| Abstract: | We report on the application of Laser Induced Breakdown Spectroscopy(LIBS) technique to the study of Ca, P, Zn and Sr evolutions for adult caries-affected teeth using nanosecond laser pulses. The aim of this work is to better understand the behaviors of Zn and Sr as trace-elements in the caries eruption with respect to the behaviors of one of the main compounds of the hydroxyapatite crystal which is the calcium. The study was focused on the investigation of these elements' evolutions from three parts of the enamel surfaces of twenty two adult caries-affected teeth; the healthy part, the dental plaque part and the caries-affected part. The decrease rates of Zn, Sr and P was, also, compared to the Ca one. Comparison concerned normalized emission line intensities. For every species, normalization was done relatively to the emission line intensities of the healthy part. Results showed that abundances of these elements decrease similarly from the healthy parts to the affected-caries parts. The higher decrease rate was noticed for the calcium. The evolutions of Zn and Sr for the three parts of the teeth surfaces cannot inform about the substitution of the calcium by these trace-elements, however the comparison of their decrease rates to the calcium one can be considered as a valuable index of this substitution. |
