Method for providing a dental prosthesis and a positioning guide for placing the dental prosthesis

Abstract

A method for designing a dental prosthesis and a positioning guide for placing the dental prosthesis on implants in the jaw while maintaining proper occlusion relates to designing the dental prosthesis and the positioning guide prior to implant placement.

Claims

1. A method of creating a digital prosthesis design of a denture, which when manufactured can be placed on at least one implant placed in a first jaw of a patient, and creating a digital guide design of a positioning guide configured to maintain proper occlusion between the denture and the opposing jaw during placement of the denture on the at least one implant, which when manufactured can be used to position the denture on the at least one implant, wherein the manufactured denture is in a desired occlusal contact with a dental anatomy of a second jaw opposite the first jaw, the method comprising: obtaining a digital first jaw model comprising a surface representation of at least a part of the first jaw and of an at least one expected implant site comprising a digital abutment representation of an abutment arranged at the at least one expected implant site, creating the digital prosthesis design comprising a distal prosthesis surface and a proximal prosthesis surface, wherein the proximal prosthesis surface comprises at least one abutment hole and creating a shape of the abutment hole larger than the digital abutment representation, obtaining a digital second jaw model of the second jaw comprising a surface representation of at least a part of the second jaw opposing the at least one expected implant site, and creating the digital guide design of the positioning guide comprising a distal guide surface which at least partly comprises a shape corresponding to the shape of a part of the digital second jaw model and a proximal guide surface which at least partly comprises a shape corresponding to the shape of a part of the distal denture surface.

2. The method according to claim 1, wherein creating the shape of the abutment hole larger than the digital abutment representation comprises creating the shape of the abutment hole at least partly on an enlarged shape of the digital abutment representation.

3. The method according to claim 1, wherein the step of obtaining a digital first jaw model further comprises: obtaining a surface scan of the expected implant site, obtaining a radiographic image of the expected implant site, and arranging the surface scan and the radiographic image in a common coordinate system.

4. The method according to claim 1, wherein the method further comprises that the digital abutment representation is a digital abutment model.

5. The method according to claim 4, wherein the method further comprises: selecting the digital abutment model from a digital abutment model library.

6. The method according to claim 4, wherein the method further comprises: providing a digital implant model, arranging the digital implant model at the expected implant site, and arranging the digital abutment model with the digital implant model.

7. The method according to claim 1, wherein the step of creating the digital prosthesis design comprises: designing a support structure on the digital prosthesis design, wherein the support structure is designed to contact at least a part of the surface representation of the first jaw.

8. A method according to claim 7, wherein the step of designing the support structure comprises: extending the support structure proximally from the digital prosthesis design.

9. A method according to claim 1, wherein the step of creating the digital prosthesis design comprises: creating a digital gingiva model of the denture, and creating at least one tooth model of the denture extending distally from the digital gingiva model.

10. A method according to claim 1, wherein the step of creating the shape of the abutment hole comprises: offsetting the digital abutment representation outwards.

11. A method according to claim 1, wherein the step of creating the shape of the abutment hole comprises: removing undercuts comprising reducing the digital prosthesis design, wherein an overlap between the digital prosthesis design and the digital abutment representation is removed when relatively shifting the prosthesis design and the surface representation of at least a part of the first jaw along a desired insertion direction between a position where the digital abutment representation is outside the abutment hole and a position where at least a part of the prosthesis surface and the surface representation of at least a part of the first jaw align with each other.

12. A method according to claim 1, wherein creating a digital prosthesis design of a denture comprises: creating a digital prosthesis design of the denture, creating a digital guide design of the positioning guide, manufacturing the denture based on the digital prosthesis design using a 3D manufacturing process, and manufacturing the positioning guide based on the digital guide design using a 3D manufacturing process.

13. The method according to claim 12, wherein the 3D manufacturing process is 3D printing.

14. The method according to claim 12, wherein the 3D manufacturing process is 3D milling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

(2) FIG. 1A-1D shows one embodiment of a method as disclosed herein for creating a digital prosthesis design and a digital guide design, and

(3) FIGS. 2A and 2B shows another embodiment of a digital prosthesis design and a digital guide design and also shows a digital drill guide design used together with the above.

DETAILED DESCRIPTION

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

(5) An embodiment of the method disclosed herein is shown in FIGS. 1A-1D, wherein it is shown how a digital prosthesis design 10 and a digital guide design 20 is created.

(6) Initially a digital first jaw model 30 is obtained. The digital first jaw model is a representation of the mandible (lower jaw), however the method disclosed herein could just as well be applied to an embodiment where the digital first model is a representation of the maxilla (upper jaw). In FIG. 1A the digital model is seen from an occlusal view.

(7) In FIG. 1B the digital first jaw model 30 is seen in a cross section along the line A-A in FIG. 1A between longitudinal sections I-I and II-II. As can be seen the digital first jaw model 30 is formed by a surface scan 31 and a CBCT scan 32 of the oral situation. The digital first jaw model may comprise other representations of the oral situation as well. For illustrative purposes the surface scan 31 and the CBCT scan 32 of the first jaw are shown slightly offset, however, these will typically be aligned together so that they are represented in correct position relative to each other in a common coordinate system.

(8) The surface scan 31 can advantageously be obtained directly by an intra oral scanner, such as the TRIOS scanner sold by 3Shape TRIOS. However, it may also be obtained by scanning a dental impression or a gypsum model of the first jaw. Surface data can be stored in a so-called STL or similar file format which is read into the system and processed in order to visualize the first jaw. The CBCT scan 32 of the first jaw can be obtained by conventional CBCT (Cone Beam Compute Tomography) scanner on the market. CBCT data can be stored in a so-called DICOM file format which is read into the system and processed in order to visualize the first jaw.

(9) The advantage of using a surface scan 31 in combination with a CBCT scan 32 is that a surface scan typically has a higher resolution than a CBCT scan. Thus, a surface scan 31 can be advantageous to use as a base for designing prostheses, surgical drill guides and other dental appliance, whereas the CBCT scan provides sub surface information which is important when planning for invasive procedures such as implant placement.

(10) The digital first jaw model 30 thus forms a representation of the jaw of the scanned person which in the current embodiment shows among other numerous dental features such as a single tooth 33, gum surface 34, gum thickness 35, sub-surface tooth structures such as a tooth root 36 of the tooth 33, jaw bone 37 and the mandibular nerve 38.

(11) Based on the established digital first jaw model 30 a user can proceed to do implant planning as shown in FIG. 1C. In the current embodiment the user proceeds with planning for two implants taking into consideration one or more dental features such as the mandibular nerve 38, density of the jaw bone 37, teeth roots etc. The user is using digital implant models 39, 40 which represents implants that he anticipates using during implant placement and places them accordingly. Such digital implant models are preferably CAD models which can be used in respective CAD software and manipulate with in a digital design environment.

(12) The user will also choose suitable abutments, similarly represented by digital abutment models 41, 42, and arrange them in the corresponding digital implant models. Similarly as above the digital abutment models are preferably CAD models which can be used in respective CAD software and manipulate with in a digital design environment.

(13) When the user is satisfied with the implant planning he can then proceed to design the digital prosthesis design 10 and the digital guide design as shown in FIG. 1D. In order to do this, the user will obtain a digital second jaw model 60, which in the current example is the maxilla (upper jaw). However, it could also be a digital model of an opposing prosthesis, such as a designed denture or a scan of an existing denture. Furthermore, the digital second jaw model 60 is in the current embodiment only a surface scan provided by an intra oral scanning process. However, as disclosed above such a surface scan can be provided by other means, such as scanning an impression or a gypsum model.

(14) Similar to what was discussed in relation to the digital first jaw model the digital second jaw model could also be a representation of the mandible when the digital first jaw model is a representation of the maxilla.

(15) The user can then proceed to create the digital prosthesis design 10 based on the digital first jaw model 30 and the digital second jaw model 60. The digital prosthesis design 10 is in the current example processed as a solid CAD model. This means the in the digital design environment the digital prosthesis design 10 is handled as an object with a thickness and a watertight mesh defining the full shape of the CAD model. The digital prosthesis design is formed by a distal prosthesis surface 80, which is the surface facing the digital second jaw model 60, and a proximal prosthesis surface 11, which is the surface facing the digital first jaw model 30. In other words, the distal prosthesis surface 80 can in general be considered to be defined by the virtual teeth and virtual gingiva anatomy surface, which includes the occlusal surface that will be in contact with the surface of the digital second jaw model 60 when evaluating occlusion, for example by using a virtual articulator. The proximal prosthesis surface 11 can generally be considered the surface of the manufactured prosthesis which when placed on the implants face the gingiva of the first jaw.

(16) The proximal prosthesis surface 11 is designed primarily based on the surface scan 31 and the planned placement of the implants represented by the digital implant models 39, 40 and the abutments represented by the digital implant models 41, 42 and can comprise the following steps: a) Generate a digital intermediate proximal surface (not shown) of the digital prosthesis design 10 by duplicating a defined part the surface scan 31, b) Subtract the implant models and the abutment models from the CAD model of the digital prosthesis design 10 using a Boolean subtraction. Since the model of the temporary prosthesis 10 is considered a solid CAD model, intermediate abutment holes can be provided by performing a Boolean subtraction, c) Generate the abutment holes 90,91 by offsetting the intermediate abutment holes to provide a gap 81, 82 between the abutment holes and the models of the implants and the abutment, and d) Remove undercuts by modifying the digital prosthesis design so that it can freely be moved relative to the digital first jaw model and the abutment models along at least one linear movement (insertion direction) between a position where the abutment models can be received in the abutment holes and a position where they are outside the abutment holes without the digital prosthesis design and the digital first jaw model overlapping or otherwise conflicts.

(17) By expanding the abutment holes 90, 91 as described above, in particular in step c) and d) tolerances can be taken into consideration when planning for the implant placement. Such tolerances can for example be surgical tolerances such as the drill not engaging the jaw bone in the exact position desired or scanner tolerances where the accuracy needed exceeds the accuracy of the digital first jaw model.

(18) In addition the user is planning to extract the tooth 33. In order to make room for healing and avoid pressure in that area a recess 83 is designed in the proximal prosthesis surface 11 opposite the planned extraction site 84 of the digital first jaw model 30.

(19) The distal prosthesis surface 80 can be generated by designing an anatomy of the prosthesis as described in the art so that the occlusive surface thereof ensure proper occlusion against antagonist teeth of the digital second jaw model 60.

(20) With the digital prosthesis design 10 properly created the digital guide design 20 can subsequently be generated.

(21) The digital guide design 20 is formed with a proximal guide surface 21 which at least in part comprises the complementary shape of the distal prosthesis surface 80. This can for example be provide by a Boolean subtraction of the digital prosthesis design 10 from the digital guide design 20.

(22) Similarly, the digital guide design is formed with a distal guide surface 22 that is generated by a Boolean subtraction of the digital second jaw model 60 from the digital guide design 20.

(23) Accordingly, seeing that the abutment holes 90, 91 are oversized there is a risk that a prosthesis manufactured based on the digital prosthesis design is placed incorrectly if not guided properly. Accordingly, by using a positioning guide manufactured based on the digital guide design the position of the prosthesis is ensured even if the implants was not placed exactly as planned, thereby ensuring the desired occlusion between the prosthesis and the opposing jaw.

(24) FIG. 2A shows a digital kit 200 comprising a digital prosthesis design 201 in the form of a digital denture comprising a digital gingiva model 202 having digital teeth models 203 provided on the distal surface of the digital gingiva model and a digital guide design 204. The digital kit 200 may be manufactured using conventional 3D manufacturing techniques. Accordingly the kit can be provided to a user in digital form whereby they can produce the kit part themselves or the kit can be shipped in physical form ready to be used by the practitioner.

(25) A digital guide design 204 is arranged on the digital teeth model. Although not shown the proximal surface 205 of the digital guide model comprises proximal recesses for receiving at least a part of the digital teeth models 203.

(26) The distal surface 206 of the digital guide design comprises distal recesses 207. The distal recesses 207 are designed based on the opposing dental situation (not shown). In the current embodiment the opposing dental situation is formed of antagonist teeth (not shown). The scan of the opposing dental situation is then used to generate the distal recesses 207. This can for example be done by a Boolean subtraction which a person skilled in the art would be able to perform. Alternatively, these recesses could also be provided based on the digital artificial teeth of an opposing denture.

(27) Although not shown the proximal surface 208 of digital prosthesis design 201 is formed with two abutment holes (not shown) slightly oversized in order to accommodate for possible implant movement that could have occurred during implant placement so that the prosthesis manufactured based on the digital prosthesis design 201 can be properly placed on the abutments (not shown.

(28) In addition, the digital kit 200 can also include a digital drill guide design 220 as shown in FIG. 2B. The digital drill guide design 220 comprises four drill guide bores 221,222,223,224. When manufactured the drill guide bores are used to guide a drill into the jaw bone in order to create implant bores in the jawbone wherein the implants (not shown) for supporting the prosthesis (manufactured based on the digital prosthesis design 201) when arranged on the jaw of patient.

(29) The digital drill guide design 220 is also formed with anchor bores 225,226,227 which is used for establishing bone anchors, which are screws that secures the drill guide to jaw bone during implant bore drilling.

(30) The proximal surface 228 of the digital drill guide design 220 is designed based on a scan of the gum surface of an edentulous patient in which the prosthesis manufactured from the digital prosthesis design 201 is to be placed.