Impact of beta-tricalcium phosphate on preventing tooth extraction-triggered bisphosphonate-related osteonecrosis of the jaw in rats

Antiresorptive or antiangiogenic drugs can cause medication-related osteonecrosis of the jaw that is refractory. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) may be caused by procedures such as tooth extraction damage the alveolar bone, release bisphosphonates (BPs) and impede healing. This study investigated strategies for BRONJ prevention and molecular mechanisms of its onset. We assessed the effectiveness of filling extraction sockets with beta-tricalcium phosphate (β-TCP). Rats were administered zoledronic acid (ZA) 1.2 mg/kg once per week for 2 weeks, and a molar was extracted. They were randomly assigned to the β-TCP group (bone defects filled with 0.01 g of β-TCP) or control group. Tissue content measurements indicated 2.2 ng of ZA per socket in the β-TCP group and 4.9 ng in the control group, confirming BP distribution and BP adsorption by β-TCP in vivo. At 4 weeks after extraction, the β-TCP group had normal mucosal coverage without inflammation. Moreover, at 8 weeks after extraction, enhanced bone healing, socket coverage, and new bone formation were observed in the β-TCP group. Connective tissue in the extraction sockets suggested that local increases in BP concentrations may suppress the local autophagy mechanisms involved in BRONJ. Filling extraction sockets with β-TCP may prevent BRONJ.