Beta tricalcium phosphate, either alone or in combination with antimicrobial photodynamic therapy or doxycycline, prevents medication-related osteonecrosis of the jaw.

Surgical trauma in those under a prolonged use of bisphosphonates, can lead to mediation-related osteonecrosis of the jaw (MRONJ). This study aimed to evaluate the preventive therapies for MRONJ. Following four cycles of zoledronic acid administration, Wistar rats had their molar extracted, and were organized into nine treatment groups: negative control group (NCG), treated with saline solution and blood-clot in the alveolus; positive control group (PCG), with blood-clot in the alveolus; BG, ß-tricalcium phosphate-based biomaterial; DG, 10% doxycycline gel; aG, antimicrobial photodynamic therapy; and DBG, aBG, aDG, and aDBG, using combination therapy. After 28 days, the lowest bone volume (BV/TV) was reported in PCG (42.17% ± 2.65), and the highest in aDBG (69.85% ± 6.25) (p < 0.05). The higher values of daily mineral apposition rate were recorded in aDBG (2.64 ± 0.48) and DBG (2.30 ± 0.37) (p < 0.001). Moreover, aDBG presented with the highest neoformed bone area (82.44% ± 2.69) (p < 0.05). Non-vital bone was reported only in the PCG (37.94 ± 18.70%). Owing to the key role of the biomaterial, the combination approach (aDBG) was the most effective in preventing MRONJ following tooth extraction.

Evaluation of Osteoconduction of a Synthetic Hydroxyapatite/ß-Tricalcium Phosphate Block Fixed in Rabbit Mandibles.

(1) Background: This study aimed to evaluate the incorporation of hydroxyapatite/ß-tricalcium phosphate blocks grafted in rabbit mandibles. (2) Methods: Topographic characterization of biomaterial was performed through scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). Ten rabbits randomly received autogenous bone graft harvested from the tibia (Autogenous Group-AG) or synthetic biomaterial manufactured in ß-tricalcium phosphate (Biomaterial Group-BG) at their right and left mandibular angles. Euthanasia was performed at 30 and 60 postoperative days; (3) Results: SEM-EDX showed a surface with the formation of crystals clusters. Histological analyses in BG at 30 days showed a slower process of incorporation than AG. At 60 days, BG showed remnants of biomaterial enveloped by bone tissue in the anabolic modeling phase. Histometric analysis showed that mean values of newly formed bone-like tissue in the AG (6.56%/9.70%) were statistically higher compared to BG (3.14%/6.43%) in both periods, respectively. Immunohistochemical analysis demonstrated early bone formation and maturation in the AG with more intense osteopontin and osteocalcin staining. (4) Conclusions: The biomaterial proved to be a possible bone substitute, being incorporated into the receiving bed; however, it showed delayed bone incorporation compared to autogenous bone.