Osteonecrosis of the jaw (ONJ) is a well-recognized complication of antiresorptive medications, such as
bisphosphonates (BPs). Although ONJ is most common after
tooth extractions in patients receiving high-dose BPs, many patients do not experience oral
trauma. Animal models using
tooth extractions and high BP doses recapitulate several clinical, radiographic, and histologic findings of ONJ. We and others have reported on rat models of ONJ using experimental
dental disease in the absence of
tooth extraction. These models emphasize the importance of dental
infection/
inflammation for ONJ development. Here, we extend our original report in the rat, and present a mouse model of ONJ in the presence of
dental disease. Mice were injected with high dose
zoledronic acid and pulpal exposure of mandibular molars was performed to induce
periapical disease. After 8 weeks, quantitative and qualitative radiographic and histologic analyses of mouse mandibles were done. Periapical lesions were larger in vehicle-treated versus BP-treated mice. Importantly, radiographic features resembling clinical ONJ, including thickening of the lamina dura, periosteal bone deposition, and increased trabecular density, were seen in the drilled site of BP-treated animals. Histologically,
osteonecrosis, periosteal thickening, periosteal bone apposition, epithelial migration, and bone exposure were present in the BP-treated animals in the presence of
periapical disease. No difference in
tartrate-resistant acid phosphatase (TRAP)+ cell numbers was observed, but round, detached, and removed from the bone surface cells were present in BP-treated animals. Although 88% of the BP-treated animals showed areas of
osteonecrosis in the
dental disease site, only 33% developed bone exposure, suggesting that
osteonecrosis precedes bone exposure. Our data further emphasize the importance of
dental disease in ONJ development, provide qualitative and quantitative measures of ONJ, and present a novel mouse ONJ model in the absence of
tooth extraction that should be useful in further exploring ONJ pathophysiological mechanisms.