Patent Application
20190231650
The present invention claims the priority to Chinese patent application No. 201610793418.1 filed on Aug. 31, 2016 with the CNIPA, the whole disclosed contents thereof is incorporated herein by reference in its entirety.
The present invention relates to the field of powder engineering, specifically, to a light-transmissive zirconia sintered body and preparation method therefor and use thereof.
Zirconia ceramic is a new type of biological powder with good biocompatibility and excellent mechanical properties, which has become the focus of dental ceramic development.
CN104016677A discloses a light-transmissive zirconia sintered body and preparation method therefor. The zirconia for dental use prepared by the method has a relatively low transmittance, poor overall texture and jade-like appearance, is not aesthetically pleasing, and has certain limitations in application.
One purpose of the present invention is to provide a novel light-transmissive zirconia sintered body and preparation method therefor.
Another purpose of the present invention is to provide use of the light-transmissive zirconia sintered body in the preparation of a fixed dental prosthesis.
In order to achieve the purpose of the present invention, the present invention first provides a powder for a light-transmissive zirconia sintered body. The powder is obtained by dispersing zirconia powder in water (pure water), adding an appropriate amount of a dispersant and a binder, mixing well to form a slurry, and then spray-granulating. The powder moisture is controlled at a range of 0.1 to 0.5% by weight during granulation, and the average particle diameter of the granulated particles is 30 to 50 μm.
Wherein, the molar percentage of yttrium oxide in the zirconia powder is 3 to 5%; the dispersant comprises at least one selected from acrylic acid, polyacrylic acid, acrylamide, polyurethane and the like; the binder comprises at least one selected from polyvinyl alcohol, polyethylene glycol, acrylic resin, carboxymethyl cellulose and the like.
The zirconia powder used in the present invention has a BET specific surface area of 5 to 15 m2/g, and an average particle diameter of 0.1 to 1.0 μm.
The zirconia powder can be prepared by hydrothermal synthesis, comprising the following steps:
S1, a soluble zirconium salt and a soluble yttrium salt are mixed at a ratio and dissolved in water, and the pH of the slurry is adjusted to 8 to 10 with ammonia water under stirring;
S2, the above slurry is subjected to hydrothermal synthesis at 140 to 200° C. for 10 to 72 h;
S3, the resultant reaction solution is washed with water and dried to obtain a powder;
S4, the powder is subjected to heat treatment at 800 to 1200° C. for 2 to 5 h, and then grinding and dispersing; and
S5, the dispersed particles are granulated to obtain a powder for a light-transmissive zirconia sintered body.
The molar ratio of the soluble zirconium salt to the soluble yttrium salt in step S1 is 95 to 97:3 to 5, preferably 96:4. The soluble zirconium salt includes zirconium oxychloride, zirconium nitrate, zirconium sulfate and the like. The soluble yttrium salt includes yttrium chloride, yttrium nitrate, yttrium sulfate and the like.
The weight parts of the feedstocks for preparing a powder for the light-transmissive zirconia sintered body of the present invention are as follows: 50 to 100 parts of zirconia powder, 0.1 to 0.5 parts of dispersant, 0.1 to 8.0 parts of binder, and 50 to 100 parts of water. Preferably, the weight parts of the feedstocks are as follows: 100 parts of zirconia powder, 0.2 parts of dispersant, 5 parts of binder, and 100 parts of water.
The present invention also provides a light-transmissive zirconia sintered body prepared from the powder. The sintered body has a three-point bending strength of ≥900 MPa, a tetragonal phase accounting for >90% of the sintered body, a light transmittance of ≥46%, and a material shrinkage rate before and after sintering controlled at 18 to 25%.
The light-transmissive zirconia sintered body of the present invention can be prepared according to the following method: a green body is prepared from the powder by isostatic pressing (holding pressure at 150 to 200 MPa for 10 to 50 s), and the green body is subjected to degreasing and biscuit firing at 900 to 1100° C. for 1 to 4 h, and then subjected to high-temperature sintering in the atmosphere under normal pressure at 1400 to 1550° C. for 1 to 4 h.
In the foregoing method, the density of the green body after isostatic pressing is 2.5 to 3.3 g/cm3.
The present invention also provides the use of the light-transmissive zirconia sintered body in the preparation of a fixed dental prosthesis (including denture).
The present invention further provides a fixed dental prosthesis, such as zirconia denture, prepared from the light-transmissive zirconia sintered body.
The zirconia sintered body provided by the present invention has the characteristics of high light transmittance and high strength, and the prepared dentures have good texture, good jade-like appearance, and are closer to the human teeth. The sintering temperature used in the preparation process is low, and the properties and quality of the product are controllable.
The following Examples are intended to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.
The percent sign “%” involved in the present invention means a percentage by mass unless otherwise specified. However, the percentage of a solution, unless otherwise specified, means the number of grams of the solute contained in 100 mL solution.
The powder for a light-transmissive zirconia sintered body of the present invention can be obtained by the following method:
zirconia powder was dispersed in pure water, an appropriate amount of dispersant and binder were added and blended to form a slurry, and then the powder for preparing the light-transmissive zirconia sintered body was obtained by spray granulation. (Table 1)
The zirconia powder was prepared by hydrothermal synthesis method comprising the following steps:
S1, the soluble zirconium salt (zirconium nitrate) and the soluble yttrium salt (yttrium nitrate) were mixed at a ratio and dissolved in water, ammonia water was added slowly under stirring, and the pH of the slurry was adjusted to 8 to 10 with ammonia water;
S2, the above slurry was transferred to a reaction kettle, and subjected to hydrothermal synthesis at 140 to 200° C. for 10 to 72 h;
S3, the resultant reaction solution was washed with water and dried to obtain a powder;
S4, the powder was subjected to heat treatment at 800 to 1200° C. for 2 to 5 h, and then grinding and dispersing; and
S5, the dispersed particles were granulated to obtain a powder for a light-transmissive zirconia sintered body.
The powder obtained in Examples 1 to 5 was subjected to isostatic pressing (holding pressure at 150 to 200 MPa for 10 to 50 s) to obtain a green body, and the green body was subjected to degreasing and biscuit firing at 900 to 1100° C. for 1 to 4 h, and then subjected to high-temperature sintering in the atmosphere under normal pressure at 1400 to 1550° C. for 1 to 4 h, to give a light-transmissive zirconia sintered body.
The various indexes of the obtained sintered body products were shown in Table 2.
The light-transmissive zirconia sintered body provided in the present invention can be used as dental powder for fixed dental prosthesis and the like, such as a denture.
Although the present invention is described in detail with general description and specific embodiments as above, it will be apparent to a person skilled in the art that some modifications and improvements can be made. Therefore, such modifications or improvements made without departing from the spirit of the present invention are intended to be within the scope of the present invention.
The light-transmissive zirconia sintered body provided in the present invention can be used for preparing a fixed dental prosthesis. The zirconia sintered body provided by the present invention has the characteristics of high light transmittance and high strength, and the prepared dentures have good texture, good jade-like appearance, and are closer to the human teeth.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201610793418.1 | Aug 2016 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2017/095746 | 8/3/2017 | WO | 00 |
