Internal root resorption is the progressive destruction of intraradicular dentin and dentinal tubules along the middle and apical thirds of the canal walls as a result of clastic activities.The prevalence, etiology, pathogenesis, histologic manifestations, differential diagnosis with cone beam computed tomography, and treatment perspectives involved in internal root resorption are reviewed.The majority of the documentation that exists in the literature is in the form of case reports, and there are only a limited number of studies that attempted to examine the histologic manifestations and biologic aspects of the disease. This might be due, in part, to the relatively rare occurrence of this type of resorption and the lack of an in vivo model, apart from the previous attempt on the use of diathermy, to predictably reproduce the condition for study. From a histologic perspective, internal root resorption is manifested in one form that is purely destructive, internal (root canal) inflammatory resorption, and another that is accompanied by repair, internal (root canal) replacement resorption that is featured by the deposition of metaplastic bone/cementum-like tissues adjacent to the sites of resorption.From a differential diagnosis perspective, the advent of cone beam computed tomography has considerably enhanced the clinician's capability of diagnosing internal root resorption. Nevertheless, root canal treatment remains the treatment of choice for this pathologic condition to date.