KR101492916B1 - Glass-infiltrated sapphire/alumina composites for tooth restorations and preparation method thereof - Google Patents

Abstract

The present invention relates to a glass infiltration sapphire / alumina composite for dental restoration and a method of manufacturing the glass infiltration sapphire / alumina composite for dental restoration. The glass infiltration sapphire / alumina composite for dental restoration according to the present invention has remarkably excellent translucency, In the heat treatment process, since the glass water penetrates into the pores of the porous preform (preform), the shrinkage does not occur and the near net-shape characteristic excellent in dimensional accuracy is obtained. Therefore, the dimensional accuracy of the crown used for treatment is high, It can be used not only as a coping material for a core but also as a crown material such as an inlay, an onlay, a veneer, and a crown, so that it is useful as a glass filling material for a variety of dental composite materials Can be used.

Description

TECHNICAL FIELD [0001] The present invention relates to a glass-infiltrated sapphire / alumina composite for tooth restoration and a method for manufacturing the same,

The present invention relates to a glass infiltration sapphire / alumina composite for dental restoration and a method of manufacturing the same, and more particularly, to a dental restoration made by infiltrating a glass into a sapphire / alumina composite excellent in mechanical strength and transmittance and a method of manufacturing the same .

With the development of the economy and the improvement of the national income, the interest in the esthetics of the dental prosthesis is increasing in response to the times when the concentration of the appearance is increasing. Therefore, many kinds of dental caries make data have been introduced in clinical practice. Among them, non - metallic restorative materials that do not use metal have been developed variously and clinical application range has been expanded.

Dental ceramics restorative materials for repairing damaged teeth can be classified into coping materials for cores and crown materials for aesthetics according to the required properties. Copping refers to a saddle-shaped cover that is placed on an abutment or damaged crown in an artificial dental prosthesis, on which the crown, the outermost layer, is placed. The function of coping is to act as a core in the prosthesis structure by absorbing and dispersing the various occlusal loads transmitted through the crown, thus requiring high mechanical properties. Typical ceramic materials include zirconia and glass-infiltrated alumina. Despite the excellent mechanical properties of zirconia of 1200 MPa or more, there is a disadvantage in that the dimensional accuracy due to shrinkage during firing is poor and the transmittance is low. The glass infiltration alumina exhibits excellent dimensional accuracy due to the near-net shape characteristics while the glass water penetrates into the porous alumina preform skeleton, but has a disadvantage that the strength is as low as 500 MPa. Therefore, these coping materials are focused on material development requiring high strength and high dimensional accuracy.

The crown material refers to a prosthetic material that restores the dentin and enamel surface of a damaged tooth and can be divided into inlay, onlay, veneer, and crown depending on the application site. They are characterized by the fact that the aesthetic characteristics are highly required because the position to be restored is the outer surface of the tooth and that high strength is not required due to abrasion or chipping with the abutment. In particular, since inlay and onlay fill the cavity of the cavity, the load is not directly applied and the restoration can be performed even with a mechanical strength of 100-150 MPa. Therefore, currently, various ceramic materials show excellent transmittance of about 30% at a wavelength of 550 nm, and studies are underway to improve their strength and apply them to crowns and bridges.

First, a tooth restoration material containing zirconia stabilized with alumina or ytria as an effective ingredient together with additives such as magnesium oxide, zirconium oxide, yttrium oxide and titanium oxide is known (Patent Document 1), and ferric chloride is mixed with zirconia A dental restorative material prepared by sintering zirconia ceramics of tooth color by mixing is known (Patent Document 2).

Next, a high strength crystal glass for teeth using a crystallized glass containing lithium disilicate crystals is known (Patent Document 3).

However, zirconia has a disadvantage in that the light transmittance is low and the harmony with the teeth color is low, resulting in deterioration of the aesthetic effect, and the dimensional accuracy is poor due to shrinkage during firing. Further, in the case of the crystallized glass, there is a problem that the esthetics are excellent but the fracture toughness is high due to the low fracture toughness, and the mechanical strength is low for application to a posterior portion or a bridge which acts on a high load.

Accordingly, the inventors of the present invention have studied glass intrusion ceramic composites having excellent translucency and mechanical strength, and confirmed that the glass penetration ceramics composite prepared by infiltrating glass into sapphire and alumina preforms have excellent translucency and mechanical strength, and completed the present invention .

Korean Registered Patent No. 2010-1002400; Korean Registered Patent No. 2008-0876059; Korean Patent Publication No. 2012-0073710.

It is an object of the present invention to provide a glass infiltration sapphire / alumina composite for dental restoration.

Another object of the present invention is to provide a method of manufacturing a glass infiltration sapphire / alumina composite for the tooth restoration.

The present invention provides a glass-infiltrated sapphire / alumina composite for dental restorative materials.

The present invention also relates to a method of manufacturing a sapphire and alumina mixture comprising the steps of (1) molding and injecting a mixture of sapphire and alumina into a mold;

Preparing a preform by plasticizing the mixture formed in step 1 (step 2); And

And a step (step 3) of heat-treating and penetrating the glass into the preform manufactured in the step 2, thereby providing a glass infiltration sapphire / alumina composite for a tooth restoration.

The glass infiltration sapphire / alumina composite for dental restoration according to the present invention is significantly superior in light transmittance as compared with a conventional glass infiltration ceramic composite, and shrinkage occurs when the glass infiltrates into the pores of the porous preform (preform) And has a near net-shape characteristic with excellent dimensional accuracy. Therefore, the crown used for treatment has high dimensional accuracy and excellent mechanical strength, so that it can be used as a coping material for a core, , Onlay, veneer, crown and the like, it can be used as a glass filling material for a variety of dental composite materials.

FIG. 1 is a graph showing particle sizes of sapphire and alumina particles used in the production of the sapphire / alumina preform of Experimental Example 1. FIG.
FIG. 2 is a graph showing the shrinkage ratio of the sapphire / alumina preform according to the sintering temperature of Experimental Example 1. FIG.
3 is a graph showing the porosity of a sapphire / alumina preform according to alumina content in Experimental Example 2. FIG.
FIG. 4 is a graph showing a glass penetration depth of a sapphire / alumina preform according to the alumina content of Experimental Example 2 (SA0: preform having an alumina content of 0 wt%, SA30: preform having an alumina content of 30 wt% : A preform having an alumina content of 50% by weight).
5 is a photograph (SEM, JEOL) of a sapphire / alumina preform plasticized at 1420 ° C of Experimental Example 2 and a glass infiltration sapphire / alumina composite prepared using the same according to alumina content (SEM, JEOL) SA30: when the alumina content is 0% by weight; SA30: when the alumina content is 30% by weight; and SA50: when the alumina content is 50% by weight to be).
6 is a photograph of a scanning electron microscope (SEM, JEOL) of a sapphire / alumina preform prepared according to the sintering temperature of Experimental Example 2 and a glass infiltration sapphire / alumina composite prepared using the same. Sapphire / alumina preform, (b) glass-infiltrated sapphire / alumina composite, 1420 占 폚: 1520 占 폚 for the sintering temperature of 1420 占 폚; 1620 占 폚 for the sintering temperature of 1520 占 폚; Case).
7 is a graph showing the transmittance of the glass-infiltrated sapphire / alumina composite of Experimental Example 3.
8 is a graph showing the analysis of the biaxial strength of the sapphire / alumina preform of Experimental Example 4. Fig.
9 is a graph showing the analysis of the biaxial strength of the glass-infiltrated sapphire / alumina composite of Experimental Example 4. Fig.
10 is a photograph of a tool dynamometer system used to measure the cutting force of a glass-infiltrated sapphire / alumina composite of Experimental Example 5. Fig.
11 is a graph showing an analysis of the cutting force of the glass-infiltrated sapphire / alumina composite of Experimental Example 6. Fig.
12 is a graph showing the marginal bonding strength of the glass-infiltrated sapphire / alumina composite of Experimental Example 7. FIG.

Hereinafter, the present invention will be described in detail.

The present invention provides a glass-infiltrated sapphire / alumina composite for a dental restoration having a structure in which glass is infiltrated into a sapphire / alumina preform filled with fine alumina particles in a gap formed by coarse sapphire particles.

The glass infiltration sapphire / alumina composite for a tooth restoration according to the present invention is characterized in that a gap formed between sapphire particles having a particle size of 20 to 30 μm is filled with alumina particles having a particle size of 0.1 to 1.0 μm, Melting glass water on the surface and penetrating into the pores of the sapphire / alumina preform.

Since the glass infiltration sapphire / alumina composite for tooth restoration is high in light transmittance due to high content of single crystal sapphire and alumina excellent in physical properties, the biaxial strength, cutting force and marginal bonding force properties are remarkably excellent, (See Experimental Examples 1 to 7), as well as a coping material for a crown material such as an inlay, an onlay, a veneer, and a crown.

At this time, the content ratio of sapphire and alumina used in the production of the sapphire / alumina preform according to the present invention is preferably 65 to 80% by weight and 20 to 35% by weight.

When the content of alumina is less than 20% by weight, the biaxial strength of the glass-infiltrated sapphire / alumina composite to be produced is low, so that it is impossible to absorb and disperse the occlusal load to withstand the tooth restoration material. The alumina scattering light significantly reduces the light transmittance and thus has a problem that the aesthetic effect is considerably deteriorated.

In addition, the glass infiltration sapphire / alumina composite for dental restoration according to the present invention can be processed into a tooth restoration material by a CAD / CAM (computer aided design / computer aided manugacturing) method, but is not limited thereto.

Glass infiltration Ceramic dental prosthesis processing methods include slip casting and CAD / CAM (computer aided design / computer aided manugacturing).

The slip casting is a method of forming a preform by applying alumina slip on a tooth model of a patient by using a molding method mainly used in glass penetration alumina, drying and plasticizing. In this case, it is important that the heat treatment is performed in a temperature range in which the preform does not cause shrinkage, and then the glass is permeated into the porous preform through the penetration heat treatment once again to complete the final product. However, since the sapphire / alumina preform according to the present invention has a shrinkage of about 10% in the plasticizing step, it can not be manufactured by a molding method by slip casting.

On the other hand, the shape processing method using CAD / CAM (computer aided design / computer aided manugacturing) method is a method in which preforms that have already been shrunk due to plasticization are processed in a 1: It is not necessary to consider shrinkage due to sintering. In addition, since the glass infiltration sapphire / alumina composite according to the present invention is considerably superior in workability as one of the considerations of CAD / CAM (computer aided design / computer aided manugacturing) processing method, the glass infiltration sapphire / And can be usefully used for dental prosthesis (Experimental Example 1 and Experimental Example 5).

The present invention also relates to a method of manufacturing a sapphire and alumina mixture comprising the steps of (1) molding and injecting a mixture of sapphire and alumina into a mold;

Preparing a preform by plasticizing the mixture formed in step 1 (step 2); And

And a step (step 3) of heat-treating and penetrating the glass into the preform manufactured in the step 2, thereby providing a glass infiltration sapphire / alumina composite for a tooth restoration.

Hereinafter, a method of manufacturing the glass infiltration sapphire / alumina composite for tooth restoration will be described in detail.

First, step 1 of the manufacturing method according to the present invention is a step of molding a mixture of sapphire and alumina into a mold. More specifically, the sapphire and alumina mixture is mixed with water, polyvinyl alcohol (PVA) and a dispersant, and is poured into a rubber mold for molding.

In this case, the particle sizes of the sapphire and alumina used in the step 1 are preferably 20 to 30 μm and 0.1 to 1.0 μm, respectively.

If the particle size of the sapphire used in the step 1 according to the present invention is less than 20 탆, the transmittance of the glass infiltration sapphire / alumina composite to be produced decreases, while when the particle size exceeds 30 탆, the mechanical strength of the composite decreases . In addition, when the particle size of alumina is less than 0.1 μm, there is a problem that the transmittance and mechanical strength of the glass-infiltrated sapphire / alumina composite produced by reducing the glass penetration power to the sapphire / alumina preform are reduced. There is a problem in that the mechanical strength is decreased due to insufficient function as a sintering agent for increasing the mechanical strength obtained by forming the neck between the sapphire particles by the fine particles.

The mixing ratio of sapphire and alumina in step 1 is preferably 65 to 80% by weight and 20 to 35% by weight.

When the content of alumina is less than 20% by weight, the biaxial strength of the glass-infiltrated sapphire / alumina composite to be produced is low, so that it is impossible to absorb and disperse the occlusal load to withstand the tooth restoration material. The alumina scattering light significantly reduces the light transmittance and thus has a problem that the aesthetic effect is considerably deteriorated.

The mixture molded in the above step 1 according to the present invention can be molded by wet slip cast molding or dry press molding, but is not limited thereto.

At this time, in the wet slip casting molding method, 70% by weight of tertiary distilled water, 3% by weight of polyvinyl alcohol (PVA) and 3% by weight of dispersant are mixed in a planetary mixer 30 minutes, and these slurries were molded into a rubber mold having a diameter of 20.0 mm and a height of 3.0 mm to form a slurry.

In the dry press molding method, the mixture prepared in the above wet slip casting molding method is sufficiently dried in an oven to obtain granules through sieving, and then molded into a 20 mm x 15 mm x 45 mm shaped workability test mold using a uniaxial press and a mold Molding method.

Next, the step 2 of the production method according to the present invention is a step of producing a preform by plasticizing the mixture formed in the step 1.

More specifically, the mixture formed in step 1 is heated to a temperature below the melting point of each additive to melt a part of the alumina, and then the molten part of alumina densifies the sapphire / alumina mixture as a plasticizer.

At this time, it is preferable that the calcination of the step 2 is performed at 1500 to 1650 ° C for 1 to 2 hours.

If the calcination temperature in step 2 is less than 1500 ° C, the densification of the mixture formed in step 1 is not properly performed, and the biaxial strength of the sapphire / alumina preform to be produced is significantly reduced. When the calcination temperature is higher than 1650 ° C The glass penetration is reduced due to the densification of the preform skeleton due to the high firing temperature, and the residual pores of the composite produced thereby are deteriorated, thereby lowering the transmittance and mechanical properties. When the calcination time is less than 1 hour, the reaction time of alumina and sapphire is short and the densification is not properly performed. As a result, the biaxial strength is lowered. If the calcination time is longer than 2 hours, There is a problem in that it is not economical from an energy point of view.

The step 2 may further include polishing the surface of the preform after the plasticization is performed.

The surface of the sapphire / alumina preform produced by calcination in step 2 is polished with a 600 mesh SiC abrasive paper, and then the surface is cleaned with compressed air, thereby promoting glass water infiltration of the sapphire / alumina preform .

Next, in the step 3 of the manufacturing method according to the present invention, the glass is heat-treated and infiltrated into the preform manufactured in the step 2.

More specifically, the glass powder is mixed with distilled water on the surface of the sapphire / alumina preform prepared in the step 2, put in a slurry state, and heat-treated at a high temperature to melt-penetrate the glass powder.

The glass powder may be at least one selected from the group consisting of silicon dioxide (SiO ₂ ), boron trioxide (B ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO), lanthanum oxide (La ₂ O ₃ ) ₂ , lanthanum aluminosilicate such as cerium oxide (CeO ₂ ), iron oxide (Fe ₂ O ₃ ), etc. These compounds are placed in a platinum crucible and heated at 1450 ° C. for 1 And then quenched and crushed on a stainless steel plate to obtain a glass powder. Further, in order to obtain a homogeneous glass, the glass powder prepared above was placed in a platinum crucible again and subjected to secondary melting under the same melting conditions as those in the primary melting for 1 hour, and then the secondary melting glass was crushed to penetrate Can be produced.

The particle size of the penetrated glass in the step 3 according to the present invention may be 80 to 120 μm, but is not limited thereto.

The heat treatment in step 3 according to the present invention can be performed at 1100 to 1200 ° C, but is not limited thereto.

Hereinafter, the present invention will be described in detail with reference to Production Examples, Examples and Experimental Examples.

However, the following Production Examples, Examples and Experimental Examples are illustrative of the present invention specifically, and the content of the present invention is not limited by Production Examples, Examples and Experimental Examples.

< Manufacturing example  1-24> Sapphire / Alumina Preform  Produce

Step 1: Molding the sapphire / alumina mixture

Sapphire particles having an average particle size of 26.4 mu m and alumina particles having a size of 0.3 mu m were mixed in the mixing ratios shown in Table 1, and then preforms were prepared by wet slip casting molding. At this time, the slip casting method was carried out in the same manner as in Example 1, except that 70% by weight of tertiary distilled water, 3% by weight of polyvinyl alcohol (PVA) and 3% by weight of dispersant (SN-5468, San Nopco, Japan) Were mixed in a planetary mixer for 30 minutes, and these slurries were molded into a rubber mold having a diameter of 20.0 mm and a height of 3.0 mm.

Step 2: sapphire / alumina Preform  Produce

The preforms were heated at a rate of 10 ° C / min and subjected to calcination heat treatment at the plasticizing temperature shown in Table 1 for 1 hour to obtain a preform. The fired preforms were polished with a 600 mesh SiC abrasive paper and cleaned with compressed air to prepare glass penetration specimens.

Sapphire weight% Alumina weight% Plasticity temperature Production Example 1 100 0 1620 ℃ Production Example 2 90 10 1620 ℃ Production Example 3 80 20 1620 ℃ Production Example 4 70 30 1620 ℃ Production Example 5 60 40 1620 ℃ Production Example 6 50 50 1620 ℃ Production Example 7 40 60 1620 ℃ Production Example 8 30 70 1620 ℃ Production Example 9 100 0 1520 ℃ Production Example 10 90 10 1520 ℃ Production Example 11 80 20 1520 ℃ Production Example 12 70 30 1520 ℃ Production Example 13 60 40 1520 ℃ Production Example 14 50 50 1520 ℃ Production Example 15 40 60 1520 ℃ Production Example 16 30 70 1520 ℃ Production Example 17 100 0 1420 ° C Production Example 18 90 10 1420 ° C Production Example 19 80 20 1420 ° C Production example 20 70 30 1420 ° C Production Example 21 60 40 1420 ° C Production Example 22 50 50 1420 ° C Production Example 23 40 60 1420 ° C Production Example 24 30 70 1420 ° C

< Example  1-12> Preparation of glass infiltration sapphire / alumina composite 1-14

First, 31% of silicon dioxide (SiO _2), 23% trioxide, boron _{(B 2 O 3), 17} % of aluminum oxide _{(Al 2 O 3), 5} % of calcium (CaO), 13% lanthanum (La ₂ O ₃ oxide ), 7% titanium dioxide (TiO ₂ ), 3% cerium oxide (CeO ₂ ), 0.68% ferric oxide (Fe ₂ O ₃ ) The raw materials for preparing the glass were prepared by mixing the first reagents, silicon dioxide (SiO ₂ ), boron trioxide (B ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO), lanthanum oxide La ₂ O ₃ ), titanium dioxide (TiO ₂ ), cerium oxide (CeO ₂ ), and iron oxide (Fe ₂ O ₃ ). The above reagents were weighed to 100 g on a glass basis, mixed with a gyro blender for 1 hour, and then put into a platinum crucible and melted at 1450 ° C for 1 hour, and quenched and crushed on a stainless steel plate to obtain a glass powder. In order to obtain homogeneous glass, these glass powders were placed in a platinum crucible again and subjected to secondary melting under the same melting conditions as in the primary melting for 1 hour. The secondary-melted glass was pulverized to prepare a glass powder for penetration having a particle diameter of 80 to 120 μm.

Next, as shown in the following Table 2, glass powder (1.3 g) was mixed with distilled water on a porous sapphire / alumina preform prepared in the above preparation example and placed in a slurry state, and the glass thus prepared was permeated into the preform, A penetration sapphire / alumina composite was prepared.

 Used preform Glass penetration temperature Glass penetration time Example 1 The preform in Production Example 3 1150 DEG C 5 minutes Example 2 The preform in Production Example 4 1150 DEG C 5 minutes Example 3 The preform in Production Example 11 1150 DEG C 5 minutes Example 4 The preform in Production Example 12 1150 DEG C 5 minutes Example 5 The preform in Production Example 19 1150 DEG C 5 minutes Example 6 The preform in Production Example 20 1150 DEG C 5 minutes Example 7 The preform in Production Example 3 1150 DEG C 80 minutes Example 8 The preform in Production Example 4 1150 DEG C 80 minutes Example 9 The preform in Production Example 11 1150 DEG C 80 minutes Example 10 The preform in Production Example 12 1150 DEG C 80 minutes Example 11 The preform in Production Example 19 1150 DEG C 80 minutes Example 12 The preform in Production Example 20 1150 DEG C 80 minutes

< Comparative Example  1-36> Preparation of Glass Penetration Sapphire / Alumina Composite 15-

A glass-infiltrated sapphire / alumina composite was prepared in the same manner as in Example 1, except that the conditions of Table 2 were used instead of the conditions of Table 2 above.

Used preform Glass penetration temperature Glass penetration time Comparative Example 1 The preform in Production Example 1 1150 DEG C 5 minutes Comparative Example 2 The preform in Production Example 2 1150 DEG C 5 minutes Comparative Example 3 The preform in Production Example 5 1150 DEG C 5 minutes Comparative Example 4 The preform in Production Example 6 1150 DEG C 5 minutes Comparative Example 5 The preform in Production Example 7 1150 DEG C 5 minutes Comparative Example 6 The preform in Production Example 8 1150 DEG C 5 minutes Comparative Example 7 The preform in Production Example 9 1150 DEG C 5 minutes Comparative Example 8 The preform in Production Example 10 1150 DEG C 5 minutes Comparative Example 9 The preform in Production Example 13 1150 DEG C 5 minutes Comparative Example 10 The preform in Production Example 14 1150 DEG C 5 minutes Comparative Example 11 The preform 1150 DEG C 5 minutes Comparative Example 12 The preform 1150 DEG C 5 minutes Comparative Example 13 The preform in Production Example 17 1150 DEG C 5 minutes Comparative Example 14 The preform in Production Example 18 1150 DEG C 5 minutes Comparative Example 15 The preform in Production Example 21 1150 DEG C 5 minutes Comparative Example 16 The preform 1150 DEG C 5 minutes Comparative Example 17 The preform 1150 DEG C 5 minutes Comparative Example 18 The preform 1150 DEG C 5 minutes Comparative Example 19 The preform in Production Example 1 1150 DEG C 80 minutes Comparative Example 20 The preform in Production Example 2 1150 DEG C 80 minutes Comparative Example 21 The preform in Production Example 5 1150 DEG C 80 minutes Comparative Example 22 The preform in Production Example 6 1150 DEG C 80 minutes Comparative Example 23 The preform in Production Example 7 1150 DEG C 80 minutes Comparative Example 24 The preform in Production Example 8 1150 DEG C 80 minutes Comparative Example 25 The preform in Production Example 9 1150 DEG C 80 minutes Comparative Example 26 The preform in Production Example 10 1150 DEG C 80 minutes Comparative Example 27 The preform in Production Example 11 1150 DEG C 80 minutes Comparative Example 28 The preform in Production Example 13 1150 DEG C 80 minutes Comparative Example 29 The preform in Production Example 14 1150 DEG C 80 minutes Comparative Example 30 The preform 1150 DEG C 80 minutes Comparative Example 31 The preform 1150 DEG C 80 minutes Comparative Example 32 The preform in Production Example 18 1150 DEG C 80 minutes Comparative Example 33 The preform in Production Example 21 1150 DEG C 80 minutes Comparative Example 34 The preform 1150 DEG C 80 minutes Comparative Example 35 The preform 1150 DEG C 80 minutes Comparative Example 36 The preform 1150 DEG C 80 minutes

< Experimental Example  1> sapphire / alumina Preform  Property evaluation

In order to evaluate the shrinkage force of the sapphire / alumina preform according to the present invention with respect to the method of manufacturing the dental prosthesis, the following experiment was conducted.

First, the particle size distribution of sapphire and alumina used in the production of the sapphire / alumina preform was measured using a particle size analyzer (Mastersizer 2000, Malvern Instruments Ltd., UK). Then, the porosity of the sapphire / alumina preforms prepared in Production Examples 1 to 24 and the shrinkage ratio before and after the plasticizing treatment of the preforms were measured. In this case, the shrinkage ratio was calculated from the mean value by measuring the diameters of twelve specimens before and after the calcination heat treatment. The measured values are shown in Fig. 1 and Fig.

As shown in FIGS. 1 and 2, the particle size of sapphire used in the sapphire / alumina preform produced according to the present invention was found to be 26.4 μm and the particle size of alumina to be 0.3 μm. Also, as the alumina content of the prepared sapphire / alumina preform increased, the shrinkage increased to a maximum of 9 to 10%, and the shrinkage rate increased as the heat treatment temperature increased. It can be seen that the shrinkage rate is increased due to the filling of alumina having a high shrinkage ratio between the coarse sapphire particles and the densification reaction of the sapphire / alumina preform is performed as the sintering temperature is increased. From this, it can be seen that the sapphire / alumina preform according to the present invention progresses in densification due to shrinkage in the plasticizing step. In addition, when the actual dental prosthesis is manufactured, the shape processing method using the CAD / CAM, which is a method of machining the block whose contraction has been completed by the plasticizing heat treatment one by one as a tooth size (actual processing), is suitable have.

Therefore, the sapphire / alumina preform according to the present invention is suitable for the CAD / CAM processing method in which the sapphire / alumina preform is densified in the plasticizing step, the probability of failure during work such as artificial teeth production is low, It can be used not only as a coping material for a core but also as a glass filling material for a variety of dental composite materials such as an inlay, an onlay, a veneer, and a crown as a crown material.

< Experimental Example  2> Sapphire / Alumina Preform  Evaluation of glass permeability

The following experiment was conducted to evaluate the porosity and glass penetration of the sapphire / alumina preform according to the present invention.

The porosity of the sapphire / alumina preforms prepared in Preparation Examples 1 to 24 was determined by measuring the dry weight, the weight of the grabber and the weight of the water by using the principle of Archimedes. The porosity of the sapphire / alumina preforms of Examples 5, 6, The glass penetration of the glass-infiltrated sapphire / alumina composite prepared in Example 18 was confirmed. The results are shown in Fig. 3 to Fig.

As shown in FIG. 3, as the alumina content added to the sapphire / alumina preform increased, the porosity of the preform decreased, and as the sintering temperature increased, the porosity decreased. From this, it can be seen that the fine alumina particles act as a sintering auxiliary agent of the coarse sapphire particles and are densified. In addition, as the alumina content is increased, the pores between the sapphire particles are filled with fine alumina to eliminate pores. Further, it can be seen that the shrinkage increases at a high plasticizing temperature and the porosity is lowered.

As shown in FIG. 4, the penetration depth decreases with an increase in the amount of fine alumina added to coarse sapphire particles. When the amount of alumina added is 70% by weight, The penetration depth was increased.

First, as the alumina content is increased, the penetration depth is decreased because the fine alumina particles are filled between the coarse sapphire particles and the glass can not penetrate the space.

Next, in the case where the alumina addition amount is 70 wt%, it can be seen that the increase of the penetration depth at a high temperature is due to the space where the glass can penetrate due to aggregation of fine alumina particles at a high plasticizing temperature. However, as shown in FIG. 3, since the porosity of the sapphire / alumina preform decreases with increasing plasticization temperature, the expansion of the pore space is related to the pore size and tortuosity rather than the overall porosity .

As shown in FIG. 5 and FIG. 6, it can be seen that as the sintering temperature of the sapphire / alumina preform is increased, the fine alumina is sintered and coalesced and grown. When the sintering is performed at 1620 ° C, . In the glass infiltration sapphire / alumina composite, the fine alumina was dispersed in the glass phase as it is when the preforms were plasticized at 1420 ° C., whereas when preforms preliminarily calcined at 1520 ° C. and 1620 ° C. were used, And it can be seen that the glass structure infiltrates into the space therebetween. The area of this glassy texture appears to be wider as the calcination temperature increases, and thus the formation of voids at the above-mentioned high temperature can be confirmed. Also, it can be seen that the framework of the sapphire / alumina preform sintered at 1520 ° C and 1620 ° C is strongly bonded without breaking or short-circuiting even after glass penetration.

From this, it can be seen that the glass penetration depth is lower as the content of alumina added is higher in the production of the sapphire / alumina preform, and in the case of the sapphire / alumina preform in which the plasticization is performed at a temperature of 1520 ° C or higher in the plasticization step, It is understood that not only the penetration depth of the glass is deep but also that the fine alumina particles serve as a sintering auxiliary agent of the coarse sapphire particles and are densified to make rigid skeleton.

Therefore, since the sapphire / alumina preform according to the present invention is manufactured at a high plasticizing temperature, the glass penetration depth is deep and the effect of reinforcing the skeleton by densification of the added alumina particles is excellent, so that a coping material But also as a glass filling material for various dental composite materials such as inlay, onlay, veneer, and crown as a crown material.

< Experimental Example  3> Sapphire / Alumina Preform  And glass penetration sapphire / alumina composites

The aesthetic effect evaluation for using a glass infiltration sapphire / alumina composite according to the present invention as a crown tooth restoration material was carried out by the following method.

The glass-infiltrated sapphire / alumina composite prepared in Examples 7 to 12 and Comparative Examples 19 to 36 was mirror-polished to a thickness of 1.0 mm, the surface was cleaned with ethanol, and then UV-visible spectroscopy (UV- 2401 PC, Shimadzu, Japan). At this time, the measured wavelength range was 300 to 800 nm, and only the transmittance at a wavelength of 550 nm, which is the maximum luminous efficiency of the human eye, was measured. The results are shown in FIG.

As shown in FIG. 7, as the content of fine alumina added to the coarse sapphire particles increases, the transmittance of the glass penetration composite decreases from 27% to 5% regardless of the preform sintering temperature. In addition, the transmittance was decreased while the calcination temperature was increased below that of the alumina content of 40 wt%, and conversely, the increase was greater. As the content of alumina increases, the transmittance decreases. As the fine alumina is filled between the coarse and fine sapphire particles, the scattering of light increases due to the increase of the glass transition area between the glass and the particles, and the porosity of the preform decreases as the fine alumina is added This is because the penetration of glass to the bottom of the preform is not smooth. The reason why the transmittance results according to the calcination temperature are inversed with respect to the alumina content of 30% by weight is that when the alumina content is 30% by weight or less, fine alumina serves as a sintering aid for coarse sapphire, The reason for this is that as the sintering temperature increases, the fine alumina coagulates to form pores and smooth glass penetration. From this, it can be seen that the glass penetration sapphire / alumina composite according to the present invention has an excellent transmittance when the alumina content is 35% by weight or less.

Accordingly, the glass-infiltrating sapphire / alumina composite according to the present invention has excellent transmittance at a wavelength of 550 nm, which is the maximum luminous efficiency of the human eye, and has a good aesthetic effect, It can be used not only as a coping material but also as a crown material such as an inlay, an onlay, a veneer, and a crown, so that it can be used as a glass filling material for a variety of dental composite materials.

< Experimental Example  4> glass penetration of sapphire / alumina composite Biaxial strength  evaluation

The biaxial strength evaluation for the use of the glass infiltration sapphire / alumina composite according to the present invention as a crown material as well as a coping material was carried out in the following manner.

The preforms and the glass infiltration sapphire / alumina composites prepared in the above Production Examples 1 to 24, Examples 7 to 12 and Comparative Examples 19 to 36 were subjected to a strength test of ASPM standard F394-78 using an Instron (3342, USA) Method. At this time, the three steel balls (3.2 mm in diameter) located on the lower side are located on a circle having a diameter of 12.0 mm, and the diameter of a pin located on the upper side is 1.6 mm. The crosshead speed was 0.5 / min. The measured biaxial strength changes of the preform and composite according to the present invention are shown in Figs. 8 and 9. Fig.

As shown in FIGS. 8 and 9, the glass-infiltrated sapphire / alumina preform according to the present invention increases biaxial strength up to 80 MPa as the content of fine alumina added to coarse sapphire increases, and the higher the plasticizing temperature The value of biaxial strength also increased. In addition, the glass-infiltrated sapphire / alumina composite according to the present invention increased the strength of the glass-infiltrated sapphire / alumina composite up to 330 MPa until the content of alumina particles added to the sapphire particles reached 30 wt% The difference in strength values according to the temperature was not significant. In this case, when the alumina addition amount is more than 30 wt%, the difference in strength according to the plasticizing temperature becomes large. In the case of the composite impregnated with glass in the preform subjected to plasticization at 1420 ° C., the strength was decreased and plasticity at 1520 ° C. and 1620 ° C. When the glass penetrated into the preform, the strength was constant or slightly increased. This is because the increase in strength due to the addition of alumina is due to the strengthening of the framework of the sapphire / alumina preform by the fine alumina particles. However, when added in a large amount of more than 30% by weight, the porosity of the preform is filled with alumina, so that the intensity of the glass infiltration sapphire / alumina composite sintered at 1420 deg. From this, it can be seen that the glass-infiltrated sapphire / alumina composite according to the present invention is a glass-infiltrated sapphire / alumina composite prepared by glass infiltration into preforms having a alumina content of 20 to 35% by weight and calcined at 1520 DEG C or higher, Able to know.

Therefore, the glass-infiltrated sapphire / alumina composite according to the present invention has a biaxial strength of 250 MPa or more and meets the biaxial strength requirement of 100 to 150 MPa required as a crown material, But also can be used as a crown material such as an inlay, an onlay, a veneer, and a crown, so that it can be usefully used as a glass filling material for a variety of dental composite materials.

< Experimental Example  5> Evaluation of Cutting Force of Glass Penetration Sapphire / Alumina Composite

In order to evaluate the workability of the glass infiltration sapphire / alumina composite prepared according to the present invention, the cutting force was evaluated by the following experimental method.

In order to evaluate the cutting force effect of the glass infiltration sapphire / alumina composite according to the plasticizing temperature in the plasticizing step for the production of the sapphire / alumina preform, in Examples 8 and 10 in which the glass penetration, transmittance and mechanical properties were excellent in the above- And a glass dipping sapphire / alumina composite (20 mm x 15 mm x 45 mm) manufactured in Example 12 was cut into a vertical machining center (DNM 400, Doosan, Korea) at a depth of 0.5 mm and 1.0 mm, 9272, Kistler, Swiss) Cutting force signals representing the cutting resistance transmitted to the sensor were measured. The machining conditions were 3,000 rpm, feed rate 500 mm / min, cutting depth 0.5 mm and 1.0 mm, and the measured cutting force signals were converted to image images using an oscilloscope (TDS 2024B, Tektronix). The apparatus for measuring the cutting force and the results are shown in Fig.

As shown in FIG. 11, the glass penetration sapphire / alumina composite prepared according to the present invention exhibited a tendency that the cutting force increased with increasing the plasticizing temperature in the production of the sapphire / alumina preform, and the cutting depth was 0.5 mm to 1.0 mm, the cutting resistance was increased. No cracks or cracks were found on the surface of the composite during cutting. This is because not only the skeleton of the preform becomes harder as the sintering temperature becomes higher, but also the cutting resistance to the specimen increases as the depth of cutting becomes deeper. From this, it can be seen that the glass penetration sapphire / alumina composite produced according to the present invention has a higher cutting force because the skeleton of the preform becomes harder when the sintering temperature is higher in producing the sapphire / alumina preform.

Therefore, the glass-infiltrated sapphire / alumina composite according to the present invention has a large cutting force due to a rigid preform skeleton and does not cause surface scraping and cracking during the cutting operation due to the high cutting power of zirconia most widely used as a conventional ceramic restoration, Can be used not only as a coping material for a core but also as a crown material such as an inlay, an onlay, a veneer, and a crown, so that it is useful as a glass filling material for a variety of dental composite materials Can be used.

<Experiment 6> Glass-infiltrated sapphire / alumina composite Marginal bonding degree  evaluation

In order to evaluate the workability of the glass infiltration sapphire / alumina composite prepared according to the present invention, marginal bonding degree was evaluated by the following experimental method.

The tooth model of the patient to be processed into the artificial tooth was scanned, and then the scanning data was converted into a CAD / CAM program and transferred to a dedicated processor (CEREC MC XL, Sirona, Germany). The sapphire / alumina preforms prepared in Preparation Examples 8, 10 and 12 were processed based on the transmitted data. At this time, the machining conditions were such that the rotating speed of the spindle was 60,000 rpm, the feed rate was 500 mm / min, and the cutting depth was 0.04 to 0.045 mm. A glass infiltration crown was prepared by placing glass on a sapphire / alumina preform manufactured through such a processing step and heat-treating it at 1150 ° C for 80 minutes. The prepared crown was inserted into the patient's tooth model again, and the marginal zone of the crown and the clearance between the crown and the model were measured. The results are shown in Fig.

As shown in FIG. 12, the clearance between the marginal portion and the model decreases as the sintering temperature increases in the sapphire / alumina preform manufacturing step. This means that the crown was produced without deformation of the preform during the glass infiltration process. From this, it can be seen that the preform was largely opened in the preform subjected to the preliminary heat treatment at 1420 ° C. because the compactness of the preform was decreased at the corresponding temperature, It can be seen that the glass penetrated into the crown. On the other hand, at the preheat temperatures of 1520 ° C and 1620 ° C, the compactness of the preform is high and the skeleton is strengthened, so that the marginal fit with the tooth model is as low as 200 to 300 μm because the glass water has less penetration into the crown.

Accordingly, the glass-infiltrated sapphire / alumina composite according to the present invention has a low marginal fit with a tooth model using a dense sapphire / alumina preform due to a high plasticity temperature treatment, and thus has excellent processability as a dental restorative material, It can be used as a glass filling material for various dental composite materials such as inlay, onlay, veneer and crown as a crown material.

Claims (12)

delete delete delete delete Mixing the sapphire and alumina mixture into a mold and molding the mixture so that the content of alumina is 20 to 35% by weight based on the total mixture (step 1);
Preparing a preform by subjecting the mixture formed in step 1 to a calcination at a temperature of 1520 to 1620 캜 for 1 to 2 hours (step 2);
(Step 3) of preparing a glass-infiltrated sapphire / alumina composite by heat-treating and infiltrating the glass into the preform produced in step 2; And
(Step 4) of processing the composite prepared in step 3 through a CAD / CAM processing method.
6. The method of claim 5,
Wherein the particle size of the sapphire and alumina in step 1 is 20 to 30 μm and 0.1 to 1.0 μm, respectively.
delete delete delete 6. The method of claim 5,
Wherein the step 2 further comprises polishing the surface of the fired preform after performing the plasticizing process.
6. The method of claim 5,
Wherein the particle size of the penetrated glass in step 3 is 80 to 120 μm.
6. The method of claim 5,
Wherein the heat treatment temperature in step 3 is 1100 to 1200 占 폚.

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