RESUMO
PURPOSE: To observe the effect of subcutaneous ectopic osteogenesis using different proportional mixtures of hydroxyapatite (HAP) and human mandible in nude mice. METHODS: After obtaining external oblique ridge of mandible, autologous bone was mixed with HAP according to certain proportion. The mixtures were divided into 5 groups (group A: autologous bone/HAP=2/1; Group B: autologous bone/HAP=1/1; Group C: autologous bone/HAP=1/2; Group D: autologous bone/HAP=a quarter; Group E: HAP). The 5 groups of mixtures were respectively implanted into nude mice subcutaneously. After 8 weeks, the specimens were obtained and hard tissue sections were completed. The new bone formation was measured after trinitrophenol staining. The data was analyzed with SPSS 13.0 software package. RESULTS: The hard tissue section showed that new ectopic bone formation area was 9.1% (Group A), 16.1% (Group B), 6.1% (Group C), 3.8% (Group D), and 1.3% (Group E), respectively. New bone formation was the most in group B, while it was the least in group E. Significant differences were found between group B and other groups(P<0.05). However, there was no significant difference between group E and group C or D (P>0.05). The retention rate of HAP was the most in group E (30.3%) and the least (16.3%) in group A. CONCLUSIONS: During 8 weeks, human autologous bone mixed with HAP helps new bone formation in nude mice. The best ratio autologous bone and HAP was 1:1. This study provides certain reference basis for dentist to make lifting surgery outside the maxillary sinus using artificial bone graft. Supported by Science and Technology Project of Ningxia Hui Autonomous Region (2011zys271).