Validation of an Osteoporotic Animal Model for Dental Implant Analyses: An In Vivo Densitometric Study in Rabbits

Purpose: The achievement of primary stability in porous and soft bone, where implants are more likely to fail, is one of the unresolved challenges of implant dentistry. Therefore, the aim of the study was to validate an osteoporotic animal model for analysis of poor-quality bone. Materials and Methods: Sixteen female New Zealand rabbits, each 6 months old and weighing 4 to 5 kg, were used in this study. The animals were anesthetized, and an in vivo densitometric analysis was performed by dual-energy x-ray absorptiometry (DEXA) to measure bone mineral density (BMD) in the calvaria, cervical spine, and tibia. Ovariectomy was then performed, and animals were fed a low-calcium diet that featured 0.07% calcium, rather than the 0.45% calcium of a standard diet, for 6 weeks. After this period, new densitometric measurements were carried out. Two-way analysis of variance was used for statistical evaluation. A P value of less than .05 was considered to be significant. Results: Together, ovariectomy and a low-calcium diet were able to induce a quick decrease in BMD, as measured at 6 weeks by DEXA. This decrease was statistically significant in the calvaria (P .001) and the cervical spine (P .05) but not in the tibia. Conclusion: Based upon this study, ovariectomy and a low-calcium diet are able to induce experimental osteoporosis in rabbits in a short period of time. Parole chiave: animal model, bone mineral density, dental implant, dual-energy x-ray absorptiometry, osseointegration, osteoporosis, rabbit