Results of longitudinal radiographic and clinical studies of 65 anterior maxillary and mandibular simple root fractures and of a study of six of these fractures have revealed that the integrity of the periodontal membrane is the essential requisite in root repair; that cementum will be found at the two fractured ends of the segments if other factors necessary for root repair are present; that the pulp is not necessary for root repair; that the prognosis for midroot and apicai fractures is more favorable than for cervical fractures; and that the prognosis for vertical fractures is unfavorable. The practicat applications of this study support the conservative and preventive approach to treatment—most simple root fractures are reparable and the fractured teeth need not necessarily be extracted.