Synergistic effects of intermittent parathyroid hormone (1-34) and masticatory force for alveolar bone remodeling in the maxilla of dogs.

INTRODUCTION

Parathyroid hormone (PTH) is a key regulator of calcium homeostasis and bone remodeling. While intermittent PTH (1-34) (teriparatide) is an established treatment for osteoporosis, its effects on alveolar bone regeneration remain unclear. This study evaluated intermittent PTH (1-34) impact on the microstructure and remodeling of canine maxillary alveolar bone under physiological masticatory force.

METHODS

In this exploratory pilot study, three male mongrel dogs were each assigned to a single dose group (n = 1 per group) and injected weekly for 20 weeks with vehicle (CON), 1.6 μg/kg PTH (PTH1.6), or 3.2 μg/kg PTH (PTH3.2). Bone microarchitecture and remodeling were assessed using micro-computed tomography (micro-CT), fluorescence labeling, and hematoxylin and eosin (H&E) staining.

RESULTS

Micro-CT revealed bone mass and density increased with higher occlusal force in all groups. Trabecular bone volume and mineral density were higher in PTH1.6 than in controls, whereas PTH3.2 values were lower than controls; given n = 1 per group, these differences are reported as individual-animal observations without statistical inference. Fluorescence labeling demonstrated the greatest new bone formation in PTH1.6. H&E staining showed no apparent differences in osteoclast or osteoblast numbers among those groups.

CONCLUSION

In this pilot large-animal model, moderate-dose intermittent PTH (1-34) administration was associated with greater alveolar anabolic response than higher-dose administration, and the magnitude of response appeared to increase with regional masticatory loading. These hypothesis-generating observations warrant confirmatory studies in appropriately powered cohorts. Optimizing PTH dosing and considering mechanical loading is critical for effective alveolar bone regeneration in the dental medicine scenarios.