DENTAL MODEL, ARTICULATOR AND METHODS FOR PRODUCTION THEREOF

TECHNICAL FIELD

This invention relates to a model of at least a part of a dental structure, said model including a dental structure and an interface. It also relates to an articulator, and further a combination of said articulator and said model, wherein said articulator comprises an upper portion and a lower portion, said upper portion including a first holding part arranged to hold a model of at least a part of an upper dental structure and including a first positioning device, said lower portion including a second holding part arranged to hold a model of at least a part of a lower dental structure and including a second positioning device, said first and second positioning devices enabling adequate positioning of and movability of said models to test the interfit them between by means of having surfaces of said first and second positioning devices in direct contact with each other and further at least one male/female device having at least one element that protrudes from, or near, one of said surfaces and a corresponding recess near or in the other one of said surfaces. Further it relates to a method for producing said model and articulator respectively.

TECHNICAL BACKGROUND

Production of dental restorations, such as inlays, crowns, bridges, and the like, is based on technologies that have evolved for many decades. The production includes many different steps and involves a number of different specialists and special equipment. In brief, a traditional manufacturing procedure includes the following steps. First a dentist makes impressions and an index of the bite of the person who is in need of a dental restoration. The impressions are used to cast an upper half model and an under half model respectively of the bite of the individual. Thereafter the cast models are positioned in an articulator in combination with the index to perform a registration of the bite, hi a subsequent step grinding is performed to obtain a flat back surface on each model half. Thereafter pinning and casting is performed to facilitate attachment of a cast base plate to the back side of each model half. After attachment thereof, again grinding has to be performed to adjust the configuration of the base plate to the form of each model half. In the next step sectionizing is performed of the model half where the dental restoration is to be inserted, i.e. dividing a portion of that model half into appropriate sections in the area for the dental restoration. Once the sectionizing is finalized the area for restoration is scanned, i.e. the sectionized area of the cast model, to prepare the

framework/coping in a CAD-program. Now the actual manufacturing of the dental restoration may be achieved, by transferring a C AD-file to the production unit. When the dental restoration is produced it will be attached to the cast model, i.e. veneering. Thereafter the dental restoration is adjusted by manual grinding and adaptation in combination with testing it in the articulator. Accordingly there are many more or less complex steps that has to be performed before a dental restoration may finally be actually applied into the mouth of a patient. As a consequence, the production requires not only access to a set of specialised, more or less costly equipment but also a number of complex activities performed by qualified specialists, which makes it very costly.

One such piece of specialised equipment is a pivoting articulator, which is used in connection with the production according to this traditional technology. Such an articulator includes numerous complex details, which of course makes it expensive and indeed also complicated in use. hi brief it includes a base plate positioned on adjustable feet to be able to level it off. Affixed to the base plate there is a solid support pillar, which at its top has a kind of hinge mechanism for a pivoting lever arm. At its outer end the lever arm has a specific pointing device that cooperates with a receiving device positioned at the base plate. Numerous of different adjustment devices are needed for its function. On top of that the dental casts have to be attached by plaster to special support plates to be able to fit them into the articulator. A large amount of plaster is needed due to a large distance between the actual transition zone of the dental structure and the interface of the articulator. As is evident, the need of using such equipment makes it hard to achieve cost efficient production.

In DE 395385, DE 602015, DE 419605, US 2,445,639 and US 2,566,131, there is presented a very old kind of prior art, wherein a simpler kind of articulator was used to test a dental restoration. However, this kind of known articulators present a design that may not always provide sufficient precision when performing a test therein. Moreover, this ancient technology does not provide for sufficient reliability and/or accuracy. Further this technology requires an extensive use of plaster in the building of the models and support structures for the model, which is undesirable because of several aspects. Firstly because plaster is not an easily controllable material, e.g. because of a relatively large volumetric change dependent on humidity. It should be noted that the prior art technology described above, which uses a total different kind of articulator, also in fact normally requires the use of plaster to build support structures of the dental model. Accordingly this is a common disadvantage concerning the above described prior art technologies. A further disadvantage with the use of plaster is that it is a brittle material.

Accordingly prior art technology involves a complex system that requires considerable investments to facilitate production of dental restorations and also many steps that requires specifically trained staff, which lead to problems concerning cost efficiency, convenience of handling and also possibly quality problems.

SUMMARY OF THE INVENTION

Accordingly, the present invention preferably seeks to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing of a model according to claim 1, an articulator according to claim 12, an articulator according to claim 18, an articulator in combination with a model according to claim 24, and/or a method according to claim 31.

Thanks to the embodiments of the invention very many advantages may be obtained. Specifically much more cost efficient production may be achieved and also at very high quality level, for a dental model that facilitates reliable testing in an articulator.

According to further aspects of the invention:

- said model is arranged to present a void and/or said interface is arranged on a body portion that includes a reference surface on one side and a transition zone adjoining it with the dental structure at the opposite side, wherein the distance between said surface and said transition zone is limited, which provides for very small amounts of material needed for the production of the model, compared to prior art methods,

- said interface includes an engagement arrangement arranged to releasably attach the model to an articulator, which provides for making the articulator being used to be made reusable.

- said engagement arrangement is arranged to enable quick -lock and -release, which provides that efficient and convenient handling may be achieved,

- said engagement arrangement includes a reference surface arranged to enable slide fitting, which provides for the reference surface, including a reference plane, to be used to enable secure and accurate positioning of a model into an articulator,

- said model is integrated with an articulator, which provides for exact and durable positioning of the model into the articulator is achieved that may be made extremely strong, e.g. with standing rough handling during transport,

- the whole of said model, including said interface and dental structure is made of a controllably curable material, which provides for high accuracy and quality may be achieved irrespective of variations in temperature and humidity.

According to a further aspect of the invention it relates to an articulator of the kind mentioned above under "technical field", wherein that said male/female device is in the form of at least two, preferably at least three, separate, discrete elements arranged near or in said surfaces and/or wherein the width W of the positioning device adjacent the transition zone between the positioning device and he holding part, is substantially wider than the width w of the holding part, wherein preferably 1,2 w < W < 5 w, to provide at least one area at that wall of the positioning device from which the holding part protrudes, such that said area will be reachable across the back side of the articulator, by the finger of a user who holds on to the articulator.

Thanks to this kind of articulator the production of a dental restoration may be made much more cost efficient than according to prior art. As is evident from the above the articulators used today are complex, including numerous adjustment devices etc., and are therefore expensive devices and relatively complex to handle, whereas an articulator according to embodiments of the invention forms a surprisingly simple instrument, which both is easy to handle and facilitates cost efficient production. A further important advantage is that it facilitates production of dental models, to be used with the articulator, that requires an extremely small amount of material compared to prior art.

According to further aspects of an articulator according to some embodiments of the invention:

- the size and position of said elements and recesses, respectively, are arranged to form a gap between the side walls of each one of said elements and recesses, respectively, when said surfaces are in contact, which provides for a movement of the articulators may be achieved that resembles the natural movements of the jaw of an individual.

- said holding part is positioned substantially centrally in relation to the positioning device to provide two reachable surfaces at the front wall of the positioning device, which provides for grip able surfaces are obtained at both sides of the positioning device, at the front surface thereof.

Further advantages of the invention will become apparent from the following description of different embodiments. 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 bur does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments of the invention will be described more in detail with reference to the figures, wherein:

Fig. 1 is a perspective view of an embodiment of an articulator according to the invention, Fig. 2 is a further perspective view of an embodiment of an articulator according to the invention and also a dental model to be fitted with the articulator, according to an embodiment of the invention, Fig. 3 is a vertical cross-sectional view along line A-A in Fig. 2, Fig. 4 is a cross-sectional view of the articulator according to lines B-B in Fig. 2, Fig. 5 is a side view of the articulator and model shown in Fig. 2, in an assembled mode, Fig. 6 is a perspective view of modified embodiment of an articulator according to the invention,

Fig. 7 is a perspective view of an alternative configuration of a male half of an articulator according to an embodiment of the invention,

Fig. 8 is a further perspective view of an alternative configuration of a female part according to an embodiment of the invention, Fig. 9 is a further perspective view of an alternative configuration according to an embodiment of the invention, Fig. 10 is a cross sectional view of a dental model along C-C in Fig. 2,

Fig. 11 shows a view from the front of a further embodiment according to the invention, of a male device,

Fig. 12 shows a side view of the male device of Fig. 11, Fig. 13 shows a view from below of the male device of Fig. 11, Fig. 14 shows a front view of a female device, intended to cooperate with a male device of the embodiment shown in Figs. 11-13, Fig. 15 shows a side view of the female device of Fig. 14, Fig. 16 shows a view from below of the device shown in Fig. 14, Fig. 17 shows the male and the female devices according to the embodiment shown in Figs. 11-16, in a dissembled mode, and

Fig. 18 shows the pair shown in Fig. 17, in an assembled mode.

DETAILED DESCRIPTION

In Fig. 1 there is shown a perspective view of an articulator according to an embodiment of the invention. There is shown an upper portion 1 and a lower portion 2 of said articulator. The upper portion 1 and the lower portion 2 of the articulator are substantially similar in the design, except for their interacting male and a female device respectively, which are described in detail below. As a consequence, both portions 1, 2 will be described jointly in the following. Each portion includes a positioning device 3, 4 and a holding part 5, 6. The holding part 5, 6 includes a support structure 51, 61 in the form of a rigid body having a kind of L-shape in a transversal cross-section. On one side of said holding part 5, 6 there is an interface 50A, 6OA arranged to hold a model 15, 16 of at least a part of a dental structure 152, 162 (see Fig. 2). Each interface 50A, 6OA includes an engagement arrangement 9 A, 1OA that enables attachment of the model 15, 16 of a dental structure 152, 162. The dental structure 152, 162 may comprise one or several dental elements. The dental element may comprise at least one of a model of a tooth, a model of a preparation, or a model of artificial dental component. The model of the artificial dental component may e.g. be a model of implant, such as a dental implant, or a model of an abutment.

The engagement arrangement 9A, 1OA (in the following merely the upper portion 1 is referred to with reference signs, but the principle is also the same for the lower portion 2) interacts with a reference surface 50, which may be flat, that forms a common reference plane Pl (see Figs. 2 and 5) together with the back side 50' of the model 15. Hence, the model 15 is intended to rest with its backside 50' in contact with said surface 50, when in correct position. According to the design shown in Fig. 1 the model 15, 16 is intended to slide into engagement with the articulator 1, 2. This is achieved by arranging the interface 50A, 6OA of the holding part 5, 6 with the engagement arrangement 9 A, 1OA that enables sliding of the model 15 into position and that also retains the model 15 with its back side 50' in contact with the reference surface 50, 60. As shown in some embodiments the reference plane Pl may be positioned parallel with a central plane P2, that extends between the upper and lower portions 1, 2. hi Fig. 1 it is shown that the engagement arrangement 9 A, 1OA has a first part 9 A at one side of said reference surface 50, in the form of a solid retracting device, here in the form of the recess (which also could be in the form of a ridge, i.e. a vice versa male/female) that is integral with the support structure 51 of the holding part 5. Extending parallel with said first part 9 A of the engagement arrangement, at the other side of the reference surface 50, there is a second part 1OA in the form of a rod-like device that is resilient, hi the shown example the resiliency is achieved by using a metal wire (having a diameter of

for example about 1-3 mm). In some embodiments the second part 1OA, has appropriate resiliency to securely press the model 15 into contact with the surface of the first part 9 A (at the opposite side). The second part 1OA may press the model 15 against the reference surface 50. A hole 59 that extends substantially perpendicularly in relation to the main extension of said rod- like device may be provided in the holding part 5. The hole 59 allows the outer end of the second part 1OA to move in and out, thereby further increasing flexibility of the rod-like device. As is evident, each model 15, 16 has a corresponding design of its interface 50B, 6OB that enables exact position of its backside 50', 60' against the reference surface 50, 60 when put into inter fit with the interface 50A, 6OA of the articulator. Thanks to providing sufficient width w' and length I' of the interface 50A, 50B good stability and reliability of an interfit may be achieved.

The interface may have an extension 1 ' in at least a first direction that is longer than the width of the dental element of said dental structure. This provides e.g. a stable connection to the articulator when connected thereto, whereby fitting possibilities are obtained. However, in other embodiments, the extension in the first direction is shorter than the width of the dental element of the dental structure.

The holding part 5, 6 is integral with the rearward portion 3, 4 of the articulator. The rearward position is also referred to as the positioning device 3, 4. The positioning device 3, 4 forms a substantially bigger body 31, 41 than the support structure 51, 61 of the holding part 5, 6. The reason for this is partly to form a positioning device 3, 4 that has appropriate width W and length L to achieve ergonomically (secure and comfortable) ability to grip and move the upper/lower portions 1 , 2 by a human being. According to an embodiment of the invention a further beneficial aspect in this regard is to form the holding part 5, 6 with substantially less width w than the width W of the positioning device. Hereby there are formed areas 32, 33; 42, 43, on each side, at the front of the body 31, 41 of the positioning device 3, 4, i.e. reachable surfaces positioned on the body 31, 41, where the holding part 5, 6 protrudes from the positioning device 3, 4. As can be seen in the figures, this provides for space and corresponding areas 32, 33; 42, 43 that enables a finger of a user to be comfortably positioned from above and below respectively around the positioning device 3, 4, which facilitates safe and comfortable gripping. According to the embodiment shown in Fig. 1 the width W of the positioning device is in the range of 2 - 9 mm, preferably 3 - 5 mm, the length L of the positioning device is in the range of 20 - 40 mm, preferably 33 - 42 mm, the width w of the holding part 5, 6 is in the range of 15 - 40 mm, preferably 20 - 25 mm, the width w'

of the interface 5OA, 50 B is in the range of 15 - 35 mm, preferably 18 - 23 mm and the length I' of the interface 50A, 50 B is in the range of 28 - 60 mm, preferably 34 - 40 mm. Further the height H of the positioning device 3, 4 is substantially larger than the height h of the holding part 5, 6. Preferably the height H of the positioning device 3, 4 is in the range 11 - 25 mm, more preferred 15 - 21 mm and the height h of the holding part 4, 5 is in the range of 2 - 9 mm, preferably 3 - 5 mm. The reason to this design will be explained in more detail below.

The positioning devices 3, 4 are arranged to be in direct contact with each other during use, by means of positioning surfaces 30, 40. In the Fig. 1 embodiment, the surfaces 30, 40 are in a form of flat surfaces. Within these surfaces 30, 40 there are arranged male/female devices 7, T, 7"; 8, 8', 8". As shown in the figure the upper portion 1 (or vice versa) is arranged with the male devices in the form of protruding elements 7, 7', 7" and the lower portion 2 being arranged with corresponding female devices in the form of corresponding recesses 8, 8', 8". hi the following merely the male devices (i.e. that protrude) will be described more in detail, since the female devices are complementary formed. As also can be seen from Fig. 1 the male devices are in the form of three separate discrete elements that protrude from the positioning surface 30, which forms one side of said central reference plane P2 of the articulator 1, which reference plane P2 is preferably positioned (at least substantially) parallel with the central, horizontal plane of the bite of the individual. Each discrete element 7, 7', 7", 8, 8', 8" has a shape that will enable desired movability of the holding parts 5, 6 in relation to each other, which movability resemble the natural movements of the jaw of the individual that is in need of a dental restoration. As is evident from the latter the exact form of the protruding elements 7, 7', 7" may differ from one articulator to another (or the elements may be made exchangeable having different configurations, i.e. a set of exchangeable elements for each portion 1, 2) due to the fact that different individuals have different patterns of movement of the jaw. hi Fig. 1 it is shown that these elements 7, 7', 7" are triangularly shaped. Each one of the elements includes a first 7a and a second 7b triangularly shaped surface that is inclined and which in their inter junction form an inclined ridge 7c that terminates in a sharp point 7d at a distance h' above the positioning surface 30. The measure h' is preferable in the range of 2,5 - 5 mm, for example about 3,5 - 4 mm. The inclination of each surface 7a, 7b is chosen such that the angle γ that is formed between the positioning surface 30 and each ridge 7c form substantially the same angle γ in the range of 143 - 152°, preferably about 145 - 149°.

The angle γ may vary in order to provide for a movement of the articulator that enables as close realistic movability as possible, depending on the constitution of the jaw of different individuals. Hence, it may be preferable to have a number of articulators having exactly the same kind of configuration except for the form of the male/female devices, to easily provide different patterns of movement. Needless to say, the form of the female device is beneficially adapted to exactly correspond to the form of the male device. However, it is foreseen that to achieve better simulation of the movement of the jaw there may be situations where some kind of deviation of the form of the male and female device may be beneficial.

As mentioned above the angle γ of each ridge 7c is preferably substantially the same, and presenting surfaces 7a, 7b, enabling sliding movements, extending between the ridges 7c. In the embodiment shown in Fig. 1 the ridges 7c are positioned such that they extend in parallel and perpendicular planes respectively in relation to the extension of the upper portion 1. Two of the protruding elements T, 7" are positioned symmetrically adjacent the sidewalls of the body 31 of the positioning device 3, such that the side wall 7e of each of said discrete elements 7', 7" are coplanar (i.e. substantially vertical) with the side walls of the holding part 3. Hence the ridges 7c delimiting these side walls 7e will extend in a plane parallel with the length direction of the upper portion 1. Both of these latter ridges 7c of each discrete element 7', 7" will present the same inclination, hi the preferred mode also the third ridge 7c, that extends in the plane perpendicular to the length extension of the upper portion 1, presents the same inclination. As is clear from the figures the two discrete elements T, 7" that are symmetrically positioned will have their respective perpendicularly extending ridges 7c, extending in the same plane, i.e. a plane that is perpendicular in relation to the length extension of the upper portion. Test have shown that the use of γ of about 147° provides a realistic movability for most applications. Also the third protruding element 7 present a corresponding configuration as has been described above, but having its vertical side wall coplanar with the rear wall of the body 31 of the positioning device 3.

In the embodiment shown in Fig. 1 , the holding part 5 and the positioning device 3 have back surfaces 39, 49, (see also Fig. 5) that are positioned substantially in the same plane, forming a common substantially flat surface. Accordingly the reference surface 50 of the holding part 5 will be positioned much closer to the back surface 39 than the reference surface 30 of the positioning device 3. Hence, there exists a distance h" between the plane P2 including the positioning surface 30 and the plane Pl including the reference surface 50 of the holding part 5. The distance h" between these planes Pl,

P2 is important due to the fact that it will enable sufficient space for attaching the model

15 within the first part 1 at an accurate and appropriate distance in relation to the model

16 that is positioned in the second part 2. hi a preferred embodiment this distance h" is in the range of 8 - 20 mm, preferably 10 - 15 mm. Thanks to the use of embodiments according to the invention, that distance h" may be kept relatively narrow, which in turn leads to the fact that considerable savings in material may be achieved in the production of each dental model 15, 16. hi some applications even further cost savings may be achieved by, reducing the distance h" in relation to one of the portions 1, 2, i.e. that portion carrying the occlusive dental model, since the model of that portion must not present any soft tissue and can therefore be made shorter. Accordingly in such an embodiment the plane P2 will not be positioned symmetrically between the reference planes Pl, P3 of the interfaces 50A, 6OB. This embodiment may e.g. be useful if either the model of the upper jaw or the model of the lower jaw requires more space than half the distance between the reference planes Pl, P3 of the interfaces 50A, 50B.

In Fig. 2 there is shown an articulator that essentially corresponds to the design of the articulator described in conjunction with Fig. 1. A minor difference lies in the shape of the engagement arrangement 9 A, 1OA, since according to the embodiments shown in Fig. 2 both parts of the holding arrangement 9 A, 1OA are formed integrally with the body 51, 61 of the holding part 5, 6 of the articulator. As is evident the dental models 15, 16 will then have a corresponding engagement arrangement 9B, 1OB as part of their interface 50B. The exact shape of the inter fit of the interfaces 50A, 50B, 6OA, 6OB may vary, e.g. presenting varying complementary shapes of a recess and protrusion respectively, and also have the inter fit arranged vice versa, i.e. the model arranged with the exterior part of the interface (e.g. common in connection with a model forming the whole bite). Regarding other aspects the dental models 15, 16 intended for the articulator in Fig. 1 are more or less the same, as is evident for the skilled person within the field. In Fig. 2 it is indicated that the back surface 50' of the dental model 15 forms the plane Pl that is common with the surface 50 of the articulator when the dental model 15 is inserted into position within the articulator. Accordingly, the back surface 50' of the model 15 is in contact with the reference surface 50. Furthermore Fig. 2 shows that there is a substantially vertical surface 154, at a first side wall, that will enable exact positioning of the model 15, lengthwise, by positioning said surface 154 in contact with the corresponding opposing surface 34 of the articulator 1 (see Fig. 1). The engagement arrangement 9B, 1OB, the reference plane 50' and the vertical surface 154 are integral with, and positioned at the periphery of, the support body 151 of the model 15.

Moreover, Fig. 2 shows that the side where the model of the dental structure 152, 162 of an individual is arranged, faces in the opposite direction in relation to the reference surface 50', 60'. The transition zone 155, 165 between the dental structure 152, 162 and the interface 150B, 160B may thanks to the embodiments of the invention be positioned very close to the reference surface 50', 60', i.e. providing a limited thickness X in the range of 2 - 10 mm, preferably 3 - 5 mm. The width w' and the length 1' of the model 15, 16, respectively, according to the shown embodiment is the same as for the interface 50B, 6OB, and then of course substantially the same as that of the interface 50A, 50B of the articulator, (see fig. 1)

Further Fig. 2 indicates that there may be a hole 158 centrally positioned within the reference surface 50', 60'. As is more clearly shown in Fig. 10 (cross section C-C of the upper dental model of Fig. 2) the dental model 15, 16 may form a hollow body 151, 152 presenting a void 156 that communicates with the opening 158, which provides for substantial saving of material, e.g. about 50% compared to a solid body 151, 152. It is also presented that the inner walls 157 may have an uneven surface (forming ridges), which may be beneficial regarding strength. To even further enhance the strength of the model 15 the polymeric material may be supplied during production in a manner to form a support structure 159 extending across the void 156. The support structure may e.g. form a framework, such as one or several bridges.

According to some embodiments of the invention the dental model 15, 16 is produced by free form fabrication (FFF), which provides for synergies. Especially in conjunction with the latter kind of embodiment this provides for many synergies, since in such an embodiment considerable cost may be saved, as a consequence of using less of expensive material and less time in the expensive FFF production equipment. On top of that it leads to less production complications, e.g. less shrinking and quicker solidification. The preferred methodology providing a beneficial way of producing these models 15, 16 by free form fabrication is explained more in detail in another application (i.e. having the title: "Method and system for obtaining data for a dental component and a physical dental model") filed by the same applicant, which has been filed exactly the same day as the present application and which is hereby introduced by way of reference. In brief that methodology makes use of storing a digital record of the design of the articulator, and especially the reference plane P2 (i.e. the common plane for the positioning surfaces 30, 40) and each interface 50 A, 60 A (defining the reference planes Pl and P3 in some embodiments) to thereby enable rational production by free

form technology of the interfaces 5OB, 6OB of the models 15, 16. hi some cases the upper and lower portion 1, 2, respectively, is produced as an integral piece together with the model 15, 16, and thereby making also the reference plane 50A, 6OA of the articulator portions 1 , 2 integral with the rest. Hence this new methodology in a surprisingly efficient manner provides for secure and reliable registration of the dental structure of an individual and also the transfer of said digital registration into a production system that enables accurate and cost efficient production of the dental model in a controllably curable material (e.g. by means of SLA (Stereo Lithography Apparatus and then e.g. using a photopolymer resin material), SLS (and then use a laser fuseable powder), 3D printing, FFF by masking, precision casting, vacuum forming etc.), thereby reducing considerable amount of costly manual adaptation otherwise needed, if using prior art methods. However, it also facilitates considerable savings of material in the actual production, since with this new methodology the amount of material used for the actual model of the dental restoration may be efficiently minimized, e.g. considerably reducing waste.

In brief the new method will be based on the following steps. First a special tray is used to obtain an impression of the bite from the individual in need of dental restoration. The tray includes devices that allow for digital registration by a scanner of the exact positioning of the tray in relation to the bite, hi the next step the impression is scanned and the exact positioning of the bite registered by means of the scanner, in a digital data file (e.g. a STL-file). Thereafter a CAD design program (preferably Procera ^® ) is used to digitally build the restoration and digitally storing said restoration. Thereafter the actual production of the model 15, 16 is produced, and also the dental restoration, whereby the interface 50B, 6OB of the model halves are adapted to fit into an upper and lower part 1, 2 of an articulator that is to be used, i.e. using the registered measurements from the scanning to exactly position the interfaces 50B, 6OB of the dental models 15, 16 in relation to the interface 50A, 6OA of the articulator. Thereafter the dental models 15, 16 are secured in the articulator and subsequently the dental restoration (not shown) fitted into its intended position. Now the veneering will be performed, i.e. positioning the dental restoration into position on its model half 15, 16 (or possibly both model halves if more than one restoration) and in this connection using the articulators to simulate the movement of the jaw of the individual, for fit checking. As already mentioned above, the chosen articulator may beneficially be adapted to have male/female devices 7, 8 that are shaped to (more or less) exactly correspond to the movement of the jaw of the individual. Accordingly a very exact veneering may be achieved and therefore the final adaptation of the restoration, i.e. grinding, may be achieved with high quality. As a

consequence of this new method very few production steps are needed, compared to a prior art technology, to produce a dental restoration ready for final affixation in the mouth of the patient. In fact, with the new technology many more dentists will be able to assist in applying dental restorations, since all needed adaptations and production steps regarding the dental restoration and model halves may be performed in a distributed manner, i.e. performing different steps at different (possibly distant) locations, since based on the digital scanning recorded from the bite that is supplied by the dentist, the digital information needed in different steps is easily transferred electronically. Accordingly, the dentist merely needs to have access to the tray for making the impression. All other operations may be performed by more or less "centralized" laboratories and production sites, involving an optimized number of specially trained people, which thanks to the high level of computerization may produce the dental restorations in an extremely cost efficient manner. A further major advantage is that the use of plaster may be totally eliminated.

In Fig. 3 there is shown a cross-sectional view of the articulators shown in Fig. 2 along a vertical plane that passes through the male/female devices 7', 7", 8', 8" that are positioned near the centre of the positioning surfaces 30, 40. The design according to the preferred embodiment is such that no gap t is formed between the male device 7 and the female device 8. However, a minor gap t may sometimes be accepted. Hence, according to a preferred embodiment said gap t should be kept within tight limits, i.e. 0 - 1 mm, preferably less than 0,5 mm.

In Fig. 4 there is shown a cross-sectional horizontal view of the articulator along B - B in Fig. 2, wherein the cross-sectional plane is positioned horizontally and (as seen in Fig. 2) below the common plane P2 of the contacting surfaces 30, 40 of the articulator, but parallel therewith. As is evident from Fig. 4 due to using discrete elements 7, 7', 7", 8, 8', 8" the gap t is continuous in each horizontal plane that crosses a male/female device, between the opposing surfaces 7a, 7b/8a, 8b of the protruding devices 7, 7', 7", and recesses 8, 8', 8" respectively. As shown in the figure the gap t will be continuous all the way, corresponding to an angle α of at least 180° (360° if positioned inside of the side edge of the contacting surfaces), in each horizontal cross-sectional plane including both the male and female device.

In Fig. 5 there is shown a side view of an articulator comprising dental models 15, 16 according to an embodiments of the invention. Most features of the embodiment shown in Fig. 5 are the same as described above. An important difference is that according to

the embodiment shown in Fig. 5 the articulator and dental models 15, 16 are integral, i.e. fixedly attached to each other. In one embodiment, this is achieved by producing both the articulator and the model halves in the very same production step, preferably by the use of FFF-technology. However, it is foreseen that different production techniques may be used for the articulator and the dental models 15, 16 respectively, e.g. FFF-technology for the dental models 15, 16 and form molding of the upper and lower portion 1, 2, respectively, of the articulator, wherein possibly different sets of male/female devices may be used during the form molding to achieve different movability of the articulators, hi such an embodiment the dental models 15, 16 and its respective portion 1 , 2 may be fixedly attached to each other by any appropriate attachment method, e.g. the use of adhesives, welding, screws, etc.

In Fig. 6 there is shown a lower portion 2 of an articulator, which in most aspects is designed in accordance with what is shown and described in relation to Figs. 1 - 4. The modification of the articulator shown in Fig. 6 resides in making the interface 6OA adjustable, e.g. to be able to adjust the distance h between the backside 49 of the articulator and the reference plane P3 of the interface 6OA. This is achieved by arranging an adjustable body 62, that is separate and adjustable in relation to the body 61 of the holding part 6. In the shown embodiment this is achieved by creating a recess within the body 61 of the holding part 6 and providing the adjustable body 62 with an outer configuration that corresponds to the configuration of the recess. As can be seen in Fig. 6 this is preferably performed in such a manner that the movement of the adjustable body 62 is totally controlled, i.e. by the use of inter fitting shapes that eliminate undesired rocking or tilting of the body 62 in relation to the holding part 6. In the embodiment shown a screw 63 is used to perform the desired adjustment, i.e. rotation of the screw will move the adjustable body 62 in relation to the holding part 6.

In Figs. 7, 8 and 9, there are shown different modifications of the male/female devices that may be used to achieve the desired movability between the upper and the lower portion 1, 2 of the articulator (in the figures merely the female portion 2 of the positioning device 4 is shown). In Fig. 8 it is shown that three discrete elements 8, 8', 8" are used. One discrete element 8', 8" is positioned at the centre of each one of the sidewalls of the body 41 of the positioning device 4 (as is also the case with the embodiment shown in Figs. 1 - 6). The third discrete element 8 is positioned at the centre of the rear wall of the body of the positioning device 4. The shape of each element 8, 8', 8" is in the form of semispherical indentations. Hence the side walls of the indentations are curved and positioned such that the centre line of the radius of the

sphere, in the horizontal plane, substantially coincides with the side walls of the positioning device 4.

hi Fig. 8, a similar figure as in Fig. 7 is shown, but with the difference that each discrete element is positioned totally within the surface 40 of the positioning device 4 and presents a shape in the form of a truncated cone. Accordingly this embodiment provides a gap t that is continuous 360° in the horizontal plane.

In Fig. 9 there is shown an embodiment, wherein the two male/female devices along the side edges of the articulator are exactly the same as shown in Figs. 1 and 2, but where the "middle wise" positioned (seen transversely) male/female devices are in the form of a resilient pin that is fixed to the upper portion 1 with its upper end and that has its lower end insertable into a corresponding hole 8 in the lower portion 2 of the articulator. Thanks to the resiliency of the pin the different halves of the articulator may be moved in a desired manner.

In Figs. 11, 12 and 13 there is shown a further embodiment of a male device 1 of an articulator according to the invention. Most of the aspects of this embodiment is similar to or exactly the same as what has been described above in relation to other embodiments. As a consequence the same reference numbers have been used for many details shown in this further embodiment indicating that they are exactly the same or at least similar or having the same function. The most distinguishing difference is that the male device shown in Figs. 11 - 13 is provided with a holding part 5 that has been divided into two legs 5', 5", to thereby provide an open space 52 in between the two legs 5', 5". An advantage with providing such an open space 52 is that it makes it possible to use the method in connection with dental models 15, 16 arranged with protruding dental elements, e.g. dental implants or a dental implant replicas, extending into (or at least partly into) the open space 52, such that these protruding parts may freely protrude into or through the open space 52 of the holding part 5. Moreover it also provides some saving of material. The distance Z between the innermost sides of the legs 5', 5", defining the with of the open space 52 is according to the shown example about 12 mm. It is evident that this distance Z may be chosen within a wide range, e.g. 5 mm - 50 mm, depending on different needs in different situations/applications.

As shown, preferably the two legs 5', 5" are differently shaped. A first leg 5' is merely provided with one support surface 50', positioned in the sliding plane 50A of the articulator. Further this leg 5' is also provided with an indentation or groove 590

adapted to support a front end of the retaining device 1OA (see Figs. 16 or 17). Moreover, as is shown in Fig. 12, the first leg 5' is arranged with a bore 591 intended to retain a part of the front portion of the retaining device 1OA. The front end of the retaining device 1OA is folded to be hidden/retained within the groove 590, whereby also a secure fixing of the retaining device is obtained (not shown). The second leg 5" is also arranged with a support surface 50" within the sliding plane 50A. Further (as also presented in the embodiment shown in Fig. 1) the second leg 5" is provided with an inclined engagement surface 9A, having the same function as already defined above, in connection with Fig. 1. Further, as is clear from both Figs. 12 and 13 the engagement surface 9 A is formed in an uppermost positioned portion of the second leg 5", having an upper surface 510 that terminates at a distance above the sliding plane 50A. In Figs.

11 and 12 it is shown that the supporting surfaces 50', 50" and engagement surface 9A do extend a limited distance from the outer ends 51', 51" of the legs along the legs, such that there is a gap between the sidewall 34 of the rearward portion 3 and said surfaces 50', 50", 9A forming a lowermost upwardly facing surface 53. Further Figs.

12 and 13 make it clear that the lowermost upwardly facing surface 53 of each leg 5', 5" is positioned at a level that is below the sliding plane 50A.

hi Figs. 14, 15 and 16 there is shown a female device 2 of an adapter adapted to interact with a male device as shown in Figs. 11 - 13. As is evident the holding part 6 of the female device 2 is designed in exactly the same manner as the male device 1. As a consequence the legs 6', 6" shown in the female device will present a mirror image of the legs 5', 5" of the male device 1.

hi Figs. 17 and 18 the embodiments presented in Figs. 11 - 16 are shown in dissembled and assembled mode respectively. The principle of interaction is exactly the same as already has been described in relation to Fig. 1 and will therefore not be described more in detail.

A further difference is the form of the notch 37, 47 that is provided for any suitable kind of retaining device (e.g. rubber band). Here the notch 37, 47 is formed all the way at the back surface of both the male and female devices 1, 2.

The invention is not limited by the examples/embodiments described above but may be varied within the scope of the appended claims. For instance, it is evident for the skilled person that the positioning and number of discrete elements may vary. It is also evident that the reference surfaces 30, 40 may vary in shape, e.g. to be inclined in relation to the

central plane P2, and/or to have parts, or the whole, thereof curved, and/or having holes and/or indentations (evenly disposed) therein, etc. Moreover it is evident that in some applications it may be desired to have some of the "steering functions" of the male/female devices integrated into a ridge that extends across the whole width (or substantial part thereof) of the positioning device 3, 4. A further aspect where the skilled person realizes that many modifications are possible relates to the choice of material for the different parts of the articulator and also the model halves. For instance if a concept is used where the same articulator may be used over and over again (interchangeable model halves) a kind of material is beneficially used that provides for high wear resistance, preferably in combination with low friction. Of course the properties of the surface may be achieved by appropriate coating. Hence, both different kind of metals and also plastic materials may be used to obtain different properties. Moreover it is evident that the exact configuration of the articulator may vary widely in relation to the configuration shown in the preferred embodiments, and still fulfilling the basic functional principles in accordance with the invention. Moreover, in most cases two models 15, 16 are seen as sufficient, however, in some cases it may be beneficial to supply three models (not shown) wherein two of them are in accordance with above, but a "recess" is arranged into the third model, which model includes the dental preparation and wherein said "recess" provides for removal of some soft tissue from the model to be able to better see the exact inter fit of the dental restoration. Finally it should be understood that some aspects of the subject matter may be made the subject for separate, divisional applications to safeguard protection per se for such aspects, e.g. the use of a void inside of the dental models (and or the articulators) is one example of such an aspect that may be claimed individually.

It will be appreciated that the invention is not limited to the embodiments presented above. Other embodiments than the above described are equally possible within the scope of the appended claims. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.