Microstructure and mineral concentration of primary and permanent teeth

OBJECTIVE: to determine variations in enamel and dentin microstructure and calcium (Ca) and phosphorus (P) concentrations from primary and permanent molars at specific areas in relation to dentin enamel junction (DEJ). METHODS: 12 freshly-extracted non-carious primary and permanent molars were sectioned. Following polishing, sections were examined in scanning election microscope (SEM) and energy-dispersive x-ray spectrometry (EDS) at five locations: enamel surface, enamel-DEJ, dentin-DEJ, central dentin and pulp dentin. RESULTS: analysis of enamel microstructure indicated that prisms in primary teeth are smaller and more numerous than in permanent teeth; primary dentinal microstructure showed that tubular density decreased with distance from the DEJ in comparison with permanent dentin, and there was a corresponding decrease in peritubular width, and a larger diameter of tubules at pulp area. EDS indicated lower Ca and P concentrations in primary teeth at all locations. CONCLUSIONS: differences in the microstructure and mineral concentration of primary dentin as compared to permanent dentin were showed with location. Such differences may be important factors in restorative protocol, caries progression, susceptibility to trauma, and tooth sensitivity.