Dentinogenesis imperfecta, also known as hereditary opalescent dentin, is a dentin development disorder with autosomal dominant transmission that affects both the primary and permanent dentition. A case is reported of a family in which the mother and her 6- and 20- year-old children were diagnosed with dentinogenesis imperfecta type II. The mouths of these patients illustrate the progressive deterioration of affected teeth if not adequately treated. The treatment of the 6-year-old son is described, and therapeutic approaches to this disorder in primary and permanent dentition are reviewed. This family exemplifies the need for the earliest possible diagnosis and treatment of dentinogenesis imperfecta to prevent extensive deterioration of the dentition and occlusion. Keywords: dentinogenesis imperfecta, complications, hereditary opalescent dentin, pathology, pediatric dentitry, tooth rehabilitation