External inflammatory resorption and replacement resorption are complicating factors that may result from traumatic dental injuries when the tooth is luxated or avulsed and replanted. Resorption may, ultimately, result in loss of the tooth. However, with appropriate treatment, the prognosis for these teeth is greatly improved, with the possibility of preventing or arresting resorption. The purpose of this paper is to review these trauma entities, to discuss factors that influence the occurrence of resorption and to describe the most appropriate treatment. A case is presented, illustrating both resorption entities, but with varying outcomes.