EP-4509091-B1 - METHOD OF PRODUCING A DENTAL ALIGNER AND PRODUCTION LINE THERETO

Inventors

• Kandil, Sherif

Dates

Publication Date

20260506

Application Date

20230817

Claims (6)

1. Method of producing a dental aligner for a treatment plan with at least an actual position and a target position of a tooth to be re-positioned, comprising the steps of - producing a set of dental models comprising at least - a first dental model based on the actual position and - a second dental model based on the target position; - carrying out a first thermoforming step of shaping an aligner material onto the second dental model to produce an aligner; - removing the aligner from the second dental model; - placing the aligner on the first dental model; - carrying out a second thermoforming step of re-shaping the aligner onto the first dental model, - wherein a second thermoforming temperature of the second thermoforming step is lower than a first thermoforming temperature of the first thermoforming step, wherein each dental model of a dental model set receives a unique model identifier to identify the at least first and second dental models of a set of dental models, wherein the aligner is marked with a unique aligner identifier related to the unique model identifier of the related set of dental models, and wherein the unique aligner identifier for said aligner is set to relate regressively to the previous dental model.
2. Method of producing a dental aligner according to claim 1, wherein the unique model identifier for a dental model includes one or a combination from the group of form and/or shape, number, colour, colour shade, code, chip, imprint.
3. Method of producing a dental aligner according to claim 1 or 2, wherein multiple dental models of one or of a plurality of sets of dental models for the same treatment plan or different treatment plans are produced randomly and/or batchwise, wherein - the unique model identifiers include information about a related set of models - the dental aligners to be thermoformed onto the dental models are provided with unique aligner identifiers, and - the dental models and the dental aligners related thereto are being matched by using the unique model identifier and the matching unique aligner identifier.
4. Method of producing a dental aligner according to one of the claims 1 to 3, wherein the unique model identifier is detected to identify the second dental model to be used for the first thermoforming step and to apply the unique aligner identifier relating to the first dental model onto the aligner.
5. Production line for producing a dental aligner, preferably according to the method of one of the preceding claims, with - a production unit (2) to produce a set of dental models with at least a first and a second dental model, - a first thermoforming unit (3) to thermoform aligner material on the second dental model to produce an aligner and - a second thermoforming unit (4) to thermoform the aligner on the first dental model to modify the shape of the aligner, wherein attaching means to attach the unique model identifiers include one or a combination from the group comprising a 3D-Printer, a laser-device, a chip insertion device, a punching device, an embossing device, a colouring device and a printing device.
6. Production line according to claim 5, characterized by identifier means to attach and/or identifying means (14) to identify unique model identifiers of the dental models.

Description

The invention refers to a method of producing a dental aligner for a treatment plan with at least an actual position and a target position of a tooth to be re-positioned and a production line to produce such a dental aligner. In order to re-position a tooth, the actual position of the tooth and the target position are determined and a treatment plan is developed devising how to achieve the re-positioning of said tooth. The dental aligner is the tool to carry out the re-positioning. Usually, a set of dental aligners is used to consecutively change the position of the tooth to be re-positioned in a step-by-step approach. Dental aligners well-suited to carry out such a treatment plan are described e. g. in WO 2016/193 424 A1 as being made from a dynamic synthetic material. Said dynamic synthetic material can be shaped into a dental aligner having a first shape, then pressure and or increased or reduced temperature can be applied to change the dental aligner into a second shape. From said second shape, the dental aligner will return into the previous, first shape once a stimulus, e.g. temperature or humidity, are applied thereto. Manufacture of said dental aligners or sets of dental aligners as described e.g. in US 2018/250 009 A1 is not yet optimized. It is therefore an object of the present invention to propose an improvement of the manufacturing method and equipment for a dental aligner or sets of dental aligners. This object is obtained by a method according to claim 1 and a production line according to claim 5. The method according to the invention of producing a dental aligner for a treatment plan with at least an actual position and a target position of a tooth to be re-positioned, comprises the steps of producing a set of dental models comprising at least a first dental model based on the actual position anda second dental model based on the target position;carrying out a first thermoforming step of shaping an aligner material onto the second dental model to produce an aligner;removing the aligner from the second dental model;placing the aligner on the first dental model;carrying out a second thermoforming step of re-shaping the aligner onto the first dental model,wherein a second thermoforming temperature of the second thermoforming step is lower than a first thermoforming temperature of the first thermoforming step. The method according to the invention relies on a set of dental models. Said models represent the actual position of the tooth to be re-positioned in a first dental model and the target position in a second dental model. The set may comprise further dental models representing intermediate positions. The dental models are manufactured either based upon a cast made from a tooth or they are made based upon digital data. The latter is preferred when making dental models for the target position or intermediate positions. The dental models are made from e. g. gypsum or a synthetic material. They are formed with a plinth which is used to fix the dental model, e. g. to be worked with a tool or for shaping a dental aligner onto said dental model. For producing one dental aligner, at least two dental models are required, a first model representing the actual position of the tooth to be re-positioned and a second model to represent either the target position or an intermediate position which shall be achieved next by the tooth to be re-positioned. This text refers to one tooth to be re-positioned but of course the teaching applies to the re-positioning of two or more teeth. The dental aligner is shaped by a first thermoforming step, said step comprising shaping an aligner material onto the second dental model, i. e. onto the dental model which bears a shape closer to the target position. The aligner material is preferably a shape-memory synthetic polymer (SMP) or metal material (shape memory alloy SMA). The aligner material is usually supplied as a sheet material, preferably as an endless sheet material. The shaping usually includes increasing the temperature of the aligner material and changing the pressure from atmospheric pressure to either vacuum or to a pressure higher than atmospheric pressure. The aligner material is shaped so that it shows a negative of the dental model without any cavities. The aligner material shaped onto the dental model usually covers at least part of the plinth in order to be sure that the entire tooth or part of tooth that shall be re-positioned is properly covered by the aligner material. The dental aligner manufactured as a result of the first thermoforming step is then removed from the second dental model. If necessary, a cooling step can precede the removal of the dental aligner in order to stabilize the aligner shape. The shaping of a dental aligner as described above with regard to the first thermoforming step applies to further shaping steps, too, although in the second thermoforming step the dental aligner is shaped onto the first dental model and temperature an