Permanent teeth in hypophosphatasia: light and electron microscopic study.

The changes in a permanent central incisor of a patient suffering from hypophosphatasia, were investigated light microscopically and compared with those of two of his primary teeth. In addition his other central incisor was studied with transmission and scanning EM. The changes in permanent teeth were similar to those of the primary dentition, including loss of cementum and the presence of deep resorption areas in dentin. Afibrillar cementum was detected with EM, and was attached to dentin surface. The presence of a thick layer of bacterial plaque was a prominent feature in all the teeth examined. A large number of bacteria was also found in resorption bays. It is suggested that bacteria may play an important role in the destruction of soft and hard tissues leading to loss of teeth in hypophosphatasia.