Methods for manufacturing a dental splint and methods for manufacturing a dental splint system

Abstract

Method for manufacturing a dental splint (4), in particular a dental splint (4) for a dental splint system, comprising the following process steps: • digital capture of a three-dimensional shape of a dentition (1) in an initial state, • Creation of a virtual dental model (16) of the dentition (1) based on digitally recorded data, • Modification of the virtual dental model (16) by means of a data processing device (8), wherein a virtual separation of one jaw (3) of the dentition (1) in the virtual dental model into two jaw halves (17) is carried out, in particular two lateral jaw halves (17), in order to create a space (18) between the jaw halves by virtually spacing the jaw halves (17) in the dental model, • Creation of a dental splint complementary to a modified virtual dental model (4).

Description

[0001] The invention relates to a method for producing a dental splint, in particular a dental splint for a dental splint system. Furthermore, the present invention relates to a method for producing a dental splint system.

[0002] Dental splints or dental splint systems are used in orthodontics to correct malocclusions. The dentition is transformed from an initial shape to a target shape by applying forces to the teeth from the dental splint. The direction in which the force acts on a tooth depends on the direction the tooth needs to be moved to achieve its desired position.

[0003] There are different types of dental aligners that are used for specific applications. Common examples include those where the force is applied by an elastic metal wire bracket and transferred to the teeth via fastening elements, so-called brackets. This design is generally known as classic braces. There are also variants that are much more inconspicuous in appearance, which is often desired, especially with dental aligners for adults, with regard to everyday use. Such dental aligners, also known as clear aligners, are usually made of a transparent plastic or a plastic film and surround the teeth in such a way that the teeth engage in a specially shaped receiving area of ​​the aligner. The receiving area is designed to correspond to a target shape for the teeth.Therefore, after the splint is applied, a force is exerted on the teeth of the dentition in the initial shape in the direction of the target shape, which ultimately forces the dentition as a whole into the specified target shape. Such plastic splints are usually molded from a manufactured model of the dentition in the target shape and produced, for example, through a thermoforming process. The model is usually fabricated by a dental technician.

[0004] The use of a dental splint to correct malocclusion is usually associated with a feeling of pressure or even pressure pain in the jaw for the patient. For this reason, it is often not possible to design a dental splint that is directly adapted to the target shape and then insert it into the patient's teeth. Firstly, severe malocclusion, i.e. large differences between the initial and target shape of the teeth, can result in the splint not fitting properly, making it difficult to use. Secondly, the use of such a dental splint, i.e. one with a shape that deviates significantly from the initial shape of the teeth, would cause unacceptable pain for the patient. In such cases, it is usually the case that either a dental splint with adjustable strength is used, or a step-by-step treatment with several dental splints is carried out in the form of a dental splint system.

[0005] The latter solution is used for clear aligners, which cannot be readjusted due to their rigid shape. In this case, the dental splint system comprises several dental splints that differ in the thickness of the plastic film from which they are made.

[0006] The problem here is that too few individual dental splints are associated with increased discomfort for the patient. The pain is particularly acute immediately after inserting a new splint, as this is when the greatest difference between the actual and desired shape of the teeth exists. Because the individual splints are taken from previously manufactured models, producing a large number of dental splints for a correspondingly large number of intermediate dentition shapes up to the target shape is associated with considerable costs. In practice, it is therefore generally difficult to find a compromise that is suitable from the perspective of both the payer and the patient.

[0007] Furthermore, there is often insufficient space laterally in the jaw to properly align all existing teeth. In this case, this not only causes the misalignment but also complicates orthodontic treatment. When a patient's teeth are so crowded, it is usually necessary to remove individual healthy teeth from the jaw to make room for the remaining teeth. The loss of otherwise healthy teeth represents a further burden for the patient.

[0008] Document US 2016 / 0 171 128 A1 discloses a method for producing a dental splint, wherein the three-dimensional shape of a set of teeth is captured in an initial state. A virtual dentition model of the set of teeth is then created based on the digital data. Using a data processing device, the virtual dentition model is modified, with segmentation of the virtual dentition model occurring, which is limited to individual teeth. The teeth are then to be adjusted in their position by wearing a dental splint produced according to the known method. The aforementioned document US 2016 / 0 171 128 A1 relates to a method for producing a dental splint for single-tooth treatment.

[0009] From the document US 2018 / 0 000 565 A1 an arrangement for producing orthodontic dental splints is known, comprising a data processing device for creating and / or modifying a virtual denture model, and a means for producing a dental splint, further comprising a force sensor for measuring a force exerted by a dental splint on a denture or a physical denture model.

[0010] US 2017 / 0 252 140 A1 discloses a system for monitoring dental usage, comprising a dental device, a sensor unit with at least one sensor attached to the dental device, a power supply connected to the dental device, and an analyzer. The sensor is configured to collect data related to the use of the dental device. The analyzer is connected to the sensor and is configured to determine the use of the dental device based on the collected data.

[0011] Document DE 699 36 923 T2 discloses a computer-implemented method for developing a treatment plan for an orthodontic patient. The known method involves creating a digital model of the patient's dentition, which includes a dental model representing the patient's teeth at a set of initial positions, and a gingival model. The gingival model represents the gingival tissue surrounding the teeth. The method further involves deriving an expected deformation of the gingival tissue from the digital model as the teeth move from the initial positions to a further set of positions.

[0012] Against this background, the object of the present invention is to remedy this situation and to provide a possibility to optimize an orthodontic measure, particularly with regard to effectiveness and duration, while keeping the burden on a patient as low as possible.

[0013] The above-mentioned object is achieved by a method having the features of claim 1 and by a method having the features of claim 7. Advantageous further developments are the subject of the dependent claims.

[0014] According to the method, the three-dimensional shape of a patient's dentition is digitally recorded in its initial state. This can involve a direct three-dimensional scan of the dentition anatomy, but can also be done using a tomographic image or by scanning a molded model of the dentition.

[0015] Based on the recorded data on the patient's dentition, a digital data processing device creates a virtual model of the dentition. The model initially depicts the initial or current state of the dentition.

[0016] Using the device used to create the model or another data acquisition device, the shape of the virtual dentition model is then changed. The change is made in such a way that the modified virtual dentition model depicts a target state of the dentition that it is intended to assume after application of a dental splint or toward which the dentition is intended to change. A special feature of the method according to the invention is that a jaw of the dentition can be separated in the virtual model. The jaw halves thus separated can then be simulated, preferably separately from one another, in their development in the model and furthermore, their relative position to one another can also be changed.

[0017] By incorporating and altering the position of the jaw components, an additional degree of freedom is created for influencing the shape of the dentition. A dental splint produced using the method according to the invention can achieve a change in the shape of the dentition, even in adults, involving the rearrangement of the teeth and a change in the jaw anatomy. With conventional dental splints, this is generally only possible in children and adolescents, whose anatomy is still changing as a result of growth. Furthermore, the method according to the invention can be used both for the upper jaw of a set of teeth and for producing a dental splint for the lower jaw. A correspondingly extensive adjustment of the lower jaw has not been readily possible in practice to date.

[0018] Once a target state of the dentition has been determined by modifying the virtual dentition model, a dental splint is created based on the modified virtual dentition model, the shape of which complements the modified virtual dentition model, i.e., in particular, the target state of the dentition. The creation of the dental splint can occur immediately or include the intermediate step of producing a physical dentition model, from which the dental splint can ultimately be molded.

[0019] The physical dental model can be produced using a 3D printing process. Alternatively or additionally, a machining process can also be used.

[0020] The dental splint is molded from the physical denture model, particularly in a deep-drawing process. The dental splint preferably consists of a film or has such a film. A particularly preferred embodiment of a film-based dental splint is a so-called clear aligner.

[0021] The thickness of the film of a dental splint produced according to the invention is preferably between 0.1 mm and 2 mm, preferably between 0.2 mm and 1.25 mm, and particularly preferably between 0.3 mm and 0.75 mm. The thickness of the film is ultimately determined by a compromise between the desired or required strength of the splint, i.e., its resistance to deformation, and suitable adaptability to the patient's actual dentition or jaw geometry. These requirements can also be incorporated into the simulation when modifying the virtual model.

[0022] The method according to the invention can be supported, in particular, with regard to optimal modification of the virtual dentition model by incorporating not only the geometric shape but also the forces acting on the dentition into the simulated model. For this purpose, preferably after the modification of the virtual dentition model, at least one value of a force is determined that would be exerted on the dentition in the initial state by a dental splint complementary to the modified virtual dentition model. Such a force can be determined directly by producing a corresponding dental splint and measuring the forces actually acting on the patient's dentition after insertion. However, calculation of the occurring forces by a data processing device is preferred.

[0023] In some cases, after incorporating one or more force values, the virtual dentition model may be further modified to better meet specific requirements. This process is preferably repeated incrementally until a target value for the force acting on the dentition from the dental splint is reached. The resulting dental splint will therefore ideally not exert a greater force on the dentition than specified by the target value.

[0024] During the simulation, which includes the creation of the virtual dentition model and its modification, additional parameters can also be included. These parameters relate primarily to the dentition geometry and / or the forces that occur. However, they can also refer to other, particularly non-physical, data. Examples of this include the patient's subjective perception of pain or the duration of treatment.

[0025] The additional parameters can be stored as a data set in a database. The database preferably contains data obtained from past applications of the method. In particular, empirically obtained relationships between forces acting on a dentition and the resulting change in the shape of the dentition can be included as data sets in the simulation. The optimization of the shape of the dental splint to be created is facilitated by relating the data set or the data contained therein with the virtual dentition model. This allows, for example, more precise predictions to be made about the effect of a specific dental splint shape on the dentition in its initial state. By comparing the actual dentition geometry of the individual case with empirical data, the effectiveness of the dental splint produced according to the invention is further improved.If newly acquired data is stored in the database during the application of the procedure, the precision of the simulation of the effect of a dental splint on a specific dentition increases continuously.

[0026] Individual aspects of the method according to the invention and advantageous embodiments are discussed in more detail below.

[0027] According to the method of the invention, to produce an optimized dental splint, the current or initial state of a dentition with malocclusions is first determined, as is common practice in orthodontics. The use of conventional dental splints, i.e., those manufactured using known methods, to move the teeth typically leads to the disadvantages described above, since the forces exerted on the teeth by a dental splint can generally only be estimated insufficiently accurately. As a result, patients suffer from pressure pain, for example.

[0028] To avoid the disadvantages described, the method according to the invention provides for the known creation of a digital model of the dentition, based on which the shape of a dental splint to be created is determined. In known methods, the anticipated effect on the position of the teeth in the jaw is determined in a similar way. In contrast, the method according to the invention pursues a holistic approach that takes into account the anatomy of the jaw and its appropriate adaptation. The virtual model of the dentition generated according to the method therefore not only depicts the current state or a state with a changed position of the teeth, but also allows a virtual division of the jaw into several parts, in particular into two lateral jaw halves. Furthermore, the jaw halves can be assessed separately from one another and their further development as a result of the application of a dental splint can be simulated.Furthermore, the method according to the invention makes it possible to take into account a relative movement of the jaw parts or halves with regard to the shape of the dental splint to be created.

[0029] According to the invention, the shape of a dental splint is determined within the framework of a simulation of the entire treatment or a subsequent treatment step. In particular, by creating a virtual model of the patient's dentition or jaw, various dental splint shapes can be tried out virtually before an actual dental splint is created. A virtual model of the dentition or jaw anatomy allows, for example, a virtual separation of the jaw and the independent assessment of the jaw halves and / or groups of teeth. Ultimately, not only individual teeth are moved, but in particular groups of teeth or entire jaw halves. The simulation enables a highly precise assessment of the interaction of the dental splint with the jaw halves or with the jaw as such. Such precision cannot be achieved with a plaster model, for example.

[0030] Once the shape of one or more dental splints has been found, the production of the corresponding dental splint(s) preferably follows. For this purpose, a physical model of the dentition in the desired shape is created, particularly using the virtual dentition model. Such a three-dimensional dentition model can then be used to create an impression of a dental splint. The production of a dental splint or model can, in particular, be initiated or run automatically. A 3D printer, for example, is suitable for the quick and cost-effective production of a dentition model in particular. The optimized dental splint can then be manufactured from the dentition model created in this way, for example using a conventional deep-drawing process.

[0031] As a result, the method according to the invention creates the possibility of producing a dental splint which has an optimized shape such that use of the dental splint is, on the one hand, pain-free for the patient or at least involves only a slight sensation of pressure. On the other hand, the dental splint shape optimized according to the method, which takes into account not only the position of the teeth but also the shape of the jaw and any possible changes thereto, often makes it unnecessary to remove healthy teeth for reasons of space. In contrast, known manufacturing processes for dental splints, even when using a digital model, usually only focus on the desired tooth positions. The problem of the often lacking space for the correct arrangement of all the teeth in the mouth cannot therefore be overcome by a conventional dental splint.The same applies to sets of dental splints manufactured according to the method, which together form a dental splint system. A further advantage is that the target shape of the dentition or the shape can be determined in various intermediate stages without the use of tools, for example in the form of machining a physical model to take an impression of a dental splint. In particular, there is no need to saw open a model of the dentition in its initial state or to incrementally machine the model shape, for example by using screws or other means that cause the dentition model to spread. These labor-intensive steps can be carried out virtually and easily integrated into the method according to the invention. The simulation of the dentition change in the virtual model also directly offers further possibilities, particularly with regard to changing the position of the jaw.The dental splint designed and manufactured according to the process therefore has a significantly improved shape for application compared to splints manufactured using the conventional method.

[0032] The force exerted on the dentition is not only directed at individual teeth, but can also be directed at groups of teeth or sections of a row of teeth and / or entire halves of the jaw. A force of no more than 363 mN, preferably no more than 245 mN, and more preferably no more than 177 mN, has proven particularly suitable. This force corresponds to a weight of no more than 37 g, preferably no more than 25 g, and most preferably no more than 18 g. With this target value as the upper limit, in most cases no damage or, at least, no unreasonable pain is caused by the use of the dental splint.

[0033] The method according to the invention can be supported by measuring the force exerted by a dental splint on the teeth and jaw or jaw parts. In particular, a real value for this force can be taken into account when the interaction of a dental splint with the dentition is simulated using a virtual dentition model. The real force can also be related to values ​​determined during the simulation. Taking into account the forces occurring in addition to a purely geometric consideration allows for more precise statements regarding an optimized dental splint shape.

[0034] By directly measuring the force exerted by a dental splint of a specific shape on the teeth and jaws, the relationship between this force and the movement of the teeth as a result of the force can be determined. The data obtained in this way can then form the basis for producing a dental splint optimized for the force exerted on the teeth. The optimization is carried out with a view to achieving the greatest possible effectiveness without causing discomfort for the patient due to excessive forces, for example, by causing pressure on the tooth roots to exceed a critical level.

[0035] The dental splint can be manufactured based on the first dental splint, for example, by reworking the first dental splint to achieve the desired, optimized shape. Reworking is performed, in particular, by a machining process, preferably grinding, milling, and / or cutting. Alternatively, a completely new dental splint can be manufactured. Such a newly manufactured dental splint is obtainable, in particular, by taking an impression from a model or by another deep-drawing process.

[0036] Typically, a dental splint system according to the invention comprises a plurality of dental splints. A common number is, for example, three dental splints, which are used successively at different stages of treatment. However, the dental splint system can equally well comprise only one dental splint if the use of a single splint is sufficient to achieve a desired dentition.

[0037] The shape of the at least one dental splint of the dental splint system is determined in particular by taking into account the force which acts on the dentition or teeth when in use, i.e. when the dental splint has been positioned in the dentures as intended. The force is always below a specified target value. The target value is usually set such that the force exerted on the teeth by the dental splint does not result in excessive pressure pain or an unpleasant feeling for the patient. In this case, the target value, i.e. the maximum exerted force, is usually selected in each individual case and depends on the patient's individual pain sensitivity.

[0038] In the case of a film-based dental splint, such as a clear aligner, the shape of a dental splint also includes the thickness of the film. The force exerted by a film-based dental splint on the teeth ultimately depends largely on the thickness of the plastic film.

[0039] The target value does not need to remain fixed for the entire treatment period, but can also be adjusted gradually or continuously. In particular, a slight increase in force is possible as treatment progresses if a patient has developed a certain tolerance to the perceived pressure, or if the movement of teeth in the dentition makes an adjustment of the force necessary.

[0040] A specific target force value cannot be specified in general; it must be determined or specified for each individual case. Typically, however, the forces exerted on the teeth during the treatment of malocclusion are in the order of a few Newtons or less. This does not preclude the possibility that significantly higher or lower forces may occur or be determined in individual cases.

[0041] Preferably, the force transmitted by the dental splint is just below the specified target value, so that maximum effectiveness of the dental splint used is guaranteed. By choosing the right shape for the dental splint, the dental splint system can be optimally designed. Thanks to the method according to the invention, the desired effect, i.e. achieving a target shape for the treated dentition, can be achieved using the smallest possible number of individual dental splints, while at the same time causing an acceptable level of discomfort to the patient. This results in considerable cost savings. Furthermore, the time and effort required for inserting and adjusting the individual splints is reduced for the patient and / or the treating dentist or orthodontist.

[0042] It is particularly preferred that all dental splints of the dental splint system be manufactured in one go or provided together as a complete dental splint system. In this case, individual dental splints of the dental splint system can be replaced at predetermined or dynamically determined times without the need for re-manufacturing, fitting, and / or fitting a new dental splint.

[0043] Within the scope of the method according to the invention, the determination of the shape of a next dental splint in the dental splint system can be supported by first measuring the force transmitted to the dentition by a first or previous dental splint. Based on this data, the shape of at least one further dental splint can then be determined. Ultimately, a key advantage of the invention lies in the ability to determine or simulate the resulting forces acting on the dentition based on the relationship between the actual shape of the dentition and the shape predetermined by a dental splint using a virtual dentition model, taking both the teeth and the jaw as such into account. On this basis, predictions can be made for subsequent treatment steps with further dental splints in the dental splint system.By optimizing the shape of the individual dental splints, the ideal number of splints can be found for the respective application scenario in order to carry out the treatment in the most efficient way possible while being gentle on the patient.

[0044] In order to be able to make concrete statements about the force that is transferred from the dental splint to the teeth, it is recommended that the force be recorded using measuring technology. A force measurement is preferably carried out at the point at which it acts on the teeth, i.e. on at least one tooth of the teeth. In a further embodiment of the method according to the invention, the force measurement can also be carried out on a plurality of teeth or even on all teeth of the teeth. Ultimately, such a multi-point force measurement results in a detailed picture of the prevailing forces when the dental splint is used. In many cases, however, a force measurement on just one tooth is sufficient, for example if the measurement is carried out at a point indicated by an extreme malocclusion.

[0045] Malocclusions often manifest themselves in incorrect angles between the teeth and the jaw. Accordingly, when using a dental splint to straighten teeth, the forces often act on the lateral surfaces of the teeth. It is therefore preferable to measure the force acting on one lateral surface of the tooth. It is understood that measuring the force acting on a tooth at one point on the tooth does not preclude the force acting on the tooth from being determined at multiple points on the tooth, particularly on different lateral surfaces. In this way, not only the magnitude of the force can be determined more precisely, but also the direction of the force vector, so that the shape of a dental splint to be produced can be determined based on more detailed data.

[0046] Force measurement is typically performed using one or more force sensors. Force transducers based on a resistive principle are particularly suitable in this context. Alternatively or additionally, piezo force transducers can be used. The two force transducers mentioned here as examples are based on functional principles that allow the corresponding force sensors to be provided in sufficiently miniaturized versions for use in the dental area.

[0047] Preferably, a force sensor is arranged between a dental splint and the dentures or a tooth within the scope of the method. It is ultimately irrelevant whether the dental splint has a recess facing the tooth for the force sensor or whether the force sensor is simply inserted between the dental splint and the tooth.

[0048] The size of the force sensor is preferably adapted to the size of the tooth on which the force sensor is positioned. The force sensor preferably essentially covers the surface of the tooth facing it. This ensures that the entire force exerted by the dental splint on the examined surface of the tooth is recorded. A diameter of the force sensor between 1 mm and 10 mm, preferably between 2 mm and 8 mm, more preferably between 3 mm and 5 mm, has proven particularly suitable in this regard. In the case of a force sensor with an irregularly shaped sensor surface, the aforementioned preferred values ​​refer to the respective maximum lateral extent. The preferred thickness of the force sensor is less than 1 mm, more preferably less than 0.5 mm, particularly preferably less than 0.25 mm.

[0049] The sensor data supplied by the force sensor is read out and / or evaluated, in particular, by a data processing device. The data processing device can be used to further process the acquired data and compare or link it with other data, in particular further sensor data. The data processing device can be a stationary computer. Portable devices such as tablet computers, smartphones, or similar devices can also be used in addition to or instead of the computer. Within the scope of the invention, however, a data processing device is also understood to mean, for example, a measuring device that can receive, record, process, and / or store digital data, in particular. This includes, for example, a digital storage oscilloscope.

[0050] The data processing device can store the received sensor data from the force sensor in the form of one or more data sets in a database. Furthermore, such a data set can also contain data derived, calculated, and / or otherwise determined from the sensor data. The same applies to a mixture of sensor data and secondary data derived from the sensor data within a data set. Alternatively or additionally, the data processing device is particularly capable of reading data sets of the type explained above from the same and / or another database.

[0051] For the sake of simplicity, the database can be integrated into the data processing device, for example, stored on an internal hard drive, or assigned to the data processing device, in particular, located in close proximity to the data processing device. Furthermore, it is also possible for the data processing device to be connected to a database that is not provided locally. In this case, the database can be provided, for example, on a remote data server that is connected to the data processing device via a data line, in particular a network. This also includes the use of corresponding cloud services.

[0052] Storing sensor data or secondary data in a database enables access to a large amount of this data. Currently measured data can thus be easily correlated with data from past measurements and model data calculated from the data. Preferably, the measured and / or determined data are statistically recorded over longer periods of time. A comparatively large database ensures a sufficiently large sample size to perform calculations to optimize the shape of a dental splint or dental splint system based on the determined and stored data, taking current measurement data into account.

[0053] The method according to the invention benefits from the inclusion of empirical data stored in a database. This data can include, in particular, measured values ​​regarding the dental geometry and / or occurring forces. However, the invention does not preclude the consideration of other, particularly subjective, parameters, such as the duration of treatment or the pain perceived by the patient.

[0054] By incorporating the sensor data from the force sensor and / or the data sets stored in the database, the data processing device can thus determine a specific shape for at least one dental splint of the dental splint system. The shape of the dental splint is determined, in particular, with the goal of achieving the greatest possible treatment effectiveness, i.e., the greatest possible force acting on the teeth or dentition. However, according to the invention, the maximum force always remains below a target value defined generally or for the individual case.

[0055] To determine the ideal dental splint shape, forces measured during the use of another dental splint can be used in individual cases to specifically consider the actual load on the jaw. The dental splint used during the measurement corresponds, in particular, to a previous treatment stage.

[0056] By incorporating previously collected data stored in the database records, predictions can also be made as to the extent to which a particular dental splint shape will have the expected effect at a specific time of treatment and / or with a given jaw or dentition geometry. The previously collected data can, in particular, be data from other patients. Through a statistical evaluation of a large amount of data, averages and probabilities for expected treatment results can be determined with a good degree of accuracy. The data or data sets can, in particular, include data on a patient's dentition geometry, the initial and / or target shape of the dentition, the forces applied, the number and duration of treatment stages, the shape, size and / or material properties of the dental splints used, the achieved treatment result and / or the patient's pain perception.Ultimately, the data sets according to the invention can contain any type of data related to the application and construction of dental splints for correcting malocclusions. The above list is therefore not intended to be exhaustive.

[0057] The force measured by the force sensor and the data records in the database, either individually or in combination, form the basis for determining one or more intermediate forms of the dentition between its initial form and the desired target form. Each intermediate form generally corresponds to a specific dental splint in the dental splint system. The number of intermediate forms found using the method according to the invention is therefore simultaneously the number of treatment stages and the number of dental splints required for this. A key result achieved by the method according to the invention is to keep this number as low as possible, while at the same time keeping the disadvantages for the patient, i.e. in particular the pain associated with the treatment, within reasonable limits.

[0058] Classifying the data sets according to specific parameter groups enables the creation or provision of profiles. Predictions about the expected course of treatment, forces encountered, required dental splint shapes, and the like can be easily made by applying the corresponding profile to a specific application. The parameters for which groups are created and / or profiles are created include, among others, dentition shapes, the number and duration of treatment steps, the shape and quality of dental splints, forces exerted on the dentition, other anatomical data and patient characteristics, and / or the occurrence and durability of treatment success.

[0059] To ensure that a dental splint of the dental splint system manufactured according to the method according to the invention exerts a force on a patient's teeth that is overall below a specified target value, it must be guaranteed that the actually measured forces are the maximum occurring in each case. Otherwise, the determination of a shape for a dental splint for a subsequent treatment step would fail. Even if the theoretically determined forces for a specific dental splint shape did not exceed a target value, the actually acting forces would in this case be higher than this without the treating person noticing and could potentially cause pain to the patient. A maximum value for the force transmitted from the dental splint to the teeth can be determined in particular by changing the position of a first dental splint on the teeth.If a maximum value for the force emanating from this first dental splint is found by changing the position accordingly, a suitable shape for another dental splint in the dental splint system can be determined with high accuracy on this basis.

[0060] In this context, the first dental splint does not have to be the dental splint that corresponds to a first treatment stage. The term is used here to differentiate it from a subsequent second dental splint, the shape of which is determined based on measurements taken on the previous first dental splint. In principle, any dental splint in the dental splint system can be such a first dental splint. Furthermore, according to the invention, it is not necessary for the position of the first dental splint to actually be changed on the patient's dentition in order to determine a maximum value for the force. The corresponding examination can also be carried out on a three-dimensional model of the dentition and / or virtually as part of a simulation, in particular on a virtual model of the patient's dentition or jaw.

[0061] Once a maximum value for the force exerted by the dental splint on the teeth has been determined, this is compared with a target value. This target value can represent the upper limit for the force exerted on the patient's teeth. If the maximum force value found is above this target value, possible corrections or further optimizations to the shape of the dental splint to be determined are necessary in order to reduce the maximum force exerted until it is below the target value. The same applies if the maximum force is excessively far below the target value. To ensure the greatest possible effectiveness of a dental splint, its shape should preferably be determined so that the maximum force exerted is just below the target value.

[0062] The goal of optimal treatment of numeral malocclusions with a dental splint system is preferably achieved with the method according to the invention by determining the minimum number of dental splints necessary to transform a patient's dentition from an initial shape to a target shape without the force exerted on the dentition by each of the dental splints exceeding the specified target value. In this regard, the virtual separation of the jaw provided for by the method has an advantageous effect, as this ultimately opens up a further degree of freedom for adapting the shape of the dental splint. The latter condition applies in particular at any time during treatment with a dental splint system manufactured according to the method according to the invention. It goes without saying that the force exerted on the dentition by a specific dental splint must be evaluated in each corresponding treatment step.Each dental splint in the dental splint system is ultimately used to transform the dentition from the initial shape to a specific intermediate shape, or from one intermediate shape to the next intermediate shape, with the target shape being achieved at the end of this series. The decisive factor here is the forces exerted by a dental splint corresponding to a specific target or intermediate shape on the dentition in the previous initial or intermediate shape.

[0063] Force measurement can be performed using a special dental splint. A force sensor is attached to the dental splint, which allows the forces exerted by the dental splint on a denture to be measured.

[0064] Typically, a dental splint has a receiving area for the teeth of the dentition into which it is to be inserted. The force sensor is preferably assigned to such a receiving area of ​​the dental splint or arranged within this receiving area. The force sensor can be provided there for direct contact with the teeth and / or positioned such that a force measurement is performed at the ideal location so that the acquired data can be used for further processing. At such a location, the magnitude of the force is usually maximum, and the direction vector of the force preferably points perpendicular to the respective tooth surface.

[0065] A particularly suitable location for measuring the force is usually on the lateral surface of a tooth. Accordingly, the force sensor is preferably arranged on or in the dental splint such that, when the splint is worn, i.e., when the dental splint is inserted into the dentures, it is located on the lateral surface of at least one tooth. It is understood that, in principle, multiple force sensors can also be assigned to one or more teeth. The arrangement of multiple force sensors is preferably carried out in the manner explained above.

[0066] The measurement of the maximum force exerted on a tooth is facilitated or ensured by matching the size of the force sensor to the size of the corresponding tooth. In this regard, a force sensor is preferred whose area essentially corresponds to the area of ​​the tooth, particularly a side surface of the tooth. This ultimately increases the probability that the point of application of the force lies within the area covered by the force sensor and is thus also detected by the force sensor.

[0067] The dental splint can have a recess for a force sensor. For use, the force sensor is then inserted into the recess and the dental splint is inserted into the patient's dentition. Alternatively, the force sensor can also be inserted or pushed into the recess after the dental splint has been inserted. However, such a design of the dental splint is not mandatory according to the invention.

[0068] A further embodiment of the dental splint further provides for the force sensor to be integrated into the dental splint and / or inseparably connected to the dental splint. Embedding the force sensor in the material of the dental splint or creating an inseparable connection between the force sensor and the dental splint significantly simplifies the handling of force measurement. In this case, it is sufficient to simply insert the dental splint into the patient's teeth. Force measurement can then begin immediately, as there is no need for separate insertion and positioning of the force sensor and its fixation in the selected location.

[0069] The invention ultimately also includes the corresponding method for measuring a force exerted by a dental splint on a denture, in order to support the inventive method for manufacturing a dental splint. The inventive measuring method enables a previously unavailable quantitative determination of the forces acting on the teeth and the associated movement paths depending on the properties of a dental splint. In the case of clear aligner splints, the dependence on the splint layer thickness or film thickness is of particular interest.

[0070] The invention is explained in more detail below using exemplary embodiments. All described and / or illustrated features are to be considered individually part of the invention, regardless of their combination in the examples or in the claims.

[0071] It shows Fig. 1 a perspective schematic representation of a typical application situation during the measurement of the force exerted by a dental splint on a denture, Fig. 2 a schematic representation of an exemplary arrangement for carrying out the method according to the invention, Fig. 3 a perspective schematic representation of a denture before the application of a dental splint, Fig. 4 a perspective schematic representation of a virtual model of the dentition of Fig. 3 and Fig. 5 one of the Fig. 3 corresponding representation of the dentition of Fig. 3 after application of a dental splint produced according to the method according to the invention.

[0072] In Fig. Figure 1 schematically illustrates a typical situation in which, to support the method according to the invention, a force exerted on a patient's dentition 1, specifically on teeth 2 of the dentition 1, is determined. A section of a jaw 3, in this case the lower jaw, is shown. To correct misalignments of the teeth 2, a dental splint 4 is placed on the row of teeth.

[0073] The shape of the dental splint 4 corresponds to a target or intermediate shape for the dentition 1. The dentition 1 is transformed from an initial shape into this target or intermediate shape by means of the dental splint 4 by forces acting on the teeth 2 when the dental splint is inserted into the dentition 1. With the aim of optimising the shape of the dental splint 4 or another dental splint 4 such that the force transmitted from the dental splint 4 to the dentition 1 when applied is always below a specified target value, the actual value of this force for the currently inserted dental splint 4 is determined in the example presented here.

[0074] The force of the dental splint 4 on the teeth 2 is measured directly. For this purpose, a force sensor 5 is provided, which is arranged between the dental splint 4 and a tooth 2 of the denture 1.

[0075] The force sensor 5 is in the example of Fig. 1 is arranged on a canine tooth 2. It is understood that the force can also be measured on another tooth 2 or on multiple teeth 2. This can be done, in particular, with force sensors 5 that differ in size, shape, and / or functionality.

[0076] In this case, a force sensor based on a resistive principle is used. A force acting on the sensor surface of the force sensor 5 leads to a measurable change in the internal electrical resistance. A force sensor 5 designed as a resistive force transducer has the advantage that it can be constructed with a small surface area and an extremely small thickness. The latter property is particularly advantageous when the force sensor 5 is to be inserted between a dental splint 4 and the teeth 2 of a denture 1. A force sensor 5 based on a piezoelectric principle has similar properties. In such a sensor, deformation of a so-called piezo crystal due to an external force leads to a potential difference at the crystal ends, which can be measured as an electrical voltage.Although the two aforementioned embodiments are preferred for the functional principle of the force sensor 5, it is understood that the force measurement can be carried out according to the invention with any force sensor 5.

[0077] To measure the force acting on the force sensor 5 from the dental splint 4, the force sensor 5 is read out via a measuring line 6. For illustration, the measuring line 6 is Fig. 1 by a cable indicated by the arrow. However, according to the invention, a wireless connection to the force sensor 5 can also serve as the measuring line 6. Ultimately, the measuring line 6 generally represents a readout channel for measurement data supplied by the force sensor 5.

[0078] In the present example, the force is measured on a side surface of a tooth 2. The possibility of measuring the force acting on the teeth 2 on another surface of the tooth 2 or on multiple surfaces is not illustrated in detail, but is possible according to the invention.

[0079] The force sensor 5 is dimensioned such that its surface area almost completely covers the side of tooth 2 facing it. The actual point of application of the force on tooth 2, i.e., the location where the force is maximum, is thus detected with a high degree of probability by the force sensor 5.

[0080] In Fig. 2 shows an example of an arrangement by means of which the method according to the invention can be carried out, including a supporting force measurement. For supporting force measurement, the Fig. 1, the force exerted by the dental splint 4 on the teeth 2 is measured on a denture 1 with an inserted dental splint 4. This is done in the manner described above by means of a force sensor 5, which is read out by a measuring and evaluation device 7 via a measuring line 6.

[0081] A central component of the measuring and evaluation device 7 is a data processing device 8, which is preferably connected to a measuring device 10 via a data line 9. However, the data processing device 8 serves in particular to carry out a simulation of the treatment to optimize the shape of the dental splint 4 within the scope of the inventive method. Starting from a digital model 16 of the dentition 1, created for example by means of an impression, the optimal shape of a dental splint 4 is determined within the scope of the simulation carried out by the data processing device 8. This determines how a dental splint 4 must be shaped to optimally influence the dentition anatomy. This is done by separating the jaw 3 of the virtual dentition model 16 into several jaw halves 17. As a result, the relative arrangement of the jaw halves 17 in the virtual model 16 can be changed.The effect of a specific design of a dental splint 4 to be created can thus be simulated under various conditions regarding the change in position of the teeth 2 and the jaw halves 17. This allows an optimal shape for the dental splint 4 to be determined. Applying the correspondingly manufactured dental splint 4 thus results not only in a change in the relative arrangement of the teeth 2, but also in a change in the jaw 3, specifically a gradual displacement of the jaw halves 17.

[0082] In Fig. 3 shows a set of teeth 1 in the initial situation. Clear misalignments of the teeth 2 are evident here. The method-based creation of a first virtual denture model 16 is carried out, in particular, on the basis of such an initial state. After the creation of a digital denture model 16, the method according to the invention allows for virtual manipulation of the reproduced denture 1 in order to simulate various effects of a dental splint 4 on the denture 1. For this purpose, a model of a dental splint 4 can be added to or assigned to the virtual denture model 16. The simulation can, in particular, include and / or determine forces occurring between the dental splint 4 and the denture 1.

[0083] The reproduction of the virtual denture model 16 is preferably carried out visually via a display device associated with the data processing device 8, such as in Fig. 2 shown.

[0084] The manipulation of the virtual denture model 16 within the framework of the simulation can be used as an example to Fig. 4. In the model shown there, the jaw halves 17 are compared to the initial state of the dentition 1 according to Fig. 3 are moved apart by a specific distance. Furthermore, position adjustments of the teeth 2 have been provided for comparison. In particular, the virtual spacing of the jaw halves 17 results in a free space 18 between the teeth 2 of jaw 3 in the model. The free space 18 ultimately creates sufficient space in jaw 3 to rearrange all teeth 2 of jaw 3 in the desired manner without having to remove individual teeth 2 from the dentition 1.

[0085] By moving the jaw halves 17, an expansion of the jaw 3 can be effected in both the transverse and sagittal directions. A dental splint 4 for the unilateral expansion of a jaw 3 can also be planned and produced according to the invention. The extent of the digitally planned expansion of the jaw 3 according to the method is preferably between 0.05 mm and 4 mm, more preferably between 0.1 mm and 2 mm. In one application example, by using dental splints 4 manufactured according to the method, with a digitally planned expansion of the jaw 3 of 2 mm, a total space gain in the jaw 3 of an additional 6.1 mm compared to the initial state could be achieved.

[0086] In the present example, the position of the free space 18 created by manipulating the virtual dentition model 16 leads, in particular, to the formation of a diastema between the anterior incisors. It is understood that a different position of the free space 18, as well as a plurality of free spaces 18, can be provided according to the invention.

[0087] A physical denture model 15 can be created from the virtual denture model thus determined. This is preferably done using a 3D printing process. The generated three-dimensional denture model 15 can subsequently be used to create an impression of a dental splint 4, for example, using a thermoforming process. Due to the method for its production according to the invention, the dental splint 4 optimally interacts with the patient's dentures 1, so that the patient's dentures 1 adapt as desired, while the treatment is accompanied by minimal discomfort for the patient.

[0088] By further adjusting the position of the teeth 2 during and / or after the formation of a corresponding free space 18 in the patient's dentition 1, a correct arrangement of all teeth 2 of the jaw 3 can ultimately be achieved. In particular, any diastema is closed, thereby ensuring a uniform appearance of the dentition 1. This final state of the dentition 1 is shown, for example, in Fig. 5 shown.

[0089] For the sake of clarity, the measuring device 10 is shown here as a separate component, but can equally well be integrated into the data processing device 8. The measuring device 10 generally represents an interface via which the measured sensor data is provided to the measuring and evaluation device 7, in particular the data processing device 8. With regard to further digital processing of the measured data, digitization of analog measured values ​​can take place, in particular, at the measuring device 10.

[0090] The measuring device 10 is preferably designed for connection to a plurality of force sensors 5. The force sensors can be connected to the measuring device 10 via measuring lines 6 in the form of connecting cables and / or wirelessly.

[0091] The measured sensor data can be read, evaluated, and / or stored in digital form by the data processing device 8. In particular, secondary data can be generated from the recorded measured values ​​using the data processing device 8. Such secondary data can be part of a model calculation aimed at determining the ideal shape of a dental splint 4 of the dental splint system, or they can form the basis for such a calculation.

[0092] The data recorded, calculated and / or otherwise determined by the data processing device 8 are stored in the form of data records in a database. In the example shown here, the data processing device 8 transmits corresponding data records via a data line 11 to an external data server 12. Alternatively or additionally, internal storage, in particular in the form of intermediate storage, can also take place in the data processing device 8 itself. Providing the database at a central location, for example in the form of a data server 12, has the advantage that the database can be fed with data records, in particular from more than one location. This enables strong and rapid growth of the database, so that statistical surveys can be carried out, for example with regard to measured forces, their dependence on the shape of the dentition 1 and the dental splint 4, and with regard to achieved treatment successes.

[0093] The database contains, in particular, data records from various patients. However, it is generally not necessary to assign the stored data to a specific patient, so the data can also be stored anonymously. Ultimately, the decisive factors are the relationships between the initial shape of the dentition 1, the desired target shape, and the number and design of the dental splints 4 used in the dental splint system, as well as the treatment success achieved and information on accompanying symptoms for the patient, such as perceived pain.

[0094] On the basis of the available data, i.e. measurement data and / or stored data in the database, the data processing device 8 can determine the shape of an ideally adapted virtual denture model 16 and thus of one or more dental splints 4, such that the force exerted by each of them on the denture 1 is below a target value, i.e., for example, is sufficiently low so as not to cause the patient unreasonable pain. Preferably, the data processing device 8 determines the optimal shape of the dental splints 4 of the dental splint system so that a minimum required number of dental splints 4 can be used to convert the denture 1 from an initial shape to a target shape, wherein the force exerted by each of the dental splints 4 on the denture 1 in the respectively corresponding intermediate form falls below the target value.

[0095] In order to determine the ideal shape of a dental splint 4, the data processing device 8 generates a virtual model of the jaw 3 or the dentition 1 in an initial form (cf. Fig. 3), a target form (cf. Fig. 5) and / or one or more intermediate forms (cf. Fig. 4), which can correspond to individual treatment stages, each with a dental splint 4. The virtual shapes can be adjusted step by step until an optimal sequence of shapes is found for the most efficient treatment possible.

[0096] After determining the shape of one or more dental splints 4, the production of a dental splint 4 according to the specified shape preferably follows. A corresponding dental splint 4 can be produced, as described above, by taking an impression from a three-dimensional model 15 of the dentition 1 created according to the specified shape, or alternatively, it can be produced directly. The dental splint 4 produced in this way is optimized according to the invention for the best possible compromise between the highest possible effectiveness of the application and the most gentle treatment for the patient.

[0097] In the example of Fig.2, a 3D printer 14 connected to the data processing device 8 via a control line 13 is shown as a representative means for carrying out the production step. Using the 3D printer 14, it is possible, for example, to quickly produce a three-dimensional denture model 15 in any desired shape, in particular the initial shape, the target shape, or any intermediate shape of the patient's dentition 1. It is understood that, instead of the 3D printer 14 shown here, any other type of device can also be provided to produce one or more dental splints 4.

[0098] A dental splint 4 produced in the aforementioned manner can also be inserted into the patient's dentition 1 to measure the force exerted on the teeth 2. Using the additional data thus obtained, the shape of the dental splint 4 can be gradually optimized, particularly by repeating the procedure. The simulation, including the documentation of the process and the storage of the acquired data, allows for the existing data to be accessed in future applications, so that no, or at least fewer, practical tests or investigations are required to determine an optimal shape for the dental splints 4 of the dental splint system.

[0099] Within the scope of the method according to the invention, a complete simulation of the treatment can be carried out using the virtual dentition model 16 in order to determine optimized shapes of the dental splints 4 to be used for the respective intermediate treatment steps. A special feature of the method lies in the possibility of being able to perform a virtual division of the jaw 3 into jaw parts, namely jaw halves 17. In contrast, known methods usually relate only to the planning and prediction of the consequences of individual treatment steps and are also generally aimed at influencing the position of the misaligned teeth 2. This considerably limits the potential of corresponding manufacturing methods for dental splints 4 compared to the present invention. List of reference symbols: 1 denture 2 teeth 3 jaws 4 Dental splint 5 force sensor 6 measuring line 7 Measuring and evaluation device 8 Data processing facility 9 Data line 10 Measuring device 11 Data line 12 data servers 13 Control line 14 3D printers 15 physical denture model 16 virtual denture model 17 jaw half 18 open space

Claims

[1] Method for producing a dental splint (4), in particular a dental splint (4) for a dental splint system, comprising the following method steps: • digital recording of a three-dimensional shape of a dentition (1) in an initial state, • Creation of a virtual dentition model (16) of the dentition (1) based on digitally recorded data, • Changing the virtual denture model (16) by means of a data processing device (8), wherein a virtual separation of a jaw (3) of the denture (1) in the virtual denture model into two jaw halves (17) takes place, in particular two lateral jaw halves (17), in order to create a free space (18) between the jaw halves by virtual spacing of the jaw halves (17) in the denture model, • Creation of a dental splint complementary to a modified virtual dentition model (4). [2] Method according to claim 1, characterized bythat the change in the virtual denture model (16) comprises a change in a relative position of the jaw halves (17) in the virtual denture model (16). [3] Method according to claim 1 or 2, characterized by that the creation of the dental splint (4) complementary to a modified virtual denture model comprises a creation of a physical denture model (15) corresponding to the modified virtual denture model and an impression of the dental splint (4) from the physical denture model (15). [4] Method according to claim 3, characterized by that the production of a physical denture model (15) corresponding to the virtual denture model (16) is carried out by means of a 3D printing process. [5] Method according to one of the preceding claims, characterized bythat after the change of the virtual denture model (16), at least one value of a force is determined which would be exerted on the denture (1) in the initial state by a dental splint (4) complementary to the changed virtual denture model, and that, preferably, a further change of the virtual denture model takes place before the creation of the dental splint (4) complementary to the changed virtual denture model (16). [6] Method according to one of the preceding claims, characterized by that before and / or after the change of the virtual denture model (16), at least one stored data set, in particular relating to the shape of a denture (1) and / or a force acting on a denture (1), is read out from a database and related to the virtual denture model (16). [7] Method for producing a dental splint system, wherein at least one dental splint (4) of the dental splint system is produced according to a method according to one of the preceding claims, characterized by , that the procedural steps of the • Modification of a virtual denture model (16) by means of a data processing device (8) up to • Creation of a dental splint complementary to a modified virtual denture model (4) be carried out several times to produce a plurality of dental splints (4) of the dental splint system.

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