External radicular resorption: selected cases and review of the literature.

External radicular resorption is a pathological process that generates the loss of cementum, dentin and bone, almost irreversibly, involving vital and pulpless teeth. The early stage is asymptomatic and might be diagnosed by a routine radiograph or a clinical examination. Radicular resorption appears because of cementoclastic, dentinoclastic or/and osteoclastic activity. The process of resorption is associated with a damage of the periodontal ligament as a result of injury and necrosis, macrophages are the first cells that are detected, followed by multinucleated cells, odontoclasts, which affect the cementum and dentin.