Teeth with amelogenesis imperfecta were obtained from three members of the same family, and studied through convergent technics of investigation: classical histology, scanning electron microscopy, high resolution electron microscopy, and crystallographic analysis. The results were compared with theoretical computer calculations. Enamel abnormalities related to the shape and irregular distribution of the crystals. Some needle-shaped crystals were found together with large ones, roughly rectangular. 42% of the crystals were distorted. Widened interplanar spacings were evidence of an hypomineralization. However, the interplanar spacings observed in high resolution electron microscopy, as well as the crystalline degree of the crystals, studied through classical crystallographic methods, revealed an apparently sound hydroxyapatite