The microcrystal alignment in human tooth enamel from carious and non-carious teeth in relation to caries susceptibility.

The degree of microcrystal alignment in the intact enamel from carious and non-carious upper incisors, lower incisors and upper canines was determined by means of electron paramagnetic resonance. The results show that a low degree of alignment is not a generally valid indication for caries-susceptibility. Upper canines have a high degree of crystallite alignment whereas lower incisors have a relatively low one. With the exception of the upper central incisors no differences in microcrystal alignment are found between the intact enamel from carious and non-carious lower incisors and upper canines. These results indicate that a possible caries-susceptibility of tooth enamel reflected by low R-values is not solely determined by the degree of microcrystal alignment.