Clinical application of laser-induced breakdown spectroscopy to the analysis of teeth and dental materials

Objectives: The luminous plasma generated during laser ablation of dental t issue and dental materials has been analyzed to determine qualitative and q uantitative elemental composition, Background Data: The use of pulsed laser s for controlled material ablation now is frequently suggested as an altern ative to mechanical drilling for the removal of caries and in tooth modific ation. Spectral analysis of the ablated plasma can be exploited to monitor precisely the laser drilling process in vivo and in real time. Methods: Tee th samples and dental materials were ablated using pulses from a Nd:YAG las er. The line positions and intensities in the spectra, recorded in real tim e, were used to identify elements and to determine their relative concentra tions. Results: From the spectra of horizontally and vertically cut tooth s lices, profiles of elemental distribution were determined; these were used in a range of monitoring applications. We showed that the transition from c aries to healthy tooth material could be identified through the decrease in calcium (Ca) and phosphorus (P) concentrations, whereas nonmineralizing el ements and organic materials increased in concentration. We also could rela te the spatial distribution of elements to their migration or accumulation over time, for example, the migration of aluminium (Al) from dental restora tive materials to the tooth matrix. Conclusions: The plasma existing during laser ablation (in vitro/in vivo) can be analyzed spectrally in real time. From the spectra, one can pinpoint high/low levels of element concentratio ns within the tooth matrix. Thus, this analysis could be used to monitor th e ablation of material during laser dental treatment.