Clinical, radiographic, and histological study of endodontically treated retained roots to preserve alveolar bone

Endodontically treated, submerged roots in two Macaca speciosa monkeys were studied clinically, radiographically, and histologically. The roots were successfully covered by soft tissue, except in two areas. In several sites, radiographic evidence of bone formation was observed; this was confirmed by histologic examination. Bone formation coronal to the submerged roots was not a predictable occurrence. Even though epithelium and inflammation commonly occurred over the amputation sites, their presence did not seem to affect bone formation.