WO2007111438A1

WO2007111438A1 - Dental prosthesis and manufacturing method thereof

Info

Publication number: WO2007111438A1
Application number: PCT/KR2007/001410
Authority: WO
Inventors: Wan Young Jang
Original assignee: Wan Young Jang
Priority date: 2006-03-25
Filing date: 2007-03-22
Publication date: 2007-10-04

Abstract

The present invention relates to a dental prosthesis, and more particularly, to a screw- engagement type dental prosthesis which enables non-preparation of the natural tooth because it is manufactured by division into three pieces, which can be simply installed, and in which the occlusal pressure can be uniformly dispersed. Also, the present invention relates to a method of casting a screw- engagement type dental prosthesis by using a bolt made of carbon or ceramics. The dental prosthesis of the present invention is characterized by comprising a keeper disposed to wrap an abutment tooth of one side from the lingual side, a base disposed to wrap an abutment tooth of other side and the keeper, and a body acting as an artificial tooth and is engaged with the base and the body by means of a screw, and is disposed to wrap the abutment tooth of one side or the abutment tooth of the other side in a direction opposite to a direction in which the keeper wraps.

Description

DENTAL PROSTHESIS AND MANUFACTURING METHOD THEREOF

[Technical Field]

The present invention relates to a dental prosthesis, and more particularly, to a screw-engagement type dental prosthesis which enables non-preparation of a natural tooth (abutment tooth) because it is manufactured by division into three pieces, which can be simply installed, and in which the occlusal pressure can be uniformly dispersed. Also, the present invention relates to a method of casting a screw- engagement type dental prosthesis by using a bolt made of carbon or ceramics.

[Background Art]

In general, prosthesis is performed when a tooth is damaged or missing due to an oral disease. The prosthesis is to wrap a weak tooth or to restore a missing portion of a tooth. Among the prosthesis methods, a crown bridge is used most generally, which employs the natural tooth positioned on either side of the missing tooth as abutment teeth. As shown in FIG. 1, the crown bridge positions an artificial tooth 12 at a site where a missing tooth was positioned, and prepares a part of the abutment tooth 10, and then securely wraps a crown over the abutment tooth 10.

However, such a crown bridge has disadvantages that it causes a pain to a patient at the time of the preparation

(prep) of the tooth, raises a secondary problem such as denaturalization of the dental pulp due to an increase of the prepared amount of the tooth structure of the abutment tooth, and induces exposure of the tooth pulp and hypersensitivity reaction, and the like. Also, since the occlusal surfaces of the abutment teeth are prepared, it is not possible to naturally restore the occlusal surfaces as usual.

Meanwhile, an inlay-type prosthesis as shown in FIG. 2 may be employed to prevent such disadvantages . The inlay prosthesis is to supportingly fit an artificial tooth at a site of a missing tooth, in such a manner that the inlay 22 secured to the side abutment tooth, is press-fit into a recess groove 21 of the artificial tooth 20. After drilling a hole at the abutment tooth (see numeral 10 of FIG. 10) so as to insert protrusions 24 of the inlay 22 thereto, the inlay 22 is inserted into the hole and bonded (cementing) from the upper side so that an insertion portion 27 can be inserted into the recess groove 21 of the artificial tooth 20. The inlay-type prosthesis can be regarded as prosthesis of a type of preparing the abutment tooth in a small amount because there is a small necessity of preparing the abutment tooth 10. However, such a conventional inlay-type prosthesis has a disadvantage that holes should be precisely drilled at the abutment tooth 10 to securely fix the inlay 22 to the abutment tooth 10. In other words, when the precision of the hole drilled at the abutment tooth is reduced, abnormal occlusal occurs thereby causing inconvenience of a patient.

In contrast to the inlay-type prosthesis, as shown in FIG. 3, there has been recently known a press-fitting type prosthesis. The press-fitting type prosthesis is constructed such that a plurality of support portions 33 is provided to wrap the abutment tooth 38, and a male body 37 formed at the support portion 33 is press-fit to a female body 36 of the artificial tooth 35.

The support portion 33 can be provided in plural number, if required, so that it can be easily assembled. However, the conventional press-fitting type prosthesis entails a merit that it has good occlusal and reduces pains of a patient since the abutment tooth 38 is not prepared. Nevertheless, there occurs a disadvantage that the bonding force is reduced because it is of a press-fitting type. Also, the artificial tooth 35 is to be inserted into two abutment teeth in a state where the support portion 33 is attached to the abutment tooth 38 and maintained in the course of the assembly and operation of the prosthesis. Thus, if the male body 37 and the female body 36 are not minutely mated with each other, there could be caused a disadvantage that abnormal occlusal occurs or deformation of the prosthesis occurs when it is used for a long time because it cannot endure the occlusal pressure.

[Disclosure] [Technical Problem]

Accordingly, the present invention has been made in an effort to solve the above aforementioned problems, and an object of the present invention is to provide a screw- engagement type dental prosthesis, which can be simply installed without any preparation of the abutment tooth and in which the occlusal pressure can be uniformly dispersed, and a manufacturing method thereof.

[Technical Solution]

To achieve the above object, the present invention provides a dental prosthesis for restoring a missing tooth, comprising: a keeper disposed to wrap an abutment tooth of one side from a lingual side,- a base disposed to wrap an abutment tooth of other side and the keeper, and a body acting as an artificial tooth and engaged with the keeper and the base by means of a screw, and disposed to wrap the abutment tooth of one side or the abutment tooth of the other side in a direction opposite to a direction in which the keeper wraps. Also, according to the dental prosthesis of the present invention, the base is disposed in a direction in which the keeper wraps the abutment tooth of the other side.

In addition, the base is provided with a base rear wall for supporting a rear wall of the body.

Moreover, the keeper includes a keeper bottom portion adapted to be seated on the missing tooth portion formed by both abutment teeth, and the base further includes a base bottom portion for wrapping the keeper bottom portion.

Furthermore, the base bottom portion is formed with an

insertion recess for inserting the keeper bottom portion

thereto, the insertion recess having a screw hole for the

screw engagement drilled therein.

In addition, the keeper bottom portion is further formed with a keeper groove, and the insertion recess is formed with an insertion protrusion to correspond to the keeper groove.

According to another aspect of the present invention, there is provided a casting method for manufacturing a dental prosthesis, wherein a step of constructing a duplication model for casting a base and a body includes a first step of inserting a titanium bolt into a screw hole for the screw engagement, a second step of performing impression, a third step of removing the titanium bolt after curing, a fourth step of inserting a carbon or ceramic bolt into a place from which the titanium bolt is removed, and a fifth step of casting by- means of filling.

In addition, the second step includes injecting impression material to an injection indicating portion, as the titanium bolt for the duplication is formed with the injection indicating portion for the duplication material, and the fourth step includes inserting the ceramic bolt to a position indicating portion, as the ceramic bolt is formed with the position indicating portion and a position determining portion.

Also, according to still another aspect of the present invention, there is provided a casting method for manufacturing a dental prosthesis, wherein a step of constructing a duplication model for casting a base and a body includes a first step of inserting a titanium bolt into a screw hole for the screw engagement, a second step of performing impression, a third step of removing the titanium bolt after curing, a fourth step of performing a wax work after obtaining a fire-resistant model by injecting filling material for the casting, and a fifth step of casting by filling.

In addition, a sub-step of inserting a correction wire into a place, from which the titanium bolt is removed, is performed between the third step and the fourth step. Furthermore, a female screw drilled at the dental prosthesis is formed by casting after obtaining a carbon bolt or a ceramic bolt by turning the compressed carbon and the ceramic .

[Description of Drawings]

FIG. 1 is a construction view of a conventional bridge prosthesis .

FIG. 2 is a construction view of a conventional inlay-type prosthesis.

FIG. 3 is a construction view of a conventional press fitting type prosthesis.

FIG. 4 is a whole perspective view of the present invention. FIG. 5 is an assembly view of an upper surface of a missing tooth portion of the present invention.

FIG. 6 is a front view of a narrow side of a keeper of the present invention.

FIG. 7 is a front view of a narrow side of a base of the present invention.

FIG. 8 is a rear view of a lingual side of a body of the present invention.

FIG. 9 is an assembly view of an upper portion of the two missing tooth portions of the present invention. FIG. 10 is an assembly view of four missing front tooth portions of the present invention.

FIG. 11 is a view explaining the attachment of a plastic keeper for performing a primary casting according to the present invention.

FIG. 12 is a view explaining the position determining work of a ceramic bolt for forming a female screw of a keeper for performing the primary casting according to the present invention. FIG. 13 is a top plan view showing bottom shapes of several keepers .

FIG. 14 is a view explaining a duplication model work for the secondary casting.

FIG. 15 is a view explaining a duplication model work for the tertiary casting.

FIG. 16 is a side view of a bolt for the duplication and casting.

FIG. 17 is a view explaining a bottom portion of a keeper according to second embodiment of the present invention. FIG. 18 is a side view of a bolt for the duplication and casting of third embodiment of the present invention.

FIG. 19 is a view explaining a duplication model work for the secondary casting according to fourth embodiment of the present invention. FIG. 20 is a side view forming female screws at a keeper hole, a base hole, and a body hole of the present invention.

FIG. 21 is a side view forming female screws at a keeper hole and a base hole of the present invention. FIG. 22 is a side view forming a female screw at a keeper hole of the present invention.

FIG. 23 is an entire perspective view of fifth embodiment of the present invention.

Explanations about the Numerals of the Drawings> 100: keeper 110: keeper wall

120: keeper bottom 130: keeper plate

140: keeper hole 200: base

210: base wall 220: base bottom portion

230: base plate 250: base hole 300: body 310: body main portion

320: occlusal portion 350: bolt

[Mode for Invention]

Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the appended drawings .

In the present invention, FIG. 4 is an entire perspective view of the present invention, FIG.5 is an assembly view of an upper surface of a missing tooth portion of the present invention, FIGS. 6, 7, and 8 are views showing a keeper, a base, and a body of the present invention, FIG. 9 is an assembly view of an upper portion of the two missing tooth portions of the present invention, FIG. 10 is an assembly view of four missing front tooth portions of the present invention, FIGS. 11 and 15 are views explaining a manufacturing method of the present invention, FIG. 16 is a side view of a bolt for the duplication and casting.

In the drawings, dispensable portions are omitted to clarify the technical gist of the present invention, and the omitted portions are the same as those shown in the conventional dental prosthesis and manufacturing method thereof .

Hereinafter, the present invention will be described in more detail with reference to the concrete embodiments .

(First embodiment)

Hereinafter the screw-engagement type dental prosthesis with non-preparation according to a first embodiment of the present invention will be described with reference to FIGs. 4 through 8.

As shown in FIG. 4, the dental prosthesis of the present invention comprises a keeper 100 wrapping an abutment tooth

410 of one side from a lingual side, a base 200 wrapping an abutment tooth 420 of the other side from the lingual side, and a body 300 inserted into a missing tooth portion 430 and wrapping the abutment tooth 410 from a narrow side in case of a molar tooth portion, and wrapping an inner inclination surface of the lip side of both abutment teeth 410, 420 in case of a front tooth portion. ' Also, bolt engagement holes, which penetrate desired portions, are drilled at the keeper 100, the base 200, and the body 300, by means of a casting method using a ceramic bolt 350. While, the keeper 100 and the base 200 wrap both abutment teeth 410, 420 from the lingual side, the body 300 wraps them from the narrow side or the lip side, so that they can be firmly supported by means of a screw engagement using common holes .

In addition, as shown in FIG. 5, since respective portion is divided into three pieces and are assembled in sequence, advantages are obtained that it is not necessary to prepare (prep) the abutment tooth 420, and the inconvenience of a patient is minimized and the assembly is simple.

Respective portion is described in more detail with reference to FIG. 6 through FIG. 8. In FIG. 6, the keeper 100 of the present invention is shown. The keeper 100 comprises largely a keeper wall 110, a keeper bottom portion 120, and a keeper plate 130. The keeper plate 130 and an inner surface of the keeper wall 110 wrap substantially the lingual side and a portion of the circular center of the abutment tooth 410, and the keeper bottom portion 120 is connected to a lower end of the keeper bottom portion 120. The keeper bottom portion 120 is a portion directly contacting with the missing tooth portion 430, and is manufactured according to the manufacturing method of the prosthesis including performing impression, waxing up, casting, and the like, so that it can duplicate the shape of the missing tooth portion 430 without causing any inconvenience. An outer surface of the keeper wall 110 has an inclination angle of 2 to 4° with respect to the vertical line and is positioned at a side of the abutment tooth 410. An inner surface of the keeper wall 110 is manufactured to duplicate an undercut of the abutment tooth 410 according to the general manufacturing method of the prosthesis. The support force of the prosthesis can be further improved by the close contact of the inner surface of the keeper wall with the undercut of the abutment tooth 410. Detailed description of the manufacturing method thereof will be explained below.

Meanwhile, the keeper plate 130 wraps the abutment tooth 410 from the lingual side and is manufactured to duplicate the shape of the abutment tooth 410 as is the keeper wall 410. While the keeper plate 130 wraps the abutment tooth from the lingual side, the body 300 screw-engaged with the keeper plate wraps it from the narrow side or the lip side, so that bonding force is secured in the front and rear teeth portions. The keeper bottom portion 120 is a portion, which is inserted into an insertion recess 221 of the base 200, and is drilled with a keeper hole 140. The keeper hole 140 is formed with a female screw so that a locking bolt 350 can be inserted into it. The keeper bottom portion 120 is formed with a bottom inclination surface 121 to facilitate the assembly with the base 200. Meanwhile, the keeper bottom portion 120 can be formed into several shapes according to the shape and position of the missing tooth portion 430. As shown in FIG. 13, the length of the keeper bottom portion 120 is varied according to the width of the missing tooth portion 430, and if the missing tooth portion 430 is curved, the keeper bottom portion 120 of a curved shape is used. While the keeper 100 is manufactured according to the general manufacturing method of the prosthesis, it is cast by using a carbon or ceramic bolt to form the accurate female screw at the keeper hole 140. The detailed manufacturing method will be described below.

Next, the base 200 of the prosthesis of the present invention will be described with reference to FIGs.4 and 7.

The base 200 is a portion wrapping the other abutment tooth 420 from the lingual side, and is provided with a base plate 230 and a base rear wall 240 substantially wrapping the abutment tooth 420 with respect to the base wall 210. The base wall 210 is formed with a base bottom portion 220 at the lower end. The base wall 210 is disposed at the missing tooth portion 430 positioned between the abutment teeth 410, 420, and the inner surface is manufactured to duplicate the undercut of the abutment tooth 420 as it is. As the base wall 210 is basically formed inclined by 2 to 4°with respect to the vertical line, the assembly of the body 300 is not suffered from any resistance from any direction. As shown in FIG. 7, since the base wall 210 is firmly inserted and engaged with the undercut of the abutment tooth 420, the support force of the prosthesis is excellent in the directions of the front and rear tooth and in the upward direction. A base rear wall 240 is a wall portion for supporting the main portion 310 of the body 300 from the lingual side.

Meanwhile, the base bottom portion 220 is formed with an insertion recess 221 for receiving the keeper bottom portion 120. The insertion recess 221 covers the keeper bottom portion 120 and supports it firmly. As the keeper bottom portion 120 is formed long along the missing tooth portion 430, the keeper 100 and the base 200 cannot be rotated and changed by means of the engagement with the insertion recess 221. Also, the base bottom portion 220 is drilled with a base hole 250, into which a locking bolt 350 is inserted, at a position corresponding to the keeper hole 140. The base hole 250 is preferably drilled with a female screw to improve the screw-engagement force, if required. It is preferable that the size of the base bottom portion 220 is extended to the keeper wall 110 so that the entire missing tooth portion 430 can be covered, and the keeper bottom portion 120 for covering the base bottom portion 220 is preferably selected to conform to the size of the extended base bottom portion.

The base 200 is manufactured according to the general manufacturing method of the prosthesis, including performing impression, waxing up, casting, and the like, however, it is manufactured by using a carbon or ceramic bolt to define the accurate position of the base hole 250. The detailed manufacturing method will be described below. Next, the structure of the body 300 of the present invention will be described in detail with reference to FIGs. 4 and 8. The body 300 is a portion replacing the missing tooth portion and is manufactured beautifully in consideration of the esthetic sense. The body 300 comprises a body main portion 310 made of steel and disposed on and engaged with the base 200, an occlusal portion 320 for defining an occlusal surface in place of the missing tooth portion, and a body plate 340.

The body main portion 310 is manufactured to conform entirely to the base bottom portion 220, the base rear wall 240, the base wall 210, and the keeper wall 110 according to the general manufacturing method of the prosthesis. Also, at least two holding pins 330 are formed at the body main portion 310 so that the occlusal portion 320 is not separated from the body main portion 310 when the occlusal portion 320 made of photo-polymer resin or ceramic material is formed at the main body portion 310. The holding pin 330 is preferably formed instantly at the body main portion 310.

The body plate 340 is provided at one side of the body main portion 310 for wrapping the abutment tooth 410 from the narrow side. While the body plate 340 wraps the abutment tooth 410 from the narrow side, the keeper plate 130 screw-engaged with the body main portion and the base plate 230 wraps the abutment teeth 410, 420 from the lingual side so that the securing force in the directions of the front and rear tooth is increased in addition to the cementing force.

Also, an engagement body hole 360 is drilled at the occlusal portion 320 and the body main portion 310 to penetrate them so that a bolt 350 can be screw-engaged into it. The body hole 360 is also drilled with a female screw to increase the screw-engagement force selectively.

FIG. 10 is an assembly view of four front tooth portions of the present invention, in which FIG. 10 (a) is a view seen from the lingual side, FIG. 10 (b) is a view seen from the lip side. When the front tooth portion is missing, the prosthesis of the present invention as described above, is constructed such that the body 300 is supported by both undercuts of the abutment teeth 410, 420, and the keeper 100 and the base plate 230 are engaged with each other by positioning them to face with each other and locking the bolt 350. Hereinafter the assembly method of the prosthesis with non-preparation of the present invention will be described with reference to FIG. 4 and FIG. 5.

At first, when the prosthesis arrives at the dentist, confirm if the satisfying bonding is accomplished in a mouth of a patient, and then clean the abutment tooth according to the general method thereby preparing the cementing. After completing the prepare, adhesives such as a dental resin, and the like, are sprayed on the keeper wall 110 and the keeper plate 130 of the keeper 100, so that it can be bonded to the abutment tooth 410 at one side. As the keeper wall 110, the keeper plate 130, and the keeper bottom portion 120 are manufactured to duplicate the abutment tooth 410 and the missing tooth portion 430, it is possible to perform the accurate bonding. Then, the cementing of the base 200 is performed at the abutment tooth 420 of the other side. The cementing method is performed as follows. As the base wall 210, the base bottom portion 220, and the base plate 230 of the base 200 are manufactured to duplicate the abutment tooth 420 and the missing tooth portion 430 as they are, it is possible to perform the accurate bonding.

In addition, as the keeper 100 and the base 200 are manufactured to be inserted accurately according to the casting method described below, the keeper hole 140 and the base hole 250 for the screw-engagement are accurately aligned. Then, the body 300 is assembled onto the upper portion of the base 200. Adhesives are sprayed on the body plate 340 and bonded to wrap the abutment tooth 410 from the lip side. As the body 300 is manufactured to duplicate the entire base 200 as it is, it is possible to perform the accurate bonding. In this instance, the body hole 360 is accurately aligned so that it is screw-engaged with the keeper hole 140 and the base hole 250. Then, the base hole 360, the keeper hole 140, and the base hole 250 are penetrated by the locking bolt 350 made of stainless or titanium material to be locked, and the bolt penetrating hole is finished by the photo-polymer resin, thereby completing the operation.

As the prosthesis is assembled after it is divided into three pieces, it is not required to prepare the abutment teeth 410, 420, and it is possible to minimize the inconvenience and pains of a patient and a secondary problem. Also, the assembly accuracy and the bonding force can be radically improved in comparison with the press fitting type prosthesis according to the screw-engagement manner in addition to the general cementing. It is possible to maintain natural occlusal feelings according to the improvement of the assembly accuracy, and to minimize the operation time of the dentist to naturalize the occlusal feelings.

Next, the manufacturing method of the prosthesis with non- preparation according to the present invention will be described with reference to FIGs . 11 through 15.

In general, the manufacturing process of the prosthesis comprises an impression performing step, a working cast making step, a waxing up step, a burying step, a recalling step, and a casting step. While the manufacturing method of the present invention is similar to the general manufacturing method, however, it is different from the general manufacturing method that a carbon or ceramic bolt is employed to drill an accurate screw-engagement hole. At first, a fire-resistant model 500 is duplicated by using a stone model produced from the duplication of a mouth of a patient. Then, a plastic pattern corresponding to the keeper wall 110 is attached to the abutment tooth 510 of the fire-resistant model 500 by using a parallel measuring device (suybey) 600 with wax. In this instance, as a plastic holder 610 is attached to the plastic pattern integrally, the holder 610 is inserted into the parallel measuring device 600 and moved to the accurate position thereby attaching it. When the attachment of the plastic pattern is completed, the holder 610 is cut, and then the keeper plate 130 is engraved by using a twenty- four gauge sheet wax and is connected to the keeper wall 110. Then, as shown in FIG. 11, the plastic pattern corresponding to the keeper bottom portion 120 is attached. It is easy to attach the plastic pattern because a plastic holder 610 is integrally formed at the plastic pattern. The plastic pattern corresponding to the keeper bottom portion 120 can be prepared as several shapes as shown in FIG. 13 according to the size and shape of the missing tooth portion 530, and it is natural that it should be selected appropriately. Then, after all of the plastic patterns corresponding to the keeper wall 110, the keeper plate 130, and the keeper bottom portion 120 have been attached to the duplicated fire- resistant model, as shown in FIG. 12, prosthetic operation is performed by using the carbon or ceramic bolt 620. This operation employing the bolt 620 is performed to drill the screw-engagement holes such as the keeper hole 140, the base hole 250, the body hole 360, and the like at the accurate positions so that they conform to each other, and occupies an important step in the screw-engagement type prosthesis of the present invention. The concrete shape of the ceramic bolt 620 is shown in FIG. 16. The operation employing the bolt is progressed by using the parallel measuring device 600 to determine the accurate position. After inserting the ceramic bolt 620 into the parallel measuring device 600, it is moved to a position to drill the keeper hole 140, and filled up by the wax, and a sprue is attached at a proper position, that is, between the keeper wall 110 and the keeper plate 130, and the like, and it is buried with material identical with that of the duplicated fire-resistant model and recalled and performed of the primary casting. Thus, the keeper 100 drilled with a female screw is manufactured by the primary casting.

Next, the manufacturing of the base 200 by using the secondary casting will be described.

Above all, it is very important to drill the base hole 250 to conform to the keeper hole 140 drilled at the keeper 100 manufactured by the primary casting. To accomplish the desired object, the present invention employs the titanium bolt 630 for the duplication and the ceramic bolt 620 for the casting, as shown in FIG. 16. As shown in FIG. 14, the titanium bolt 630 for the duplication is inserted into the keeper hole 140 of the metal cast keeper 100, and then entire duplication is performed with silicon impression material. In this instance, the impression performing material is filled to an indicating portion shown in FIG. 16, and then it is cured. When the curing is completed, the titanium bolt 630 for the duplication is rotated so that it can be removed by using a hexagonal wrench, and then the ceramic bolt 620 for the casting is rotated so that it can be inserted into a position according to the bolting indicating position, and filling material is injected. When the curing of the filling material is completed and is separated, the ceramic bolt 620 for the casting can be positioned at a position identical with that of the titanium bolt 630 for the duplication on the duplication model of the filling material, so that the manufacturing prepare of the secondary structure is completed. Next, the engraving of the base 200 is performed as shown in FIG. 15. In other words, the base wall 210, the base bottom portion 220, and the base plate 230 are engraved by using the plastic pattern on the duplication model of the filling material, which has been duplicated with including the keeper 100 at the prior step. In this instance, the shape of the base wall 210 is contrary to the keeper wall 110, and faces with the duplicated keeper wall 110. As the manufacturing method is the same as that of the keeper wall 110, it is omitted. After cutting the plastic pattern corresponding to the base bottom portion 220 to conform to the size and length, a hole is drilled at a position for drilling the base hole 250, and the base wall is positioned accurately by using the holder 610 attached to the plastic pattern and is bonded by using the wax. Then, gaps such as a hole for the duplicated filling keeper 100, a vacant space, a hole for the ceramic bolt 620, and the like are filled. The base rear wall 240 and the base plate 230 are also engraved by the same method. The description thereof is omitted, as it is identical with before. Then, the base 200 is cast through the secondary casting process including cutting of the entire plastic pattern to conform to the size and the length, trimming up, filling, recalling, casting, and the like.

Next, the manufacturing process of the body 300 of the present invention will be described with reference to FIG. 15. After arranging the previously cast keeper 100 and the base 200 on the original model, and then engage them with the titanium bolt 630 for the duplication shown in FIG. 16. As was the second casting process, the third duplication model is manufactured through duplicating with using silicon impression material, inserting the ceramic bolt 620 as was performed previously, and injecting the filling material. The structure for constructing the missing tooth portion is engraved on the third duplication model by using the free wax up method. In this instance, the occlusal portion 320 for defining the occlusal surface can be defined as a metal occlusal surface, a photo-polymer occlusal surface, a porcelain occlusal surface, and the like, and although it is manufactured according to the general manufacturing method, the body hole 360 is necessarily drilled for inserting the titanium bolt 630. The body plate 340 is engraved by the twenty-four gauge wax thereby finishing the manufacturing. Then, the sprue is buried and the casting is performed. After the casting, the metal occlusal surface is finished as it is, and the occlusal surface is formed by the resin or the porcelain, and then completed, in case of the occlusal surface made of resin or porcelain.

When the third casting process is completed through the method as described above, it is possible to obtain the prosthesis in which the keeper hole 140, the base hole 250, and the body hole 360 are accurately aligned with each other. As respective casting process has been performed by alternatively using the particularly manufactured ceramic bolt 620 or the titanium bolt 630 as shown in FIG. 16, it is possible to drill the accurate screw holes to achieve simplification of the assembly and provide convenient prosthesis to a patient. The advantages of the present invention described above can be estimated as excellent in comparison with the disadvantages of the conventional press fitting type prosthesis (confer FIG. 3), and the like.

(Second Embodiment)

Next, the second embodiment of the prosthesis with non- preparation of the present invention will be described with reference to FIG. 17. The second embodiment is the same as the first embodiment except that various types of keeper grooves 123 are formed at the keeper bottom portion 120 of the keeper 100. The keeper 100 and the base 200 cannot be moved relatively as the keeper bottom portion 120 and the insertion recess 221 of the base bottom portion 220 are inserted so that they can be fit to each other.

However, when the missing tooth portion is more than two as shown in FIG. 9, the engagement force can be reduced. Accordingly, in the second embodiment of the present invention, as shown in FIG. 17, various types of keeper grooves 123 are formed at a bottom inclined surface 121. In this instance, it is natural that an insertion protrusion 222 is formed at the insertion recess 221 of the base 200 so that it can be engaged with the insertion recess. It is important to form the insertion groove 123 and the insertion protrusion 222 without an undercut .

(Third Embodiment) Next, the third embodiment of the present invention will be described with reference to FIG. 18. The third embodiment is the same as the first embodiment except that the position of the titanium bolt 630 for the duplication and the position of the ceramic bolt 620 for the casting are designed differently. The simple and wide portions of the titanium bolt 630 for the duplication and the ceramic bolt 620 for the casting make it easy to reproduce the positions, and it is possible to make a bolt with high precision.

(Fourth embodiment) Next, the fourth embodiment of the present invention will be described with reference to FIG. 19. The fourth embodiment is directed to a method of manufacturing the prosthesis with non-preparation without using the ceramic bolt 620 for the casting. The manufacturing process is the same as the casting process of the first embodiment except the features described below. The process described with reference to FIG. 11 through FIG. 14 will be progressed identically. After inserting the titanium bolt 630 for the duplication into the keeper hole 140 of the keeper 100 primary cast, following the manufacturing of the duplication model for the secondary casting, identical duplication is performed by using the impression material. Then, instead of inserting the ceramic bolt 620 after removing the titanium bolt 630, filling material for the casting is injected into the entire space including a space in which the titanium bolt for the duplication was positioned, thereby obtaining the same fire-resistant model including the upper portion of the bolt for the duplication, and performing the wax work, and then performing the burying and the casting. In the manufacturing of the body 300 through the third casting, a ceramic bolt 620 can be economized by the same method. In other words, the keeper 100 and the base 200 manufactured through the primary and secondary casting are filled with the titanium bolts 630 for the duplication, and are duplicated by using impression material, and the third casting is performed by direct injecting the filling material. However, in the fourth embodiment, since the ceramic bolt 620 is omitted and direct casting is performed by using filling material, a correction wire 640 is required to prevent breakage of the shape of the bolt, as shown in FIG. 19 (b) . The correction wire 640 is bent roundly at the end thereof so that it is not fallen into a hole, and then the filling material is injected.

Next, with reference to FIGs. 20, 21, and 22, the drilling of female screws for the locking bolt 350 in the keeper hole 140, the base hole 250, and the body hole 360 will be described. FIG. 20 shows that all of the keeper hole 140, the base hole 250, and the body hole 360 are drilled with female screws to be engaged with each other by the locking bolt 350, and as shown in FIG. 21, the keeper hole 140 and the base hole 250 are drilled with female screws so that they can be easily engaged with each other by the locking bolt 350. FIG. 22 shows that a female screw is drilled at the keeper hole 140 and an inclination surface close contacting with lower surface of the head of the locking bolt 350 is formed at the body hole 360, and they are engaged with each other by using the locking bolt 350. The female screws drilled at the inner surface of the keeper hole 140, the base hole 250, and the body hole 360 can be drilled automatically by using the ceramic bolt having a shape identical with that of the locking bolt 350 at the time of casting the keeper 100, the base 200, and the body 300. Meanwhile, the locking bolt 350 is manufactured into a shape identical with that of a portion corresponding to the engagement portion of the real prosthesis of the used bolt for the duplication or the used bolt for the casting. Then, the fifth embodiment of the present invention will be described with reference to FIG. 23. The fifth embodiment is the same as the first embodiment except that the rear walls of the keeper 100 and the base 200 are omitted as shown in FIG. 23. As the rear wall of the base is omitted, the body 300 wraps the entire bottom surface of the base 200, and prevents moving of the base 200, thereby improving the engagement force.

[industrial Applicability]

As described above, according to the dental prosthesis of the present invention, it is not necessary to prepare the abutment tooth so that the pains of a patient and occurrence of a secondary problem can be minimized, and it can be simply installed, and it is possible to disperse the occlusal pressure uniformly so that the dental operation can be facilitated. Also, it is possible to drill an accurate screw engagement hole by using a specially devised titanium bolt or a ceramic bolt.

Claims

[CLAIMS] [Claim l]

A dental prosthesis for restoring a missing tooth, comprising: a keeper disposed to wrap an abutment tooth of one side from a lingual side, a base disposed to wrap an abutment tooth of other side and the keeper, and a body acting as an artificial tooth and engaged with the keeper and the base by means of a screw, and disposed to wrap the abutment tooth of one side or the abutment tooth of the other side in a direction opposite to a direction in which the keeper wraps .

[Claim 2] The dental prosthesis according to claim 1, wherein the base is disposed in a direction in which the keeper wraps the abutment tooth of the other side.

[Claim 3]

The dental prosthesis according to claim 2, wherein the base is provided with a base rear wall for supporting a rear wall_of the body.

[Claim 4]

The dental prosthesis according to claim 1, wherein the keeper includes a keeper bottom portion adapted to be seated on a missing tooth portion defined by both abutment teeth, and the base further includes a base bottom portion for wrapping the keeper bottom portion.

[Claim 5]

The dental prosthesis according to claim 4, wherein the base bottom portion is formed with an insertion recess for inserting the keeper bottom portion thereto, the insertion recess having a screw hole for the screw engagement drilled therein.

[Claim 6] The dental prosthesis according to claim 5, wherein the keeper bottom portion is further formed with a keeper groove, and the insertion recess is formed with an insertion protrusion to correspond to the keeper groove.

[Claim 7] A casting method for manufacturing the dental prosthesis according to any one of claims 1 through 6, wherein a step of constructing a duplication model for the casting a base and a body includes a first step of inserting a titanium bolt into a screw hole for the screw engagement, a second step of performing impression, a third step of removing the titanium bolt after curing, a fourth step of inserting a carbon or ceramic bolt into a place from which the titanium bolt is removed, and a fifth step of casting by means of filling.

[Claim 8] The casting method for manufacturing the dental prosthesis according to claim 7, wherein the second step includes injecting impression material to an injection indicating portion, as the titanium bolt for the duplication is formed with the injection indicating portion for the duplication material, and the fourth step includes inserting the ceramic bolt to a position indicating portion, as the ceramic bolt is formed with the position indicating portion and a position determining portion.

[Claim 9] A casting method for manufacturing the dental prosthesis according to any one of claims 1 through 6, wherein a step of constructing a duplication model for the casting a base and a body includes a first step of inserting a titanium bolt into a screw hole for the screw engagement, a second step of performing impression, a third step of removing the titanium bolt after curing, a fourth step of performing a wax work after obtaining a fire-resistant model by injecting filling material for the casting, and a fifth step of casting by means of filling.

[Claim lθ]

The casting method for manufacturing the dental prosthesis according to claim 9, wherein a sub-step of inserting a correction wire into a place, from which the titanium bolt is removed, is performed between the third step and the fourth step. [Claim 11]

The casting method for manufacturing a dental prosthesis according to claim 9, wherein a female screw drilled at the dental prosthesis is formed by casting after obtaining a carbon bolt or a ceramic bolt by turning the compressed carbon and the ceramic .