A novel PMMA-ZrO2 composite (PZC) was prepared by resin infiltrated to ceramic method. The composite mechanical properties were evaluated and correlated to its microstructure. Partially sintered zirconia ceramics (PSZC) were made by isostatic pressing and partially sintering. Subsequently, the PZC was prepared by vacuum infiltrating prepolymerized MMA into PSZC, followed by in-situ polymerization. When PSZC-70% was used as the matrix, the bending strength, elastic modulus, and fracture toughness of the prepared composite i.e PZC-70% were 202.56±12.09 MPa, 58.71±3.98 GPa, and 4.60±0.26 MPa·m1/2, corresponding to 25.69%, 23.31%, and 169.01% improvement, respectively, in comparison with the control matrix. Among them, the fracture toughness improvement was the most prominent. According to SEM images of the fracture surfaces, each pore of zirconia skeleton was filled by organic resin contributing to the bending strength improvement. These weak interfaces between zirconia skeleton and organic resin absorbed energy and terminated the growth of microcracks which might be responsible for significant improvement in fracture toughness. This PZC material is anticipated to be a new member of the dental CAD/CAM family.

LED has characters of small size, long life and low power consumption, and it is environmental friendly. These advantages make LED have a huge market in the lighting industry. LED with the light distribution design can meet the requirements of the application under different circumstances. With the acknowledgement of the principles of light distribution design, based on optical engineering software LightTools, we study the light distribution design of LED back light module for direct-down illumination and LED shadowless lamp. After the secondary optics light distribution design of the LED light, its transmittance and uniformity has been noticeably improved. We depict different types of micro-structure on the surface of 3mm thickness PMMA diffuser, test and analysis the optical properties of the diffuser under different microstructure.

The objective of this study is to compare the degradation of three strontium-containing calcium phosphate cement (Sr-CPC) and one calcium phosphate cement without strontium (CPC) in vivo. Three Sr-CPCs, containing 1%, 5%, 10% strontium respectively, and a CPC without strontium were tested in this study. The specimens in rod-shape (2 mm  6 mm) were prepared, and were implanted in the erector spine muscle of 15 New Zealand rabbits. After 4, 8 and 12 weeks, 5 rabbits were sacrificed respectively and the specimens were taken out, cleaned, dryed and weighed. The weight losses of the specimens were calculated and the data were analyzed by ANOVA. The results showed that the CPC containing 5%, 10% strontium showed obviously higher degradation rates at the three observation periods than that containing 1% strontium and that without strontium (P<0.05). Addition of 1% strontium into CPC did not increase degradation rate (P>0.05), and the CPC containing 5% and 10% strontium showed no difference in degradation rate at the three observation periods (P>0.05).

The aim of this investigation is to study the effect of SnO coatings on the bond strength between titanium and porcelain. The coatings were produced by sol-gel method and heat-treatment at 300°C. Once the coatings have been formed on the titanium substrates, self-made porcelain was fused. The specimens with pre-oxidation before porcelain fused were set as control group. It was shown SnO gel formed completely at 300°C and was composed by SnO and SnO2 in the form of a uniform film. The bond strength between titanium and porcelain of the specimens with SnO coatings was greater than those in control group statistically, which might prove that the coatings reduced the oxidation of titanium surface in the porcelain fusing progress. EDS result showed almost all fractures between titanium and porcelain occurred at the oxide layer. Si and Sn might attend the reaction at interface. It was concluded that the SnO coatings produced in this study can improved the titanium-porcelain bond strength.

Partially sintered zirconia ceramics (PSZCs) for dental uses were prepared from zirconia nanopowder via isostatic pressing and partially sintering. The open porosities, pore diameters, grain sizes and mechanical properties of the ceramics with different densities were studied. The results show that the pores formed in the PSZCs are all open pores, with a diameter distribution of 60nm~130nm and a grain size distribution of 120~170nm. The machinability becomes worse when the density of PSZC is higher than 75% of the theoretical density, so a ceramic named PSZC-70% with density of 70%TD was selected as the target material. Its bending strength is 168 MPa and fracture toughness is 1.8 MPa·m1/2. A dental restoration framework can be obtained via machining the PSZC-70% on a dental CAD/CAM system.