IADR Abstract Archives
Impact of Ovariectomy on Alveolar Bone Repair
Objectives: Most implants are placed into adults >50yo, whose bone healing potential may be compromised. To model age-related bone loss, we generated ovariextomized (OVX) rats then directly tested whether the resulting decline in bone density compromised alveolar bone repair.
Methods: Three experimental groups were examined: young (2mo) rats, aged (>12mo) rats and young rats that underwent OVX. Micro-CT analyses were conducted on all three groups. In the young and young+OVX groups maxillary first molars (M1) were extracted. Eight weeks later, osteotomies were created using two drill speeds in the healed M1 site. Tissues were collected at post-osteotomy days 1 and 7 then processed for molecular and cellular analyses.
Results: Compared to young rats, micro-CT imaging of long bones confirmed that aged and young+OVX rats both showed a significant loss in bone volume/total volume (BV/TV). Micro-CT analyses of alveolar bone, however, failed to demonstrate any significant differences in BV/TV among the experimental groups. Changes in craniofacial bone micro-architecture may be difficult to quantify; therefore, we used histology and histomorphometric analyses to determine whether an osteoporotic phenotype compromised alveolar bone repair. Initially there were no discernable differences in healing responses between the young and the young+OVX groups. On day 7, however, a dramatic change was observed. While osteotomies created in young rats were filled with new bone those created in the young+OVX group showed no evidence of repair.
Conclusions: Micro-CT analyses verified a reproducible decline in long bone mineral density following OVX surgery in rats; a similar decline was not observed in the alveolar bone from the same experimental groups. While drill speeds had minimal effect on the amount of new alveolar bone formed after osteotomy, OVX did. These data have relevance when considering the expected bone healing capacity in an elderly human population.
Methods: Three experimental groups were examined: young (2mo) rats, aged (>12mo) rats and young rats that underwent OVX. Micro-CT analyses were conducted on all three groups. In the young and young+OVX groups maxillary first molars (M1) were extracted. Eight weeks later, osteotomies were created using two drill speeds in the healed M1 site. Tissues were collected at post-osteotomy days 1 and 7 then processed for molecular and cellular analyses.
Results: Compared to young rats, micro-CT imaging of long bones confirmed that aged and young+OVX rats both showed a significant loss in bone volume/total volume (BV/TV). Micro-CT analyses of alveolar bone, however, failed to demonstrate any significant differences in BV/TV among the experimental groups. Changes in craniofacial bone micro-architecture may be difficult to quantify; therefore, we used histology and histomorphometric analyses to determine whether an osteoporotic phenotype compromised alveolar bone repair. Initially there were no discernable differences in healing responses between the young and the young+OVX groups. On day 7, however, a dramatic change was observed. While osteotomies created in young rats were filled with new bone those created in the young+OVX group showed no evidence of repair.
Conclusions: Micro-CT analyses verified a reproducible decline in long bone mineral density following OVX surgery in rats; a similar decline was not observed in the alveolar bone from the same experimental groups. While drill speeds had minimal effect on the amount of new alveolar bone formed after osteotomy, OVX did. These data have relevance when considering the expected bone healing capacity in an elderly human population.