JPH10277059A - Dental prosthesis and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dental prosthesis which eliminates manual work by using most of the machining and/or grinding technique by a CAD/CAM apparatus and has excellent aesthetic properties and sufficient strength and a process for producing the same. SOLUTION: A block consisting of any among metals, alumina based ceramics and zirconia based ceramics is used as a material for an inner crown and a block consisting of any among plastics, silica based ceramics and calcium phosphate based ceramics is used as a material for an outer crown. The dentition shape on an abutment tooth side and the dentition shape on an antagonist tooth side are measured by a measuring instrument of a contact type or noncontact type from a plaster mold formed by impression taking of the oral cavity. These shapes are displayed on a graphical display device and an inner crown shape and outer crown shape are plotted. The block bodies described above are cut out by an NC-controlled machining and/ or grinding machine in accordance with the threedimensional coordinate data obtd. by the plotting, by which the inner crown 1a and the outer crown 1b are produced and fitted. The dental prosthesis l is thus produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dental prosthesis such as a crown and a bridge and a method for producing the same, and more particularly, to an inner crown produced by cutting and / or grinding by a CAD / CAM apparatus. The present invention relates to a dental prosthesis comprising an outer crown and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in the case of dental prostheses such as crowns and bridges, in which aesthetics similar to natural teeth are required, a resin precast crown, a porcelain baked precast crown, a resin, etc. Forefront bridges, porcelain firing bridges, all-ceramic crowns and the like are used. In the production of these dental prostheses, an impression (a negative type of a tooth) was obtained from the oral cavity of a patient who formed an abutment, and a model (a duplicate of a tooth) was prepared from the impression using plaster or the like. Later, it is manufactured as follows based on the model.

[0003] Resin forehead crown, porcelain baking forehead crown,
In the case of resin veneering bridges and porcelain baked bridges, a wax mold for the core part is first made using a wax on the abutment tooth model by the lost wax casting method, and this wax mold is buried in the refractory investment material. After the investment material has hardened, it is placed in an electric furnace and heated to incinerate the wax mold.Metal is cast in the resulting mold, and the casting is dug out of the investment material, and then cut and polished to form a metal core. Then, a hard resin for a crown is laid and polymerized on the obtained core portion, or a porcelain material is laid and fired. In the case of an all-ceramic crown, a double model is manufactured using a refractory model material, porcelain is laid on the double model and fired, and then the refractory double model is removed, and the shape is corrected and polished. Have been made.

Normally, these operations are performed by a dental technician. However, not only the shape of the oral cavity and the site for preparing the prosthesis differ from patient to patient, but also extremely high dimensional accuracy on the order of several μm is required. This is a complicated operation, requiring not only the skill of a technician but also a great deal of cost and time. Furthermore, since most of these technical operations are manual operations, there is a difference in accuracy and productivity due to the skills of the technicians, and the demand for dental prostheses will increase due to the increase of elderly people in the future. Is becoming a social issue.

Therefore, it is urgently necessary to develop a method capable of stably supplying a dental prosthesis of a certain quality in a short time. Recently, a crown and a bridge are designed on a screen using a computer. Attention has been paid to CAD / CAM systems for producing dental prostheses by cutting and / or grinding, and many studies have been made. However, these studies are currently in a transitional state, and a dental prosthesis production system that can cover a wide range of applications from inlays to bridges has not yet been completed.

An example of a system currently in practical use is the SEREC system (Siemens, Germany). This system is a system for cutting a dental prosthesis from a ceramic block. Because of the use of silica-based ceramics with emphasis on (1), the strength properties are insufficient, and the use site is limited to cases of inlays and crowns. In addition, a system (DCS, Switzerland) for shaving a dental prosthesis coping (inner crown) from a titanium block and building and firing porcelain on it in accordance with the customary method is being studied. . However, in this method, the production of the outer crown part requiring aesthetics is not different from the conventional one, only a part of the technical operation is replaced by machining, and the most important operation is the building and firing of porcelain The difficult part still requires manual work by a technician.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned conventional drawbacks and maximizes the cutting and / or grinding technology using a CAD / CAM apparatus in the production of dental prostheses such as crowns and bridges. It is an object of the present invention to develop a method for producing a dental prosthesis having excellent aesthetics and sufficient strength in a short time by eliminating manual work, and a dental prosthesis produced by the production method. I do.

[0008]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies in order to solve such problems, and as a method of minimizing the manual operation operation, an abutment tooth model produced by taking an impression from the oral cavity. Based on the above, an inner crown shape is designed on CAD / CAM, and an inner crown is manufactured by cutting and / or grinding any block of metal, alumina-based ceramic, or zirconia-based ceramic, and then obtaining The outer crown shape is designed on CAD / CAM based on the inner crown, and the outer crown is manufactured by cutting and / or grinding any block of plastic, silica-based ceramic, or calcium phosphate-based ceramic. And a method for producing a dental prosthesis by bonding the inner and outer crowns together with dental cement. The dental prosthesis was composed of an inner crown made of a material with excellent mechanical strength and an outer crown made of a material with excellent aesthetic properties. The invention was completed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dental prosthesis according to the present invention is a dental prosthesis having a composite structure in which an inner crown and an outer crown are joined to each other, wherein the inner crown is CAD / CAM. Any one of a plastic, silica-based ceramic, and calcium phosphate-based ceramic, which is made of any one of a cut and / or ground metal, an alumina-based ceramic, and a zirconia-based ceramic, and whose outer crown is cut and / or ground by CAD / CAM. It is characterized by the fact that it consists of, and as a manufacturing method, a tooth form and a mating tooth side of the abutment tooth side with a contact type or non-contact type measuring instrument from a gypsum model manufactured by taking an impression of the oral cavity and making it The tooth shape is measured and displayed on a graphic display device to draw the inner crown shape and the outer crown shape, and cutting and / or grinding by NC control is performed based on the three-dimensional coordinate data obtained by the drawing. To prepare an inner crown and an outer crown with carved blocks Koki, it is characterized in that bonding the inner crown was manufactured and the outer crown.

[0010] Incidentally, any of metals having excellent mechanical properties, alumina-based ceramics, and zirconia-based ceramics are used for manufacturing the inner crown, and specific examples of the metal include:
Examples include a dental gold alloy, a dental gold-silver palladium alloy, a dental silver alloy, a dental titanium alloy, and a dental Co-Cr alloy. Among them, the dental titanium alloy is preferable from the viewpoint of biostability. As the alumina-based ceramic and the zirconia-based ceramic, those generally used can be used because there is no particular limitation on the color tone and the like. Any of an aesthetically pleasing plastic, a silica-based ceramic, and a calcium phosphate-based ceramic is used for the production of the outer crown. Specific examples of the plastic include:
Acrylic plastics, urethane-based plastics, polysulfone-based plastics and the like can be mentioned. Silica-based ceramics include silica-based crystallized glass, and calcium-phosphate-based ceramics include calcium phosphate-based crystallized glass. Examples of the dental cement used for bonding the inner crown and the outer crown include dental resin cement, dental glass ionomer cement, dental zinc phosphate cement, and dental carboxylate cement. Resin cement for dental use is preferably used in view of stability in the inside and adhesive strength.

In order to carry out the method for producing a dental prosthesis according to the present invention, first, a dental impression material is used to form a tooth shape on an abutment tooth side and a tooth shape on a mating tooth side in a patient's mouth. And take an impression. At this time, the impression acquisition of the dentition shape that matches the upper and lower jaws may be simultaneous impression acquisition, or the impression acquisition may be performed separately for the upper and lower jaws. A plaster model is produced based on this impression. Next, the three-dimensional coordinate data of the tooth shape on the abutment tooth side and the tooth shape on the opposing tooth side are measured from the gypsum model using a contact type or non-contact type measuring instrument, and a graphic display device such as a computer is used. The abutment tooth shape of the patient is graphically displayed on a CRT screen using a wire frame or the like. At this time, the positional relationship of the upper and lower jaw teeth is determined in advance by setting a certain reference point on the plaster model of the upper and lower jaws, and the shape measurement data of the plaster model of the upper teeth and the gypsum model of the lower teeth. When the reference points are adjusted using the above, the positional relationship between the upper and lower jaw teeth can be reproduced graphically on the graphic display device. It is preferable that the three-dimensional coordinate data of the tooth row shape on the abutment tooth side and the tooth row shape on the opposing tooth side, which are graphically displayed, be stored in a memory in a computer as a digital signal. A memory such as a magnetic drum built in the computer or a memory medium such as a floppy disk separately set in the computer may be used.

That is, the inner crown is manufactured by automatically designing a cap of a fixed thickness having a margin line as an edge on the CRT based on the abutment tooth shape graphically displayed on the CRT, and then using a mouse or the like. Is used to deform the wire frame of the cap to appropriately adjust the thickness of the periphery and the like. In the case of a bridge, the inner crown of the missing tooth portion is also designed, but this is done by connecting an arbitrary point of the inner crown of the abutment tooth located on both sides of the missing tooth designed on the CRT with a wire and deforming. Design the inner crown of the missing tooth (pontic inner crown). In addition, a cement space may be produced by offsetting an arbitrary size on the inner surface side of the inner crown as needed. If the three-dimensional coordinate data obtained by the drawing is stored in a memory in a computer, the stored three-dimensional coordinate data can be used as a standard model, so that subsequent design operations can be simplified. .

When the design of the inner crown is completed and three-dimensional coordinate data is obtained as a digital signal, a machining command is transmitted to an NC-controlled cutting and / or grinding machine based on the three-dimensional coordinate data, and the inner crown is transmitted. The block of material is cut and / or ground to produce the inner crown. The block used at this time usually has a rectangular parallelepiped shape, but it is preferable to use a block having a shape similar to the shape of a crown or a bridge in advance because the amount of cutting and / or grinding is reduced.

Next, the outer crown is manufactured by using a wire frame to determine the positional relationship between the three-dimensional coordinate data of the inner crown designed in the above-described manufacturing of the inner crown and the three-dimensional coordinate data of the dentition on the opposing tooth side. It is possible to draw and design the shape of the crown or bridge arbitrarily so as to fit in the space between them, but it is easier to use the standard data of the crown and bridge registered in advance. Can be designed. At this time, a reference point such as a contact point with the opposing tooth is set and displayed graphically, and the mating dentition model is temporarily deleted from the screen to prevent interference with the opposing tooth during design. If a color change occurs, make that part a graphic display as a discoloration plane, and operate the mouse to suppress the discoloration area and compare the form of the outer crown to the space space with the dentition on the opposing tooth side It can be easily fitted. In addition, a cement space may be produced by offsetting an arbitrary size on the inner surface side of the outer crown as necessary.
If the three-dimensional coordinate data obtained by the drawing is stored in a memory in the computer, the stored three-dimensional coordinate data can be used as a standard model, so that the subsequent design operation can be simplified.

When the design of the outer crown is completed and three-dimensional coordinate data is obtained as a digital signal, an NC-controlled cutting and / or grinding machine based on the three-dimensional coordinate data is used as in the case of the inner crown. The processing command is transmitted to the outer crown and the block of the outer crown material is cut and / or ground to form the outer crown. In the case of the outer crown, if necessary, characterization such as stain may be performed using a dental hard resin or dental porcelain for adjusting the color tone with the remaining teeth of the patient. The inner crown and the outer crown produced in this way are joined together using dental cement to complete a dental prosthesis.

[0016]

EXAMPLES Hereinafter, the dental prosthesis and the method for producing the same according to the present invention will be described more specifically with reference to examples. Example 1 As shown in FIG. 1, the inner crown 1a is a dental titanium alloy,
The dental prosthesis 1 in which the outer crown 1b was formed of a silica-based ceramic and had a maxillary 5th to 7th bridge shape was produced by the following method. First, using a dental impression material, impressions of the tooth shape on the abutment tooth side and the tooth shape on the opposing tooth side in the oral cavity of a patient were obtained, and a gypsum model was prepared from this impression. Next, the three-dimensional coordinate data of this gypsum model is measured using an optical non-contact measuring device, and the shape of the abutment tooth of the patient is graphically displayed as a wire frame on a CRT screen of a computer, and the margin line is set as a margin. After designing a cap having a thickness of 0.5 mm on the CRT, the wire frame of the cap was deformed using a mouse, and the edge was gradually thinned to design the inner crown. A cement space was provided on the inner surface side of the inner crown with an offset of 50 μm. The design of the inner crown was similarly performed for the abutment on both sides of the missing tooth. Next, an arbitrary point on each cap between both abutment teeth was tied with a wire and deformed to design a pontic portion. After accumulating the three-dimensional coordinate data obtained by the drawing in a memory in a computer, the dental titanium alloy block was cut and ground based on the three-dimensional coordinate data to produce the inner crown 1a. Next, from the three-dimensional coordinate data of the inner crown designed at the time of manufacturing the inner crown and the three-dimensional coordinate data of the tooth shape on the opposing tooth side, the positional relationship between the two is graphically displayed in a wire frame, and the space between the two is displayed. The bridge shape is designed to fit in the space, and 50 on the inner side
A cement space was provided with an offset of μm. Next, after storing the three-dimensional coordinate data obtained by the drawing in the memory in the computer, the outer crown 1b was manufactured by cutting and grinding the silica-based ceramic block based on the three-dimensional coordinate data. The inner crown 1a and the outer crown 1b produced in this way are bonded with dental resin cement, and the upper jaw 5-7 bridge shape in which the inner crown 1a is made of a dental titanium alloy and the outer crown 1b is made of a silica-based ceramic. The dental prosthesis 1 was completed. Obtained dental prosthesis 1
Had sufficient strength and excellent aesthetics, and was also excellent in fitting accuracy in the oral cavity.

Example 2 As shown in FIG. 2, a dental prosthesis 1 having a crown shape of a lower molar tooth in which an inner crown 1a was made of a dental silver alloy and an outer crown 1b was made of acrylic plastic was produced by the following method. In the same manner as in Example 1, impressions of the tooth shape on the abutment tooth side and the tooth shape on the opposing tooth side in the oral cavity of the patient were obtained using a dental impression material, and a gypsum model was formed from this impression. Produced. Next, the three-dimensional coordinate data of this gypsum model is measured using an optical non-contact measuring device, and the shape of the abutment tooth of the patient is graphically displayed as a wire frame on a CRT screen of a computer, and the margin line is set as a margin. After designing a cap having a thickness of 0.5 mm on the CRT, the wire frame of the cap was deformed using a mouse, and the edge was gradually thinned to design the inner crown. In addition, on the inner side of the inner crown
A cement space was provided with an offset of 50 μm. After storing the three-dimensional coordinate data obtained by the drawing in the memory in the computer, the dental silver alloy block was cut and ground based on the three-dimensional coordinate data to produce the inner crown 1a. Next, from the three-dimensional coordinate data of the inner crown designed at the time of manufacturing the inner crown and the three-dimensional coordinate data of the tooth shape on the opposing tooth side, the positional relationship between the two is graphically displayed in a wire frame, and the space between the two is displayed. The crown shape was designed to fit into the space, and a 50 μm offset cement space was provided on the inner surface. Next, after storing the three-dimensional coordinate data obtained by the drawing in a memory in a computer, the acrylic plastic block was cut and ground based on the three-dimensional coordinate data to produce the outer crown 1b. The thus-prepared inner crown 1a and outer crown 1b are bonded with a dental resin cement, and the lower crown is formed of a dental silver alloy and the outer crown 1b is made of acrylic plastic. Prosthesis 1 was completed. The obtained crown, which is the dental prosthesis 1, had sufficient strength and excellent aesthetics, and also had excellent fitting accuracy in the oral cavity.

[0018]

As described above in detail, the method for producing a dental prosthesis according to the present invention does not require complicated manual operation such as a conventional method for producing a dental prosthesis, and is almost completely unnecessary. Is replaced by machining, so that a dental prosthesis with a certain quality can be manufactured in a short time, and the obtained dental prosthesis has excellent strength, esthetics, and excellent fitting precision. Thus, the degree of contribution to the dental medical field is very large, for example, reduction of the production cost of dental prostheses and elimination of problems such as shortage of technicians.

[Brief description of the drawings]

FIG. 1 shows an upper jaw 5 in which an inner crown is a dental titanium alloy and an outer crown is made of a silica-based ceramic according to a first embodiment of the present invention.
It is sectional drawing of the dental prosthesis of a 7th bridge part shape.

FIG. 2 is a cross-sectional view of a dental prosthesis having a lower molar crown shape in which an inner crown is a dental silver alloy and an outer crown is made of an acrylic plastic according to a second embodiment of the present invention.

[Explanation of symbols]

 1 dental prosthesis 1a inner crown 1b outer crown

Claims (2)

[Claims] 1. A dental prosthesis comprising a composite structure in which an inner crown (1a) and an outer crown (1b) are joined to each other, wherein the inner crown (1a) is cut and / or ground. A dental prosthesis, wherein the outer crown (1b) is made of one of a cut and / or ground plastic, a silica-based ceramic, and a calcium phosphate-based ceramic. Things (1). 2. Using a contact type or non-contact type measuring device, a tooth row shape on an abutment tooth side and a tooth row shape on a mating tooth side are measured from a gypsum model produced by taking an impression of the oral cavity. The shape of the inner crown and the outer crown are displayed on a graphic display device, and the block is cut out by an NC-controlled cutting and / or grinding machine based on the three-dimensional coordinate data obtained from the drawing to form the inner crown. A method for producing a dental prosthesis having a composite structure in which an inner crown and an outer crown are joined to each other, wherein the inner crown and the outer crown are joined together.