Presence of enamel on the lingual surface of rabbit permanent incisors.

Permanent incisors from fetal New Zealand white rabbits aged 25-30 d in utero were processed for light microscopy. Examination of transverse and longitudinal sections of demineralized specimens revealed the development of a complete enamel covering of the incisal tip and an enamel extension on the linguoincisal surface of unerupted teeth, as evidenced by the presence and distribution of ameloblasts, enamel matrix and enamel space. Formation of lingual enamel appeared to be completed within a few days before eruption of the incisor. The transition from the enamel-covered to enamel-free areas coincided with a gradual disintegration of the orderly ameloblast layer. The findings indicate that, histologically, the linguoincisal part of the rabbit permanent incisor is characterized by amelogenesis.