at least partially thermostable platform 7 on which the dental splint 1 can be accommodated. Since the dental splint 1 is accommodated on the platform 7 for trimming without a deep-draw model associated with it, the thermostable platform 7 must be able to absorb the excess energy of the laser beam of the laser 4 without damage and to guide it in a suitable way. The laser 4 is arranged in a fixed position, and therefore the platform 2 must be arranged displaceable in several spatial directions, in a preferred embodiment in five spatial directions, in order to be able to carry out the trimming process with the laser 4. Therefore, in order to ensure a secure accommodation of the dental splint 1 on the platform 7 of the holder 2 in all positions, the holder 2 has a stop 8 for the dental splint 1, by means of which the dental splint 1 can be accommodated in a force-connection manner. In order to be able to carry out precision machining with the laser 4 in all positions, the accommodation of the dental splint 1 must be carried out without play.

[0017] The camera 6 transmits the required image data. On the basis of the image data, the calculation unit 5 determines the cut line required for trimming the dental splint 1 and displaces the holder 2 so that the laser beam can follow this required cut line. The camera 6 is then arranged in the area of ​​the laser 4, so that the optical axes of the camera 6 and the laser 4 are located in the same area, so that the positional changes of the holder 2 required for trimming can be more easily determined by the calculation unit 5.

[0018] As can be seen in particular from FIG. 3, the platform 7 has one or more through holes 9, and the suction device 3 can be connected to the holder 2 via an inlet 10 on the side of the platform 7 facing away from the dental splint 1. This allows a fluid communication between the inlet 10 and the at least one through hole 9 to be established, which allows the vapors to be sucked out, which are generated around the dental splint 1 directly during the trimming process with the laser 4, to be sucked out on the side of the platform 7 facing away from the dental splint 1. This increases the freedom of movement of the holder 2 and allows the distance between the inlet 10 and the dental splint 1 to be reduced. Moreover, this facilitates the generation of a negative pressure by the suction device 3, which facilitates the accommodation of the dental splint 1 on the platform 7.

[0019] If the stop 8 of the platform 7 is of an annular design, the dental splint 1 can be accommodated on the circumferential side over its free deep-drawn edge 11 on the platform 7, so that a play-free, force-connected accommodation of the dental splint 1 can be achieved, independent of changes in the position of the holder 2. In this case, the platform 7 together with the stop 8 forms a accommodation 12 for the free deep-drawn edge 11 of the dental splint 1.

[0020] If the holder 2 has a cross slide 13 and a rotating table 14 to which an at least partially thermostable platform 7 is assigned, the holder 2 can be displaced in an easily controllable, space-saving and cost-effective manner.

[0021] Five degrees of freedom of movement are represented in the coordinate system depicted in Fig. 2. In addition to the three translational degrees of freedom, the platform 7 can at least partially rotate. This can be realized, for example, via a rotating platform 14. A further rotational degree of freedom can be realized, for example, in that the slide of the cross slide 13 serves as an axial support by which the longitudinal axis of the platform 7 is guided, so that the platform 7 is supported so as to be axially slidable and rotatable about its axis.

Claims

1. A device for trimming a dental splint (1), comprising a spatially displaceable holder (2) for the dental splint (1), a suction device (3), a laser (4) and a computing unit (5), 1. The device according to claim 1, wherein the laser (4) is in a fixed position and a camera (6) is provided for determining the position of the dental splint (1), and the holder (2) has an at least partially heat-stable platform (7) and a stopper (8) for receiving the dental splint (1) released from the deep-drawing mold in a force-connected manner and without play.

2. 2. The device according to claim 1, characterized in that the camera (6) is arranged in the area of ​​the laser (4) such that the dental splint (1) is oriented transversely to the optical axis of the camera (6) at the detection position.

3. 3. The device according to claim 1 or 2, characterized in that the platform (7) has at least one through hole (9) which is in fluid communication with an inlet (10) of the suction device (3) mounted on the side of the platform (7) opposite the laser (4).

4. 3. Apparatus according to claim 1 or 2, characterized in that the platform (7) is at least partially displaceable in five spatial directions.

5. 3. The device according to claim 1 or 2, characterized in that the stopper (8) is annular and forms together with the platform (7) a receiving part (12) for a free deep-drawn edge (11) of the dental splint (1).

6. 3. Apparatus according to claim 1 or 2, characterized in that the holder (2) comprises a cross slide (13).

7. 3. Apparatus according to claim 1 or 2, characterized in that the holder (2) has a rotating table (14) to which the at least partially thermostable platform (7) is assigned.

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