Zirconium oxide mixture for manufacturing false teeth and application of zirconium oxide mixture

Abstract

The invention relates to a zirconium oxide mixture for manufacturing false teeth and application of the zirconium oxide mixture. The zirconium oxide mixture is prepared from the following components in percentage by weight: 90 to 94 percent of ZrO2, 5 to 8 percent of Y2O3, 0.5 to 2 percent of single-walled carbon nanotubes, 0.01 to 0.3 percent of Fe2O3, 0.01 to 0.3 percent of Er2O3 and 0 to 0.05 percent of CaF2. The invention also discloses a method for preparing a zirconia porcelain block by using the mixture and a false tooth prepared by using the zirconia porcelain block. According to the mixture disclosed by the invention, the corrosion resistance of the false tooth is also improved while the strength of the false tooth is maintained, so that the service life of the false tooth is prolonged.

Description

Technical Field

[0001] The invention relates to the field of material synthesis, in particular to a zirconium oxide mixture for making artificial teeth and application thereof. Background Art

[0002] Zirconia has gradually become a popular material for making dentures, because zirconia ceramics have good biocompatibility and have a enamel texture and transparency close to that of natural human teeth. However, due to the complex and changeable environment in the oral cavity, changes in saliva pH and chemical substances, dentures will be corroded during long-term use, and poor corrosion resistance will release harmful substances on the one hand, and on the other hand, it will cause the denture to deform and be damaged, thus affecting the chewing and biting functions. Therefore, a zirconia ceramic with high corrosion resistance is needed. Summary of the invention

[0003] In view of the existing deficiencies, the present invention provides a zirconium oxide mixture for making dentures and application thereof.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a zirconium oxide mixture for making dentures, comprising the following components in weight percentage: 90-94% ZrO2, 5-8% Y2O3, 0.5-2% single-walled carbon nanotubes, 0.01-0.3% Fe2O3, 0.01-0.3% Er2O3, and 0-0.05% CaF2.

[0005] Preferably, the length of the single-walled carbon nanotube is less than 500 nm.

[0006] Preferably, the particle sizes of the ZrO2, Y2O3, Fe2O3, Er2O3 and CaF2 powders are all 20-200 nm.

[0007] A zirconium oxide ceramic block is prepared by using any of the above-mentioned zirconium oxide mixtures for making dentures.

[0008] Preferably, the preparation steps are as follows:

[0009] Powdered ZrO2, Y2O3, Fe2O3, Er2O3, CaF2 and single-walled carbon nanotubes with nanometer particle sizes are weighed in proportion and then mixed evenly to obtain a zirconium oxide mixture;

[0010] Pre-pressing the zirconium oxide mixture into a zirconium oxide blank;

[0011] The zirconia blank is cold isostatically pressed and then sintered to obtain a zirconia ceramic block.

[0012] Preferably, the pre-pressing pressure is 40-70 MPa, and the holding time is 20-50S.

[0013] Preferably, the cold isostatic pressing pressure is 100-300 MPa, and the holding time is 5-15 min.

[0014] Preferably, the sintering includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 950-1050°C, the holding time is 1-3h, and the heating rate is 10-50°C / min, and the high-temperature sintering temperature is 1300-1450°C, the holding time is 1-3h, and the heating rate is 1-10°C / min.

[0015] Preferably, the pre-sintering is preceded by heat preservation, wherein the heat preservation temperature is 150-200°C and the heat preservation time is 0.5-1h.

[0016] A denture is made using the zirconium oxide ceramic block as described in any one of the above items.

[0017] The beneficial effects of the present invention are as follows: the single-walled carbon nanotubes and CaF2 of the present invention can better adapt to the changes in pH in the oral cavity while ensuring the strength of the denture, thereby improving the corrosion resistance of the denture, and utilizing their corrosion resistance characteristics to resist chemical corrosion in the oral cavity, thereby extending the service life of the denture and avoiding the release of harmful metal substances during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the polarization curve obtained by conducting an electrochemical corrosion resistance test on the sample and the reference product in Example 2 of the present invention; DETAILED DESCRIPTION

[0019] In order to more clearly illustrate the purpose, technical solutions and advantages of the embodiments of the present invention, the present invention will be further described in conjunction with the embodiments below, and a clear and complete description will be given. Obviously, the embodiments described are partial embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0020] A zirconium oxide mixture for making dentures comprises the following components in weight percentage: 90-94% ZrO2, 5-8% Y2O3, 0.5-2% single-walled carbon nanotubes, 0.01-0.3% Fe2O3, 0.01-0.3% Er2O3, and 0-0.05% CaF2; wherein the length of the single-walled carbon nanotubes is less than 500nm, and existing single-walled carbon nanotubes can be used, dispersed in a mixed acid of 98% H2SO4 and 65% HNO3 (3:1, V / V), ultrasonicated for 24 hours in an ice water bath at 0°C, and then washed with ultrapure water until neutral to obtain truncated single-walled carbon nanotubes; the particle sizes of ZrO2, Y2O3, Fe2O3, Er2O3, and CaF2 powders are all 20-200nm.

[0021] A zirconium oxide ceramic block is prepared using the above-mentioned zirconium oxide mixture, and the preparation steps are as follows:

[0022] The powdered particles of nanometer-sized ZrO2, Y2O3, Fe2O3, Er2O3, CaF2 and single-walled carbon nanotubes are weighed in proportion and then mixed evenly to obtain a zirconium oxide mixture. That is to say, the particle sizes of the powder particles in the ZrO2 powder, Y2O3 powder, Fe2O3 powder, Er2O3 powder and CaF2 powder are all nanometer-sized. Their particle sizes can be the same or different. For example, their particle sizes are all selected to be 150nm; the length of the single-walled carbon nanotubes can be based on According to the situation, 300nm, 400nm or 500nm is selected; firstly, 90-94% of ZrO2, 5-8% of Y2O3, 0.5-2% of single-walled carbon nanotubes, 0.01-0.3% of Fe2O3, 0.01-0.3% of Er2O3, and 0-0.05% of CaF2 are weighed according to the following weight percentages; after weighing, the components are mixed together and stirred evenly to obtain a zirconium oxide mixture, which is used as a raw material for making dentures;

[0023] The zirconium oxide mixture is pre-pressed to obtain a zirconium oxide blank, the pre-pressing pressure is 40-70 MPa, and the holding time is 20-50 seconds;

[0024] The zirconia blank is cold isostatically pressed and then sintered to obtain a zirconia ceramic block; the cold isostatic pressing pressure is 100-300MPa, and the holding time is 5-15min; the sintering includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 950-1050℃, the holding time is 1-3h, and the heating rate is 10-50℃ / min, the high-temperature sintering temperature is 1300-1450℃, the holding time is 1-3h, and the heating rate is 1-10℃ / min; after the high-temperature sintering is completed, the temperature is first quickly cooled to 1000℃±100℃, and then slowly cooled to 700℃±100℃, and finally quickly cooled to room temperature.

[0025] As a further improvement, heat preservation is carried out before pre-sintering, and the heat preservation temperature is 150-200℃ and the heat preservation time is 0.5-1h. In this way, the moisture in the raw materials can be better evaporated at low temperature to avoid the formation of bubbles in the final product due to the lack of time for the moisture to evaporate and escape.

[0026] A denture is formed by carving a zirconium oxide ceramic block as described in any one of the above items. The denture has an appropriate cutting end size, a natural color transition, and uniform light transmittance and strength.

[0027] Example 1

[0028] Weighing 92.61% by weight of ZrO2, 6% by weight of Y2O3, 1% by weight of single-walled carbon nanotubes, 0.2% by weight of Fe2O3, 0.15% by weight of Er2O3, and 0.04% by weight of CaF2, wherein the particle sizes of ZrO2 powder, Y2O3 powder, Fe2O3 powder, Er2O3 powder, and CaF2 powder are all 180 nm, and the length of the single-walled carbon nanotubes is 400 nm, and then mixing them uniformly to obtain a zirconium oxide mixture;

[0029] The zirconia mixture is pre-pressed into a zirconia blank using a dry pressing mold, the pre-pressing pressure is 60 MPa, and the holding time is 40 seconds;

[0030] The zirconia blank is cold isostatically pressed and then sintered to obtain a zirconia ceramic block; the cold isostatic pressing pressure is 260MPa, and the holding time is 14min; the sintering includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 980℃, the holding time is 2h, and the heating rate is 15℃ / min. At this time, when the temperature rises to 150℃, it is kept for 0.5h, and then continued to rise to 980℃, the high-temperature sintering temperature is 1400℃, the holding time is 2h, and the heating rate is 6℃ / min; after the high-temperature sintering is completed, the temperature is first quickly cooled to 1000℃, and then slowly cooled to 700℃, and finally quickly cooled to room temperature to obtain a zirconia ceramic block.

[0031] The transparency of the prepared zirconia ceramic block was 54%, and the strength was 880 MPa, which means that the zirconia ceramic block prepared from the zirconia mixture has sufficient transparency and strength to meet the needs of making dentures.

[0032] Example 2

[0033] The zirconia ceramic block (sample) prepared above and the zirconia ceramic block (reference) currently sold on the market were subjected to an electrochemical corrosion resistance test in simulated artificial saliva;

[0034] The composition of artificial saliva is: NaCl 0.4g / L, KCl 0.4g / L, CaCl2·2H2O 0.795g / L, NaH2PO4·2H2O 0.78g / L, Na2S·2H2O 0.005g / L, urea 1g / L, distilled water 1L; the pH value is adjusted to 5.0;

[0035] The samples and reference substances were immersed in artificial saliva for 24 h, respectively. Then, the samples and reference substances were used as working electrodes, platinum sheets were used as auxiliary electrodes, and saturated calomel electrodes were used as reference electrodes. Each electrode was immersed in artificial saliva electrolyte and connected to an electrochemical workstation. The initial point was set to -1500 mV, the final potential was set to +500 mV, the scanning speed was set to 5 mV / s, and the sensitivity was set to 10 -2 ; The polarization curves of the sample and the reference were measured respectively, such as Figure 1 As shown in , 1 is the polarization curve of the sample, 2 is the polarization curve of the reference, and the self-corrosion potential (Ecorr), corrosion current density (Icorr) and polarization resistance (Rp) of the sample and the reference in the electrolyte can be obtained from the polarization curve. Table 1 shows the test results of simulated corrosion in artificial saliva of the sample and the reference.

[0036] Ecorr(V) <![CDATA[Icorr(μA / cm 2 )]]> Rp(kΩ) Reference -0.880±0.030 18.560±4.058 3.002±1.025 sample -1.357±0.045 5.532±1.620 3.725±0.450

[0037] Table 1

[0038] From Table 1 and Figure 1 It can be concluded that the corrosion current density of the sample is significantly lower than that of the reference, and the polarization resistance is also greater than that of the reference, which means that under normal oral environment, the sample has stronger corrosion resistance than the reference.

[0039] It should be understood that those skilled in the art may make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A zirconium oxide mixture for making dentures, characterized in that: The invention comprises the following components in weight percentage: 90-94% ZrO2, 5-8% Y2O3, 0.5-2% single-walled carbon nanotubes, 0.01-0.3% Fe2O3, 0.01-0.3% Er2O3, and 0-0.05% CaF2.

2. The zirconium oxide mixture for making dentures according to claim 1, characterized in that: The length of the single-walled carbon nanotube is less than 500 nm.

3. The zirconium oxide mixture for making dentures according to claim 1, characterized in that: The particle sizes of the ZrO2, Y2O3, Fe2O3, Er2O3 and CaF2 powders are all 20-200nm.

4. A zirconia ceramic block, characterized in that: The zirconium oxide mixture for making dentures is prepared using any one of claims 1 to 3.

5. The zirconia ceramic block according to claim 4, characterized in that: The preparation steps are as follows: Powdered ZrO2, Y2O3, Fe2O3, Er2O3, CaF2 and single-walled carbon nanotubes with nanometer particle sizes are weighed in proportion and then mixed evenly to obtain a zirconium oxide mixture; Pre-pressing the zirconium oxide mixture into a zirconium oxide blank; The zirconia blank is cold isostatically pressed and then sintered to obtain a zirconia ceramic block.

6. The zirconium oxide ceramic block according to claim 5, characterized in that The pre-pressing pressure is 40-70MPa, and the holding time is 20-50S.

7. The zirconium oxide ceramic block according to claim 5, characterized in that The cold isostatic pressing pressure is 100-300 MPa, and the holding time is 5-15 min.

8. The zirconia ceramic block according to claim 5, characterized in that The sintering includes pre-sintering and high-temperature sintering. The pre-sintering temperature is 950-1050°C, the holding time is 1-3h, and the heating rate is 10-50°C / min. The high-temperature sintering temperature is 1300-1450°C, the holding time is 1-3h, and the heating rate is 1-10°C / min.

9. The zirconium oxide ceramic block according to claim 8, characterized in that : Before the pre-sintering, insulation is performed, the insulation temperature is 150-200°C, and the insulation time is 0.5-1h.

10. A denture characterized by : It is made by using the zirconium oxide ceramic block as described in any one of claims 4 to 9.

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