纳米羟基磷灰石复合树脂材料细胞毒性及在牙体缺损修复中的应用

Nano-hydroxyapatite/composite resin: cytototoxicity and application in dental restoration

BACKGROUND: It has been found that the compressive strength and flexural strength of nano- hydroxyapatite combined with light-cured resin matrix can neet the requirements of dental restorative materials. OBJECTIVE: To detect the cytotoxicity of nano-hydroxyapatite/composite resin, and to analyze its effects on the dental restoration. METHODS: In vitro test: passage 5 periodontal ligament fibroblast-like cells and L-929 cells suspensions were cultured in the 10%, 50%, 100% of nano-hydroxyapatite/composite resin extracts, respectively, and fresh maintenance medium functioned as negative control group. Absorbance values were detected within 7-day culture. In vivo repair test: 57 cases with tooth defect were enrolled containing 37 males and 20 females aged from 15 to 31 years old, and all were subjected to nano-hydroxyapatite/composite resin treatment. A 3-year follow-up was undergone to detect the completeness, marginal adaptation and color matching of the restoration, as well as the periodontal probing depth, sulcus bleeding index, tooth mobility, dental plaque index, gingival crevicular fluid and aspartate aminotransferase level. RESULTS AND CONCLUSION: In vitro test results showed that the different concentrations of nano- hydroxyapatite/composite resin extracts had no effects on both periodontal ligament fibroblast-like cells and L-929 cells. In vivo repair test results found that after 3 years of follow-up, the periodontal probing depth, sulcus bleeding index, tooth mobility, dental plaque index, gingival crevicular fluid and aspartate aminotransferase level of patients were significantly decreased than those before repair (P < 0.05), but the alkaline phosphatase level revealed no significant change (P > 0.05). Unfortunately, three cases with incomplete restoration, four cases with color mismatching, and three cases with the inadaptable edge occurred. To conclude, the nano-hydroxyapatite/composite resin holds good biocompatibility and no cytotoxicity, which can maintain a good periodontal health condition in the dental restoration.