The polarized light microscopy and ultrastructure of Polynesian pigmented tooth enamel

Abstract

Transmitted and polarized light microscopy of unerupted and erupted teeth affected by a pigmented anomaly found in two geographically isolated Polynesian populations, the New Zealand Maori and the French Polynesian Marquesas Islander, showed similar histological characteristics. Mounted in water, the pigmented areas were positively birefringent and covered with a thin negatively birefringent surface layer 200-250 μm thick. Cervical areas were negatively birefringent. Transmission electron microscopy of argon-ion-beam thinned specimens of affected enamel revealed large voids, disruption in the packing of crystals and spacing at prism boundaries. In the surface layer of enamel from erupted and..