Effect of parathyroid hormone (1-34) on early bone healing of sinus augmentation in healthy rabbit

Abstract

Purpose: This study evaluated effect of administering intermittent parathyroid hormone [PTH (1-34), henceforth PTH] on early-stage bone healing of maxillary sinus augmentation and compared two different schedules of PTH administration in healthy rabbit. Materials and Methods: Bovine bone mineral was grafted on sinuses of 25 female New Zealand white rabbits. The animals were randomly divided into three groups: PTH (n =10); PTH was injected subcutaneously 5 days a week for 2 weeks and killed at 2 weeks (n=5) or 4 weeks (n=5) postoperatively, Saline (n=10); saline was injected and killed as same amount and schedule as the PTH group, PTH_mod (PTH modified interval, n=5); PTH was injected 2 days a week for 4 weeks and killed at 4 weeks postoperatively. The dosage of PTH was 10 µg/kg/day. Radiographic and histomorphometric analyses were performed. Result: The new bone area (NBA) did not differ significantly among the saline, PTH and PTH_mod groups. The NBA in the PTH group in the total augmented area and in the demarcated window, center, and Schneiderian membrane regions increased significantly from 2 to 4 weeks. The number of osteoclasts decreased significantly from 2 to 4 weeks in the saline and PTH groups, with no difference between the two groups. The PTH_mod group had larger number of osteoclasts than the saline and PTH groups in the Schneiderian membrane region. Osteocalcin was expressed in the PTH and PTH_mod groups and not in the saline group. Conclusion: Intermittent PTH might not stimulate new bone formation in healthy rabbits during the first 4 weeks of healing. In the PTH group, the consistency of NBA was increased at 4 weeks.