Effects of parathyroid hormone on the microarchitecture and bone remodeling of alveolar bone under physiologic mastication forces: An in vivo study in dogs

Abstract

Abstract Background This study investigates the anabolic effects of intermittent parathyroid hormone (PTH) administration on alveolar bone under physiological mastication force. Methods Three mongrel dogs were each injected once weekly for 20 weeks with vehicle (CON), 1.6 µg/kg PTH (PTH1.6), or 3.2 µg/kg PTH (PTH3.2). Bone density and maxillary alveolar trabecular bone remodeling were evaluated through bone microarchitectural and histomorphometric analyses using micro-computed tomography (micro-CT), fluorescence labeling, and hematoxylin and eosin (H&E) staining. Results Micro-CT showed that bone mass and density increased with increasing occlusal force in all subjects. Trabecular bone volume and bone mineral density increased significantly in the PTH1.6 subject but decreased in the PTH3.2 subject when compared to the control subject. Fluorescence labeling showed that new bone formation was the greatest in the PTH1.6 subject, followed by the PTH3.2 and CON subjects. In all subjects, new bone formation increased with increasing occlusal forces. H&E staining revealed no significant differences in the number of osteoclasts and osteoblasts according to PTH dose or occlusal force. Conclusions Our results showed that moderate doses of PTH had greater anabolic effects than high doses. Furthermore, bone density and formation were enhanced with stronger occlusal forces.