[Dental study of hypophosphatasic child].

Hypophosphatasia is a hereditary disease characterized by congenital deficiency of tissue alkaline phosphatase. One of its dental features is the shedding of teeth. We have experienced a case which was referred to our clinic with the chief complaints of loss and shedding of lower deciduous central incisors and was diagnosed to be highly suspected of hypophosphatasia as a result of hematological examination at the pediatric clinic. As a result of close systemic and dental examination and further study of changes in the course for two and a half years, the following findings were obtained: 1. Low serum alkaline phosphatase level and hypercalcemia were the systemic findings of the disease. 2. There was no delayed ossification in terms of carpal bone age. 3. X-ray cephalography revealed no particular cephalic abnormality, except the lack of development of frontalis and mandibular. 4. Dental findings comprised marked resorption of upper alveolar bone in the front teeth area and pronounced instability of front deciduous teeth. 5. As for changes in oral symptoms, extraction of A because of pronounced instability was followed by spontaneous shedding of A. About one year later, A was extracted because of marked instability. At the time of this writing, A was slightly instable without any abnormality in the other teeth. 6. Pathohistological study of the extracted teeth disclosed only a little resorption of cement of root apex and dysgonic periodontium without any marked tissue changes.