Hereditary amelogenesis imperfecta. I. Epidemiology and clinical classification in a Swedish child population.

This study was performed in order to classify different hereditary enamel defects and to estimate their prevalence in a Swedish population. 425,000 children 3-19 years of age were screened in the Public Dental Service for suspected hereditary enamel defects in a well-defined region of Sweden. 182 of the 193 affected children were available for a thorough examination performed by one of the authors. 105 (58%) of these children could be diagnosed as Hereditary Amelogenesis Imperfecta (H.A.I.). 62 (34%) children exhibited enamel defects not related to H.A.I. and in 15 (8%) children no definite diagnosis could be made concerning H.A.I. The group of children diagnosed as H.A.I. could be classified into 12 different clinical subgroups based on two basic types, the hypoplastic and the hypomineralized. 63 of the 105 children showed the hypoplastic type of H.A.I. and 42 the hypomineralized type of H.A.I. Hypomineralized areas of the teeth were a common secondary finding in the hypoplastic type of H.A.I. Usually clinical signs of hereditary enamel defects could be identified both in the primary and in the permanent dentition. The prevalence of H.A.I. in the population studied was estimated to be 1 in 4,000.