Dynamic virtual articulator for simulating occlusion of teeth

Abstract

Disclosed is a computer-implemented method of using a dynamic virtual articulator for simulating occlusion of teeth, when performing computer-aided designing of one or more dental restorations for a patient, where the method includes the steps of: providing the virtual articulator including a virtual three-dimensional model of the upper jaw and a virtual three-dimensional model of the lower jaw resembling the upper jaw and lower jaw, respectively, of the patient's mouth; providing movement of the virtual upper jaw and the virtual lower jaw relative to each other for simulating dynamic occlusion, whereby collisions between teeth in the virtual upper and virtual lower jaw occur; wherein the method further includes: providing that the teeth in the virtual upper jaw and virtual lower jaw are blocked from penetrating each other's virtual surfaces in the collisions.

Claims

1. A computer-implemented method of simulating occlusion of teeth, the method comprises using a dynamic virtual articulator when performing computer-aided designing of one or more dental restorations for a patient, the method further comprises: providing the dynamic virtual articulator, the dynamic virtual articulator including a virtual three-dimensional model of the upper jaw and a virtual three-dimensional model of the lower jaw resembling the upper jaw and lower jaw, respectively, of the patient's mouth, wherein the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw include three dimensional models of teeth without restorations, and at least one of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw with three dimensional models of teeth including one or more dental restorations; displacing the at least one or more virtual dental restorations vertically relative to the jaw from an original position on at least one of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw in order to provide a relative offset of the at least one or more virtual dental restorations; providing movement of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw relative to each other for simulating dynamic occlusion, whereby collisions between the teeth in the virtual upper and virtual lower jaw occur; and providing that the teeth in the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw are blocked from penetrating each other's virtual surfaces in the collisions while permitting penetration of the at least one or more displaced virtual dental restorations, wherein the permission of the penetration is based on a preference of an operator or a user.

2. The computer-implemented method according to claim 1, wherein the method further comprises simultaneous modeling of the one or more displaced virtual dental restorations and collision testing of the virtual upper jaw and virtual lower jaw.

3. The computer-implemented method according to claim 1, wherein the method further comprises fixing the virtual upper jaw to the occlusal axis such that the virtual lower jaw is configured to move relative to the virtual upper jaw.

4. The computer-implemented method according to claim 1, wherein the method further comprises defining a search structure on the virtual upper jaw configured for searching on predefined circular paths around the occlusal axis for detecting collisions with the surface of the lower jaw model.

5. The computer-implemented method according to claim 1, wherein a part of the one or more virtual dental restorations which causes a collision is configured to be automatically removed from the respective virtual jaw.

6. The computer-implemented method according to claim 1, wherein the method further comprises that the movement of the virtual upper jaw and the virtual lower jaw relative to each other is configured to be digitally recorded.

7. The computer-implemented method according to claim 1, wherein the method further comprises aligning the virtual upper jaw and virtual lower jaw to correspond to the anatomical alignment of the jaws in the mouth of the patient.

8. The computer-implemented method according to claim 1, wherein the method further comprises positioning a virtual alignment plane relative to the virtual upper jaw and the virtual lower jaw, where the virtual upper jaw and virtual lower jaw defines a virtual model of the set of teeth, wherein the method comprises the steps of: visualising the virtual alignment plane and the virtual upper jaw and virtual lower jaw; and automatically positioning the virtual alignment plane and the virtual lower jaw and virtual upper jaw relative to each other based on one or more parameters.

9. The computer-implemented method according to claim 8, wherein the positioning of the virtual alignment plane relative to the virtual model of the set of teeth is configured to be performed by the operator by selecting one or more virtual points relative to the virtual model of the set of teeth within which point(s) the virtual alignment plane should be moved to.

10. The computer-implemented method according to claim 8, wherein the virtual alignment plane and/or the virtual model of the set of teeth is/are semi-transparent or translucent such that both the virtual alignment plane and the virtual set of teeth are visible simultaneously.

11. The computer-implemented method according to claim 8, wherein the method further comprises positioning a virtual alignment plane relative to the virtual upper jaw and the virtual lower jaw, where the virtual upper jaw and virtual lower jaw defines a virtual model of the set of teeth, wherein the method comprises the steps of: visualising the virtual alignment plane and the virtual upper jaw and virtual lower jaw; and automatically positioning the virtual alignment plane and the virtual lower jaw and virtual upper jaw relative to each other.

12. The computer-implemented method according to claim 1, wherein the method further comprises that during the movement of the virtual upper jaw and the virtual lower jaw relative to each other all the collisions occurring between teeth are registered, and after the movement is finished, modeling of the collision points of the displaced virtual model of the one or more dental restorations is performed.

13. The computer-implemented method according to claim 1, wherein a predefined motion of the virtual upper jaw and the virtual lower jaw relative to each other is configured to be played.

14. The computer-implemented method according to claim 1, wherein the method further comprises designing the one or more dental restorations.

15. The computer-implemented method according to claim 1, wherein the positions of teeth within the upper jaw are unchanged relative to the virtual three dimensional model of the upper jaw in the dynamic virtual articulator and the positions of the teeth within the lower jaw are unchanged relative to the virtual three dimensional model of the lower jaw included in the dynamic virtual articulator.

16. A virtual articulator system for simulating occlusion of teeth, where the system comprises: a virtual articulator comprising a virtual three-dimensional model of the upper jaw and a virtual three-dimensional model of the lower jaw resembling the upper jaw and lower jaw, respectively, of the patient's mouth, wherein the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw include three dimensional models of teeth without restorations, and at least one of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw with three dimensional models of teeth including one or more dental restorations; wherein the controller is further configured for displacing the at least one or more virtual dental restorations vertically relative to the jaw from an original position on at least one of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw in order to provide a relative offset of the at least one or more virtual dental restorations; a controller configured for moving the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw relative to each other for simulating dynamic occlusion when performing computer-aided designing of the one or more dental restorations for a patient, whereby collisions between the teeth in the virtual upper and virtual lower jaw occur; and wherein the controller is further configured to provide that the teeth in the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw are blocked from penetrating each other's virtual surfaces in the collisions while permitting penetration of the at least one or more displaced virtual dental restorations, wherein the permission of the penetration is based on a preference of an operator or a user.

17. A computer-implemented method of simulating occlusion of teeth, the method comprises using a dynamic virtual articulator when performing computer-aided designing of one or more dental restorations for a patient, the method further comprises: providing the dynamic virtual articulator, the dynamic virtual articulator including a virtual three-dimensional model of the upper jaw and a virtual three-dimensional model of the lower jaw resembling the upper jaw and lower jaw, respectively, of the patient's mouth, wherein the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw include three dimensional models of physical teeth without restorations, and at least one of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw with three dimensional models of teeth including one or more dental restorations; displacing the virtual model of the one or more dental restorations vertically relative to the jaw from an original position on at least one of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw in order to provide a relative offset of the virtual model of the one or more dental restorations; providing movement of the virtual three-dimensional model of the upper jaw and the virtual three-dimensional model of the lower jaw relative to each other for simulating dynamic occlusion, whereby collisions between the teeth in the virtual upper and virtual lower jaw occur; detecting collisions of only the physical teeth during simulation of the dynamic occlusion by letting the displaced virtual model of the one or more dental restorations be penetrable; and using the physical teeth as a guide for determining the relative movement between the upper jaw and lower jaw.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIG. 1 shows an example of a flow chart of the method.

(3) FIG. 2a-2b show examples virtual articulators.

(4) FIG. 3a-3d show an example of movements of the jaws for simulating occlusion.

(5) FIG. 4a-4b show an example of modelling of a restored tooth.

(6) FIG. 5 shows a schematic example of movement along the occlusial axis.

(7) FIG. 6 shows an example of a virtual model of a set of teeth.

(8) FIG. 7 shows an example of a virtual occlusal plane.

(9) FIG. 8 shows a first example of a virtual occlusal plane and a virtual model before they are adjusted relative to each other's positions.

(10) FIG. 9 shows a second example of a virtual occlusal plane and a virtual model while they are adjusted relative to each other's positions.

(11) FIG. 10 shows an example of a virtual occlusal plane and a virtual model after they are adjusted relative to each other's positions.

(12) FIG. 11 shows an example of a virtual articulator.

(13) FIG. 12 shows an example of a flow chart of an embodiment of the invention.

(14) FIG. 13a-13c show an example of a movement of the virtual upper jaw and the virtual lower jaw relative to each other.

(15) FIG. 14a-14d show an example of displacing the position of a prepared tooth for designing the restoration.

(16) FIG. 15a-15d show an example of displacing the position of a gingival part for designing the restoration.

(17) FIG. 16 shows an example of an occlusal compass.

(18) FIG. 17 shows an example of playing a recording of the jaw movements.

(19) FIG. 18 shows an example of modeling a restoration to compensate for collisions with the opposite teeth.

(20) FIG. 19a-19d show examples of virtual articulators resembling physical articulators form different manufacturers.

(21) FIG. 20a-20b show an example of a virtual articulator, which only exists as a virtual articulator.

(22) FIG. 21a-21e show examples of the traces of movement.

(23) FIG. 22a-22b show an example of virtual simulation of orthodontic treatment planning.

(24) FIG. 23a-23b show an example of virtual simulation of dental displacement.

(25) FIG. 24a-24d show an example of an orthodontic appliance for displacing teeth.

DETAILED DESCRIPTION

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

(27) FIG. 1 shows an example of a flow chart showing the steps of the computer-implemented method of using a dynamic virtual articulator for simulating occlusion of teeth, when performing computer-aided design of one or more dental restorations for a patient.

(28) In step 101 the virtual articulator comprising a virtual three-dimensional model of the upper jaw and a virtual three-dimensional model of the lower jaw resembling the upper jaw and lower jaw, respectively, of the patient's mouth is provided.

(29) In step 102 movement of the virtual upper jaw and the virtual lower jaw relative to each other is provided for simulating dynamic occlusion, whereby collisions between teeth in the virtual upper and virtual lower jaw occur;

(30) In step 103 the teeth in the virtual upper jaw and virtual lower jaw are provided to be blocked from penetrating each other's virtual surfaces in the collisions.

(31) FIG. 2 shows examples virtual articulators.

(32) FIG. 2a) shows a virtual upper jaw 204 with teeth 206 and a virtual lower jaw 205 with teeth 206. Six teeth 207 in the upper jaw 204 have been restored, and the virtual articulator 208 are used to simulate the movements of the jaws 204, 205 to test if the restored teeth 207 fit into the mouth of a patient. The virtual articulator 208 is indicated by two axes, an occlusial axis 209 and a laterotrusial-mediotrusial axis 210. The jaws 204, 205 moves up and down along the occlusial axis 209, and the jaws 204, 205 performs forward-sidewards movements to both left and right along the laterotrusial-mediotrusial axis 210. The jaws 204, 205 can also perform protrusion, which is direct forward movement, and retrusion, which is direct backward movement. The axes for these movements are not shown in the figure.

(33) In the figure only movement along the occlusial axis 209 is shown, while there is no movement along the laterotrusial-mediotrusial axis 210 or along the protrusial-retrusial axes (not shown). This is also seen in the window 211 in the upper left of the figure, where the parameter “occlusion” is 6.60 and the parameter “laterotrusion” is 0.00, and the parameter “pro-/retrusion” is also 0.00. The different movement directions possible may be: protrusion; retrusion; laterotrusion to the right; laterotrusion to the left; mediotrusion to the right; mediotrusion to the left; latero-re surtrusion to the right; latero-re surtrusion to the left.

(34) FIG. 2b) shows another virtual articulator 208 with setting opportunities 209, 210 for controlling the movement of the jaws 204, 205 along an occlusial axis, a laterotrusial-mediotrusial axis, a protrusial-retrusial axis etc. The indentations 240 indicate where the dental technician will arrange a default occlusal plane in the form of a rubber band.

(35) FIG. 3 shows an example of movements of the jaws for simulating occlusion.

(36) Both jaws 204, 205 comprise non-modified teeth 206, and the upper jaw 204 also comprises restored teeth 207. The movements are made to simulate, if the restored teeth 207 fit into the mouth.

(37) FIG. 3a) shows the jaws 204, 205 in a first position, where no teeth 206 in the jaws 204, 205 have collided with the restored teeth 207.

(38) FIG. 3b) shows the jaw 204, 205 in a second position, where the jaw 204, 205 have moved closer to each other, but there is still no collision between any of the teeth 206 or the restored teeth 207.

(39) FIG. 3c) shows the jaws 204, 205 in a third position, where the jaw 204, 205 have moved even closer to each other.

(40) FIG. 3d) shows the jaws 204, 205 in the third position with a circle 212 at a point 213, where the teeth of the jaws 204, 205 have collided. The collision is between a restored tooth 207a in the upper jaw 204 and a tooth 206a in the lower jaw 205.

(41) FIG. 4 shows an example of modelling of a restored tooth.

(42) FIG. 4a) shows the upper jaw 204, turned around relative to the preceding figures, with the restored tooth 207a, another restored tooth 207 and an un-modified tooth 206. The restored tooth 207a has collided with a tooth in the lower jaw, as shown in FIG. 3d), and the collision points 214 are indicated on the tooth 207a. The shades of the collision points may indicate the penetration depth or the pressure with which the tooth 207a and the tooth in the lower jaw collided. Thus the shades from light to dark indicate a depth mapping or pressure mapping, where light shade indicates low depth or light pressure and dark shade indicates large depth or hard pressure.

(43) It may be so that the teeth are not completely rigid, but are a little bit soft, and the teeth may therefore give or deform a little when colliding with each other. Thus it may be so that the virtual teeth are not defined to be completely rigid, but are a little bit soft or resilient, and the virtual teeth may therefore give or deform a little when virtually colliding with each other.

(44) FIG. 4b) shows the same as FIG. 4a) and also tools for modelling the restored tooth 207a. Since the tooth 207a collided with a tooth in the lower jaw, see FIG. 3d), the restored 207a) can be modelled such that it will not collide with the tooth in the lower jaw. The tooth 207a can be modelled by dragging or morphing it to the left or right side indicated by the tools 215, and by dragging the tooth 207a up and down indicated by the tool 216. The tooth 207a can also be modelled by dragging or morphing points on it to the left side or right side indicated by tools 217, and by dragging or morphing it to the neighbor teeth indicated by tools 218.

(45) While morphing or dragging the tooth 207a, the collision points 214 will change corresponding to these shape changes of the tooth, and the tooth 207a can then be modelled such that there will no longer be any collision with the teeth in the lower jaw, and the collisions points 214 will then disappear from the tooth 207a indicating that the tooth 207a has been modelled to avoid collisions with opposing teeth.

(46) FIG. 5 shows a schematic example of movement along the occlusial axis.

(47) The figure shows the upper jaw 204 with teeth 206 and the lower jaw 205 with teeth 206. Some of these teeth may be restored teeth, and therefore the occlusion may be tested.

(48) The occlusial axis 209 is indicated, and the upper jaw 204 is shown to be fixed to the occlusial axis. The lower jaw 205 can move relative to the upper jaw 204 and therefore the lower jaw can rotate around the occlusial axis 209.

(49) Thus the virtual articulator performs collision test and evaluate the response along the occlusial axis 209, i.e. for any given configuration of the other degrees of freedom, i.e. the other axes, see FIG. 2, and thereby finding the first position on the occlusial axis for which the two jaw models are in contact. This reduces the dimensionality of the calculation problem and allows for the use of more specialized search structures, which are aimed at calculating the first point of intersection with a 3D model along a given circular path 219 around the static rotation axis 209 of occlusion. Thus for each motion step along one of the other axes, i.e. for each degrees of freedom, it may be calculated when and at which points the teeth 206 in the jaws 204, 205 will collide along the occlusial axis 209.

(50) FIG. 6 shows an example of a virtual model of a set of teeth.

(51) The virtual model 601 of the set of teeth from a patient comprises a virtual lower arch 602 and a virtual upper arch/jaw 603. Six front teeth 604 in the upper arch 603 are marked in a different color than the rest of the teeth 605 of the set of teeth. These six teeth 604 may be teeth which should be or have been restored. The virtual model 601 may be shown in a graphical user interface, in which an operator, such as a dental technician or dentist, can design, simulate and/or model for example restorations for a patient.

(52) FIG. 7 shows an example of a virtual occlusal plane.

(53) The occlusal plane 706 is visualized as a flat, circular plane, but it is understood that the occlusal plane can have any shape etc. The occlusal plane is a plane passing through the occlusal or biting surfaces of the teeth, and it represents the mean of the curvature of the occlusal surface. Thus the occlusal plane can be flat or undulating following the different heights of the different teeth.

(54) A contour of a standard set of teeth 707 is shown on the occlusal plane 706 for assisting the operator to better match the 3D position of the occlusal surface 706 with a virtual model.

(55) A virtual articulator 708 is indicated by two axes, an occlusial axis 709 and a laterotrusial-mediotrusial axis 710. The upper and lower arches of the virtual model can move up and down along the occlusial axis 709, and the arches can perform forward-sidewards movements to both left and right along the laterotrusial-mediotrusial axis 710. The arches can also perform protrusion, which is direct forward movement, and retrusion, which is direct backward movement. The axes for these movements are not shown in the figure.

(56) The different movement directions possible may be: protrusion; retrusion; laterotrusion to the right; laterotrusion to the left; mediotrusion to the right; mediotrusion to the left; latero-re surtrusion to the right; latero-re surtrusion to the left.

(57) FIG. 8 shows a first example of a virtual occlusal plane and a virtual model before they are adjusted relative to each other's positions.

(58) The occlusal plane 806 with the standard set of teeth 807 and the virtual model of the lower arch 802 are shown together. The occlusal plane 806 is shown to be inclined relative to the virtual model of the lower arch 802, and the occlusal plane 806 and the virtual model of the lower arch 802 are intersecting each other as seen by the intersection line 811.

(59) FIG. 9 shows a second example of a virtual occlusal plane and a virtual model while they are adjusted relative to each other's positions.

(60) The occlusal plane 906 with the standard set of teeth 907 and the virtual model of the lower arch 902 are shown together. The occlusal plane 906 and the virtual model of the lower arch 902 are nearly aligned as their inclinations are the same or almost the same, but the occlusal plane 906 and the virtual model of the lower arch 902 are still intersecting each other a little bit as seen by the intersection line 911 because some of the teeth of the lower arch 902 are a little bit higher than the vertical position of the occlusal plane 906. The occlusal plane 906 and the lower arch 902 are not aligned horizontally yet, because the standard set of teeth 907 on the occlusal plane 906 are not overlapping with the teeth of the lower arch 902.

(61) FIG. 10 shows an example of a virtual occlusal plane and a virtual model after they are adjusted relative to each other's positions.

(62) The occlusal plane 1006 with the standard set of teeth 1007 and the virtual model of the lower arch 1002 are shown together. The occlusal plane 1006 and the virtual model of the lower arch 1002 are aligned as their inclinations are the same, and the occlusal plane 1006 and the virtual model of the lower arch 1002 are still intersecting each other a little bit as seen by the intersection line 1011 because some of the teeth of the lower arch 1002 are a little bit higher than the vertical position of the occlusal plane 1006. The occlusal plane 1006 and the lower arch 1002 are aligned horizontally, because the standard set of teeth 1007 on the occlusal plane 1006 are overlapping with the teeth of the lower arch 1002. The alignment may be a 3-point alignment, i.e. using three points for performed the alignment.

(63) FIG. 11 shows an example of a virtual articulator.

(64) The virtual articulator 1108 is a virtual version of a physical, mechanical device used in dentistry to which casts of the upper and lower teeth are fixed and reproduces recorded positions of the lower teeth in relation to the upper teeth. An articulator can be adjustable in one or more of the following areas: condylar angle, Bennett side-shift, incisal and cuspid guidance, and shape of the glenoid fossae and eminintiae. An articulator may reproduce normal lower movements during chewing. An articulator may be adjusted to accommodate the many movements and positions of the lower teeth in relation to the upper teeth as recorded in the mouth. Thus the virtual articulator may perform all the movements etc. as the mechanical articulator.

(65) The virtual articulator 1108 comprises a bottom base 1109 onto which the virtual model of the lower teeth or lower jaw is adapted to be arranged, a top base 1110 onto which the virtual model of the upper teeth or upper jaw is adapted to be arranged. The different virtual joints, slides or setting means 1111 indicates the joints, slides and other settings of a mechanical articulator where the different areas mentioned above can be adjusted to the features of a specific patient.

(66) FIG. 12 shows an example of a flow chart of an embodiment of the invention.

(67) In step 1201 the movement of the virtual upper jaw and the virtual lower jaw relative to each other is started.

(68) In step 1202 all collisions during the movement of the virtual upper jaw and the virtual lower jaw relative to each other are registered.

(69) In step 1203 the movement of the virtual upper jaw and the virtual lower jaw relative to each other is finished.

(70) In step 1204 each area of the restorations where a collision point was registered is modelled.

(71) FIG. 13 shows an example of a movement of the virtual upper jaw and the virtual lower jaw relative to each other.

(72) FIG. 13a) shows the first position of a movement between the upper jaw 1304 and the lower jaw 1305. Both the lower jaw and the upper jaw comprise teeth 1306, and the upper jaw comprises a number of restorations 1307.

(73) FIG. 13b) shows a position during the movement of the jaws. The upper jaw 1304 is moved relative to the lower jaw 1305, and the restoration 1307 is colliding with a tooth 1306 as seen by the collision point 1314 comprising a contact area.

(74) FIG. 13c) shows the end position of the movement of the jaws, and all the collision points are marked on the teeth and restorations. The restoration 1307 can now be modelled by virtually removing or remodeling material from the restoration, whereby the collision in point 1314 will not happen again when the jaws are moved relative to each other, both virtually and in the patient's mouth.

(75) FIG. 14 shows an example of displacing the position of a prepared tooth for designing the restoration.

(76) FIG. 14a) shows an example of a 3D representation of a set of teeth 1400, where a tooth 1401 has been prepared for a restoration, such as a crown. Two neighbor teeth 1402 are also shown. The tooth roots 1403 are indicated. The tooth roots 1403 may be derived from a CT scan or may be extrapolated based in a normal 3D scan. Showing the tooth roots 1403 in the 3D representation is optional, since designing a restoration does not require seeing the tooth root, but it may a help for the operator designing the restoration. The gingival 1404 is also seen.

(77) FIG. 14b) shows that the preparation 1401 is vertically displaced from its position at the gingival 1404 and from the neighbor teeth to reduce the distance to the antagonist when designing the restoration.

(78) FIG. 14c) shows that a restoration 1405, here in the form of a crown, is designed on the preparation, when the preparation is displaced from the gingival 1404 and the neighbor teeth. Thus the restoration is designed in a different occlusion than the normal occlusion of the teeth. The upper edge of the restoration 1405 is shown to be substantially flush or level with the two neighbor teeth 1402 when being designed.

(79) FIG. 14d) shows the situation when the preparation 1401 with the restoration 1405 is positioned in its actual position again after designing the restoration 1405. Because the restoration 1405 was designed to be level with the neighbor teeth 1402 when it was displaced, the restoration 1405 is shorter than the neighbor teeth 1402, when it is positioned in its original position again. Thus in the mouth of the patient, the restoration will be shorter than the neighbor teeth, and the restoration, which may be more fragile than the real teeth, is therefore protected better.

(80) FIG. 15 shows an example of displacing the position of a gingival part for designing the restoration.

(81) FIG. 15a) shows an example of a 3D representation of a set of teeth 1500 with a missing tooth in a region of the gingival 1506. The missing tooth may have been broken, died, pulled out due to disease etc. A restoration should be made to replace the missing tooth in the region 1506. Two neighbor teeth 1502 are also shown. The tooth roots 1503 are indicated. The tooth roots 1503 may be derived from a CT scan or may be extrapolated based in a normal 3D scan. Showing the tooth roots 1503 in the 3D representation is optional, since designing a restoration does not require seeing the tooth root, but it may a help for the operator designing the restoration. The gingival 1504 is also seen.

(82) The restoration to made to replace the missing tooth may be a bridge. The bridge may comprise a pontic in the place of the missing tooth and two crowns on the neighbor teeth 1502.

(83) FIG. 15b) shows that the two neighbor teeth have been prepared and are now prepared teeth 1501. The region of the gingival 1506 of the missing tooth is displaced from its original position at the gingival.

(84) FIG. 15c) shows that a restoration, here in the form of a bridge, is designed. A pontic 1507 is arranged in the place of the missing tooth, and crowns 1505 have been designed on the two preparations 1501. The pontic is attached to the crowns. The pontic 1507 is designed, when the region of the gingival 1506 is displaced from its original position. The upper edge of the pontic 1507 is substantially flush or level with the designed crowns 1505 on the two prepared neighbor teeth 1501.

(85) FIG. 15d) shows the situation when the pontic 1507 and the region of the gingival 1506 is positioned in its actual position again after designing the pontic 1507. Because the pontic 1507 was designed to be level with the crowns 1505 of the neighbor teeth, when it was displaced, the pontic 1507 is shorter than the crowns 1505 neighbor teeth, when the pontic 1507 is positioned in its original position again. Thus in the mouth of the patient, the pontic will be shorter than the crowns of the neighbor teeth, and the pontic, which may be more fragile than the crowns of the neighbor teeth, is therefore protected better.

(86) FIG. 16 shows an example of an occlusal compass.

(87) The occlusal compass indicates movements during dynamic occlusion in the following directions: protrusion; retrusion; laterotrusion to the right; laterotrusion to the left; mediotrusion to the right; mediotrusion to the left; latero-re surtrusion to the right; latero-re surtrusion to the left.

(88) The occlusal compass indicates the contact or collision in different movement directions with different colors. The colors may be according to the international coloring scheme. The occlusal compass used in the virtual simulation is a unique digital tool.

(89) FIG. 17 shows an example of playing a recording of the jaw movements.

(90) The movement of the virtual upper jaw and the virtual lower jaw relative to each other has been recorded, and before and/or after modeling a restoration, the recording can be played to test the modeling. A predefined motion sequence may also be played.

(91) FIG. 18 shows an example of modeling a restoration to compensate for collisions with the opposite teeth.

(92) During the movement of the virtual upper jaw and the virtual lower jaw relative to each other the collisions, marked with on the restoration, occlusion between teeth are registered, and after the movement is finished, modeling of the collision points of the restoration is performed.

(93) FIG. 19 shows examples of virtual articulators resembling physical articulators form different manufacturers.

(94) FIG. 19a) shows an articulator from KaVo.

(95) FIG. 19b) shows an articulator from SAM.

(96) FIG. 19c) shows an articulator from Denar.

(97) FIG. 19d) shows the articulator from Denar with the occlusal plane arranged relative to the virtual teeth model.

(98) FIG. 20 shows an example of a virtual articulator, which only exists as a virtual articulator.

(99) FIG. 20a) shows a 3 Shape virtual articulator. The articulator does not exist as a physical articulator.

(100) FIG. 20b) shows the 3 Shape virtual articulator with the occlusal plane arranged relative to the virtual teeth model.

(101) FIG. 21 shows examples of the traces of movement.

(102) FIG. 21a) shows an example of a first collision point 2114 between an unmodified tooth 2106 and another unmodified tooth or restoration 2107 at time t1.

(103) FIG. 21b) shows an example of a subsequent collision point 2114 between the unmodified tooth 2106 and the other unmodified tooth or restoration 2107 at time t2.

(104) FIG. 21c) shows an example of another subsequent collision point 2114 between the unmodified tooth 2106 and the other unmodified tooth or restoration 2107 at time t3.

(105) FIG. 21d) shows the trace of the motion for the other unmodified tooth or restoration 2107 and the tooth 2106 at the three time instances, t1, t2, t3.

(106) The trace of the motion between the tooth 2106 and the other unmodified tooth or restoration 2107 is indicated by the arrows 2120. The surface of collision points 2114 may be denoted the trace motion, the motion trace surface etc.

(107) Thus when unmodified teeth are simulated relative to each other, their motion traces or their surfaces cannot penetrate each other. The same may be the case for a restoration relative to an unmodified tooth.

(108) However, it may alternatively be the case that when a restoration and an unmodified tooth are simulated relative to each other, the motion surface of the restoration may penetrate the unmodified tooth.

(109) Thus the term collision surface or trace of collisions points or collision points surface is used for both describing when unmodified teeth are simulated to move relative to each where the teeth collide and do not penetrate each other and for describing when a restoration is simulated relative to unmodified teeth where the restoration may penetrate the unmodified teeth, i.e. the restoration and the unmodified may penetrate each other.

(110) The simulated collisions or collision surfaces between unmodified teeth may determine the motion which can be performed between the upper and lower teeth models.

(111) This determined motion may then be used and studied when designing the restoration.

(112) FIG. 21e) shows the trace 2120 of a motion for a restoration 2107 and a tooth 2106 at the four time instances, t1, t2, t3, t4. The motion is shown at the three time instances t1, t2, t3, t4 and time instance lying in between and before and after.

(113) In FIG. 21e) the restoration 2107 and the tooth 2106 are shown to penetrate each other in the motion.

(114) The surface of collision or penetration points may be denoted the trace motion 2120.

(115) The tooth 2106 is shown to move relative to the restoration 2107, however it may be vice versa, i.e. that the restoration 2107 moves relative to the tooth 2107.

(116) FIG. 22 shows an example of virtual simulation of orthodontic treatment planning.

(117) FIG. 22a) shows a virtual orthodontic model of teeth with an upper model 2204 and a lower model 2205 in a virtual articulator 2208 for simulating the occlusion. The simulation of occlusion in the virtual articulator can detect and study malocclusion, and assist and/or determine an orthodontic treatment planning. An orthodontic treatment can also be performed for pure cosmetic reasons, if the patient's teeth are arranged aesthetically.

(118) FIG. 22b) shows a zoom-in on the teeth in the virtual models 2204, 2205, where contact areas or collision points 2214 are registered during simulation of the occlusion. The detected contact areas or collision points 2214 can be used in determining the treatment planning to be performed.

(119) FIG. 23 shows an example of virtual simulation of dental displacement.

(120) FIG. 23a) shows a virtual upper teeth model 2304 of a patient's teeth before orthodontic treatment, where the teeth 2307 are not arranged aesthetically. The contact areas or collision point 2314 detected or registered in a virtual articulator simulation are shown on the teeth.

(121) FIG. 23b) shows an example of the virtual upper teeth model 2304 with a suggested final result which can be obtained after displacement of the teeth 2307.

(122) Based on the image in FIG. 23b) a patient can decide whether he wish to have the dental displacement performed for obtaining the aesthetic set of front teeth.

(123) FIG. 24 shows an example of an orthodontic appliance for displacing teeth.

(124) FIG. 24a) shows a virtual upper model 2404 and a virtual lower model 2405, where a virtual orthodontic appliance 2430 in the form of a splint is shown to be arranged in the teeth in the upper model 2404. The physical appliance may be worn by a patient on his teeth for treating temporal mandibular dysfunction. The appliance 2430 may be virtually designed using a virtual articulator, e.g. as shown in FIG. 22a).

(125) FIG. 24b) shows a top view of the appliance 2430 on the virtual teeth model 2404.

(126) FIG. 24c) shows a perspective side view of the appliance 2430 on the virtual teeth model 2404.

(127) FIG. 24d) shows a bottom view of the appliance 2430.

(128) The appliance design in FIG. 24 are the courtesy of and kindly provided by Tridentestense Ortodonzia S.r.l, Italy.

(129) 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 utilized and structural and functional modifications may be made without departing from the scope of the present invention.

(130) 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.

(131) 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.

(132) When a claim refers to any of the preceding claims, this is understood to mean any one or more of the preceding claims.

(133) 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.