A microscopic investigation of enamel in wombat (Vombatus ursinus)

Summary A study of the enamel of continuously growing Vombatus ursinus molars was carried out using the techniques of light microscopy, hardness testing, scanning electron microscopy and transmission electron microscopy. From the erupted end to within 8 mm of the growing end, mature enamel was observed and it was found that between comparable areas there were no significant ultrastructural differences in enamel; however, small (12nm diameter), loosely packed needle-like crystals characteristic of developing enamel were observed near the growing end. Mature enamel was found to consist of three optically-translucent regions interleaved with two opaque regions. Opaque enamel was softer than translucent enamel. The opacity and relative softness characteristic of two of the enamel regions was not related to prism pattern or orientation; it was, however, related to the presence of voids (28 nm diameter) in these regions.