WO2013053903A1

WO2013053903A1 - Method of globally designing a set of teeth

Info

Publication number: WO2013053903A1
Application number: PCT/EP2012/070293
Authority: WO
Inventors: Tais Clausen
Original assignee: 3Shape A/S
Priority date: 2011-10-12
Filing date: 2012-10-12
Publication date: 2013-04-18

Abstract

Disclosed is a method of virtually designing a number of 3D teeth restorations for a patient, where the method comprises: - providing a number of initially composed 3D virtual teeth restorations, where each of the virtual teeth restorations is represented by a separate surface; - defining a centre of modification in relation to the initially composed 3D virtual teeth restorations; and - modifying the shapes and/or the positions of at least two of the initially composed 3D virtual teeth restorations simultaneously to obtain a modified set of 3D virtual teeth restorations, where the magnitude of the modification depends on the distance to the centre of modification.

Description

Method of globally designing a set of teeth

Field of the invention This invention generally relates to a method and a system for designing a number of teeth for a patient.

Background of the invention

When a patient requires a dental restoration, such as a crown, a bridge, an abutment, or an implant, the dentist will prepare the teeth e.g. a damaged tooth is grinded down to make a preparation where a crown is glued onto. An alternative treatment is to insert one or more implants, such as titanium screws, into the jaw of the patient and mount a crown or a bridge on the implant. After preparing the teeth or inserting an implant the dentist can makes an impression of the upper jaw, the lower jaw and a bite registration or a single impression in a double-sided tray, also known as triple trays. The impressions are sent to the dental technicians who manufacture the restorations e.g. the bridge. The first step to manufacture the restoration is traditionally to cast upper and lower dental models from impressions of the upper and the lower jaw, respectively. The dental models are usually made of gypsum and often aligned in a dental articulator using the bite registration. The articulator simulates the real bite and chewing motion. The dental technician builds up the dental restoration inside the articulator to ensure a nice visual appearance and bite functionality. A proper alignment of the cast in the articulator is crucial for the final restoration. CAD technology for manufacturing dental restoration is rapidly expanding improving quality, reducing cost and facilitating the possibility to manufacture in attractive materials otherwise not available. The first step in the CAD manufacturing process is to create a 3-dimensional model of the patient's teeth. This is traditionally done by 3D scanning one or both of the dental gypsum models. The 3-dimensional replicas of the teeth are imported into a CAD program, where the entire dental restoration, such as a bridge substructure, is designed. The final restoration 3D design is then manufactured e.g. using a milling machine, 3D printer, rapid prototyping manufacturing or other manufacturing equipment. Accuracy requirements for the dental restorations are very high otherwise the dental restoration will not be visual appealing, fit onto the teeth, could cause pain or cause infections.

Summary Disclosed is a method of virtually designing a number of 3D teeth restorations for a patient, where the method comprises:

- providing a number of initially composed 3D virtual teeth restorations, where each of the virtual teeth restorations is represented by a separate surface;

- defining a centre of modification in relation to the initially composed 3D virtual teeth restorations; and

- modifying the shapes and/or the positions of at least two of the initially composed 3D virtual teeth restorations simultaneously to obtain a modified set of 3D virtual teeth restorations, where the magnitude of the modification depends on the distance to the centre of modification. The separate surfaces of the virtual teeth restorations allow for a highly individualized modification and a detailed visualization of the virtual teeth restorations.

The magnitude of the modification of the sizes and/or positions of the virtual teeth restorations depends on the distance to a centre of modification, such that 3D virtual teeth restorations are modified relatively with the distance to the centre of modification, i.e. the magnitude of the modification may increase or decrease with the distance to the centre of modification. When modifying the shapes of the initially composed 3D virtual teeth restorations, the shapes of the separate surfaces are modified where the magnitude of the modification depends on the distance to the centre of modification. A the virtual surface of a tooth restoration closer to the centre of modification may hence be modified more or less than the virtual surface of a tooth restoration which is farther away from the centre of modification. The modification of the shape may e.g. relate to the form or size of the virtual tooth restoration.

It is an advantage that more 3D virtual teeth restorations can be modified or designed simultaneously, as this will save time for the dental designer, and furthermore it will provide a better visual result if the teeth restorations are designed simultaneously, because they will maintain both their individual and common characteristics.

It is an advantage of the present invention that modification can be applied to two or more teeth restorations while providing that the modification of the restorations depends on the distance to the centre of modification.

The separate surfaces of the neighbouring virtual teeth restorations may be arranged with a distance to each other, or such that contact is provided at a contact point, or even in some have a partial overlap. Disclosed is a method of virtually designing a number of 3D teeth restorations for a patient, where the method comprises:

- providing a number of initially composed 3D virtual teeth restorations; - modifying at least two of the initially composed 3D virtual teeth restorations simultaneously to obtain at least two modified 3D virtual teeth restorations.

Global positioning

In some embodiments the positions of the 3D virtual teeth restorations are modified simultaneously.

In some embodiments, the modifying is such that the relative positions of the individual 3D virtual teeth restorations changes and/or such that the 3D virtual teeth restorations move relative to the patient's oral cavity.

It is an advantage that more teeth restorations are moved simultaneously when designing the teeth restorations. This allows for instance that an operator visually can inspect the effect of the modifications on a computer screen in real-time.

In some embodiments the positions of the virtual teeth restorations relative to each other are maintained, such as maintained while modifying the initially composed 3D virtual teeth restorations to obtain said modified 3D virtual teeth restorations.

It can be advantageous that the position of the individual tooth restorations relative to its neighbour teeth restorations is not changed.

In some embodiments the contact between the virtual teeth restorations are maintained, such as maintained while modifying the initially composed 3D virtual teeth restorations to obtain said modified 3D virtual 3D teeth restorations. It is an advantage that if two tooth restorations has a contacting surface, then this contacting surface may be maintained such that the two tooth restorations still is in contact along this surface even though the tooth restorations have been moved.

In some embodiments predefined contact points between the virtual teeth restorations are maintained, such as maintained while modifying the initially composed 3D virtual teeth restorations to obtain said modified 3D virtual 3D teeth restorations.

In some embodiments, the centre of modification is defined in or on one tooth restoration. The tooth restoration in which the centre of modification is located is then referred to as the centre of modification tooth restoration. Alternatively the centre of modification may be defined between two teeth restorations or at a distance from the teeth restorations, such as when the centre of modification is offset from the teeth restorations along the median line of the set of teeth or when the centre of modification is arranged at the patient's gingiva. The centre of modification may also be referred to as a point of origin.

In some embodiments the positions of the virtual teeth restorations are modified with a point of origin in one tooth restoration.

In some embodiments the position of the centre of modification tooth restoration is modified maximally.

Thus the position of the tooth restoration in which the centre of modification is placed is modified the most.

In some embodiments, the magnitude of the modification for one of said separate virtual surfaces differs from the magnitude of the modification for another one of said separate virtual surface. In some embodiments the positions of the virtual teeth restorations are modified relatively with the distance to the centre of modification,

For example, the closer the teeth restorations are to the centre of modification, the more are their positions modified. Alternatively, the farther away the teeth restorations are from the centre of modification, the more are their positions modified.

In some embodiments the positions of the different 3D points of the virtual teeth restorations are modified relatively with the distance to the centre of modification.

For example, the closer a 3D point of a teeth restoration is to the centre of modification, the more is the position of that 3D point modified. And the further away a 3D point is to the centre of modification, the less is the position of that 3D point modified.

Alternatively, the opposite can be the case, such that the farther away a 3D point of a teeth restoration is from the centre of modification, the less is the position of that 3D point modified. In some embodiments the positions of the virtual teeth restorations closest to the centre of modification are modified more than the positions of the virtual teeth restorations most far away from the centre of modification, such as wherein the positions of the virtual teeth restorations are modified proportionally with the distance to the centre of modification.

The distance from the centre of modification may be measured along the arch of the jaw.

In some embodiments the positions of the virtual teeth restorations are modified inversely proportionally with the distance to the centre of modification. Thus the position of the teeth restorations closest to the centre of modification tooth restoration will be modified more than the position of the teeth restorations most far away from the centre of modification tooth restoration along the arch of the jaw.

Thus the closer neighbour teeth restorations will be modified more in their position than the teeth restorations which are more far away from the centre of modification, measured along the arch.

In some embodiments the positions of the different 3D points of the teeth restorations are modified proportionally with the distance to the centre of modification.

For example, the 3D points of a neighbour tooth restoration will be moved less in the direction of the centre of modification tooth restoration if the 3D points are on a surface of the neighbour tooth restoration which is facing towards the centre of modification tooth restoration, than if the 3D points are on a surface of the neighbour tooth restoration which is facing away from the centre of modification tooth restoration.

In some embodiments the positions of the different 3D points of the teeth restorations are modified inversely proportional with the distance to the centre of modification.

For example, the 3D points of a neighbour tooth restoration will be moved more in the direction of the centre of modification tooth restoration if the 3D points are on a surface of the neighbour tooth restoration which is facing towards the centre of modification tooth restoration, than if the 3D points are on a surface of the neighbour tooth restoration which is facing away from the centre of modification tooth restoration.

In some embodiments the positions of the teeth restorations are modified based on a Gaussian function. The position of the centre of modification, e.g. on a tooth restoration, will be influenced, affected, impacted mostly, which may be defined as 100% or value 1 impact. The positions of the other teeth restorations will be impacted, influenced, affected relative to their distance from the centre of modification, such as 50% or ½. The graph of a Gaussian is a characteristic symmetric "bell curve" shape that quickly falls off towards plus/minus infinity, thus the impact may be determined by a Gaussian function or curve or distribution, such that the impact on the position is relatively bigger the closer the teeth restorations are to the centre of modification. As a Gaussian functions flattens off or levels off, the impact quickly fall off when the distance to the centre of modification increases.

In some embodiments the positions of the teeth restorations are modified by translations and/or rotations.

The translations may be in all three directions in space, and rotations may typically be around the natural vertical direction of the teeth.

In some embodiments the positions of the teeth restorations are modified by translations, when the teeth restorations are viewed in a front view.

It is an advantage because translations may be best seen in a front view of the teeth.

In some embodiments the positions of the teeth restorations are modified by translations and rotations, when the teeth restorations are viewed in an occlusal view.

It is an advantage because both translations and rotation may be best seen in an occlusal view of the teeth.

Morphing In some embodiments the teeth restorations are modified by morphing the 3D shape of the teeth restorations.

In some embodiments, modifying the teeth restorations comprises morphing the 3D shape of the teeth restorations.

Morphing may comprise changing the distribution of virtual material of the restoration tooth, and/or morphing may comprise keeping the volume of the restoration tooth constant.

Morphing or warping or modifying, e.g. positions, may be used for modifying the shape of a 3D object according to specified rules. The rules are typically described as a set of constraints that must be met by the morphed object. A morphing method/algorithm may work by creating a morph object and setting up various morphing constraints for it. After this, the morph object can be used for morphing various 3D objects like splines, points, etc. The implementations of a morphing method may comprise defining a basic abstract morph class. The actual morph classes to be used may also be defined.

The morph classes may differ in the kind of morphing constraints they implement. One morph class may have the morph constraint that it specifies that a given point in 3D space must be moved to another given point in 3D space. All points close to this point may also be moved, so a smooth transition is achieved. In another morph class a set of point to point constraints can be specified. Furthermore in the morph class where a set of point to point constraints are specified, transition parts of the model may be morphed using a cosine function. In yet another morph class a set of line segment to line segment constraints can be specified. The part of space defined by one line segment may be morphed into another line segment.

In yet another morph class the area in space defined by a 3D spline is morphed into another 3D spline. In some embodiments the size of the teeth restorations are kept constant while morphing the one or more teeth restorations.

It may be an advantage that the size is not changed. In some embodiments the aspect ratio of the teeth restorations are kept constant, while morphing the one or more teeth restorations.

It may be an advantage that the aspect ratio is not changed.

In some embodiments the length/width relationship of the teeth restorations is kept constant while morphing the one or more teeth restorations.

It may be an advantage that the length/width relationship is not changed.

Thus if the length is reduced, then the width is reduced correspondingly, such that the aspect ratio, which is the length/width relationship, is kept constant.

E.g. if the length is doubled, then the width is also doubled.

When the aspect ratio is kept constant, then the anatomy of each tooth restoration is maintained, conserved, preserved, such that it does not change appearance, form and shape.

Symmetric design

In some embodiments the modification is performed on one tooth restoration, and the modified design is simultaneously transferred to the corresponding tooth restoration, such as a corresponding tooth restoration on the other side of the jaw or a corresponding tooth restoration in the antagonist.

It is an advantage that the design can be transferred or cloned or copied. The corresponding tooth restoration is the symmetrical tooth on the other side of the median line of the jaw. For example the corresponding tooth of the left central in the upper jaw, tooth no. 8, is the right central of the upper jaw, tooth no. 9, and the corresponding tooth of the right lateral in the lower jaw, tooth no. 23, is the left lateral in the lower jaw, tooth no. 26, and the corresponding tooth of the right canine in the upper jaw, tooth no. 1 1 , is the left canine in the upper jaw, tooth no. 6, etc. Normally, each tooth has a corresponding tooth in the other side of the jaw, and if for example all the anterior teeth in the upper jaw should be restored, then there is a total of 6 teeth restorations to be designed, and these 6 teeth restorations can be divided in 3 pairs, where each pair comprises 2 corresponding teeth, where one pair is the two centrals, tooth no. 8 and tooth no. 9, another pair is the two laterals, tooth no. 7 and tooth no. 10, and another pair is the two canines, tooth no. 6 and tooth no. 1 1 . Thus in for example the upper jaw the two centrals are corresponding teeth, the two laterals are corresponding teeth, and the two canines are corresponding teeth. The corresponding teeth may also be denoted symmetry pairs, symmetrical pairs etc.

It is an advantage that each modification of one tooth restoration is simultaneously applied, effected, cloned, copied on or transferred to the corresponding tooth restoration. Thus the corresponding tooth restoration is modified simultaneously with the modification of the one tooth restorations. Hereby the dental technician or the user of the software can directly see how a modification will affect the look of two corresponding teeth. For the visual appearance and aesthetics of teeth, the corresponding teeth should preferably have the same size, shape etc.

In some embodiments the modification is performed on at least two tooth restorations, and the modified design is simultaneously transferred to the at least two corresponding tooth restorations on the other side of the jaw.

For some patients it can be an advantage that a number of teeth restorations can be modified as a group, and the modifications simultaneously cloned, copied or applied to the corresponding teeth restorations in the other side of the jaw. For example the restorations of the left central, tooth no. 8, the left lateral, tooth no. 7 and the left canine, tooth no. 6, in the upper jaw, can be modified globally as a group, and simultaneously the corresponding teeth restorations is modified, that is the right central, tooth no. 9, the right lateral, tooth no. 10, and the right canine, tooth no. 1 1 . In some embodiments the modification comprises designing the shape, form and/or size of the one or more teeth restorations.

In some embodiments the modification comprises providing the same length for the modified tooth restoration and the corresponding tooth restoration.

In some embodiments the modification comprises providing the same width for the modified tooth restoration and the corresponding tooth restoration. In some embodiments the method comprises rotation one or more tooth restorations without simultaneously rotating the corresponding tooth restorations. It is an advantage that the size and shape of the tooth restorations can be simultaneously cloned to the corresponding tooth restoration, since it provides an esthetic look of the teeth that the shape and size of the corresponding teeth are similar. Furthermore, it is an advantage that a tooth restoration can be rotated relative to its neighbor teeth without rotating its corresponding tooth restoration, because it may look natural and provide an esthetic look that a tooth is rotated relative to its neighbor teeth, also when its corresponding tooth on the other side of the median line of the jaw is not rotated similarly.

Disclosed is a method of virtually designing a number of 3D teeth restorations for a patient, wherein the method comprises:

- selecting a composed set of teeth comprising a number of 3D virtual teeth restorations arranged spatially relative to each other forming a high aesthetic composition, where each of the virtual teeth restorations is represented by a separate surface;

- applying the composed set of teeth to a virtual three dimensional representation of the patient's present oral situation to obtain an initial set of teeth comprising at least two or more of said 3D virtual teeth restorations; - defining a centre of modification in relation to the initial set of teeth; and

- modifying one or more parameters of two or more of the 3D virtual teeth restorations in the initial set of teeth to obtain a modified set of teeth restorations, where the magnitude of the modification of the one or more parameters depend on the distance to the centre of modification.

The teeth in the initial set of teeth may be the same teeth as those of the composed set of teeth, such as when the composed set of teeth only has the teeth which are to be designed. The difference between the initial set of teeth and the composed set of teeth can then be the relative location of the teeth in the sets of teeth. The initial set of teeth may have fewer or more teeth than the composed set of teeth. The common teeth shared by the composed and the initial set of teeth may be the same.

According to an aspect of the invention, disclosed is a method of designing a number of dental restorations for a patient, wherein the method comprises:

- selecting a composed set of teeth comprising a number of teeth, where the number of teeth are arranged spatially relative to each other forming a high aesthetic composition;

- applying the composed set of teeth to a virtual three dimensional representation of the patient's present oral situation to obtain an initial set of teeth;

- optionally modifying one or more parameters of one or more of the teeth in the initial set of teeth to obtain a modified set of teeth.

In some embodiments, one or more parameters of two or more of the teeth in the initial set of teeth to obtain a modified set of teeth, such as of three or more, such as of four or more. The advantage of modifying two or more teeth may be that the design process is faster compared to a process where the teeth are modified one at a time. Further, applying the exact same or very similar modifications to several teeth may provide that a more aesthetically composition is obtained compared to when the teeth are modified one at a time.

The dental restoration(s) may be the physical realisation of the designed modified set of teeth. Thus in order for physically providing the modified set of teeth to the patient, a number of dental restorations may be manufactured.

Consequently, it is an advantage that the method provides that larger dental restorations, such as partial or full dentures, can also easily and effectively be made using CAD technology.

Conventionally, primarily smaller dental restorations such as crowns and bridges on a couple of teeth are made using CAD technology. But by means of the present method, larger dental restorations can advantageously be made, because the designed dental restorations or teeth are made from an interrelated composed set of teeth, whereby it is easy and fast to design the new teeth, because the starting point is a set of teeth where the teeth are arranged spatially relative to each other forming a high aesthetic composition. Traditionally, the user would have to arrange every single tooth separately, which is very time consuming if several teeth should be designed. Thus traditionally, the teeth are stored separately in a CAD program, which is fine when making smaller dental restorations such as crowns and bridges, where only one or a few designed teeth are used. But according to the present method, the designed teeth are stored or can be composed as a whole set of interrelated teeth facilitating that larger dental restorations comprising a high number of teeth can be designed. A high aesthetic composition is defined as providing an aesthetically pleasing, visually pleasing, nice, beautifully looking, e.g. symmetrical, smile. It is an advantage that a user can create a set of teeth for a patient, where the starting point in the process is a composed set of teeth comprising a number of teeth. Thus the composed set of teeth is a number of teeth, i.e. more than one teeth, for example two teeth, four teeth, seven teeth or all teeth in the upper and/or lower arch of the mouth. The teeth in the composed set of teeth are arranged spatially relative to each other and interrelated with each other. The spatial arrangement or interrelation may comprise the position, direction, rotation, height etc. of the teeth relative to each other. Thus the composed set of teeth is an entirety of interrelated teeth, instead of a number of single, individual teeth which can be arranged side by side as known from prior art.

Thus it is an advantage of the invention that the user can create nice dental restorations or a nice set of teeth for the patient by using a composed set of teeth as a starting point. The composed set of teeth provides better quality and e.g. symmetry of the designed teeth.

It is an advantage that the composed set of teeth are interrelated, because this makes it very easy for the user to very quickly design a desired set of teeth. According to prior art computer-implemented methods of designing teeth, the separate teeth for making a dental work on more than one tooth is selected one by one, i.e. when making a bridge covering three teeth, three separate teeth was selected and arranged side by side on a line where the bridge should be. This in prior art the teeth must be modified individually, one at a time, and, it is highly probable that the modifications the user is making to one tooth will not match the modification of another tooth or of all the other teeth, so one little modification on one tooth can destroy the entire aesthetics, and the user must repeatedly perform new modifications to restore the aesthetics of all teeth. But when the starting point for designing a number of teeth is a number of composed, interrelated teeth, and not single teeth, it is much easier and faster for the user to design a nice set of teeth in a short time. The patient may have several different reasons for having a dental restoration made, for example cosmetic reasons if the patient wishes to have nicer teeth, for health reasons if the patient has bad or poor teeth, if the patient has been in an accident where some or all of his/hers teeth were broken etc..

Thus it is an advantage that the set of teeth can be designed to look very much or exactly like the patient's original non-broken set of teeth by selecting a composed set of teeth which resembles the patient's original set as good as possible and then modifying one or more parameters for the teeth corresponding to the patient's original set of teeth so that the modified set of teeth completely or nearly completely resembles the special look of the patient's original set of teeth.

The user can be a dental technician, a dentist etc.

It is an advantage that all the patient's teeth can be replaced with the teeth designed according to the method or just some of the patient's teeth can be replaced. The expression "set of teeth" means a number of teeth, e.g. six teeth or e.g. the complete set of teeth a patient can have.

The patient's oral situation can belong to one or more of the following cases:

- no teeth left;

- one or more teeth left;

- one or more preparations;

- one or more implants;

The present method is a method of designing a number of dental restorations, thus the method relates to the field of restorative dentistry or prosthodontics, also known as dental prosthetics or prosthetic dentistry, which is associated with missing or deficient teeth. Thus restorative and prosthetic dentistry are different technical fields than orthodontics. Orthodontics is concerned with displacement of teeth due to malocclusion, where the teeth are moved into desired positions by means of wires and brackets or braces or shells, which the patient must wear over longer time periods. Thus in orthodontics the teeth are displaced, whereas in restorative dentistry the teeth are restored, e.g. crowns, bridges, abutments, implants, dentures etc. are made and arranged in the patient's mouth. So in orthodontics the teeth are moved relative to each other, whereas in restorative dentistry one or more teeth are at least partly replaced with a restoration in the form of a crown, implant, denture etc. Or where a tooth is missing, a restoration is made, such that the missing tooth is replaced with a restoration, e.g. a pontic in a bridge, an implant etc.. Thus a dental restoration refers to the replacement of missing tooth structure.

Dental restorations may comprises crowns, bridges, pontics, abutments, implants, dentures, inlays, onlays, post and core or inlay core, removables etc.

In some embodiments the method comprises modifying the entire initial set of teeth collectively, when modifying the one or more parameters of teeth in the initial set of teeth.

It is an advantage that the user very quickly can modify one or more parameters for the entire initial set of teeth, since hereby the initial set of teeth can be designed quickly and reliable. It is an advantage that the user can visually see and therefore test and evaluate different modifications for the initial set of teeth to evaluate which set of teeth is the best for the specific patient. Thus collective modification of the entire initial set of teeth allows for easy and quick testing of different teeth designs and looks, and this interactive modification of the initial set of teeth is both an advantage for the patient and the user, since both can actually see the different ways the teeth can look like. Modifying the entire set of teeth collectively at one go may be denoted global modification or common modification or collective modification.

Modifying one tooth at a time may be denoted local modification or individual modification or separate modification or single modification.

Thus the method provides that the teeth can be modified both commonly and individually. This is an advantage because modifications which should apply for all teeth can be modified collectively in order to ensure a fast and identical modification, e.g. that all teeth should be 0.2 mm longer, whereas a modification which should just apply for a single tooth can be applied individually, e.g. if just one tooth should be a little crooked relative to the rest of the teeth.

It is an advantage that the method comprises the option of modifying the entire set of teeth collectively at a time or at one go, because this saves a lot of time for the user who is designing the set of teeth for the patient. Traditionally the user could only modify one tooth at a time, because software applications for teeth design or teeth restorations only supported the modification of one tooth at a time. Conventionally, designing entire teeth sets for a patient has previously been performed by manual handcraft, because modifying one tooth at a time digitally is also time consuming. It is therefore an advantage that several teeth or an entire set of teeth can be modified collectively, since it provides a better result and saves a lot of time.

It is an advantage that the teeth can be modified collectively due to their interrelation according to this method, because it makes it very easy for the user to very quickly design a nice set of teeth. According to prior art methods, only one tooth could be modified at a time, and if each tooth is modified separately, it is highly probable that the modifications the user is making to one tooth will not match the modification of another tooth or of all the other teeth, so one little modification on one tooth can destroy the entire aesthetics, and the user may repeatedly perform new modifications to compensate for the previous ones. But when the entire set of teeth can be modified as a whole according to the present method, it is much easier and faster for the user to design a nice set of teeth in a short time. A coordinate system for the whole or entire set of teeth may be defined, a coordinate system for each individual tooth may be defined, and a coordinate system for the face may be defined.

The different coordinate systems may be shown on the screen depending on the mode the program is in.

Each individual tooth in a set of teeth can be saved or stored individually, and its interrelation to the other teeth is also saved.

It is a further advantage that if the patient originally had quite short teeth for instance, and the patient has broken his teeth and wishes to have a new set of teeth looking like the original set of teeth, and if there is no composed set of teeth available that resembles the patient's original short teeth, then the initial set of teeth can collectively at one go become shortened, such that the finalised set of teeth really resembles the specific wishes of the patient. In some embodiments the method comprises modifying a number of teeth in the initial set of teeth collectively, when modifying the one or more parameters of teeth in the initial set of teeth.

Thus besides modifying the entire set of teeth at one go or modifying a single tooth at a time, a number of teeth can be modified collectively, i.e. a subset, e.g. five of the teeth, in a larger set of teeth can be modified collectively. This may be denoted group modification or subset modification.

In some embodiments the method comprises selecting at least a number of the designed dental restorations or teeth for manufacturing.

The modified set of teeth is the virtual design of the new set of teeth. In order for providing the new teeth to the patient a number of dental restorations may be required. Thus in order for manufacturing these new teeth, the required dental restorations may be determined. The dental restorations may be based on the difference between the existing teeth and the designed teeth in the modified set of teeth. If the patient e.g. misses an entire tooth or an entire tooth needs to be pulled out of the patient's mouth, then for example an implant with an abutment and/or crown or veneering may be manufactured and incorporated at the place of the missing tooth, or a bridge may be manufactured where a pontic is arranged at the place of the missing tooth. The bridge may be attached to the neighbor teeth, and thus the two neighbor teeth may be prepared by grinding them such that a crown can be attached on each neighbor teeth. Thus based on the modified set of teeth, it may be determined that one or more dental restorations are required to obtain the modified set of teeth, and these dental restorations may thus be designed. For example it may be determined that the modified set of teeth requires that a bridge is made, e.g two crowns with a pontic in between should be made and these two teeth should be prepared for attachment of the crowns, and one normal crown not included in a bridge may also be required as well as an implant with a crown on the implant abutment. In some embodiments the method comprises modifying one or more parameters of one or more of the teeth in the composed set of teeth before applying the virtual three dimensional representation of the patient's present oral situation to obtain a modified composed set of teeth.

It is an advantage that modifications can be made to the composed set of teeth, since hereby modifications which should for example definitely be made, can be made already up front in the design process. For example if the patient wishes that his central teeth should be crocked in a certain way, the user can make this modification to the central teeth in the composed set of teeth, such that the design with the crocked central teeth is the starting point for the potential further modifications. This may make the design process faster and more user-friendly, since the modifications can be performed in different steps. Thus modifications on the set of teeth can be made both before the patient's present oral situation or present set of teeth are applied to the composed set of teeth and after the patient's present oral situation or present set of teeth has been applied to the composed set of teeth. Thus the composed set of teeth may be a regular or template composed set of teeth or a modified composed set of teeth.

In some embodiments the method comprises obtaining the three dimensional virtual representation of the patient's present oral situation by scanning the present oral situation using an intraoral scanner and/or scanning the surface of a negative impression of the patient's present oral situation and/or scanning the surface of a positive model of the patient's present oral situation.

It is an advantage to obtain a 3D representation of the patient's present oral situation or present set of teeth since the composed set of teeth can be overlayed on the present teeth to match and/or compared the two sets of teeth, and when the virtual representation of the oral situation is obtained by some means of scanning, the representation can be of very high quality such that the final design or modified set of teeth will be of very high quality and with a good match to the remaining teeth.

In some embodiments the method comprises obtaining a three dimensional virtual representation of the patient's original unprepared set of teeth by scanning the original unprepared set of teeth using an intraoral scanner and/or scanning the surface of a negative impression of the patient's original unprepared teeth and/or scanning the surface of a positive model of the patient's original unprepared teeth. The three dimensional virtual representation of the original unprepared set of teeth can be obtained before the patient's teeth are prepared.

It is an advantage that before the set of teeth are prepared, a so called pre- preparation scan can be made, so that the patient's original set of teeth can be visualized too, so that the user can take account of the patient's original teeth when designing the new teeth in order to provide a modified set of teeth which is a perfect replica or imitation of the patient's original set of teeth, if this is what the patient wishes.

In some embodiments the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the curve of the teeth defined by the relative position of teeth. In some embodiments the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the scaling of the teeth.

The scaling of the teeth comprises the length, the width etc of the teeth. In some embodiments the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the rotation of teeth relative to the median line of the face.

In some embodiments the rotation of teeth relative to the median line of the face creates a composition or a combination of compositions selected from:

- a basic aesthetic composition;

- a strong aesthetic composition; or

- a soft aesthetic composition.

It is an advantage that the rotation of the teeth relative to the median line of the face can be modified, because this angle is important for the aesthetic look of the teeth. There may be three typical or classical aesthetic compositions for the rotation of the teeth; the basic aesthetic composition, where the rotation of the teeth is neutral or normal relative to the median line; the strong aesthetic composition, where the rotation is such that the distal point of a tooth is turned outwards relative to the median line; and the soft aesthetic composition, where the distal point of the tooth is turned inwards relative to the median line.

Thus it is an advantage that the rotation of the teeth provides one of or a combination of the three classical compositions.

In some embodiments the one or more parameters comprise:

- the geometric shape of the central teeth. In some embodiments the geometric shape of the central teeth is or is a combination selected from:

- an oval shape;

- a triangular shape; or

- a rectangular/square shape.

It is an advantage that the geometric shape of the teeth can be modified, because the shape of the teeth is important for the aesthetic look of the teeth. There may be three different typical or classical types of shape of a central tooth; an oval shape, where the light reflected from the labial surface of the tooth resembles a round or an oval shape; a triangular shape, where the light reflected from the labial surface of the tooth resembles a triangular shape; and a rectangular/square shape, where the light reflected from the labial surface of the tooth resembles a rectangular/square shape. In some embodiments the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the geometric shape of the premolars and/or molar.

For the premolar and molar teeth the geometric shape may be denoted e.g. N, T, K.

In some embodiments the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise: - the length of the teeth.

It is an advantage that the length of the teeth can be modified, because the length of the teeth is important for the aesthetic look of the teeth. Teeth length can be measured in millimeters or other measuring systems.

- the length of the teeth relative to other teeth.

It is an advantage that the relative length of the teeth can be modified, because the relative length of the teeth is important for the aesthetic look of the teeth.

- the size of specific teeth relative to other specific teeth.

- the size of lateral teeth relative to the central teeth.

It is an advantage that the size of e.g. the lateral teeth relative to the central teeth can be modified, because the relative size the teeth, or the size of the lateral teeth relative to other teeth, is important for the aesthetic look of the teeth.

For example the size of the lateral teeth may be about 61 .8% of the size of the central teeth, which corresponds to the golden proportion which the human brain experiences as visually pleasing or attractive. Another example it that the laterals may be 77% the size of the centrals, which however may appear to be too large for some patients. Yet another example it that the laterals may be 2/3 the size of the centrals. However, the size of the lateral teeth relative to the central teeth may be any other relation decided by the user and/or the patient. In some embodiments the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the size of cuspid teeth relative to the lateral teeth. It is an advantage that the size of e.g. the cuspid or canine teeth relative to the lateral teeth can be modified, because the relative size the teeth, or the size of teeth relative to other teeth, is important for the aesthetic look of the teeth.

For example the size of the cuspid or canine teeth may about 61 .8% of the size of the lateral teeth, which corresponds to the golden proportion which the human brain experiences as visually pleasing or attractive. Another example it that the cuspids may be 2/3 the size of the laterals, which however may appear to be too large for some patients. However, the size of the cuspids teeth relative to the lateral teeth may be any other relation decided by the user and/or the patient.

- the size of the gap between teeth.

It is an advantage that the size of the gap between teeth can be modified, because the size of the gap between teeth is important for the aesthetic look of the teeth. The gap between the central teeth in the upper and/or lower arch may be modified, and this gap is the most visual gap. However, all or some gaps may be modified.

- shape of the teeth.

It is an advantage that the shape or morph of the teeth can be modified, because the general shape of the teeth is important for the aesthetic look of the teeth. Shaping or morphing may comprise smoothing, deforming, relocating, deleting or adding material. E.g. when relocating material, material from the thickest part of a tooth can be moved to a narrower part of the tooth.

In some embodiments the method comprises mirroring of teeth.

It is an advantage that mirroring can be performed, because then the user does not need to work on or modify all teeth which should be designed, the user can just design teeth in e.g. the left side of an arch, and then mirror the designed teeth to the right side of the arch. One or more teeth can be mirrored.

It is an advantage that mirroring can be performed, if the patient needs to have one or more teeth in e.g. his/hers left side of an arch designed, then the patient's real, unbroken teeth in the right side of the arch can be resembled or scanned and copied to the left side of the arch by mirroring. In some embodiments the method comprises cloning of teeth.

Cloning may comprise copying of teeth or creating new teeth similar to other teeth. The cloning may be cloning from one or more existing teeth, cloning from one or more pre-prepared teeth, i.e. before they were prepared, cloning from one or more teeth in a wax up scan etc.

In some embodiments the method comprises providing collision mapping relative to the antagonist.

It is an advantage that the collision mapping with the antagonist can be provided, because hereby it is easy and fast for the user to check if there is actually space enough for the designed teeth in the mouth of the patient.

In some embodiments the method comprises virtually fitting the modified set of teeth to a virtual retention means.

The virtual retention means corresponds to the real retention means. The retention means is/are adapted for retaining the dental restorations, i.e. the new teeth. The dental restorations may be denoted the new teeth, the physical realization of the modified set of teeth, prosthesis or prosthetic parts. Thus the retention means may be the preparation tooth or die for a crown or bridge, the retention means may be the jaw bone for an implant, the retention means may be the implant for an abutment, the retention means may be the abutment for a crown, the retention means may be the artificial gingival part of a denture,

Thus the dental restorations or one or more of the artificial teeth in the modified set of teeth may be attached to a retention means, such as to one or more retention means. If the modified set of teeth is a bridge, then the retention means may be two prepared teeth or dies. If the modified set of teeth is a number of teeth for a full or partial denture, the retention means may be the gingival part of the denture.

Fitting may also be denoted connecting.

The set of teeth may be attached to the retention means.

Thus designing a number of dental restorations may comprise determining the attachment of the dental restorations to the retentions means for realizing the modified set of teeth.

In some embodiments the method comprises cutting the modified set of teeth to the retention means.

Cutting may also be denoted virtual cutting or digital cutting.

It is an advantage that the set of teeth is not virtually fitted, aligned or fixed to the retention means before the designing of the set of teeth is completed, because it may be easier and visually better to design the teeth when they are not fitted to the retention means. Furthermore, it requires less processing power of the processing unit to modify and/or move the set of teeth in the coordinate system, when the set of teeth is not fitted or fixed in the correct position, e.g. the anatomical position. The correct position may be based on the position of the retention means, such as preparations, and/or based on the margin line from a real or virtual model of the patient's teeth. The transition or interface between the retention means, such as an existing preparation tooth, and the modified set of teeth may be determined by a joint spline, and thus the retention means and the modified set of teeth each have a spline, and these two splines are fitted together or joined at the transition or interface.

The transition or interface between the retention means and the modified set of teeth may be determined for determining the dental restorations, e.g. the shape, size, internal form, external form, thickness etc. The internal surface of the set of teeth or the dental restorations should fit onto, be cut, or connect to the external surface of the retention means. The internal surface of the dental restorations may correspond to the shape of the external surface of the retention means. There may be a cement gap between the dental restorations and the retention means, and this cement gap may have the same thickness along the entire surface or the thickness may vary, e.g. due to drill compensation etc.

Thus the set of teeth may comprise dental restorations, which may comprise or be a crown, which may be glued to a prepared tooth, a bridge that may be glued to one or more prepared teeth, a crown that may be glued to an implant abutment where the implant is screwed into the jaw bone, the set of teeth for a denture that may be inserted in the gingival part of the denture which is arranged, either removably or fixed, in the patients mouth.

In some embodiments the method comprises virtually cutting the modified set of teeth to the gingival.

The virtual cutting may be performed automatically. After designing the new teeth, the new teeth should be cut to the gingival of the virtual model so that the dental restorations, e.g. artificial teeth, produced based on the designed modified set of teeth will fit to the real gingival in the patient's mouth in cases where the dental restoration is close to or in contact with the gingival. In case of a denture, the modified set of teeth may virtually be cut to the gingival, whereby the artificial teeth in the denture are produced so that they fit to the artificial gingival of the denture. The part of the artificial teeth which will be visible in the denture may be designed to fit to the gingival. There may be a part of the artificial teeth which will be non-visible in the denture, because they are arranged inside the gingival part of the denture. The artificial gingival is typically made of an acrylic material.

A pontic in a bridge may be automatically cut or fitted to a preparation line or margin line in the gingival.

The preparation line or margin line may be for the pontic. A gap or space between the pontic and the gingival may be defined. There may be no gap between the pontic and the gingival and this may correspond to a gap of zero millimeters.

A crown may be automatically cut or fitted to a preparation line or margin line in the gingival.

A gap or space between the crown and the gingival may be defined, and the gap may be zero millimeters.

In some embodiments the method comprises fitting the modified set of teeth to its anatomical correct position in the gingival.

It is an advantage that the set of teeth is not fitted, aligned or fixed to the gingival before the designing of the set of teeth is completed, because it is easier and visually better to design the teeth when they are not fitted to the gingival. Furthermore, it requires less processing power of the processing unit to modify and/or move the set of teeth in the coordinate system, when the set of teeth is not fitted or fixed in the correct anatomical position. The correct anatomical position may be based on the position of the retention means, such as preparations, and on the margin line from a real or virtual model of the patient's teeth.

The transition between an existing preparation tooth and the new, designed tooth may be determined by a joint spline, and thus the preparation and the designed tooth each have a spline, and these two splines are fitted together or joined at the transition.

In some embodiments the set of teeth may be fitted/cut to the retention means and/or to the gingival before the set of teeth becomes the modified set of teeth. This may increase the processing time as the interface between the set of teeth and the retention means and/or gingival should then be calculated each time any change is made to the set of teeth, but it may in some cases be preferred by the user that the set of teeth is visualized correctly relative to the gingival.

In some embodiments the method comprises virtually designing the retention means.

If for example the retention means, e.g. a tooth, is not prepared for attachment of the dental restoration(s) before the virtual three dimensional representation of the patient's oral situation is obtained, then the retention means may be virtually designed. The retention means may be designed based on the modified set of teeth and the dental restorations.

The retention means may also be virtually designed even though they were already prepared prior to the virtual three dimensional representation of the patient's oral situation was obtained, because the designed modified set of teeth or dental restoration may require or gain from that the retention means were prepared differently. In some embodiments the method comprises adding virtual guiding lines to be overlaid on the teeth.

It is an advantage that by adding guiding lines it becomes easier for the user to control the modifications of e.g. the rotation or angles of the teeth relative to each other, or modifying e.g. the length of teeth, since the length of the teeth can be measured by means of the guiding lines. In some embodiments the method comprises designing dental restorations or teeth in the lower and/or upper arch and fitting the lower and upper arch together. In some embodiments the composed set of teeth comprises a composed set of anterior teeth and a composed set of molar teeth, where each of the composed sets of teeth is selected separately.

It is an advantage that different parts of the composed set of teeth can be selected separately, since this provides even further options for designing an obtaining a desired modified set of teeth.

In some embodiments the composed set of teeth is selected from an electronic library comprising a number of different composed sets of teeth, where the composed sets of teeth can be standard sets of teeth and/or can be added to the electronic library by the user.

It is an advantage that the composed sets of teeth can comprise typical combinations of the parameters which determine the set of teeth. For example the composed sets of teeth can comprise a strong composition with rectangular teeth, soft composition with rectangular teeth, a soft composition with oval teeth etc.

In some embodiments the method further comprises that the user has the option of generating the composed set of teeth by defining the one or more parameters of the composed set of teeth.

It is an advantage that a composed set of teeth can be generated dynamically this way. The parameters may be selected from the same set of parameters used when modifying the composed set of teeth. The user defines a number of parameters for the composed set of teeth, which could be the curve or smile curve, i.e. the relative position of the teeth and the height of teeth, the aesthetic composition, i.e. the rotation of the teeth, for example the basic, strong or soft composition, the shape of the central or front teeth, e.g. oval, triangular or rectangular shape terms, and the shape of the premolars and molars, and a composed set of teeth will be generated based on that. In some embodiments the method comprises designing a permanent or a temporary prosthesis.

In some embodiments the method comprises designing a partial denture prosthesis or a full denture prosthesis.

The denture can be a removable or fixed denture.

In some embodiments the method comprises scanning the contours of the patient's face by means of a face scanner for designing the dental restorations or set of teeth taking the patient's face into consideration.

It is an advantage to design the set of teeth taking the patient's face into consideration, because then the teeth can be adjusted to match the face, e.g. oval teeth may suit an oval face form, long teeth may suit an oblong face form etc. or vice versa. When performing a face scan, the midline is found, which can be advantageous or useful to use, when designing the teeth.

Alternatively and/or additionally, X-ray scanning can be used for obtaining information about the patient's face or bone structure, and this information can be used for designing the dental restorations or new teeth.

In some embodiments the method is configured to be performed in an existing electronic program for digital dental restoration work.

The present invention relates to different aspects including the methods described above and in the following, and corresponding methods, devices, systems, uses and/or product means, each yielding one or more of the benefits and advantages described in connection with the first mentioned aspect, and each having one or more embodiments corresponding to the embodiments described in connection with the first mentioned aspect and/or disclosed in the appended claims.

In particular, disclosed herein is a computer program product comprising program code means for causing a data processing system to perform the method, when said program code means are executed on the data processing system.

Disclosed is also a computer program product comprising a computer- readable medium having stored there on the program code means.

In particular, disclosed herein is a system for virtually designing a number of 3D teeth restorations for a patient, where the system comprises:

- means for providing a number of initially composed 3D virtual teeth restorations, where each of the virtual teeth restorations is represented by a separate surface; - means for defining a centre of modification in relation to the initially composed 3D virtual teeth restorations; and

- means for modifying the shapes and/or the positions of at least two of the initially composed 3D virtual teeth restorations simultaneously to obtain a modified set of 3D virtual teeth restorations, where the magnitude of the modification depends on the distance to the centre of modification.

In particular, disclosed herein is a system for designing a number of dental restorations for a patient, wherein the system comprises: - means for selecting a composed set of teeth comprising a number of 3D virtual teeth restorations arranged spatially relative to each other forming a high aesthetic composition, where each of the virtual teeth restorations is represented by a separate surface;

- means for applying the composed set of teeth to a virtual three dimensional representation of the patient's present oral situation to obtain an initial set of teeth comprising at least two or more of said 3D virtual teeth restorations;

- means for defining a centre of modification in relation to the initial set of teeth; and

- means for modifying one or more parameters of two or more of the 3D virtual teeth restorations in the initial set of teeth to obtain a modified set of teeth restorations, where the magnitude of the modification of the one or more parameters depend on the distance to the centre of modification.

- means for providing a number of initially composed 3D virtual teeth restorations;

- means for modifying at least two of the initially composed 3D virtual teeth restorations simultaneously to obtain at least two modified 3D teeth restorations.

In particular, disclosed herein is a system for designing a number of dental restorations for a patient, wherein the system comprises: - means for selecting a composed set of teeth comprising a number of teeth, where the number of teeth are arranged spatially relative to each other forming a high aesthetic composition;

- means for applying the composed set of teeth to a virtual three dimensional representation of the patient's present oral situation to obtain an initial set of teeth;

- means for optionally modifying one or more parameters of one or more of the teeth in the initial set of teeth to obtain a modified set of teeth. The methods and systems may be computer-implemented methods and systems for computer-implemented design. The systems may be computer- implemented systems.

Designing a number of dental restorations may be denoted designing a set of teeth, thus disclosed is a method of designing a set of teeth for a patient, wherein the method comprises:

Disclosed is also a dental restoration for a patient designed by means of the method according to any of the embodiments.

Disclosed is also a non-transitory computer readable medium storing thereon a computer program, where said computer program is configured for causing computer-assisted generation of dental preparation guide configured for validating the preparation of at least one tooth for a dental restoration by performing the method of any one of the embodiments.

Brief description of the drawings

The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non- limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:

Fig. 1 shows an example of a flow chart of the method.

Fig. 2 shows an example of a composed set of teeth.

Fig. 3 shows an example of modification of a composed set of teeth.

Fig. 4 shows an example of a patient's present oral situation. Fig. 5 shows an example of an initial set of teeth, where the composed set of teeth is applied to the patient's present oral situation.

Fig. 6 shows examples of collective modifications of different parameters of the initial set of teeth using a prior art method.

Fig. 7 shows examples of individual modifications of different local parameters of the initial set of teeth.

Fig. 8 shows an example of a finalised set of teeth.

Fig. 9 shows examples of retention means for the designed set of teeth. Fig. 10 shows an example of an initial composed set of teeth restorations.

Fig. 1 1 shows examples of simultaneous symmetric designing of teeth restorations.

Fig. 12 shows an example of mirroring a design of a tooth restoration.

Fig. 13 shows examples of designing teeth restorations by global morphing/repositioning.

Detailed description

In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

The method is performed in a computer program suitable for performing the method. A screen connected to the computer may be provided on which the user can view the user interface of the program, and by means of e.g. a computer keyboard, a computer mouse, a touch screen, a space ball, a touchpad etc. the user can perform demands, such as selecting features and modifying parameters or features viewed on the screen. The program performs calculations or shows the changes on the screen view corresponding to the demands the user has made. The program, in which the method can be performed, can be a part of a larger program, it can be a separate program, the program can have means for communicating with other programs, other hardware, software or firmware etc.

Fig. 1 shows an example of a flow chart of the method. In step 101 a composed set of teeth is selected, where the composed set of teeth comprises a number of teeth, and where the number of teeth are arranged spatially relative to each other.

In step 102 a virtual three dimensional representation of the patient's present oral situation is provided.

In step 103 the composed set of teeth is applied to the virtual three dimensional representation of the patient's present oral situation to obtain an initial set of teeth.

In step 104 one or more parameters of two or more of the 3D virtual teeth restorations in the initial set of teeth are modified to obtain a modified set of teeth restorations, where the magnitude of the modification of the one or more parameters depend on the distance to the centre of modification.

Fig. 2 shows an example of a composed set of teeth.

The composed set of teeth 201 is in this example seen from below and is the teeth of the upper arch. The figure shows an example of the curve of the teeth defined by the relative position of teeth. The composed set of teeth can be selected from an electronic library containing a number of different composed set or teeth, or the user can design the composed set of teeth himself by defining one or more parameters for the teeth. The teeth in the composed set of teeth 201 are arranged relative to each other, they are interrelated spatially.

The teeth in the composed set of teeth 201 can be selected based on a number of parameters, such as size, shape etc.

The median line 206 is shown and a line 212 perpendicular to the median line is shown. The function of the line 212 is for improved visual direction for the user. Thus a global coordinate system for the complete composed set of teeth is defined, whereby rotation, positioning etc. can be controlled for the complete composed set of teeth. The box 213 around the first molar tooth indicates that a coordinate system can be defined for each tooth, whereby rotation, positioning etc. can be controlled for each individual tooth. Fig. 3 and the following figures show screen-shots from a program where the method can be performed. Fig. 3 shows an example of modification of a composed set of teeth using a prior art method.

A tooth 305 in a composed set of teeth 301 is modified individually. In this example, the tooth 305 is rotated relative to the median line 306. A coordinate system 307 specific for the tooth 305 is shown on the tooth 305 for indicating to the user that that the program is in the mode, where the tooth can be modified with respect to positioning, e.g. rotation, translation etc. The tooth can also be modified for example with respect to shape, e.g. length, thickness, distribution of mass etc. Fig. 4 shows a three dimensional virtual representation of a patient's present oral situation.

The present oral situation 402 is in this example a case where the right central teeth 408, which may be denoted no. 9 in some dental notations, is prepared for a crown, the left central teeth no. 8, 409 is missing, the lateral teeth no. 7, 410, is also prepared for a crown, and the canine or cuspid no. 6, 41 1 , is unmodified and not prepared for a dental restoration.

The three dimensional virtual representation can be obtained by scanning the patient's present oral situation or set of teeth using an intraoral scanner and/or scanning the surface of a negative impression of the patient's present teeth and/or scanning the surface of a positive model of the patient's present teeth.

Fig. 5 shows an example of an initial set of teeth, where the composed set of teeth is applied to the patient's present oral situation.

The initial set of teeth 503 is a combination of the composed set of teeth 501 and the patient's present oral situation 502. In this case, four teeth, 508, 509, 510, 51 1 , from the composed set of teeth 501 are applied to the present oral situation 502. However, in other cases, all teeth from a composed set of teeth may be applied to the present oral situation, such that no present or original teeth are left. In other cases, more or less than four teeth from the composed set of teeth are applied to the present oral situation, depending on how many teeth the patient wishes to have exchanged.

Fig. 6a shows an example of collective rotation of the initial set of teeth.

The parameter which is collectively modified is in this example rotation, and the modification is performed on the composed four teeth, 608, 609, 610, 61 1 , in the initial set of teeth 603 with respect to the median line. The four composed teeth 608, 609, 610, 61 1 are all four rotated collectively so that they all have become skew with respect to the remaining teeth in present oral situation. The global or common rotation is indicated with a circle 614 with markers, and it is clearly seen that the composed teeth have been rotated simultaneously and uniformly or identically, for example if comparing the length of tooth 61 1 with the length of the corresponding teeth 51 1 in fig. 5. This is an example of global rotation, where a number of teeth are rotated collectively, i.e. simultaneously and e.g. identically.

Fig. 6b) shows an example of collective shaping of the initial set of teeth using a prior art method.

The parameter which is changed in order to collectively modify the teeth restorations is in this example the shape of the teeth, and the modification is performed on the composed four teeth 608, 609, 610, 61 1 , in the initial set of teeth 603. The composed teeth 608, 609, 610, 61 1 are all four collectively reshaped or morphed such that their shape or geometry is changed simultaneously and uniformly or identically. The global or common shaping or morphing is indicated by dots 615 on the collectively modified teeth and by dots 616 forming a line along the biting edge of the collectively modified teeth. It is seen that the teeth 608, 609, 610, 61 1 have been collectively shaped or morphed with a centre of modification at the mesial point of the biting edge of tooth 609, and that the shaping or morphing is directed to a small compression at the centre of modification, whereby the two central teeth 609, 608 have got sloped biting edges, which are in opposite directions. The other composed teeth 610, 61 1 are only slightly reshaped or morphed as a result of the collective shaping or morphing with centre of modification at tooth 609.

Fig. 7 shows examples of individual modifications of different local parameters of the initial set of teeth using a prior art method. Fig. 7a) shows an example of individual scaling of a single tooth in the initial set of teeth.

The parameter which is individually modified is in this example scaling, and the tooth 708 in the initial set of teeth 703 is modified. The other teeth 709, 710, 71 1 are not modified in this example. The coordinate system 717 indicates the scaling of the tooth 708. By means of the scaling, tooth 708 can become bigger or smaller, longer or shorter, wider of narrower. In this case, the tooth 708 has been modified to be longer than before, i.e. tooth 708 is made longer than it was in the composed set of teeth. When moving for example a pointer arrow by means of e.g. a computer mouse over a single tooth then the coordinate system 717 for that tooth is seen when the program is in the individual scaling mode

Fig. 7b) shows an example of individual rotation of a single tooth in the initial set of teeth. The parameter which is individually modified is in this example rotation, and it is the tooth 708 in the initial set of teeth 703 which is modified. The other teeth 709, 710, 71 1 are not modified in this example. The initial set of teeth 703 is seen from below in this figure instead of from the front as in the other figures, since the individual rotation is better illustrated in this view. The rotation system 718 indicates the rotation of the tooth 708. The tooth 708 has been rotated with respect to the median line such that the mesial part of the tooth 708 points more outwards. Fig. 8 shows an example of a finalised set of teeth.

The finalised set of teeth 804 is obtained when the modifications of the initial set of teeth are finished and no more modifications will be performed. The finalised set of teeth 804 is the set of the teeth that will be manufactured and inserted into the patient's mouth. The modified set of teeth may be manufactured as a number of dental restorations.

Fig. 9 shows examples of retention means for the designed set of teeth.

Fig. 9a) shows an example where the retention means is a patient's present oral situation 902, which is in this example a case where the right central teeth 908, which may be denoted no. 9 in some dental notations, is prepared for a crown, the left central teeth no. 8, 909 is missing, the lateral teeth no. 7, 910, is also prepared for a crown, and the canine or cuspid no. 6, 91 1 , is unmodified and not prepared for a dental restoration.

The present oral situation 902 can be represented by a three dimensional virtual representation of the patient's present set of teeth or missing set of teeth. The three dimensional virtual representation can be obtained by scanning the patient's present oral situation or set of teeth using an intraoral scanner and/or scanning the surface of a negative impression of the patient's present teeth and/or scanning the surface of a positive model of the patient's present teeth. Fig. 9b) shows an example where the retention means is an implant bridge 919 onto which a full denture is adapted to be arranged. On the side opposite to where the denture should be attached, the implant bridge 919 comprises protrusions 920 from holes for receiving implants (not shown). The implant bridge may a standard bridge. Alternatively, the implant bridge may be customized for the patient and may be modelled automatically based on the shape of the patient's dental arch. The patient's dental arch may be determined by means of scanning the patient's mouth using an intraoral scanner and/or scanning the surface of a negative impression of the patient's mouth and/or scanning the surface of a positive model of the patient's mouth.

Fig. 9c) shows an example where the retention means is an implant bridge 919 comprising pins 921 where each pin is adapted to receive an artificial tooth having a hole in it for fitting over the pin, or where the pin is adapted to be covered by veneering in the form of e.g. ceramics or composite material for resembling teeth. On the side opposite to the pins 921 , the implant bridge 919 comprises protrusions 920 from holes for receiving implants (not shown). The implant bridges shown in fig. 9c) may be difficult to model automatically because the final shape of such an implant bridge is customized to the dental arch and the denture and as seen from the figures the implant bridges are not primarily based on standard geometrical forms. The implant bridge in fig. 9c) may therefore be provided by cut-back of the preliminary model of the denture. From the figure it can be seen that the cut-back vary from tooth to tooth depending on the position of the tooth. The cut-back also varies depending on the type of the tooth and from which side of the tooth the cutback is provided.

Fig. 10 shows an example of an initial composed set of teeth restorations. The initially composed virtual teeth restorations 1001 are the six anterior teeth in the upper jaw of a patient. The present teeth in the patient's mouth are the teeth 1002. The restorations are the left canine, tooth no. 6, which has reference number 1006; the left lateral, tooth no. 7, which has reference number 1007; the left central, tooth no. 8, which has reference number 1008; the right central, tooth no. 9, which has reference number 1009; the right lateral, tooth no. 10, which has reference number 1010; and the right canine, tooth no. 1 1 , which has reference number 101 1 .

In fig. 10a) the initial composed set of teeth restorations 1001 are seen in a front view in the graphical user interface of the software program for performing the method.

In fig. 10b) the initial composed set of teeth restorations 1001 are seen in a bottom view.

Even though the initial composed set of teeth restorations in fig. 10 provide an aesthetic look, and a beautiful smile, the patient, the dental designer and/or the dentist may still wish to modify the initial composed teeth restorations, for example to make them visually fit better to the patient's existing teeth and/or to make the teeth restorations look more like the original teeth the patient had in the places where the teeth restorations is to be arranged. Thus the initial composed set of teeth restorations may be modified.

In fig. 1 1 a modification is performed on one tooth restoration and the modified design is then simultaneously cloned, copied or applied to the corresponding tooth restoration on the other side of the median line of the jaw.

In fig. 1 1 a) the right central restoration of tooth no. 9 with reference number 1 109 is marked or activated for modification, which is visualised by modification lines and markers 1 1 17.

In fig. 1 1 b) the right central tooth restoration 1 109 is modified by extending its length, and it is seen that the corresponding tooth restoration, which is the left central, tooth no. 8, with reference number 1 108, of the modified tooth restoration 1 109, is simultaneously modified correspondingly, namely extending the length of the tooth restoration 1 108. Hereby both tooth restorations, 1 109 and 1 108, are now longer than in the initial composed set of teeth restorations.

The two corresponding tooth restorations are extended with the same length, so if they had the same length before the modification, the will also have the same length after the modification. But if they did not have the same length before the modification, they may also have different lengths after the modification.

Alternatively, the modification of the length may provide that the lengths of two corresponding tooth restorations become equal, even though the lengths were not the same before the modification. In fig. 1 1 c) the left lateral restoration of tooth no. 7 with reference number 1 107 is marked or activated for modification, which is visualised by modification lines and markers 1 1 17.

In fig. 1 1d) the left lateral tooth restoration 1 107 is modified by extending its length, and it is seen that the corresponding tooth restoration, which is the right lateral, tooth no. 10, with reference number 1 1 10, of the modified tooth restoration 1 107, is simultaneously modified correspondingly, namely extending the length of the tooth restoration 1 1 10. Hereby both tooth restorations, 1 107 and 1 1 10, are now longer than in the initial composed set of teeth restorations.

The lengths of the two tooth restorations, 1 107 and 1 1 10, are not the same, tooth restoration 1 107 is longer than tooth restoration 1 1 10.

In fig. 1 1 e) the right canine restoration of tooth no. 1 1 with reference number 1 1 1 1 is marked or activated for modification, which is visualised by modification lines and markers 1 1 17. In fig. 1 1f) the right canine tooth restoration 1 1 1 1 is modified by extending its depth, and it is seen that the corresponding tooth restoration, which is the left canine, tooth no. 6, with reference number 1 106, of the modified tooth restoration 1 1 1 1 , is simultaneously modified correspondingly, namely extending the depth of the tooth restoration 1 106. Hereby both the teeth restorations, 1 106 and 1 1 1 1 , now have a bigger depth than in the initial composed set of teeth restorations.

The above examples show that the length and depth of teeth restorations can be modified using symmetric simultaneous designing. However, for example the width of teeth restorations may also be modified, and other dimensions of the teeth restorations may also be modified by means of simultaneous symmetric design of corresponding teeth restorations. Fig. 12 shows an example of mirroring a design of a tooth restoration.

In fig. 12a) an initial composed set of teeth restorations 1201 are seen.

In fig. 12b) the left central tooth restoration 1208, tooth no. 8, in the upper jaw has been designed, such as modified by extending the length of the tooth restoration. Now the user wishes to mirror the design of the tooth restoration 1208 to the corresponding tooth restoration, which is the right central tooth restoration 1209, tooth no. 9. This is indicated by the horizontal arrow 1222 pointing from the tooth restoration 1208 to the tooth restoration 1209.

In fig. 12c) the result of the mirroring of the design of tooth restoration 1208 to the tooth restoration 1209 is seen.

In fig. 13a) an initial composed set of teeth restorations 1301 are seen in a front view.

In fig 13b) the initial composed set of teeth restorations 1301 are seen from below. The initially composed virtual teeth restorations 1301 are the six anterior teeth in the upper jaw of a patient.

Two sections 1323 of a circle are seen encircling the teeth restorations, and this defines the circle of influence of the modification to the teeth restorations. The circle sections 1323 encircles the two central teeth restorations, 1308 and 1309, and the two lateral teeth restorations, 1307 and 1310, and the circle sections 1323 pass through the two canine teeth restoration 1306 and 131 1 . The location of the circle sections 1323 indicates which of the teeth restorations that are selected for a global or group morphing or positioning or repositioning. In this case the two central tooth restorations and the two lateral tooth restorations are selected for global morphing/positioning.

In fig. 13c) teeth restorations 1307, 1308 and 1309 are selected/marked/indicated for global morphing/positioning, which can be seen by the locations of the circle sections 1323 which encircle these three teeth restorations.

In fig. 13d) teeth restorations 1308, 1309 and 1310 are selected/marked/indicated for global morphing/positioning, which can be seen by the locations of the circle sections 1323 which encircle these three teeth restorations. The teeth restorations 1308, 1309 and 1310 are globally morphed, where the direction of the morphing is outwards, which is vertically upwards on the figure.

Thus the teeth restorations which are in the circle of influence marked by the circle sections 1323 are morphed/positioned with basis in the centre of modification (not shown) of the circle sections 1323. The centre of modification is defined in the tooth restoration 1309, and this tooth restoration is therefore morphed/repositioned the most when using this software feature. The teeth restorations 1308 and 1310, which are also within the circle sections 1323, have a larger distance to the centre of modification, and these teeth restorations are morphed/repositioned less than tooth restoration 1309. Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilised and structural and functional modifications may be made without departing from the scope of the present invention.

In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The features of the method described above and in the following may be implemented in software and carried out on a data processing system or other processing means caused by the execution of computer-executable instructions. The instructions may be program code means loaded in a memory, such as a RAM, from a storage medium or from another computer via a computer network. Alternatively, the described features may be implemented by hardwired circuitry instead of software or in combination with software.

Claims

Claims:

1 . A method of virtually designing a number of 3D teeth restorations for a patient, where the method comprises:

- modifying the shapes and/or the positions of at least two of the initially composed 3D virtual teeth restorations simultaneously to obtain a modified set of 3D virtual teeth restorations, where the magnitude of the modification depends on the distance to the centre of modification.

2. The method according to any one or more of the preceding claims, wherein the relative positions of the teeth restorations are modified simultaneously.

3. The method according to any one or more of the preceding claims, wherein the positions of the virtual teeth restorations relative to each other are maintained.

4. The method according to any one or more of the preceding claims, wherein the contact between the virtual teeth restorations are maintained.

5. The method according to any one or more of the preceding claims, wherein predefined contact points between the virtual teeth restorations are maintained.

6. The method according to any one or more of the preceding claims, wherein the centre of modification is defined in or on one tooth restoration.

7. The method according to any one or more of the preceding claims, wherein the position of the centre of modification tooth restoration is modified maximally.

8. The method according to any one or more of the preceding claims, wherein the magnitude of the modification for one of said separate virtual surfaces differs from the magnitude of the modification for another one of said separate virtual surface.

9. The method according to any one or more of the preceding claims, wherein the positions of the different 3D points of the virtual teeth restorations are modified relatively with the distance to the centre of modification.

10. The method according to any one or more of the preceding claims, wherein the positions of the virtual teeth restorations closest to the centre of modification are modified more than the positions of the virtual teeth restorations most far away from the centre of modification, such as wherein the positions of the virtual teeth restorations are modified proportionally with the distance to the centre of modification.

1 1 . The method according to any one or more of the preceding claims, wherein the positions of the virtual teeth restorations are modified inversely proportional with the distance to the centre of modification

12. The method according to any one or more of the preceding claims, wherein the positions of the different 3D points of the teeth restorations are modified proportionally with the distance to the centre of modification

13. The method according to any one or more of the preceding claims, wherein the positions of the teeth restorations are modified based on a Gaussian function.

14. The method according to any one or more of the preceding claims, wherein the positions of the teeth restorations are modified by translations and/or rotations.

15. The method according to any one or more of the preceding claims, wherein the positions of the teeth restorations are modified by translations, when the teeth restorations are viewed in a front view.

16. The method according to any one or more of the preceding claims, wherein the positions of the teeth restorations are modified by translations and rotations, when the teeth restorations are viewed in an occlusal view.

17. The method according to any one or more of the preceding claims, wherein modifying the teeth restorations comprises morphing the 3D shape of the teeth restorations.

18. The method according to any one or more of the preceding claims, wherein the size of the teeth restorations is kept constant while morphing the one or more teeth restorations.

19. The method according to any one or more of the preceding claims, wherein the aspect ratio of the teeth restorations is kept constant, while morphing the one or more teeth restorations.

20. The method according to any one or more of the preceding claims, wherein the length/width relationship of the teeth restorations is kept constant while morphing the one or more teeth restorations.

21 . The method according to any one or more of the preceding claims, wherein the modification is performed on one tooth restoration, and the modified design is simultaneously transferred to the corresponding tooth restoration, such as a corresponding tooth restoration on the other side of the jaw or a corresponding tooth restoration in the antagonist.

22. The method according to any one or more of the preceding claims, wherein the modification is performed on at least two tooth restorations, and the modified design is simultaneously transferred to the at least two corresponding tooth restorations on the other side of the jaw.

23. The method according to any one or more of the preceding claims, wherein the modification comprises designing the shape, form and/or size of the one or more teeth restorations.

24. The method according to any one or more of the preceding claims, wherein the modification comprises providing the same length for the modified tooth restoration and the corresponding tooth restoration.

25. The method according to any one or more of the preceding claims, wherein the modification comprises providing the same width for the modified tooth restoration and the corresponding tooth restoration.

26. The method according to any one or more of the preceding claims, wherein the method comprises rotating one or more tooth restorations without simultaneously rotating the corresponding tooth restorations.

27. A method of virtually designing a number of 3D teeth restorations for a patient, wherein the method comprises:

- applying the composed set of teeth to a virtual three dimensional representation of the patient's present oral situation to obtain an initial set of teeth comprising at least two or more of said 3D virtual teeth restorations;

- defining a centre of modification in relation to the initial set of teeth; and

28. The method according to any one or more of the preceding claims, wherein the method comprises modifying the entire initial set of teeth collectively, when modifying the one or more parameters of teeth in the initial set of teeth.

29. The method according to any one or more of the preceding claims, wherein the method comprises modifying a number of teeth in the initial set of teeth collectively, when modifying the one or more parameters of teeth in the initial set of teeth.

30. The method according to any one or more of the preceding claims, wherein the method comprises selecting at least a number of the designed dental restorations for manufacturing.

31 . The method according to any one or more of the preceding claims, wherein the method comprises:

- modifying one or more parameters of one or more of the teeth in the composed set of teeth before applying the virtual three dimensional representation of the patient's present oral situation to obtain a modified composed set of teeth.

32. The method according to any one or more of the preceding claims, wherein the method comprises obtaining the three dimensional virtual representation of the patient's present oral situation by scanning the present oral situation using an intraoral scanner and/or scanning the surface of a negative impression of the patient's present oral situation and/or scanning the surface of a positive model of the patient's present oral situation.

33. The method according to any one or more of the preceding claims, wherein the method comprises obtaining a three dimensional virtual representation of the patient's original unprepared set of teeth by scanning the original unprepared set of teeth using an intraoral scanner and/or scanning the surface of a negative impression of the patient's original unprepared teeth and/or scanning the surface of a positive model of the patient's original unprepared teeth.

34. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the curve of the teeth defined by the relative position of teeth.

35. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the rotation of teeth relative to the median line of the face.

36. The method according to any one or more of the preceding claims, wherein the rotation of teeth relative to the median line of the face creates a composition or a combination of compositions selected from:

- a basic aesthetic composition;

- a strong aesthetic composition; or

- a soft aesthetic composition;

37. The method according to any one or more of the preceding claims, wherein the one or more parameters comprise:

- the geometric shape of the central teeth.

38. The method according to any one or more of the preceding claims, wherein the geometric shape of the central teeth is or is a combination selected from:

- an oval shape;

- a triangular shape; or

- a rectangular/square shape.

39. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the geometric shape of the premolars and/or molar.

40. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the length of the teeth .

41 . The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the length of the teeth relative to other teeth.

42. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the size of specific teeth relative to other specific teeth.

43. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the size of lateral teeth relative to the central teeth.

44. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the size of cuspid teeth relative to the lateral teeth.

45. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- the size of the gap between teeth.

46. The method according to any one or more of the preceding claims, wherein the one or more modified parameters of the initial set of teeth and/or of the composed set of teeth comprise:

- shape of the teeth.

47. The method according to any one or more of the preceding claims, wherein the method comprises mirroring of teeth.

48. The method according to any one or more of the preceding claims, wherein the method comprises cloning of teeth.

49. The method according to any one or more of the preceding claims, wherein the method comprises providing collision mapping relative to the antagonist.

50. The method according to any one or more of the preceding claims, wherein the method comprises virtually fitting the modified set of teeth to a virtual retention means.

51 . The method according to any one or more of the preceding claims, wherein the method comprises cutting the modified set of teeth to the retention means.

52. The method according to any one or more of the preceding claims, wherein the method comprises virtually cutting the modified set of teeth to the gingival.

53. The method according to any one or more of the preceding claims, wherein the method comprises fitting the modified set of teeth to its anatomical correct position in the gingival.

54. The method according to any one or more of the preceding claims, wherein the set of teeth may be fitted/cut to the retention means and/or to the gingival before the set of teeth becomes the modified set of teeth.

55. The method according to any one or more of the preceding claims, wherein the method comprises virtually designing the retention means.

56. The method according to any one or more of the preceding claims, wherein the method comprises adding virtual guiding lines to be overlaid on the teeth.

57. The method according to any one or more of the preceding claims, wherein the method comprises designing dental restorations in the lower and/or upper arch and fitting the lower and upper arch together.

58. The method according to any one or more of the preceding claims, wherein the composed set of teeth comprises a composed set of anterior teeth and a composed set of molar teeth, where each of the composed sets of teeth are selected separately.

59. The method according to any one or more of the preceding claims, wherein the composed set of teeth is selected from an electronic library comprising a number of different composed sets of teeth, where the composed sets of teeth can be standard sets of teeth and/or can be added to the electronic library by the user.

60. The method according to any one or more of the preceding claims, wherein the method further comprises that the user has the option of generating the composed set of teeth by defining the one or more parameters of the composed set of teeth.

61 . The method according to any one or more of the preceding claims, wherein the method comprises designing a permanent or a temporary prosthesis.

62. The method according to any one or more of the preceding claims, wherein the method comprises designing a partial denture prosthesis or a full denture prosthesis.

63. The method according to any one or more of the preceding claims, wherein the method comprises scanning the contours of the patient's face by means of a face scanner for designing the dental restorations taking the patient's face into consideration.

64. The method according to any one or more of the preceding claims, wherein the method is configured to be performed in an existing electronic program for digital dental restoration work.

65. A computer program product comprising program code means for causing a data processing system to perform the method of any one or more of the preceding claims, when said program code means are executed on the data processing system.

66. A computer program product according to the previous claim, comprising a computer-readable medium having stored there on the program code means.

67. A system for virtually designing a number of 3D teeth restorations for a patient, where the system comprises:

- means for providing a number of initially composed 3D virtual teeth restorations, where each of the virtual teeth restorations is represented by a separate surface;

- means for defining a centre of modification in relation to the initially composed 3D virtual teeth restorations; and

68. A system for designing a number of dental restorations for a patient, wherein the system comprises: - means for selecting a composed set of teeth comprising a number of 3D virtual teeth restorations arranged spatially relative to each other forming a high aesthetic composition, where each of the virtual teeth restorations is represented by a separate surface;

69. A dental restoration for a patient designed by means of the method of any one or more of claim 1 -64.

70. A non-transitory computer readable medium storing thereon a computer program, where said computer program is configured for causing computer- assisted generation of dental preparation guide configured for validating the preparation of at least one tooth for a dental restoration by performing the method of any one of claims 1 to 64.