CN113476157A

CN113476157A - Zirconia dental crown and preparation method thereof

Info

Publication number: CN113476157A
Application number: CN202110776367.2A
Authority: CN
Inventors: 崔春姬; 宋柄沂
Original assignee: Shanghai Senyi Medical Technology Co ltd
Current assignee: Shanghai Senyi Medical Technology Co ltd
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2021-10-08

Abstract

The application relates to the field of zirconia crowns, in particular to a zirconia crown and a preparation method thereof. The inner surface of the zirconia crown is provided with a bonding surface, the bonding surface is formed by sintering coating liquid coated on the inner surface of the crown, the coating liquid is prepared by mixing a mixture and a solvent according to the proportion of 1 (2-4), and the mixture is prepared from the following raw materials in percentage by weight: aluminum powder: 30-40%; elemental carbon powder: 60-70%; additive: 0 to 3 percent. This application is through forming the coarse and firm bonding surface in zirconia crown inner face, makes zirconia crown and the bonding strength who treats the restoration tooth show the improvement to the probability of droing of crown has been reduced.

Description

Zirconia dental crown and preparation method thereof

Technical Field

The application relates to the field of zirconia crowns, in particular to a zirconia crown and a preparation method thereof.

Background

The damage and loss of teeth not only affect the normal chewing of people, but also affect the beautiful appearance. Zirconia is a commonly used restorative material for dentistry, and not only meets the strength and beauty required by teeth, but also has low thermal conductivity, good corrosion resistance, high light transmittance and excellent biocompatibility.

The preparation method of the zirconia ceramic tooth comprises the steps of firstly obtaining a zirconia ceramic block by zirconia powder and fluxing agent through a forming process and a pre-sintering process, then cutting the zirconia ceramic block into a tooth crown shape, and finally sintering at high temperature to obtain the zirconia tooth crown. The tooth restoration method comprises the steps of firstly embedding the inner surface (inner wall of a crown inner cavity) of a zirconia crown on a tooth to be restored, then bonding the zirconia crown and the tooth to be restored through a cement, and completing the tooth restoration after curing.

The inventor believes that the problems of low bonding strength, insufficient shear resistance and high zirconia crown falling probability exist between the dental crown and the tooth which are fixed by the cement, and the improvement of the use experience of customers is not facilitated.

Content of application

In order to improve the connection strength of the zirconia crown and the tooth and reduce the phenomenon of dental crown falling, the application provides the zirconia crown and the preparation method thereof.

In a first aspect, the present application provides a zirconia crown, using the following technical solution:

the inner surface of the zirconia crown is provided with a bonding surface, the bonding surface is formed by sintering a coating solution coated on the inner surface of the crown, the coating solution is prepared by mixing a mixture and a solvent according to the proportion of 1 (2-4), and the mixture is composed of the following raw materials in percentage by weight:

aluminum powder: 30-40%;

elemental carbon powder: 60-70%;

additive: 0 to 3 percent.

Through adopting above-mentioned technical scheme, mix the coating with aluminium powder and carbon simple substance powder and the zirconia crown inner face, on the lateral wall of crown inner chamber promptly, form unevenness's bonding surface in the crown inner chamber after the sintering, when adopting the cement to bond zirconia crown and damaged tooth, can form the mechanical meshing structure of similar mortise-tenon joint between cement and the zirconia crown, and then the bonding strength between reinforcing zirconia crown and the defective tooth, reduce the probability that the zirconia crown drops.

The reason for the above phenomenon may be that, under high-temperature sintering, the re-melting phenomenon occurs on the inner surface of the zirconia crown; meanwhile, the carbon elemental powder reacts with the aluminum powder to form aluminum carbide, and aluminum carbide grains penetrate into the inner surface of the zirconia crown and are mutually permeated and bonded with the remelted zirconia grains, so that the rugged and firmly connected structure is formed on the inner surface of the crown.

The carbon powder is specially limited, and graphite powder, graphene powder or carbon black, charcoal, coke, bone charcoal, sugar charcoal, activated carbon and other amorphous carbon powder can be adopted. The solvent is not particularly limited either, and the powder can be dispersed well without reacting with the raw material powder.

Preferably, the solvent is one of water and absolute ethyl alcohol or a combination thereof.

By adopting the solvent, the solvent can be quickly evaporated at high temperature on the premise of ensuring the full dispersion and mixing of the aluminum powder and the carbon powder, and cannot react with the raw material powder to influence the reaction of the aluminum powder and the carbon powder, thereby being beneficial to improving the bonding strength of the zirconia crown and the teeth.

Preferably, the additive is nano-silica.

By adopting the technical scheme, the bonding strength of the dental crown and the tooth can be improved by adding the nano-scale silicon dioxide. The reason for this is probably that the silica can be melted to form vitreous in the high-temperature sintering process, the vitreous can play a role of a cement, the bonding strength between the aluminum carbide and the zirconia is enhanced, and the probability of the falling of the uneven bonding surface is reduced; finally, the bonding strength of the crown and the tooth is enhanced.

In addition, the excessive addition of the nanosilica leads to an excessive content of glass produced, which penetrates into the pores of the bonding surface, which reduces the roughness of the bonding surface and is not favorable for enhancing the bonding fastness of the cement.

Preferably, the particle size of the aluminum powder is-200 meshes.

By adopting the aluminum powder with the granularity, compact and uniform pores can be formed on the inner surface of the dental crown, so that the bonding strength of the cement and the inner surface of the dental crown can be improved, and the bonding strength of the tooth and the zirconia dental crown can be further improved. The reason may be that aluminum powder with smaller particle size is adopted, so that on one hand, the aluminum powder and the carbon simple substance powder can be ensured to fully react to form aluminum carbide; on the other hand, because the particles have a tendency of agglomeration to increase the particle size during high-temperature sintering, the aluminum powder with smaller particles is beneficial to forming more and denser pore structures on the dental crown.

Preferably, the particle size of the elementary carbon powder is-200 meshes.

By adopting the carbon simple substance powder with the granularity, the roughness of the inner surface of the dental crown is improved, compact and uniform pores are formed on the inner surface of the dental crown, and finally, the bonding strength of the tooth and the zirconia dental crown is improved.

In a second aspect, the present application provides a method for preparing a zirconia crown, comprising the steps of:

s1, processing the zirconia ceramics into a tooth shape, coating the mixed solution on the inner surface of the tooth, and drying for 5-10 min to obtain a pre-sintered body;

and S2, sintering the pre-sintered body at 1500-1550 ℃ for 20-50 min to obtain the zirconia dental crown with the bonding surface.

By adopting the technical scheme, the moisture in the coating liquid is dried in advance before high-temperature sintering, the probability of generating defects such as cracks on the bonding surface in the sintering process can be reduced, and the melting reaction process of the raw material powder can be accelerated.

And adopt 1500 ~ 1550 ℃ of temperature, under the prerequisite of guaranteeing the formation of the unsmooth bonding face of crown inner surface, be favorable to forming more even compact hole on the bonding face, and then promote the improvement of bonding strength. The reason for this may be that above 1500 ℃, aluminum carbide can be fully produced and penetrate into the zirconia crown; however, a sintering temperature higher than 1550 ℃ easily causes the grains of the elemental carbon powder, the aluminum powder or the aluminum carbide to be rapidly increased, reduces the porosity of the inner surface of the dental crown, and is not favorable for improving the bonding strength.

Preferably, the drying temperature is 180-220 ℃.

By adopting the drying temperature, on one hand, the dental crown and the mixture are preheated; on the other hand, the water is quickly evaporated, and the coating liquid on the inner surface of the dental crown is prevented from flowing to cause uneven mixture distribution.

Preferably, in step S2, the pre-sintered body is preheated at 800-900 ℃, and then heated to 1500-1550 ℃ at a rate of 20-30 ℃/min for sintering.

By adopting the technical scheme, the bonding strength between the tooth and the zirconia crown is favorably improved. The reason for this may be that, in the sintering process, if the initial temperature is too high or the temperature rising speed is too fast, the carbon powder and the aluminum powder coated on the inner surface of the dental crown may be rapidly heated and melted; because the temperature rise of the inner surface of the zirconia crown is slow, the inner surface of the zirconia crown does not absorb enough heat to be remelted, so that the generated aluminum carbide crystal grains cannot mutually permeate with the inner surface of the zirconia crown, the firmness of a bonding surface is further reduced, and finally, the bonding strength of a tooth and the zirconia crown is not favorably improved.

In summary, the present application has the following beneficial effects:

1. this application is through scribbling carbon simple substance powder and aluminite powder at zirconia crown internal surface, forms the coarse and firm bonding surface in the crown internal surface after the sintering, utilizes this bonding surface, and the adhesive effect that improves the adhesive is showing, and then improves the bonding strength of tooth and zirconia crown.

2. In the application, nano silicon dioxide is further added into the coating liquid, and the silicon dioxide can form glass during high-temperature sintering and permeate into the strong aluminum carbide and the zirconium oxide, so that the bonding effect is realized, and the falling probability of a bonding surface is reduced; finally, the bonding strength of the crown and the tooth is enhanced.

3. According to the preparation method, the initial sintering temperature and the heating speed are controlled, so that the connection strength of the bonding surface and the zirconia crown is guaranteed, and the bonding strength of the crown and the tooth is improved.

Detailed Description

Examples

Example 1, a zirconia crown, prepared as follows:

s1, processing the zirconia ceramics into tooth shape, coating the mixed solution on the inner surface of the tooth, and drying for 10min at 180 ℃ to obtain a pre-sintered body;

s2, preheating the pre-sintered body at 800 ℃, and then heating to 1500 ℃ at the speed of 30 ℃/min for sintering, wherein the sintering time is 40 min.

Wherein, the selection of raw material components of the coating liquid and the corresponding use amount are shown in table 1.

Example 2, a zirconia crown, prepared as follows:

s1, processing the zirconia ceramics into tooth shape, coating the mixed solution on the inner surface of the tooth, and drying for 5min at 220 ℃ to obtain a pre-sintered body;

s2, preheating the pre-sintered body at 900 ℃, and then heating to 1550 ℃ at a speed of 20 ℃/min for sintering for 30 min.

Examples 2 to 4, a zirconia crown, were different from example 1 in that the selection of each raw material component and the corresponding amount thereof were as shown in table 1.

Table 1 selection of raw material components and their respective amounts (kg) of coating slips in examples 1 to 4

The aluminum powder has the granularity of 200-300 meshes, the graphite powder with the granularity of the carbon simple substance powder within the range of 200-300 meshes is obtained from hydrophilic nano-silica of Shanghai Yien chemistry, and the cas number is 7631-86-9.

Example 5 is a zirconia dental crown different from example 1 in that the powdery aluminum has a particle size of 100 to 200 mesh.

Example 6 is a zirconia dental crown different from example 1 in that the particle size of the elemental carbon powder is graphite powder in the range of 100 to 200 mesh.

Example 7, a zirconia crown, differs from example 1 in that the elemental carbon powder is carbon black N330.

Example 8 is a zirconia crown different from example 1 in that the elemental carbon powder is activated carbon having a particle size of 200 to 300 mesh.

Example 9 a zirconia crown, which is different from example 1 in that the baking is not performed in step S1, and the mixed solution is sintered directly after the coating.

Example 10, a zirconia crown, was different from example 1 in that, in step S2, the sintering temperature was 1400 ℃.

Example 11, a zirconia crown, was different from example 1 in that, in step S2, the sintering temperature was 1600 ℃.

Example 12, a zirconia crown, differs from example 1 in that the specific operation of step S2 is as follows: the pre-sintered body is preheated at 800 ℃, and then is heated to 1500 ℃ at the speed of 40 ℃/min for sintering.

Example 13, a zirconia crown, differs from example 1 in that the specific operation of step S2 is as follows: the pre-sintered body is preheated at 1000 ℃, and then is heated to 1500 ℃ at the speed of 30 ℃/min for sintering.

Example 14, a zirconia crown, differs from example 1 in that the specific operation of step S2 is as follows: directly placing the pre-sintered body at 1500 ℃ for sintering for 50 min.

Comparative example

Comparative example 1, a zirconia crown, differs from example 1 in that aluminum powder was not added to the raw material components of the coating liquid.

Comparative example 2, a zirconia crown, differs from example 1 in that no elemental carbon powder was added to the raw material components of the coating liquid.

Comparative example 3, a zirconia crown, differs from example 1 in that aluminum powder and elemental carbon powder were not added to the raw material components of the coating liquid.

Performance test

Test 1: bonding Strength test of zirconia crowns to teeth

Test samples: the zirconia crowns of examples 1 to 14 and comparative examples 1 to 3 were used as samples.

The test steps are as follows: 1) selecting 48 first premolars extracted from the upper jaw in 30 days due to orthodontic treatment, removing soft tissues and dental calculus on the surface of the tooth root, cleaning by ultrasonic waves, placing in physiological saline, and refrigerating at 4 ℃ for later use. The root tip is required to be completely developed, and the tooth body has no carious lesion and wedge-shaped defect. The hidden cracks are not generated in the tooth body under the observation of a body microscope, and the teeth with the dental fracture and the tooth root absorption, the dental fluorosis, the tetracycline pigmentation and the hidden fissured teeth are eliminated.

2) The labial and buccal surfaces of the isolated teeth are prefabricated into a plane with the area of 4mm by using a standard carborundum vehicle, the thickness is 1 +/-0.1 mm, the exposed surface of the plane is a tooth enamel layer, and the preparation thickness of the damaged tooth edge is simulated.

3) And sequentially grinding and polishing the silicon carbide sand paper of 200#, 400#, 600# and 1000# into standard surfaces (namely bonding interfaces) with uniform roughness, thereby obtaining the simulation to-be-repaired body.

4) Bonding and fixing the zirconia crown sample and the simulated body to be repaired by using 3M Rely X lubricating 2 glass ionic cement, standing and curing for 24h, and measuring the bonding strength of the zirconia crown and the simulated body to be repaired.

5) The test method comprises the following steps: and (3) carrying out an anti-shearing strength test by adopting a DZS-III hard brittle material detector, wherein a loading head of the hard brittle material detector moves downwards at a speed of 0.2mm/min, and the loading head is parallel to the direction of the bonding interface and is close to the bonding interface for shearing. The loading head of the detector descends uniformly and slowly to separate the zirconia crown from the cement, the detector of the hard brittle material detects the maximum load value F at the fracture moment of the cement, each group of samples measures three times, and the average value of the samples is recorded. Since the bonding interface was set to 4mm by 4mm in the preparation of the simulated prosthesis, it was found that the bonding area was 16mm²According to the formula, the shear strength value P (MPa) is the maximum load at break F (N)/bonding area S (mm)²) The shearing strength of the zirconia crown test sample can be obtained, the higher the shearing strength is, the higher the bonding strength between the zirconia crown and the simulated body to be repaired is, and the test result is shown in table 2.

TABLE 2 bonding Strength test results of zirconia crowns and simulated bodies to be restored

And (3) analyzing test results:

(1) as can be seen by combining examples 1-13 and comparative examples 1-3 with Table 2, the shear strength of examples 1-13 is higher than that of comparative examples 1-3, wherein in example 1, the inner surface of the zirconia crown is coated with a coating solution containing aluminum powder and carbon powder, and in comparative examples 1-3, the coating solution is at least one of aluminum powder and carbon powder. In addition, as can be seen from comparative examples 1 to 3, the improvement of the bonding strength between the zirconia crown and the defective tooth cannot be promoted by adopting the aluminum powder and the carbon simple substance powder alone.

The reason for the above phenomenon may be that, during high-temperature sintering, the elemental carbon powder reacts with the aluminum powder to form aluminum carbide grains, and a rough bonding surface is formed on the inner surface of the crown, when the zirconia crown is bonded to a damaged tooth by using a cement, a mechanical engagement structure similar to a mortise-and-tenon joint can be formed between the cement and the zirconia crown, so that the bonding strength between the zirconia crown and the damaged tooth is enhanced, and the probability of the zirconia crown falling off is reduced. Meanwhile, the remelting phenomenon of the inner surface of the zirconia crown is caused, aluminum carbide crystal grains permeate into the inner surface of the zirconia crown and are mutually permeated and bonded with the remelted zirconia crystal grains, so that the connection strength between the bonding surface and the crown is enhanced, and finally, the bonding strength between the zirconia crown and the defective tooth is enhanced.

(2) As can be seen by combining examples 1 and 2 to 4 with Table 2, examples 2 to 4 all had higher shear strengths than example 1. Wherein, compared with the embodiment 1, the coating liquid of the embodiments 2 to 4 is added with the nano silicon dioxide.

The reason for this may be that the nanosilica is melted at high temperature into a vitreous substance which can act as a cement and which has good fluidity and can penetrate into the bonding interface between the aluminum carbide and the inner surface of the zirconia to strengthen the bond, and finally, the bonding strength between the zirconia crown and the defective tooth is further improved.

(3) As can be seen by combining examples 1 and 5 to 6 with Table 2, the shear strengths of examples 1 to 6 are all higher than those of examples 5 to 6. In example 1, the particle sizes of the aluminum powder and the carbon simple substance powder in example 1 are both 200-300 meshes; the granularity of the aluminum powder in the embodiment 5 is 100-200 meshes; in example 5, the particle size of the elemental carbon powder is 100 to 200 meshes.

The reason for this may be that an excessively large particle size is disadvantageous for increasing the number of pore structures on the bonding surface, and an excessively small particle size is disadvantageous for forming pore structures on the bonding surface. The use of powder raw materials of appropriate particle size facilitates the formation of dense and uniform pores to increase the bonding strength of the cement to the inner surface of the crown and, ultimately, the bonding strength between the zirconia crown and the defective tooth.

(4) As can be seen by combining examples 1 and 10 to 11 and by combining Table 2, the shear strength of example 1 is higher than that of examples 10 to 11. The sintering temperature in the embodiment 1 is 1500 ℃, and the sintering temperatures in the embodiments 10-11 are 1400 ℃ and 1600 ℃ respectively.

The reason for the above phenomenon may be that when the temperature is lower than 1500 ℃, the aluminum powder and the carbon powder cannot fully react to generate aluminum carbide, which is not favorable for generating a rough bonding surface; and the zirconia cannot be remelted at a too low temperature, so that aluminum carbide is difficult to permeate into the inner surface of the zirconia crown, and the bonding strength between the bonding surface and the zirconia crown is not improved. However, when the sintering temperature is higher than 1550 ℃, the grains of the carbon powder, the aluminum powder or the aluminum carbide are easily and rapidly increased, the porosity of the inner surface of the dental crown is reduced, and the bonding strength is not easy to improve.

(5) As can be seen by combining examples 1 and 12 to 14 with Table 2, the shear strength of example 1 is higher than that of examples 12 to 14. Wherein, the presintered body in the embodiment 1 is preheated at 800 ℃, and then is heated up to 1500 ℃ at the speed of 30 ℃/min for sintering; the pre-sintered body of example 12 was preheated at 800 ℃ and then heated to 1500 ℃ at a rate of 40 ℃/min to be sintered. The pre-sintered body of example 13 was preheated at 1000 ℃ and then heated to 1500 ℃ at a rate of 30 ℃/min to be sintered. The pre-sintered body in example 14 was directly sintered without preheating.

The reason for the above phenomenon may be that, in the sintering process, because the coating liquid is located in the inner surface of the dental crown, the heating rate of the inner surface of the dental crown is slow, if sintering is directly performed, the raw material in the coating liquid forms aluminum carbide grains, and the inner surface of the dental crown does not absorb enough heat and is remelted, so that the generated aluminum carbide grains cannot permeate into the inner surface of the dental crown, and the bonding strength between the bonding surface and the dental crown is not improved. The bonding firmness after the bonding surface is formed is guaranteed, and finally, the bonding strength between the zirconia crown and the defective tooth is enhanced.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The zirconia dental crown is characterized in that an adhesive surface is arranged on the inner surface of the zirconia dental crown, the adhesive surface is formed by sintering coating liquid coated on the inner surface of a tooth, the coating liquid is prepared by mixing a mixture and a solvent according to the proportion of 1 (2-4), and the mixture is composed of the following raw materials in percentage by weight:

aluminum powder: 30-40%;

elemental carbon powder: 60-70%;

additive: 0 to 3 percent.

2. The zirconia crown according to claim 1, wherein said solvent is one of water and absolute ethanol or a combination thereof.

3. The zirconia crown of claim 1, wherein said additive is nanosilica.

4. The zirconia crown according to claim 1, wherein said aluminum powder has a particle size of-200 mesh.

5. The zirconia crown according to claim 1, wherein said elemental carbon powder has a particle size of-200 mesh.

6. The method for preparing a zirconia crown according to any one of claims 1 to 5, comprising the steps of:

7. The method for preparing a zirconia crown according to claim 6, wherein the drying temperature in step S1 is 180-220 ℃.

8. The zirconia crown of claim 6, wherein in step S2, the pre-sintered body is preheated at 800-900 ℃ and then sintered at a temperature of 20-30 ℃/min to 1500-1550 ℃.