Apatite crystallite alignment in sound human tooth enamel studied by E.S.R.

The degree of microcrystal alignment in enamel of clinically sound upper and lower central incisors, canines and premolars was determined by means of electron paramagnetic resonance. The results show that the degree of alignment depends on the individual properties of the enamel as determined by biological variations, tooth morphology and tooth position. Upper incisors and canines have a much higher degree of crystallite alignment as compared to all other teeth investigated. These results indicate that the caries susceptibility of tooth enamel is not defined only by the degree of microcrystal alignment.