Preventive effect of teriparatide on medication-related osteonecrosis of the jaw in rats

This study aimed to investigate the preventive effect of teriparatide (TPD) administration on medication-related osteonecrosis of the jaw (MRONJ) before tooth extraction due to periodontal lesions in bilaterally ovariectomized female rats treated with zoledronic acid. Thirty skeletally mature Sprague-Dawley rats were randomly divided into three groups: control (CONT, n = 10), zoledronic acid (ZA, n = 10), and zoledronic acid and teriparatide (ZA-TPD, n = 10). The rats were sacrificed 8 weeks after tooth extraction. Micro-computed tomography analysis of the tibia showed that bone mineral density was highest in the CONT, followed by that in the ZA and ZA-TPD groups (CONT/ZA, p = 0.009; CONT/ZA-TPD, p < 0.001; ZA/ZA-TPD, p < 0.001). In the trabecular bone analysis of the extraction site, significant differences in specific bone surface (CONT/ZA, p = 0.010; CONT/ZA-TPD, p = 0.007; ZA/ZA-TPD, p = 0.002) and trabecular thickness (CONT/ZA-TPD, p = 0.002; ZA/ZA-TPD, p = 0.002) were observed. Histological analyses of the extraction sites revealed characteristic MRONJ lesions in the ZA group. Osteonecrosis, inflammatory cells, and sequestrum were less frequently observed in the ZA-TPD group than in the ZA group. In conclusion, TPD administration before tooth extraction helped reduce the occurrence of MRONJ in rats treated with zoledronic acid, confirming its preventative effects.