WO2001062180A1

WO2001062180A1 - The method and its materials for alveolar ridge protection

Info

Publication number: WO2001062180A1
Application number: PCT/KR2000/000135
Authority: WO
Inventors: Sang-Kohn Chang
Original assignee: Chang Sang Kohn
Priority date: 2000-02-21
Filing date: 2000-02-21
Publication date: 2001-08-30
Also published as: AU2697400A; EP1185213A1; CN1351482A

Abstract

The present invention relates to the method and its materials for alveolar ridge protection and provided to retain the original root form of alveolar ridge by inserting titanium body formed similarly with the natural root form of teeth into the vacancy of tooth pulled out, by filling the vacancy of tooth pulled out with titanium particle mixed with mixing agents to enhance the osteogenic potential property, and by filling the vacancy of tooth pulled out with titanium threads to form the similar root form of natural teeth. Titanium mesh contains bone graft materials can be filled the vacancy of tooth pulled out form the similar root form of natural teeth and protects alveolar ridge to remain as a solid fills in alveolar ridge bone. This eliminates the wearisome of bone graft operation to implant in patient's good time and retains the face appearance good.

Description

THE METHOD AND ITS MATERIALS FOR ALVEOLAR RIDGE PROTECTION

Technical Field

The present invention relates to a method and a material for alveolar ridge protection, and more particularly, the present invention relates to a method and a material for protecting an alveolar ridge which is an eminent line defined by an alveolar bone.

Background Art Generally, in the case that a tooth is extracted, an alveolar bone absorption phenomenon naturally occurs. In order to enable an aesthetic bridge work, specifically, in the case of anterior teeth of an upper jaw, if an alveolar ridge absorbing phenomenon is serious, a bone grafting surgery is first implemented to restore to some extent an outline of the alveolar bone. Thereafter, an implant is installed to restore an original facial profile.

As a result, if facial profile constriction is induced by alveolar bone change after tooth extraction, a person can get wrinkles around the mouth, whereby a problem is caused in terms of a physiognomy of the person. That is to say, by the alveolar bone absorption, a ridge which is an eminent shape of a teeth part, is changed in its configuration.

Moreover, this alveolar bone absorption imposes an adverse influence on manufacture of an artificial tooth, in particular, of an upper jaw. In the case of a lower jaw, the alveolar bone absorption imposes an adverse influence on upkeep and stability of an artificial tooth, whereby a surgical operation cannot but be implemented with difficulty. In the conventional method, because a bone grafting surgery must be implemented before an implant is installed, a required sum is increased, which is burdensome to a surgery receiver .

Also, the alveolar bone absorption makes a periphery of an alveolar bone tissue where an implant is to be installed, inadequate, to limit a size and a width of the implant, whereby a surgical operation cannot be performed as desired. Even a prognosis after the surgical operation is not good in comparison with the lower jaw.

A material which is used for preventing the alveolar bone absorption phenomenon, is called a bone grafting material. A variety of bone grafting materials are known in the art . Hereinbelow, conventional bone grafting materials, a grafting method, and problems caused therefrom will be described.

An autogenous bone graft means that a portion of a bone is cut at a donor site of a hard bone, an ilium or the like inside or outside an oral cavity and then, grafted to a desired part.

However, upon grafting a vital bone marrow and a cancellous bone, a dental root of a corresponding part tends to be absorbed, and, due to lack of an autogenous bone grafting material in the oral cavity, the autogenous bone graft cannot but be limited in its use.

Next, allograft and xenograft materials are disclosed in the art. In this connection, while a frozen allograft material has been extensively used, a percentage of success is limited to a certain value. In the case of a frozen and demineralized or decalcified bone morphogenetic protein: BMP), evident clinical data capable of rendering conviction for use are lacked, and uneconomy is caused. As another bone grafting material, a synthetic bone graft material is disclosed in the art. Calcium phosphate is used as the synthetic bone graft material. The calcium phosphate has two types of chemical structures. First, tribasic calcium phosphate (hydroxylapatite : HA) as being a permanent non- resorbable material can be divided into HA-S (having a diameter of no greater than 15 μm) which is a greatly fine particle, HA-500 and HA- 100 (having a diameter of 500 to 1,000 μm) each of which possesses a spherical particle shape. Second, beta tricalcium phosphate (TCP) as being a bio-resorbable ceramic material possesses a fine particle shape (having a diameter of no greater than 100 μm) , and has a slow absorbing speed. The beta tricalcium phosphate is not absorbed at a constant absorbing rate.

Both of HA and TCP do not have bone inductive capacity and serve as an extender for an autogenous type bone graft and a non-irritative filler.

Further, aluminum calcium phosphorus pentoxide as being a resorbable implant material possesses a highly fine particle shape (having a diameter of no greater than 70 μm) and is used in a state wherein it is mixed with a fixing agent. After 3 weeks use, the aluminum calcium phosphorus pentoxide reveals an absorbing phenomenon in a histological test and exhibits tissue growth between particles.

On the other hand, plaster of Paris (made of calcium sulfate: PP) serves as a mixing agent which is used along with the above-described bone grafting materials. The calcium sulfate as being one of synthetic implant materials has good tissue affinity and hygroscopicity but insufficient osteogenic property.

A mixture (HA/PP) which is obtained by mixing, at a ratio of 1:1, HA particles (product name: orthomatrix HA-500) as being a high-density deposit and plaster of Paris (regulation of FDA: USG medical grade calcium sulfate hemihydrateB containing 0.85% K₂S0₄) prevents movement of a gingival dissected epidermis toward an end of a dental root and functions to bind HA particles one with another. The mixture eases a clinical manipulation and is able to be filled without difficulty in a desired part. Therefore, the mixture is regarded as a material having biological compatibility and biological resorbability . In addition, alpha-ketoglutarate and malate which are two kinds of organic acid and used as fixing agents, have biological compatibility and biological resorbability. The alpha-ketoglutarate and malate exhibit a histological sign of tissue growth between particles. In the conventional art, a frozen allograft bone as a synthetic bone, a bone replacement material (product name: Bioplant HTR, hydroxylapatite, silicate) or the like is filled, immediately after tooth extraction, in a vacancy defined by the tooth extraction. As a lengthy period of time primarily passes, an osteogenic pattern is effected in a manner such that the bone replacement material is deposited, with the lapse of time, around HA particles in the alveolar bone. However, if a substantial period of time is secondarily passes, a gradual absorption phenomenon is very slowly progressed. Also, since the frozen allograft bone is formed by crushing a bone of a human being, cow or sheep, due to a possibility of being attacked with a mad cow disease or AIDS, its use is decreased or limited. In the case of HTR, when observed from the standpoint of its structure, as shown in FIG. 7, outermost calcium hydrate (Ca(OH)₄) (CH) reacts with a blood factor of marrow to produce a bone. Polyhy- droxyethylmetaacrylate (PHEMA) which is placed inward of the calcium hydrate, has an X-ray contrastability and is absorbed into the human body upon completion of bone production. Also, polymethylmetaacrylate (PMMA) which forms an innermost layer, is a plastic material which has biological compatibility, is not willing to be broken even by severe impact from the outside. PMMA is not absorbed into the human body upon completion of bone production and instead, remains in a bone to perform a function of maintaining a shape. However, because a strength of a plastic material is lower than that of a surrounding bone, if a dental implant is installed at a place of molar teeth of an upper jaw where quality, that is, a density of a bone is low, a surrounding bone having a high density cannot be realized around an alveolar bone, whereby initial basic fastenability and stability are deteriorated. Following tooth extraction, although an implant is installed after a predetermined period of time lapses from grafting of HTR, density increase of the surrounding bone cannot be still anticipated. Hence, when it is necessary to install an implant at a place of a low density bone, an implant which has a large width, must be unavoidably selected.

Conventionally, in the case that an implant having a width of no less than 5-6 mm is installed, since a large amount of the surrounding bone should be removed, the surrounding bone must have sufficient height and width .

Further, while an absorbing phenomenon of an alveolar bone can be prevented by filling, simultaneously with tooth extraction, the replacement material of a synthetic bone in a vacancy defined by the tooth extraction, upon installing an implant thereafter, because a reaming process must be conducted using a ratch drill so as to partially remove the material thereby to define in the alveolar bone a space for a dental implant body of the implant, bothersomeness is caused. As a consequence, while the bone grating material can temporarily prevent an absorbing phenomenon of an alveolar ridge, by the fact that it should be at least partially removed for installation of the dental implant, bothersomeness and uneconomy are caused to both of a dentist and a surgery receiver.

While it was reported that the non-resorbable bone grafting material used in the alveolar bone, such as HA, maintains a shape of the alveolar bone for a period of no less than 10 years, in a permanent basis, a partial volume change cannot but be induced. Furthermore, a problem which is provoked due to a density difference between the surrounding bone and a part filled with the artificially grafted bone grafting material, is continuously left as a subject of study.

Disclosure of the Invention

Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to improve the above-described conventional method for bone graft and a material for alveolar ridge protection.

According to one aspect of the present invention, there is provided method and material for alveolar ridge protection, characterized in that a titanium body which is formed to have a contour similar to a dental root of a natural tooth, is inserted into a vacancy which is defined by tooth extraction, in such a way as to maintain a configuration of an alveolar bone.

According to another aspect of the present invention, the titanium body is divided into at least two body segments including an upper titanium body segment and a lower titanium body segment, the upper titanium body segment having therein a well and a locking taper surface and being mechanically coupled with an implantation post of the lower titanium body segment . According to another aspect of the present invention, one or more lower titanium body segments can be mechanically coupled with the upper titanium body segment by virtue of their implantation posts and the well and locking taper surface of the upper titanium body segment.

According to another aspect of the present invention, the titanium body can be selectively embedded into the alveolar bone or projected out of a gum.

According to another aspect of the present invention, each of the titanium body and the body segments has a groove for receiving a dental handpiece which groove is defined by inward depression of an upper end of the titanium body or the body segment.

According to another aspect of the present invention, the titanium body has an outer surface which is ground with great precision.

According to another aspect of the present invention, an outer surface of the titanium body is treated with titanium plasma spray (TPS) or tribasic calcium phosphate (hydroxylapatite : HA) .

According to another aspect of the present invention, each of the titanium body and the upper titanium body segment is formed or defined, on an outer surface thereof, with a pin, a groove or the like for facilitating mechanical integration between the titanium body or upper titanium body segment and the alveolar bone .

According to another aspect of the present invention, the titanium body can fill the vacancy which is defined by tooth extraction, in cooperation with titanium powder.

According to another aspect of the present invention, there is provided method and material for alveolar ridge protection, characterized in that titanium powder is mixed with a mixing agent to form a filling body which has a contour similar to a dental root of a natural tooth, the filling body being inserted into a vacancy which is defined by tooth extraction, in such a way as to effect osseointegration thereof with an alveolar bone.

According to another aspect of the present invention, the titanium powder and the mixing agent can be used together with a bone grafting material .

According to another aspect of the present invention, different particle sizes of the titanium powder can be adopted.

According to another aspect of the present invention, the titanium powder is composed of spherical particles . According to another aspect of the present invention, the titanium powder is coated with HA or TPS.

According to another aspect of the present invention, there is provided method and material for alveolar ridge protection, characterized in that a titanium thread having a low grade of softness is filled in a vacancy which is defined by tooth extraction, to create a contour similar to a dental root of a natural tooth, in such a way as to thereby effect osseointegration thereof with an alveolar bone. According to another aspect of the present invention, the titanium thread can be filled, together with a bone grafting material, in the vacancy defined by tooth extraction.

According to another aspect of the present invention, there is provided method and material for alveolar ridge protection, characterized in that a titanium mesh which is formed to have a contour similar to a dental root of a natural tooth and contains therein a bone grafting material, is filled in a vacancy which is defined by tooth extraction.

According to another aspect of the present invention, the titanium powder and the titanium thread are accommodated in the titanium mesh in such a way as to be formed as a whole into the shape of a dental root of a natural tooth.

According to still another aspect of the present invention, the titanium thread is filled in the vacancy defined by tooth extraction in a state wherein the titanium thread is wound on a circumferential outer surface of the titanium body.

According to yet still another aspect of the present invention, the titanium body and the titanium mesh can be ready-made to have an average standard size of surgery receivers . By the features of the present invention, an alveolar bone absorption phenomenon is prevented by taking necessary action immediately after tooth extraction, and, since a dental arch form can be maintained as it is, upon installing a dental prosthesis after lapse of a predetermined period of time from tooth extraction, aesthetic treatment is permitted. Also, in the case that an implant cannot be installed immediately after tooth extraction due to an economic situation of a patient, by inserting a device of the present invention into a vacancy, that is, an opening defined by tooth extraction, an alveolar ridge can be protected.

Thereafter, upon installing an implant, only an upper structure can be removed, and then, the permanent implant can be immediately installed in an alveolar socket. In the conventional art, an alveolar bone is seriously absorbed at a part which is left alone without taking any necessary step after tooth extraction, and due to this, a bone grafting surgery must be implemented. On the contrary, in the present invention, because the bone grafting surgery which causes bothersomeness, can be omitted, aesthetic implant installation is enabled, and, upon implementing a surgical operation, convenience of a dentist can be enhanced. Moreover, an economical burden of a patient can be decreased. Besides, by preventing in advance an alveolar bone absorption phenomenon, facial profile constriction can be minimized, and thereby, psychological withering of the dentist and patient can be avoided. Brief Description of the Drawings

The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description when taken in conjunction with the drawings, in which:

FIGs. 1A, IB and 1C are cross-sectional views of teeth, illustrating a progress in which an eminent part of an alveolar ridge is absorbed after tooth extraction, in the conventional art;

FIG. ID is a cross-sectional view illustrating alveolar bone absorption due to periodontitis ;

FIG. IE is a cross-sectional view illustrating physiological absorption of an alveolar ridge due to attainment of an advanced age;

FIGs. 2A, 2B and 2C are cross-sectional views of an upper jaw, illustrating, with the lapse of time, facial profile constriction which is induced by alveolar bone absorption after tooth extraction in the conventional art;

FIG. 3A is a front view of a normal upper jaw part prior to removal of teeth;

FIG. 3B is a front view illustrating artificial replacement of a remaining alveolar bone portion after alveolar bone absorption of anterior teeth of an upper jaw;

FIG. 4 is a cross-sectional view of a lower jaw part, indicating a problem of an artificial tooth depending upon a condition of an alveolar bone; FIG. 5 is a cross-sectional view of a lower jaw part, indicating a problem depending upon a condition of an alveolar bone;

FIG. 6 is a cross-sectional view for explaining a conventional method for implementing a bone grafting surgery;

FIG. 7 is a cross-sectional view illustrating a structure of an HTR;

FIGs. 8A through 8D are cross-sectional views of an alveolar bone part, for explaining a method of using a material for alveolar ridge protection, in accordance with an embodiment of the present invention;

FIGs. 9A through 9F are cross-sectional views of an alveolar bone part, for explaining a method for implementing a surgery according to the present invention, in a state wherein an alveolar bone is absorbed;

FIGs. 10A and 10B are cross-sectional views of an alveolar bone part, illustrating another embodiment of the present invention; FIG. 11 is of a cross-sectional view and another exemplary enlarged perspective view of an embodiment which is defined by simultaneously combining FIG. 9 and FIG. 10;

FIG. 12 is a cross-sectional view illustrating another embodiment of a method for alveolar ridge protection, according to the present invention;

FIG. 13 is a cross-sectional view illustrating another embodiment which is obtained by varying the embodiment of FIG. 12; FIG. 14A is a plan view illustrating a titanium thread as being another embodiment of the present invention;

FIGs. 14B, 14C and 14D are cross-sectional views for explaining a surgery implementing method; FIG. 14E is a cross-sectional view suggesting the fact that a portion of the present invention can be used in place of a bone screw upon implementing an autogenous bone flap grafting surgery according to the conventional art ; FIG. 15 is a cross-sectional view illustrating an exemplary use of a titanium body of the present invention;

FIGs. 16A and 16B are cross-sectional views illustrating another embodiment for use of a titanium body of the present invention;

FIG. 17 is a cross-sectional view illustrating still another embodiment for use of a titanium body of the present invention;

FIG. 18 is a cross-sectional view illustrating a state wherein the titanium body is installed together with an embedding implant;

FIG. 19 is a perspective view illustrating an implant body which is used upon installing a conventional implant; FIG. 20 is a cross-sectional view illustrating a reaming work performed upon installing a conventional implant ;

FIG. 21 is of a perspective view and a cross- sectional view taken along the line A-A, illustrating an outer contour of a proper titanium body of the present invention;

FIG. 22 is a perspective view illustrating another embodiment of an outer contour of a titanium body of the present invention; FIG. 23A is an exemplary perspective view of a titanium thread as being another embodiment of the present invention;

FIG. 23B is a perspective view illustrating use of the titanium thread; FIG. 23C is a cross-sectional view illustrating a filling status of the titanium thread when a surgery is implemented;

FIG. 23D is a cross-sectional view illustrating a state wherein the titanium thread is filled in an innermost part of a dental root which is refracted to a great extent;

FIG. 24 is a side view illustrating another embodiment of the present invention;

FIG. 25 is an explanatory view of another embodiment of the present invention;

FIG. 26 is a cross-sectional view of an upper jaw part, indicating a problem which is induced upon installing a conventional implant;

FIG. 27A is a cross-sectional view illustrating a state wherein the present invention is applied to an upper jaw part;

FIGs. 27B and 27C are cross-sectional views for explaining a surgery implementing method;

FIG. 28 is an explanatory view exemplarily illustrating particles of titanium powder which is applied to another embodiment of the present invention;

FIG. 29 is a perspective view of a tooth, illustrating a measurement reference for application of the present invention; and FIG. 30 is a cross-sectional view for illustrating a measurement reference for a premolar tooth of an upper jaw and for explaining a measurement method.

Best Mode for Carrying Out the Invention

Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. The present invention provides a diversity of solutions including a thing which is made of pure titanium or titanium alloy and has a shape of a dental root, and so forth. A basic concept of the present invention is in that, using properties of pure titanium such as biological compatibility with the human body, biomechanical and bio-functional osteogenesis , etc., a dental implant can permanently preserve its shape in an alveolar bone, and due to this, the alveolar bone can maintain a surrounding outline around a non-functional embedding titanium temporary implant or non- functional embedding titanium permanent implant, in such a way as to prevent an alveolar ridge from being absorbed.

Therefore, main spirit of the present invention is in that a titanium body which has biological compatibility, non-resorbability and bone affinity and possesses an average size of a dental root of a corresponding tooth, is inserted into a vacancy, that is, an opening defined by tooth extraction, immediately after tooth extraction, in such a way as to prevent the alveolar ridge of the alveolar bone from being absorbed.

If a predetermined period of time is elapsed after a natural tooth is removed, the alveolar bone gradually shows, due to its physiological characteristics, a bone absorption phenomenon. This bone absorption phenomenon can be generally classified into alveolar ridge absorption (physiological absorption of the alveolar bone) due to tooth extraction, pathological absorption due to periodontitis , and absorption due to aging of the alveolar bone.

As shown in FIGs. 1A, IB and 1C, if a tooth T is extracted from an alveolar bone B and a gum G, as blood clots in a vacancy V which is defined by removal of a dental root R, blood clot BC remains in the vacancy V. Then, as time passes, osteogenic induction results in to cause ossification. In the case that the tooth is lost, the alveolar bone develops a bone absorption phenomenon as time passes, whereby a subsidence S is generally created. In FIGs. ID and IE, a symptom by periodontitis is illustrated. Due to periodontitis, an absorption area A of the alveolar bone B is formed around the tooth T, and thereby, the tooth T is considerably exposed out of the gum G. Owing to these physiological and pathological changes, after the natural tooth is removed, when viewing an outer appearance of a patient, as shown in FIG. 2, facial profile constriction is induced accompanying the alveolar bone absorption, whereby the patient can get wrinkles around the mouth. In the drawing, the UP represents an upper lip.

Due to this, even though prosthetics is implemented after the tooth is removed, since a corresponding lower part of the alveolar bone is continuously disappeared, a jaw bone is constricted, whereby manufacture of a prosthesis is made difficult. Also, due to disharmony in shape between a set of teeth and a jaw arch, malocclusion is caused.

That is to say, in spite of the presence of an alveolar ridge line L as shown in FIG. 3A, in the case that an artificial tooth AT is implanted by prosthetics to reach the alveolar ridge line L, as shown in FIG. 3B, an outer appearance is awkward, and it is difficult to reproduce an outer appearance of a natural tooth. In this connection, while it is possible to manufacture the prosthesis to have a dental root -shaped hollow contour, a defect is caused in that aesthetic appeal is impaired.

Also, after serious alveolar bone absorption, although a prosthetic restoration surgery is implemented for an arch of a partially removed tooth, functionality can be deteriorated. Extremely, due to an excessive bias phenomenon in occlusal force by the presence of a partial denture, a part of constricted mucosa which has a short ridge shape and reveals serious absorption, can provoke a pain. In FIG. 4 which illustrates a cross- section of a lower jaw part, when an artificial tooth flange F is installed on the alveolar bone B and then the artificial tooth AT is implanted, because a dental crest DC of an occlusal surface S below the artificial tooth flange F has a ridge- shaped contour, a pain can be provoked. In the drawing, the TG represents the tongue.

In particular, if at least four teeth of anterior teeth of an upper jaw are extracted and the alveolar bone absorption is severe, it is difficult to perform a bridge work and install an implant. In this regard, in FIG. 5 which illustrates a cross-section of a lower jaw, since a height H measured from an inferior alveolar nerve canal IC to an upper surface of the alveolar bone B is small, it is actually impossible to install the implant.

If left and right central incisors and lateral incisors of the anterior teeth of the upper jaw are removed, in a state wherein alveolar bone absorption is severe, however aesthetically a bridge work of the upper jaw may be implemented, a natural arch line upon existence of the natural tooth cannot be properly reproduced. Therefore, unless special necessary action such as a bone grafting surgery is taken immediately, no dentist can solve the problem with respect to aesthetics. In FIG. 6, by incising the gum G of the alveolar bone B of the lower jaw, an autogenous bone grafting material is inserted into the alveolar bone B, and then, after being repositioned, the gum G is sutured at a suturing part ST. In FIGs. 8A to 8D, when fracture of the tooth T along the line F-F with respect to the alveolar bone B is induced by impact from the outside, etc., after tooth extraction is effectuated (see FIG. 8B) and a depth is measured using a gauge G for measuring a depth and a width, a titanium body TB of the present invention is inserted into the alveolar bone B and suturing is performed at the suturing part ST.

If it is improper to insert a normal dental-root shaped body due to the alveolar bone absorption phenomenon, as shown in FIGs. 9A through 9E, after the tooth T is extracted from the alveolar bone B and a depth is measured using the gauge G for measuring a depth (see FIG. 9C) , a cylindrical enlarged opening EO of a predetermined length is defined from a top of an opening 0 defined by tooth extraction, by means of a ratch reamer LR having a diameter of 2-3 mm. Then, the titanium body of the present invention, having integrally formed therewith a post P, is extendedly inserted up into a lower end of the dental root and suturing is performed at the suturing part ST.

In the same manner as the method of FIG. 8, in FIG. 10, in order to enable alveolar ridge protection and dental implant installation, the titanium body TB is inserted into the opening O defined by tooth extraction. However, the titanium body TB is divided into an upper titanium body segment TBU which can be separated upward and a lower titanium body segment TBL which has a shape of an abutment A to render a basic structure for implant installation. The upper titanium body segment TBU has a well part W defined by depression on a lower surface thereof and a locking taper LC for performing a mechanical coupling function. As in the conventional implant system, the lower titanium body segment TBL has a post P at an upper end thereof so as to enable implant installation to be implemented afterward. By this configuration, due to the fact that pre-operations such as drilling for allowing a cylindrical implant body to be inserted into the opening 0, or the like, are not needed, burden of a dentist and a patient is lessened in respect of time and economy, the patient's fear for the drilling operation is eliminated, and equipment for performing the drilling operation can be omitted. In addition, as shown in FIG. 10B, an upper end of the titanium body TB can be extended to an upper surface of the gum G, by which a secondary surgery for installing an implant can be implemented without anesthesia.

In FIG. 11 which can be obtained by simultaneously combining FIG. 9 and FIG. 10 with each other, due to the fact that other titanium bodies TBL and TBL' are used in such a way as to be coupled with the upper titanium body segment TBU, alveolar ridge protection and implant installation can be simultaneously enabled. Besides, by differentiating lengths and widths of the titanium bodies TBL and TBL' from each other, a strength of the dental implant can be increased to sufficiently endure occlusal force. In these ways, depending upon a condition of a lower part of the alveolar bone, bone graft can be effected in different patterns.

By mixing the conventional bone grafting material with titanium powder, titanium can be prepared in the form of titanium particles. In succession, by using a dental root-shaped solid element along with an mixing agent of the conventional bone grafting material, it is possible to configure the titanium body TB as shown in FIG. 12. If the conventional bone grafting material is used in an attempt to increase strength of the alveolar bone around an alveolar socket at a place where the tooth is extracted, due to properties such as non- resorbability, biological compatibility and bone affinity, as osteogenic induction results in, tissue growth effect is expected. In addition to this, when the titanium particles TP are added to the conventional bone grafting material, a compact bone is depositedly produced around a nucleus of the titanium particle TP, whereby bone quality and osseointegration force are improved.

Further, as can be readily seen from FIG. 13, sizes of titanium particles TP1, TP2 , TP3 , ..., can be differentiated one from another, and as in the case of titanium particle TP4 , a configuration of titanium particle can be varied.

By using a combination of the conventional bone grafting material with a titanium thread TT or a titanium mesh TM, manipulation of the dentist can be eased and economical gain can be elevated. Afterwards, when an implant is actually installed, an adverse influence is not imposed on the reaming process, and a density of a surrounding bone can be elevated. In the case of the titanium thread TT, when it is made to have a uniform and easy-to-use thickness, as shown in FIG. 14, the titanium thread TT can be filled in the opening 0 which is curved in conformity with an end of the dental root, using a dental handpiece TO, to be compressed, or, at the same time with this, by filling the bone grafting material, a result as shown in FIG. 14C can be obtained.

In FIG. 14D, an insertion surgery into the low- density alveolar bone of the upper jaw teeth is illustrated. Also, in this case, only the titanium thread TT can be inserted into the opening in such a way as to be compressed, or, simultaneously with this, the bone grafting material can be filled in the opening. In FIG. 14E, upon grafting an autogenous bone flap SB, when use of a titanium screw for joining bones is impossible, the titanium thread TT is used in a manner such that the titanium thread TT is put into interconnected insertion holes. Then, by making a knot, simple fastening is enabled. In the drawing, the SB represents an alveolar ridge of the lower jaw, which is sharply absorbed. In FIG. 15, under this concept, a titanium body TB possessing a configuration of an unfunctional embedding implant which has a shape most similar to the conventional implant and is formed by reproducing a dental root-shaped contour of the natural tooth, is inserted into the opening immediately after tooth extraction, while having a predetermined average size. An HA or TPC coating C can be applied to a surface of the titanium body TB to exist in the alveolar bone B.

In FIG. 16, upon inserting the titanium body TB, an outer surface of the titanium body TB is ground with great precision to define a ground surface P, so that convenience is enhanced upon use and the titanium body TB can be easily removed. In this way, a removable unfunctional embedding implant (RUFEI) is realized. Relying upon an insertion method, the titanium body TB is divided into a submerge type titanium body and a non- submerge type titanium body.

Applying these types, the titanium body is inserted into the opening defined by tooth extraction immediately after tooth extraction, and an upper portion of the titanium body is separably formed so that the upper portion can be interchanged with the abutment A of the conventional dental implant thereby to be used as a dental implant. Therefore, a lower portion of the titanium body TB is not removed. In this way, an irremovable functional embedding implant (IRFEI) is realized (see FIG. 18) .

In the conventional art, as shown in FIG. 19, in the case that the implant is installed immediately after tooth extraction, a circular column- shaped implant body IB has on a circumferential outer surface thereof an externally threaded portion OT . A hexagonal nut N for grasping a dental handpiece is threadedly inserted into an internally threaded portion IT which is defined in a center portion of the implant body IB. An HA coating or a TPS coating C is applied to an outer surface of the titanium body TB, whereby, upon manufacture of an implant, since a machining procedure and a surgical operation are complicated to a great extent, a manufacturing cost is increased. Also, generally, it is troublesome for all patients to undergo immediate implant installation after tooth extraction, due to difficulty of a surgery and an extended surgery time.

Actually, in the case of U.S.A., when installing one implant, economical burden of a patient is within the range between 2,000 $ and 3,000 $ (excluding a cost required for implementing a bridge work for an upper part) .

Also, even though the implant is installed immediately after tooth extraction, in the case of the conventional implant, since it has a cylindrical shape, a drilling operation must necessarily be performed for a following slight reaming work through the opening. Accordingly, as shown in FIG. 20, due to use of various surgery devices and complexity of a method of inserting a drill in the alveolar bone, an additional cost cannot but be caused to the patient.

However, in the present invention, even though the implant is installed immediately after tooth extraction, in the case of a normal opening defined by tooth extraction, since it is sufficient to select and then immediately insert the IRFEI or RUFEI into the opening without the need of taking any action, burden of the dentist and patient can be remarkably diminished, and an easiest way of protecting an alveolar ridge is rendered.

In the case of the IRFEI, that is, immediate implant installation, the titanium body has a contour similar to a dental root of a natural tooth and a large surface area. Also, the implant body defines its contour not of a cylindrical shape but of an elliptical shape. By this, because rotation of the implant body is reliably prevented, the implant can be adopted as an ideal implant (see FIG. 21) .

Also, upon secondary installation of the IRFEI, the upper portion of the titanium body TB is separated, and the remaining lower portion of the titanium body TB is, as shown in FIG. 22, formed on an outer surface thereof with a saw tooth-shaped projecting pin or an atypical undercut, whereby mechanical integration between the lower portion and the alveolar bone is facilitated and an outer surface area can be increased to the maximum. Of course, the HA coating or TPS coating can be applied to the lower portion of the titanium body TB to additionally promote osseointegration.

In FIG. 23A, a titanium thread TT which is made of titanium and has predetermined shape and thickness is provided in the form of a thread. As shown in FIG. 23C, the titanium thread TT has the thickness and softness so that the titanium thread TT can be directly filled in the opening O defined by tooth extraction. By partially mixing a mixing agent, a density of the titanium thread TT can be adjusted.

Hence, in this method, due to sufficient softness of the titanium thread itself, it is possible to fill the titanium thread TT in the opening 0 to every nook and corner, irrespective of a shape of the opening O. In another method, as shown in FIG. 23B, the implant body IB of the implant material can be filled in the opening 0 in a state wherein the titanium thread TT is wound around the implant body IB.

Furthermore, as shown in FIG. 24, a titanium mesh TM which is woven with the titanium thread TT of a small thickness so as to have a shape of a dental root of a tooth, is placed in a mold for forming the dental root part while having a net-shaped outline, and then, a variety of bone grafting materials BG are filled in the titanium mesh TM of a sag-shaped configuration. By placing the resultant in the alveolar socket, the outer titanium mesh TM having the sag-shaped configuration functions to maintain an outer appearance and form a solid element of a predetermined shape. Since the bone grafting materials are filled at a predetermined ratio in the titanium mesh TM, tissue growth can be anticipated.

Due to this, a contour which is desired for the titanium particles, can be maintained as it is, the particles are prevented from being dispersed, and an outer shape of the resultant can be held. On the contrary, in the case of ceramic particles, it is difficult to form the entire ceramic particles into an agglomerate. Also, while it is required to fill the ceramic particles in a certain defective part, the particles cannot be fixedly maintained in place. Therefore, the conventional HA particles has a disadvantage in that they cannot continuously hold a predetermined shape and instead, are likely to be dispersed.

If the titanium mesh TM is filled in the opening 0, upon taking necessary action for dental implant installation afterward, other than the case of the IRFEI, drilling perforation for a new implant must be performed to result in a strength and a thickness not so as to disturb a reaming process. Regardless of a shape of a selected implant, free choice of the dentist must be permitted.

In FIG. 25, a method of using particles made of titanium plasma spray, according to the present invention, is illustrated. Titanium particles of titanium fine powder shape (having a diameter of 10-20 μm) are mixed with a mixing agent MA which has biological compatibility, so as to form a solid element which possesses a dental root-shaped contour. The solid element can have a diversity of average sizes of dental roots. As occasion demands, the resultant is inserted into the opening. This method is by far more economical than the conventional process for producing the bone grafting material, and mass production is enabled. Above all things, appropriateness for the dentist is markedly improved.

At this time, the powder is not a kind of derivative which renders possibility of bone growth, but a simple permanent non-resorbable alveolar ridge protection material which uses a property of a biological compatible material. As known in the art, the powder experiences osseointegration occurs. Depending upon a proportion of the mixing agent, a density of the powder can be easily altered, whereby quality of a bone can be improved at a place wherein the implant is installed and it is possible to increase a density of the bone.

The conventional bone grafting material is generally aimed at its functions such as biological compatibility, non-resorbability, bone inductive capacity, auxiliary osteogenic property, etc. In the case of the present invention, since titanium particles are used as a bone grafting material, the bone grafting material has X-ray non-transmissibility, and, depending upon a composition of the particles, a density of a surrounding bone can be remarkably increased in comparison with the conventional method.

Specifically, as shown in FIG. 26, when a grade, that is, a density of the upper jaw bone UB is low, in the conventional method, the more a density of a bone is low, the more a relative size of the implant body IB is increased or a length of the implant body IB is increased so as to raise a percentage of success. However, in the case that the titanium particles are used, as shown in FIG. 27B, a drilling process is performed to define the opening which has a slightly larger or the same thickness than or as the implant body IB, and, by fully filling the titanium particles TP and the mixing agent MA using the dental handpiece TL as shown in FIG. 27C and then by finishing by the medium of the dental handpiece TL ' having a slightly larger size than the dental handpiece TL, a kind of concreted titanium body TB is formed. Thereafter, since it is possible to install the conventional implant body IB, quality of surrounding bone tissue is improved, and, since an amount of the alveolar bone to be removed is decreased, effectiveness of the method can be doubled.

As shown in FIG. 28, after making fine spherical powder of pure titanium into titanium particles TP, by filling the titanium particles in the opening defined by tooth extraction using a high-pressure injection device, it is possible to prevent alveolar bone absorption.

Also, by the fact that the particles are fine and various surface treatments (including the HA coating C) are possible, production of the alveolar bone is promoted, and osteogenic property is constantly maintained around a nucleus of the titanium particle. Therefore, even though a lengthy period of time is elapsed, the absorption phenomenon does not occur. This method can be classified as described below: 1. A method of using TPS powder of spherical type titanium particles as it is;

2. A method of using TPS powder of spherical type titanium particles after applying the HA coating to it;

3. A method of using TPS powder of spherical type titanium particles along with the mixing agent MA (PP, alphaketoglutarate, marlate, etc. can be selected); and

4. A method of using TPS powder of spherical type titanium particles along with the HA coating and the mixing agent (PP, alphaketoglutarate, marlate, etc. can be selected) .

Actual sizes of the above-described solid titanium bodies of the present invention will be given below.

If a temporary implant is installed as the RUFEI to have a thickness of a dental root of each tooth and a flat shape, in a cone-shaped configuration as shown in FIG. 29, having widths for maximally maintaining the contour of the alveolar bone, a major width LW, a minor width TW and an entire tooth length L are standardized as follows. It is to be readily noted that values given below must not be understood to limit the scope of the present invention, and instead, can be varied depending upon a human race, an age, a territory, etc.

Sizes of an RUFEI for a central incisor of anterior teeth of an upper jaw: 1. Normal size

Major width 6.0 mm Minor width 5.0 mm Length of entire RUFEI 12.0 mm 2. Small size

Major width 5.5 mm Minor width 4.5 mm Length of entire RUFEI 11.0 mm

Sizes of an RUFEI for a lateral incisor of anterior teeth of an upper jaw: Major width 4.5 mm Minor width 3.5 mm Length of entire RUFEI 10.0 mm

Sizes of anterior teeth of a lower jaw: Major width 3.5 mm Minor width 2.5 mm Length of entire RUFEI 11.0 mm Sizes of a canine tooth:

1. Normal size

Major width 6.5 mm Minor width 5.5 mm Length of entire RUFEI 14.0 mm

2. Small size

Major width 5.5 mm Minor width 4.5 mm Length of entire RUFEI 13.0 mm

Sizes of a lower premolar tooth: Major width 5.0 mm Minor width 4.0 mm Length of entire RUFEI 10.0 mm

An upper premolar tooth UT has a dental root which is gradually greatly branched toward a free end thereof. As a consequence, since the dental root is forked, while an upper half of the dental root can be standardized, in the case of a lower half of the dental root, as shown in FIG. 30, a space which was occupied by the lower half, cannot but be filled with titanium particles or the like, or, by drilling the forked part to a predetermined size, the above-described RUFEI or IRFEI can be used. However, only one type for a minimum dental root shape can be prepared and properly used, which has sizes as given below.

Upper half: Major width 5.0 mm Minor width 4.0 mm

Length of entire RUFEI 7.0 mm

Lower half: Using the bone grafting material of the present invention

Sizes of the RUFEI enabling broad use of the lower premolar tooth: Major width 5.0 mm

Minor width 4.0 mm Length of entire RUFEI 11.0 mm

Mesio-buccal root (mbr) , disto-buccal root (dbr) and palatal root (pr) are combined to be standardized to a 3 union root form, or a single dental root form is defined, as given below.

<— 3 union root form: mbr-width 2.0 mm, mbr-length 5.0 mm dbr-width 2.0 mm, dbr-length 5.0 mm pr-width 4.0 mm, pr-length 10.0 mm

I Single root form is obtained by dividing the 3 union root form.

Second molar tooth of upper jaw - the same as described above

First molar tooth of lower jaw (mr and dr are combined to be standardized to a 2 union root form, or a single dental root form is defined as given below)

1. 2 union root form: mr-major width 4.0 mm minor width 2.5 mm length 7.0 mm dr-major width 4.5 mm minor width 3.0 mm length 7.5 mm

2. Single root form is obtained by dividing the 2 union root form.

Second molar tooth of lower jaw - the same as described above

In particular, in the case of molar teeth, because a deviation is great, it is advantageous to separate respective roots. Further, in an exceptional case, implantation can be implemented by manipulating titanium particles and powder. Also, titanium bodies of the IRFEI and RUFEI must have requisites as described below.

First, a head should be defined at an upper end thereof with a groove or a depression for grasping, so as to ease handling thereof. After the titanium body performed its function for a predetermined period of time, it must be able to be easily removed when the patient desires a dental implant to be installed. In the case of the RUFEI, an upper end thereof must have a rounded outline so that an influence of occlusal force can be minimized, and also, a lower end thereof must have a rounded outline so that a maximum surface area is allowed with respect to the surrounding alveolar bone and the occlusal force can be dispersed to the maximum. Moreover, the surface of each titanium body must be ground with high precision so that, even though the titanium body is maintained in the alveolar bone for a lengthy period of time, the titanium body is not coupled with the alveolar bone and held in a functionally fixed status . When removing the upper structure of the RUFEI or

IRFEI which is inserted into the opening for provisionally maintaining the alveolar bone for the sake of the permanent implant, in order to allow a position of the RUFEI or IRFEI to be discerned with the naked eye through the gum of a corresponding part, an upper end of the temporary implant is formed of a plastic material which is made of polymethylmetaacrylate of good biological compatibility and is black, so that, upon installation of the permanent implant, the temporary implant can be discerned with the naked eye and then removed. However, in order to avoid complexity of a manufacturing procedure, the temporary implant can be made of the same titanium material .

The lower structure of the IRFEI should be configured in a manner such that it can be reliably maintained in a coupled status with the alveolar bone even upon removal of the upper structure . In order to ensure osseointegration, a special TPS coating or HA coating must be applied to the lower structure, and, additionally, the lower structure must be provided with a pin shaped figure or a groove so that mechanical coupling force is created.

Industrial Applicability

As a result, the method and the material for alveolar ridge protection according to the present invention provide advantages in that, since a removable unfunctional embedding implant (RUFEI) is inserted into an opening defined by tooth extraction immediately after the tooth extraction, a natural absorption phenomenon of an alveolar bone is prevented, and since the RUFEI is reliably maintained in the alveolar bone as a solid element even though a lengthy period of time is elapsed, a bridge work can be implemented in a convenient manner, aesthetics can be improved, and bothersomeness which is caused by the conventional bone grafting surgery for aesthetic bridge work, can be eliminated.

Also, the present material and method are inexpensive when compared to the conventional alveolar bone restoring material and its surgery, and the present material can be mass-produced and afforded to all patients who underwent tooth extraction.

In the case of IRFEI, by varying its shape, the

IRFEI can perform afterward a function of an actual implant, whereby a pain of a patient, which is provoked by a drilling process for implant installation, can be lessened.

Moreover, because the present material is not changed inside the alveolar bone in a permanent basis and does not experience any volume change, facial profile constriction is minimized and wrinkles are not formed around the moth, whereby it is possible to maintain good looks even with attainment of an advanced age . Further, upon manufacture of an artificial tooth of an upper jaw, as maintaining force is increased, a masticating function is enhanced, and a number of places where pains are provoked by the presence of the artificial tooth, can be decreased. In the case of a lower jaw, if a patient severely undergoes alveolar bone absorption, it is difficult to manufacture the artificial tooth of the lower jaw. However, in the case of a patient who underwent the surgery according to the present invention, difficulties are not caused upon manufacture of the artificial tooth, whereby a masticating function is enhanced and economical burden can be decreased.

In addition to this, in the present invention, an alveolar bone collapse phenomenon which occurs after tooth extraction, is reduced, whereby a cause of malocclusion can be eliminated. Due to the fact that the present material is placed upon implementing a variety of bone grafting surgeries, particularly, when quality of a bone of the upper jaw is inferior, by the presence of titanium, a strength and a density of the surrounding alveolar bone can be increased, whereby circumstances around the implant can be maintained in a favorable status. In the case of installing the conventional implant, if quality of a bone is inferior, a width of the implant cannot but be enlarged to obtain initial basic fastenability and stability. However, in the present invention, with a reduced removal amount of the alveolar bone and adequate size selection of the implant, stability can be easily rendered. In addition, in the conventional dental implant system, since the implant is installed immediately after tooth extraction or after a predetermined period of time is elapsed, treatment for the alveolar bone is effected from necessity rather than for the purpose of protection. However, in the present invention, alveolar ridge protection is inevitably effected after tooth extraction of all patients.

Due to this, as all patients experience the surgery according to the present invention upon tooth extraction, difficulties caused upon installing a prosthesis due to alveolar bone absorption can be eliminated. It is important that, simultaneously with prevention of the alveolar bone absorption, because facial profile constriction does not occur even with attainment of an advanced age, wrinkles are not formed around the mouth. Besides, upon installing the implant immediately after tooth extraction, burden of the patients for the drilling process can be lessened, and the surgery can be implemented in a short period of time.

Furthermore, in comparison with the conventional cylindrical shape, since the present material has a shape similar to that of a dental root of a natural tooth, excellent resistance against occlusal force and superior force dispersion are accomplished. In succession, in the conventional art, all patients have a fear for tooth extraction and a lingering desire for a natural tooth, and thereby, experience a great degree of psychological impact . However, in the present invention, due to the fact that burden for a surgical operation is lessened at the same time with tooth extraction, since it is possible to naturally extend awareness for a prosthesis in odontology to the implant, psychological impact due to tooth extraction can be diminished to the minimum. Actually, while, in the conventional art, a great deal of cost is required for installing the implant, in the present invention, economical burden can also be lessened, psychological impact of all patients can be further diminished.

Claims

1. Method and material for alveolar ridge protection, characterized in that a titanium body which is formed to have a contour similar to a dental root of a natural tooth, is inserted into a vacancy which is defined by tooth extraction, in such a way as to maintain a configuration of an alveolar bone.

2. The method and material as claimed in claim

1, characterized in that the titanium body is divided into at least two body segments including an upper titanium body segment and a lower titanium body segment, the upper titanium body segment having therein a well and a locking taper surface and being mechanically coupled with an implantation post of the lower titanium body segment.

3. The method and material as claimed in claim

2, characterized in that one or more lower titanium body segments can be mechanically coupled with the upper titanium body segment by virtue of their implantation posts and the well and locking taper surface of the upper titanium body segment.

4. The method and material as claimed in claims 2 or 3 , characterized in that the titanium body can be selectively embedded into the alveolar bone or projected out of a gum.

5. The method and material as claimed in any one of the claims 1 to 3 , characterized in that each of the titanium body and the body segments has a groove for receiving a dental handpiece which groove is defined by inward depression of an upper end of the titanium body or the body segment .

6. The method and material as claimed in any one of the claims 1 to 3 , characterized in that the titanium body has an outer surface which is ground with great precision.

7. The method and material as claimed in any one of the claims 1 to 3 , characterized in that an outer surface of the titanium body is treated with titanium plasma spray (TPS) or tribasic calcium phosphate

(hydroxylapatite : HA).

8. The method and material as claimed in any one of the claims 1 to 3 , characterized in that each of the titanium body and the upper titanium body segment is formed or defined, on an outer surface thereof, with a pin, a groove or the like for facilitating mechanical integration between the titanium body or upper titanium body segment and the alveolar bone.

9. The method and material as claimed in any one of the claims 1 to 8 , characterized in that the titanium body can fill the vacancy which is defined by tooth extraction, in cooperation with titanium powder.

10. Method and material for alveolar ridge protection, characterized in that titanium powder is mixed with a mixing agent to form a filling body which has a contour similar to a dental root of a natural tooth, the filling body being inserted into a vacancy which is defined by tooth extraction, in such a way as to effect osseointegration thereof with an alveolar bone .

11. The method and material as claimed in claim 10, characterized in that the titanium powder and the mixing agent can be used together with a bone grafting material .

12. The method and material as claimed in claims 10 or 11, characterized in that different particle sizes of the titanium powder can be adopted.

13. The method and material as claimed in claims 10 or 11, characterized in that the titanium powder is composed of spherical particles.

14. The method and material as claimed in any one of the claims 10 to 13, characterized in that the titanium powder is coated with HA or TPS.

15. Method and material for alveolar ridge protection, characterized in that a titanium thread having a low grade of softness is filled in a vacancy which is defined by tooth extraction, to create a contour similar to a dental root of a natural tooth, in such a way as to thereby effect osseointegration thereof with an alveolar bone.

16. The method and material as claimed in claim 15, characterized in that the titanium thread can be filled, together with a bone grafting material, in the vacancy defined by tooth extraction.

17. Method and material for alveolar ridge protection, characterized in that a titanium mesh which is formed to have a contour similar to a dental root of a natural tooth and contains therein a bone grafting material, is filled in a vacancy which is defined by tooth extraction.

18. The method and material as claimed in any one of the claims 10 to 17, characterized in that the titanium powder and the titanium thread are accommodated in the titanium mesh in such a way as to be formed as a whole into the shape of a dental root of a natural tooth.

19. The method and material as claimed in claim

17, characterized in that the titanium thread is filled in the vacancy defined by tooth extraction in a state wherein the titanium thread is wound on a circumferential outer surface of the titanium body.

20. The method and material as claimed in any one of the claims 1 to 18, characterized in that the titanium body and the titanium mesh can be ready-made to have an average standard size of surgery receivers.