THE ABSENCE OF CORRELATIONS BETWEEN A CLINICAL CLASSIFICATION AND ULTRASTRUCTURAL FINDINGS IN AMELOGENESIS IMPERFECTA

This study was performed to examine whether a clinical classification of different phenotypes of amelogenesis imperfecta could be discernibl e at the ultrastructural level. Seventeen primary teeth from 16 childr en with hypomineralization, hypomaturation, or hypoplastic variants of the disease were collected for histologic studies of the enamel by me ans of polarized light microscopy, scanning electron microscopy (SEM), and secondary ion mass spectrometry (SIMS). Polarization microscopy s howed that the enamel was hypomineralized; in six teeth a wavy configu ration of the enamel prisms also appeared. Three histomorphologic main types could be discerned. In 10 of the teeth extensive hypomineraliza tion of the bulk of the enamel was found. One tooth had an unusually t hick enamel with only a thin normally mineralized surface layer. SIMS images showed less pronounced signals from Ca2+ and Na+ but with stron ger signals from Cl- and CN-, representing the organic component of en amel. The SEM images showed an irregular prism pattern with marked int erprismatic areas. Irrespective of the clinical appearance or the here ditary pattern the main findings were hypomineralized enamel with or w ithout wavy bands. Neither of the analytical methods used in this pape r distinguishes between the clinical phenotypes of amelogenesis imperf ecta.