[The factors influencing the flexural strength of zirconia ceramic restorations].

Zirconia material has a very broad application prospect in prosthodontics,and restorations made of zirconia through CAD/CAM technology have been applied widely in recent years. In this paper we summarized the features of zirconia material which used for all ceramic restorations and the factors which affected its flexural property. We also sated the relevant indicators and methods used for evaluation of flexural property of zirconia material in order to lay a basis for its clinical use.

[The experimental research of the influence of cervical settling method on marginal accuracy of wax patter].

Objective: To study the influence of cervical settling method on marginal accuracy of wax patters.

Methods: 24 wax patterns were made on the standard cast specimens and round capsules of which twelve patters were made with the method of cervical settling (experiment group), twelve patters were made with the method of wax dripping (control group). Marginal accuracy of patterns were measured before sublation, sublation half an hour and twenty-four hours.

[Research advances of adult stem cells and dental stem cells].

Human stem cells have a major effect in the development of human bodies. Acting as an in vitro model, human stem cells have a great value in the study of the mechanism of individual development and in the cell-replacement treatments and gene therapy of tissue deficiency diseases. The study of stem cells has been given rise to a keen interests in the bio-medical area at present.

[The test of metal-ceramic bonding strength among three ceramic alloies].

Purpose: To compare the metal-ceramic bonding strength of different ceramic alloies.

Methods: 30 wax sheets were divided into 6 groups at random. Each group included 5 sheets.

[A study on the rate of collagenase in the degradation of human root dentin in vitro].

Objective: The purpose of this study was to evaluate the effect of degradation of human root dentin collagen treated with collagenase after demineralization.

Methods: The root dentin samples were demineralized by incubating with PH5.0 lactate acid at 37 degrees C.

[Experimental study of the effect on marginal seating of the castings by different investing methods].

Objective: The purpose of this study was to observe the effect on marginal seating of the castings with and without ring investments.

Methods: Standarded as-cast specimens and round capsules simulated post tooth crowns were made. 12 wax pattern were prepared on the as-cast specimens.

[Clinical effects of three systems of dental implants].

Objective: To evaluate the clinical value of dental implants including Brånemark, Steri-oss and BLB systems.

Methods: The total 384 implants of different materials and shapes were inserted normally. According to the Chinese standard of dental implantation, the success rates of three types were compared.