[Effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys].

OBJECTIVE: To investigate the effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys in vitro. METHODS: The bond strength of coating-substrate interface sintered at different temperatures (300, 400, 500, 600 degrees C) was tested by scratching method. The Sol-Gel coating was analyzed by scanning electron microscope (SEM), and its corrosion resistance was assessed by a static immersion method. RESULTS: The bond strength of coating-substrate interface reaches the peak at 400 degrees C. The Sol -Gel coating can apparently inhibit the release of metal ions and improve the corrosion resistance of nickel-chromium alloy. CONCLUSION: Sol-Gel coating can evidently improve corrosion resistance of the nickel-chromium alloy, which has great potential in prospective clinical practice.

[The experimental study on biodegradable gel membrane applied to prevention of postoperative adhesion of abdominal cavity surgery].

OBJECTIVE: To develop a new type of anti-adhesion gel membrane and explore its applying technique. METHODS: 24 adult New Zealand white rabbits were used for the experiment research project, the animals were divided into two groups: the experiment group (18 adult New Zealand white rabbits) and the control group (6 adult New Zealand white rabbits). The animal models were established via the abdominal cavity. The biodegradable gel membrane was covered to the surface of the operating region in experimental animal group, while the 0.9% NaCL was directly rinsing the operating region in the controlled group. The specimens were collected at postoperatively week 2, 4 or 8 respectively. The samples were evaluated by global and histological observation. RESULTS: In the experiment group, a few adhed zones were observed in 2 and 4 weeks after operation, but in 8 weeks after operation, the adhesion zone was disappeared. In the control group, a few adheol zones were founded in 2 weeks after operation. In 4 weeks after operation, the adhed zone become conspicuously emerged. In 8 weeks after operation, the cicatri band was occurred. CONCLUSION: The biodegradable gel membrane usd into the postoperative abdominal cavity is effective and easy to manipulate, and it could be used as a high-effect, cheap drug of anti-adhesion in operation for surgeons.

[The study of cell biocompatibility of new pattern biphasic calcium phosphate nanocomposite in vitro].

OBJECTIVE: To study the cell biocompatibility of porous biphasic calcium phosphate nanocomposite in vitro. METHODS: Bone marrow mesenchymal cell (BMSCs) obtained from SD rat bone marrow were in vitro induced and proliferated. Afler their osteoblast phenotypes were verified, BMSCs were seeded onto prepared porous biphasic calcium phosphate nanocomposite (Experiment group) and common porous hydroxyapatite (Control group). The cell adhesion was evaluated by scanning electron microscope. Synthesis of alkaline phosphatase enzyme (ALP) and osteocalcin were detected and cell cycle was detected by flow cytometry. RESULTS: BMSCs could fully attach to and extend on the material in experiment and control group, Moreover, experiment group were superior to control group in adhesion, proliferative abilities and osteogenic activity. CONCLUSION: BMSCs can differentiate to osteoblast phenotype; the porous biphasic calcium phosphate nanocomposite as bone tissue engineering scaffold has good cell biocompatibility.

[Mode of new bone formation following distraction osteogenesis in mandibular lengthening].

OBJECTIVE: To investigate the mode and influential factor of new bone formation following distraction osteogenesis in mandibular lengthening. METHODS: Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custom-made distractor was used to lengthen the mandible at a rate of 1 mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectively at 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology. RESULTS: Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that distractor loosed. CONCLUSION: The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.