Dentinal dysplasia is one of the rarest hereditary disturbances of dentin formation characterized by the teeth present with short blunt roots, considerably reduced or obliterated pulp spaces, periapical abscess or cysts without an obvious causative factor, and spontaneous exfoliated. These features were observed on a patient referred for prosthodontic assessment, and an investigation of other members of the family revealed that the father and two siblings were also affected. The report described the clinical, radiographic, histologic and scanning electron microscopic features and discussed the features which separated from dentinogenesis imperfecta.