PTHの間歇的投与がラット脛骨に埋入されたインプラント周囲の骨量と骨質に与える影響

Objectives: Intermittent injection of parathyroid hormone (PTH) is used to treat osteoporosis. The concept of bone quality was updated 20 years ago; however, these updates have not been adopted in implant dentistry. This study aimed to investigate the effects of intermittent administration of PTH on bone quality around implants in rat tibiae. Methods: Grade IV-titanium-threaded implants that were 3.5 mm long and 2.0 mm wide were placed in a randomly selected side of the proximal tibiae of 12-week-old female Wistar rats. Three weeks after implant placement, the rats were randomly divided into PTH-administration and saline-injection groups (PTH and VC, respectively; n = 7 per group). Micro-computed tomographical, histomorphometric, and immunohistochemical analyses were performed to evaluate bone quality and quantity surrounding the implants. Results: PTH significantly increased bone volume and bone mineral density in bones not associated with the implants as compared to these values in the VC group. PTH significantly increased bone area and the amount of collagen within the total inside areas of all implant threads compared to that observed in VC. Moreover, PTH significantly increased the number of osteoblasts, osteocytes, and osteoclasts in the total inside and/or outside areas of all implant threads and altered the ratio of type I and III collagen to total collagen fibers. Conclusions: Within the limitations of this study, intermittent administration of PTH improved both bone quantity and bone quality based on the types and numbers of bone cells and the types of collagen fibers surrounding implants placed into rat tibiae.長崎大学学位論文 学位記番号:博(医歯薬)甲第1258号 学位授与年月日:令和2年6月3日Author: Yusuke Uchida, Shinichiro Kuroshima, Yusuke Uto, Riho Kanai, Maaya Inoue, Masayoshi Suzue, Takashi SawaseCitation: Journal of Oral Biosciences, 62(2), pp.139-146; 2020Nagasaki University (長崎大学)課程博