Tooth resorption is a perplexing problem for all dental practitioners. The etiologic factors are vague, diagnoses are educated guesses, and often the chosen treatment does not prevent the rapid disappearance of the calcified dental tissues. Although the occurrence of resorption cannot always be predicted, resorption can be identified radiographically. However, even this diagnostic tool has limitations because resorption on the buccal or lingual surface of the tooth usually cannot be discerned until 20% to 40 of the tooth structure has been demineralized. The diagnostic dilemma is further compounded by the need to differentiate internal resorption (resorption initiated within the pulp tissue) form external resorption (resorption initiated in the periodontium). Since the etiologic factors, diagnosis, treatment, and prognosis differ for these various types of resorptive defects, the practioner must be able to diagnose resorption radio graphically or clinically, distinguish internal from external resorption, and commence appropriate treatment to halt the resorptive processes.