Chemical Changes of Enamel Occlusal Surfaces Affected by Incipient Dental Caries: an EDX Study

The aim of this study is to assess the quantitative ions changes in enamel occlusal surfaces affected by white-spot and brown-spot dental caries. Energy dispersive X-rays analysis (EDX) has been used for qualitative and quantitative chemical analysis of 30 enamel samples (10 sound enamel samples, 10 white-spot enamel samples, 10 brown-spot enamel samples). For samples with white-spot and brown-spot carious lesions, the mean percentages of calcium and phosphorus ions were considered. The statistical study used test t for independent samples. P-values less than 0.05 were considered to be statistically significant. It was recorded a significant decrease of calcium and phosphorus ions levels for enamel surfaces associated with whitespot and brown-spot lesions, comparing with sound enamel (p < 0.05). The highest decrease of calcium ions mean values was recorded for white-spot enamel surfaces (from 51.21 wt% in sound enamel samples to 28.37 wt% in white-spot enamel samples). The same decreasing trend was recorded for phosphorus ions between sound enamel samples and brown-spot and white-spot enamel samples (from 20.36 wt% in sound enamel surfaces to 17.88 wt% for white-spot enamel surfaces and 18.60 wt% for brown-spot enamel surfaces). The study proved the existance of significant mineral loss in white-spot carious lesions and brownspot carious lesions comparing with sound enamel. White-spot carious lesions also present significant Ca, P ions loss comparing with brown-spot carious lesions.