Objective:Intermittent administration of parathyroid hormone (PTH) is used to treat osteoporosis by enhancing bone architecture. The purpose of this study was to investigate the detail effects of intermittent administration of PTH on bone quality and quantity around implants in rat tibia.
Methods:The titanium threaded implants were placed in 12-week-old-female wistar rat tibiae, and then, they were randomly divided into two groups at 3 weeks post-implantation; intermittent PTH administration group (80 μg/kg, every other day; PTH) and saline group as a control (vehicle control; VC) (n=7 per group). Rats were euthanized at five weeks after drug administration. Tibiae including placed implants were harvested. Three-dimensional structural, histomorphometric and immunohistochemical analyses were conducted inside and outside areas of implant threads.
Results:Micro-CT analysis showed that intermittent administration of PTH was effective on bone in this study. PTH significantly increased bone mass around implants inside areas of the threads, whereas PTH did not increase it outside area of the threads. PTH significantly increased osteocyte numbers inside area of all threads. PTH increased the number of osteoblasts and osteoclasts inside areas of almost threads, but not outside areas of the threads. Moreover, administration of PTH induced both increased and decreased total collagen amounts inside areas of some threads. On the other hand, it increased type III collagen amounts inside areas of some threads.
Conclusions:Our findings suggests that intermittent administration of PTH has different effects on bone quality in a site-dependent manner. Application of PTH administration may contribute to upregulating bone quality around dental implants in clinical situations.