JPH05241499A - Tooth model - Google Patents

Abstract

PURPOSE:To provide the tooth model for training the restoration of a dental crown suitable for learning a treatment to restore the dental crown by cutting the tooth with a cutting bar to form a cavity, subjecting the cut part to an acid etching treatment and plugging the cavity with a plugging material. CONSTITUTION:The enamel part 12 on the surface of the dental crown part of the tooth forming member of this tooth model 10 consists of a hard blank material contg. dense inorg. powder and the dentin part 14 therein consists of a blank material softer than the blank material of the enamel part. In addition, the respective blank materials forming the enamel part 12 and the dentin part 14 have >=50kg/cm<2> strength of adhesion to the plugging material on the surface of the treated part after the acid etching treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended for dental medical students to obtain a dental crown repair treatment in which a caries carved portion of a tooth is cut with a cutting bar to form a cavity, which is acid-etched and filled with a filling material. The present invention relates to a tooth model for practice of crown restoration.

[0002]

2. Description of the Related Art In dental treatment, crown restoration is the most frequently performed healing procedure, and its progress is remarkable. Generally, in dental crown repair, firstly, the caries-affected dentin is removed, and after cavity formation, it is backed, acid-etched, and bonded, and then the inlay is made after filling or impression and occlusion. Repair, finish and polish.

The tooth model used for practical training in order to acquire these series of crown restoration techniques distinguishes between the enamel chamber on the surface of the crown and the dentin inside the crown, and the cutting feeling is natural. It is desirable to match the teeth. In particular, when practicing the same day filling procedure using a resin for crown restoration, acid treatment for strengthening the adhesion between the resin and the surface of the treatment area causes unevenness on the treatment surface like natural teeth. It is required to occur.

However, although many tooth models for dental treatment training have been proposed, a tooth model satisfying the above conditions has not been developed yet. That is, the conventional tooth model is entirely made of a resin material such as melamine, acrylic, or epoxy, or a glass-based material. Such a conventional tooth model has a structure different from that of a natural tooth, remarkably different in stickiness at the time of cutting, different cutting feeling,
Furthermore, it is inactive against the acid used in the acid etching treatment, or on the contrary, is too violently dissolved, and reacts completely differently from natural teeth.

Therefore, the development of an improved tooth model to be used by dental students for training to acquire a crown restoration treatment method has been awaited.

[0006]

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an enamel portion and a dentin having a shape corresponding to that of natural tooth enamel and dentin. Part, the enamel part and the dentin part have the same hardness and viscosity and cutting feeling as the enamel and dentin of natural teeth, and have the same acid etching treatment as natural teeth. Another object of the present invention is to provide a tooth model for practicing crown restoration training, in which unevenness is generated on the surface of the treated portion and the surface of the treated portion has high adhesive strength to the filling material.

[0007]

A tooth model of the present invention is a tooth-shaped member in which the enamel portion on the surface of the crown portion is made of a hard material containing a dense inorganic powder, and the inner dentin portion is the enamel portion. Each material that is softer than the above material and that forms the enamel part and the dentin part has an adhesive strength of 50 kg / cm ² or more to the filler on the surface of the treated part after the acid etching treatment. It has a feature.

As a tooth model satisfying the above conditions, for example, the enamel part is made of a material containing hydroxyapatite powder having a porosity of 0 to 20%, and the dentin part is hydroxyapatite having a porosity of 20 to 60%. A tooth model which is made of a material containing powder and in which the enamel portion is harder than the dentin portion can be mentioned.

In the present invention, the crown portion, the enamel portion and the dentin portion mean the portions of natural teeth which occupy corresponding positions of the crown, enamel and dentin.

Next, the present invention will be described. FIG. 1 is a schematic cross-sectional view showing an enlarged example of the tooth model of the present invention.

A molar tooth model 10 having substantially the same size and shape as a human tooth has an enamel portion 1 on the surface of the crown.
2 and the inside thereof is formed as a dentin portion 14, and the enamel portion 12 is made of a material different from that of the dentin portion 14, that is,
The enamel part is made of a hard material containing a dense inorganic powder, while the dentin part is made of a material softer than the material of the enamel part.

The thickness of the layer of the enamel portion 12 on the surface of the crown portion is about 2000 μm at maximum as in the case of the natural tooth, the thickest at the apex portion and the incisal edge, and becomes gradually thinner toward the cervical line 16.
The cervical line 16 sharpens like a sword and disappears. As for the type of teeth, the surface enamel becomes thicker in the order of incisors, canines, premolars, and molars. Furthermore, it is necessary to adjust the thickness of each of the upper jaw, the lower jaw, the labial side, and the lingual side.

The dentin portion 14 constitutes at least the inner side of the enamel portion which constitutes the surface of the crown portion, and may further constitute the portion corresponding to the tooth root below the cervical line (root portion). Good. In the crown part, the dentin part is a contraction of the outer shape of the tooth, but the shape is slightly different depending on the thickness of the surface enamel part layer. The root portion may have a conical shape like a natural tooth or a cylindrical shape or the like so that it can be easily fixed to an articulator or the like. Since the root portion is usually buried in the jaw, there is no restriction on the shape, and it is preferable to change it arbitrarily according to the application. Further, the material of the tooth root portion is not limited to the material of the dentin portion, and may be made of any material.

In the present invention, each material forming the enamel part and the dentin part has an adhesive strength of 50 kg / cm ^{2 with} respect to the filler on the surface of the treated part after the acid etching treatment.
That is all.

In the present invention, the acid etching treatment means
This means an acid etching treatment used in ordinary dental treatment, and specifically, a 35-40% orthophosphoric acid solution is applied to a tooth and treated for about 1 minute. This acid etching process
In dental treatment, it is an indispensable treatment for forming fine irregularities on the surface of the treated portion to increase the adhesive area and enhance the adhesive strength to the filling material.

When the materials for forming the enamel portion and the dentin portion have an adhesive strength of 50 kg / cm ² or more to the filler on the surface of the treated portion after the acid etching treatment, the carious portion is cut to form a cavity. The crown restoration practice of forming, acid etching and filling can be performed under the same conditions as natural teeth.

As a specific example of a tooth model satisfying the above conditions, the enamel portion on the surface of the crown portion of the tooth-shaped member is made of a material containing hydroxyapatite powder having a porosity of 0 to 20%, and the dentin therein. The part is made of a material containing hydroxyapatite powder having a porosity of 20 to 60%, and the enamel part may be a tooth model harder than the dentin part.

In the present invention, the porosity of the hydroxyapatite powder is indicated by the value measured by the mercury intrusion method.

Hydroxyapatite is the main component of natural teeth, and the material containing hydroxyapatite causes fine irregularities on the treated surface due to the acid etching treatment,
The adhesion strength of the surface of the treated part to the sealing material is 50 kg / cm
² or more.

The porosity of the hydroxyapatite powder in the enamel portion is preferably 0 to 20%. Porosity is 20
When it exceeds%, it becomes softer than the enamel of natural teeth.

On the other hand, the porosity of the hydroxyapatite powder in the dentin part is preferably 20 to 60%. When the porosity is less than 20%, the dentin becomes harder than the natural tooth dentin, and when the porosity exceeds 60%, the dentin becomes softer than the natural tooth dentin.

The hydroxyapatite powder used in the production method of the present invention may have a porosity of 40% to 80%, and even if it is a synthetic hydroxyapatite powder produced using calcium salt and phosphorus salt as raw materials, It may be a natural hydroxyapatite powder derived from animal or fish bones. The natural hydroxyapatite powder is particularly preferable because it is inexpensive and the porosity can be arbitrarily controlled by selecting the heat treatment conditions in the manufacturing process.

In order to approximate the cutting feeling of the enamel portion of the tooth model of the present invention to that of natural tooth enamel, together with the hydroxyapatite powder, other inorganic powders, for example,
Quartz, glass, alumina, borosilicate glass, mullite,
It is preferable to contain a relatively hard powder such as zirconia or silicon nitride. The particle size of the inorganic powder is 50 μ in order to make the hardness and machinability of the enamel part uniform.
m or less is preferable.

The material forming the enamel part and the dentin part is preferably a composite material based on a (meth) acrylic acid ester resin.

Such a composite material can be obtained by polymerizing and curing a mixture of an inorganic powder and a polymerizable monomer or a resin liquid material containing a polymerizable monomer under a specific catalyst or under specific conditions.

As a method for producing the tooth model of the present invention,
For example, first, the dentin part mixture is polymerized and hardened in a dentin-shaped female mold to produce a dentin part, and then a required amount of the enamel part mixture is injected into the tooth model female mold. The method of fixing the dentin part produced in the above and polymerizing and hardening can be mentioned.

As the polymerizable monomer, monofunctional and polyfunctional (meth) acrylic acid ester monomers are preferably used.

Examples of the monofunctional (meth) acrylic acid ester-based monomer include esters of acrylic acid or metalluric acid with a lower aliphatic alcohol, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and methacrylic acid. 2-ethylhexyl acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like can be mentioned.

As the polyfunctional (meth) acrylic acid ester-based monomer, a polyvalent ester of acrylic acid or methacrylic acid and a polyhydric alcohol, for example, bisphenol A is used.
Dimethacrylate, bisphenol A diglycidyl methacrylate, triethylene glycol dimethacrylate, bismethacryloxyethoxyphenyl propane, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, tetra Examples thereof include methylol methane trimethacrylate, tetramethylol methane triacrylate, tetramethylol methane tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and 2,2-bis (4-methacryloxyethoxyphenyl) propane.

These monomers may be used alone or in admixture of two or more. By using a monofunctional monomer in combination with a polyfunctional monomer, the hardness of the enamel part and the dentin part can be appropriately changed, and the enamel part can be provided with the polyfunctional monomer and the dentin part with the monofunctional monomer. Preference is given to using mainly functional monomers.

Further, these (meth) acrylic acid ester-based monomers may be mixed with other crosslinkable monomers such as divinylbenben and diallyl phthalate.

For the purpose of adjusting the viscosity of the liquid mixture and preventing sedimentation of inorganic powder such as hydroxyapatite powder, (meth) acrylic acid ester-based polymer powder, that is, homopolymers and copolymers of methacrylic acid ester and acrylic acid ester. The above powder, and a mixture of two or more kinds of powder are used as necessary.

In order to achieve the above object, the powder of the (meth) acrylic acid ester-based polymer is preferably a polymer powder which swells or dissolves when mixed with the above-mentioned monomer and is integrated after the polymerization, and is a powdery methacrylic acid. Particularly preferred are methyl acid homopolymers, methyl methacrylate-ethyl methacrylate copolymers, methyl methacrylate-propyl methacrylate copolymers, methyl methacrylate-butyl methacrylate copolymers and the like.

The ratio of the resin component of the enamel portion to the inorganic powder is preferably 50%: 50% to 5%: 95% by weight. When the amount of the inorganic powder is less than 50%, the hardness of the enamel portion is lower than that of the natural tooth, and when it exceeds 95%, the enamel portion becomes harder and brittle than the enamel of the natural tooth.

The ratio of the resin component of the dentin portion to the inorganic powder is preferably in the range of 80%: 20% to 50%: 50% by weight. When the amount of the inorganic powder is less than 20%, the hardness of the dentin part is lower than that of the natural tooth, and when it exceeds 50%, the dentin part becomes harder and more brittle than the dentin of the natural tooth, and the reaction is strong in acid etching treatment. Too much.

As the polymerization catalyst, a usual catalyst for vinyl polymerization is used, and examples thereof include benzoyl peroxide, benzoyl peroxide, amine, potassium persulfate, ammonium persulfate, and azobisisobutylnitrile. The addition amount of the polymerization catalyst is 0.1 to 3% by weight with respect to the (meth) acrylic acid ester-based monomer. If it is less than 0.1% by weight, the polymerization reaction takes too long, and if it is too small, the polymerization reaction becomes insufficient and the resulting tooth model becomes too soft. On the other hand, if the amount added exceeds 3% by weight, the polymerization reaction will occur rapidly, and curing will start during molding, and air bubbles will be generated inside the finished tooth model, which is not preferable.

Furthermore, pigments, stabilizers and the like may be added to the liquid homogeneous mixture, if necessary.

Although one example of the method for producing the tooth model of the present invention has been described above, the tooth model of the present invention may be produced by any method as long as it satisfies the characteristics of the structure and material of the present invention. ..

[0039]

[Function] The tooth model has an enamel part and a dentin part corresponding to the enamel and dentin of natural teeth, and the hardness, stickiness and cutting feeling of the material are similar to those of natural teeth. is doing. Each material has irregularities on the treated surface under the condition of acid etching treatment in dental treatment, and the adhesive strength of the treated surface to the dental filling material is 50 kg / cm ² or more. When this tooth model is used for the practice of crown restoration treatment, the same effect as the practice using the natural teeth can be obtained.

[0040]

The present invention will be described in more detail with reference to the following examples.

Preliminary Test A homogeneous mixture was prepared by mixing a hydroxyapatite powder having a porosity of 50%, a monomer mixture consisting of 9 parts by weight of methyl methacrylate and 1 part by weight of trimethylolpropane triacrylate in a weight ratio shown in Table 1 (Table 1 Composition a to c)
A hydroxyapatite powder having a porosity of 10% and a monomer mixture consisting of 5 parts by weight of bisphenol A diglycidyl methacrylate and 5 parts by weight of triethylene glycol dimethacrylate in a weight ratio shown in Table 1 (a homogeneous mixture (composition d in Table 1 ~ G) to polymerize and cure, 1
A cube of 0 × 10 × 10 (mm ² ) was prepared, its machinability was determined, and the adhesive strength to the filler after the acid etching treatment was measured.

The cutting property was judged by the dentist 10 by cutting with a cutting bar to determine whether the cutting feeling was equivalent to that of natural tooth enamel or that of dentin.

The adhesive strength was measured by the method shown in FIG.

That is, a Teflon resin film 24 having a hole with a diameter of 4 mm is attached to the upper surface of each of the cubes 20, and the surface 22 of the cube 20 at the hole portion is brush-painted with a 40% phosphoric acid solution to remove the acid. It was etched, held for 1 minute and washed with water. A sufficient amount of the filler Belfeel LxWk XII (manufactured by Kanebo) 26 was filled in the holes and cured by photopolymerization. Anterior composite resin for anterior teeth (made by Kanebo) is applied thickly on the upper surface of the hardened filling material 26 to form a layer 3
No. 4 was formed, and an acrylic resin cube 28 having the same size as the cube 20 was allowed to stand on the upper surface of the layer 34 and cured. In this way, the cube 20 and the cube 28 were bonded together by the filling material 26 and the front tooth composite resin 34. The front tooth composite resin 34 has sufficient adhesiveness to the cured filler and the acrylic resin cube 28. Through holes 30 and 32 each having a diameter of 4 mm are formed in the center of the side surfaces of the respective cubes 20 and 28, and iron cores are inserted into the through holes 30 and 32, respectively, and a force is applied in the direction of separating both cubes, that is, in the arrow direction. In addition, the adhesive strength between the surface 22 of the cube 20 and the filling material 26 was measured. The results are shown in Table 1.

[0045]

[Table 1]

From the above results, the cubes prepared with the compositions a to c were judged to be dentin in their machinability, and the cubes prepared from the compositions d to g were judged to be enamel in their machinability. 50k adhesive strength of the surface of the
It was found to be g / cm ² or more.

Example Using the homogeneous mixture (compositions a to g in Table 1) used in the preliminary test as the enamel part and the dentin part shown in Table 2, FIG.
A tooth model 10 composed of the enamel part 12 and the dentin part 14 shown in FIG.

The dentist 10 performed a cavity formation with a cutting bar, an acid etching treatment, and a filling with a dental composite resin on each of the obtained tooth models, and evaluated the machinability and adhesiveness. The results are shown in Table 2.

[0049]

[Table 2]

From the above results, the enamel part is made of a material different from that of the dentin part, and the enamel part is harder than the dentin part. Adhesive strength to the sealing material is 50kg
It can be seen that the tooth model having a density of / cm ² achieves the object of the present invention.

[0051]

The tooth model of the present invention has an enamel part and a dentin part corresponding to the enamel and dentin of natural teeth, and each material has unevenness on the treated surface under the condition of acid etching treatment in dental treatment. Since the adhesive strength of the treated surface to the dental filling material is 50 kg / cm ² or more, this tooth model is cut with a cutting bar to form a cavity, acid-etched, and filled with the filling material. When used in practice to acquire treatment, the same practice effect as using natural teeth can be obtained.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a part of an embodiment of a tooth model of the present invention.

FIG. 2 is a diagram showing a method for measuring adhesive strength.

[Explanation of symbols]

10 ... Molar tooth model, 12 ... Enamel part, 14
・ ・ ・ Dentin part, 16 ・ ・ ・ Neck line, 20, 28 ・ ・ ・ Cube, 24 ・ ・ ・ Teflon resin film, 26 ・ ・ ・ Filler, 30,
32 ... Through hole, 34 ... Composite resin for front teeth.

Claims (2)

[Claims] 1. An enamel portion on the surface of a crown portion of a tooth-shaped member is made of a hard material containing a dense inorganic powder, and a dentin portion therein is made of a material softer than the material of the enamel portion, and The tooth model, wherein each material forming the enamel part and the dentin part has an adhesive strength of 50 kg / cm ² or more to the filler on the surface of the treated part after the acid etching treatment. 2. An enamel portion on the crown surface of a tooth-shaped member is made of a material containing hydroxyapatite powder having a porosity of 0 to 20%, and a dentin portion inside thereof has a porosity of 20 to 60.
% Of hydroxyapatite powder, and the enamel part is formed harder than the dentin part.