Asymmetrical tooth defects observed in hypoplastic primary teeth and amelogenesis imperfecta: case reports.

Two rare cases of asymmetrical tooth destruction affecting the primary dentition and 1 case of hypoplastic, vertical striping X-linked amelogenesis imperfecta which affects the permanent dentition in an asymmetrical manner, are presented. The etiology of the conditions are discussed with respect to inheritance, preeruptive and posteruptive influences. The asymmetrical gross tooth destruction reported in the 2 primary dentitions may be multifactorial in origin but genetic influences cannot be excluded. Factors that may disturb ameloblasts and result in their producing hypoplastic enamel include genetic causes, nutritional deficiency, maternal illnesses, birth injury, and trauma (Kreshover et al. 1958). This paper presents 2 unusual cases of tooth destruction and 1 case of hypoplastic amelogenesis imperfecta and discusses the possible reasons for the atypical distribution of defects. Variations in the number and form of teeth are, in general, genetically determined, but modifications may also arise as a result of a number of other influences. For example, the absence of teeth such as lateral incisors or third molars may be an inherited anomaly--as may other conditions such as amelogenesis imperfecta and dentinal dysplasia. On the other hand, pre-eruptive influences such as systemic illnesses or local trauma may result in alteration of the tooth bud components during tooth formation. Dental structures generally are well protected from damaging influences during intrauterine life but children with premature or traumatic births tend to have a higher incidence of dental anomalies in the primary dentition (Rosenzweig and Sahar 1962). Kreshover et al. (1958) examined the prevalence of developmental dental abnormalities in primary teeth and concluded they were more common than previously thought. Microscopic examination of the teeth of both jaws showed a prominent incremental line extending over the incisal and occlusal portions of the deciduous anterior and posterior teeth. Rosenzweig and Sahar (1962) and Kreshover et al. (1958) found that children with hypoplastic teeth had a greater dmf rate than those without hypoplasia and suggested that hypoplastic teeth may be more susceptible to dental caries than normally calcified teeth. Case 1 A 4-year-old Caucasian female was referred to the pedodontic clinic for management of gross enamel erosion and severe wear of the primary teeth on