A mouse model of inflammatory root resorption induced by pulpal infection

Objective. The present study was undertaken to determine the frequency and extent of apical root resorption associated with induced periradicular lesions in mice. Study design. Bone and root resorption was quantified by using two- and three-dimensional micro-computed tomography (mu-CT) in the lower first molars of mice subjected to pulp exposure and infection. Results. mu-CT measurements showed significant apical resorption in exposed and infected teeth, resulting in an average distal root shortening of 12.7% (P < .001 vs unexposed). These findings were confirmed with three-dimensional reconstituted images that showed thinning and shortening of the distal root. Tartrate-resistant acid phosphatase clastic cells were associated with resorption lacunae on the cememtum of root apices, as well as on bone at the periphery of the periradicular lesions. Brown and Brenn staining showed the presence of bacteria in dentinal tubules adjacent to resorbed cementum. Conclusions. Apical root resorption is a prominent and consistent finding associated with periradicular infection in the mouse. This species represents a convenient model for studying the pathogenesis of inflammatory root resorption in vivo.