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Proceedings Paper

Debris screening and heat diffusion in Er:YAG drilling of hard dental tissues
Author(s): Boris Majaron; Dusan Sustercic; Matjaz Lukac
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Paper Abstract

A systematical investigation of Er:YAG laser drilling of both human dentin and enamel with pulselengths between 50 microsecond(s) and 1.2 ms is presented. At the shorter pulselengths, the influence of heat diffusion is negligible. Consequently, ablation of tissue starts abruptly at a well-defined fluence value, which is independent of the pulselength. Depths and volumes of the resulting craters show a quasi-logarithmical dependence on the applied laser fluence. An improved analytical model of the laser beam screening by the ejected debris is developed, which fits well to the experimental data. With longer laser pulses, ablation turns up only gradually, with differential ablation efficiency slowly increasing with applied laser fluence. Such double-threshold behavior is explained by a simple model of dynamical interplay between the ablation front and heat-diffusion wave. The model enables us to derive expressions for pulselength and laser fluence ranges in which such behavior should be expected for any combination of tissue and laser properties. Also, it predicts qualitatively the amount of thermal side effects in a general laser ablation process.

Paper Details

Date Published: 15 May 1997
PDF: 12 pages
Proc. SPIE 2973, Lasers in Dentistry III, (15 May 1997); doi: 10.1117/12.273593
Show Author Affiliations
Boris Majaron, Jozef Stefan Institute/Univ. of Ljubljana (Slovenia)
Dusan Sustercic, Univ. Dental Clinic/Univ. of Ljubljana (Slovenia)
Matjaz Lukac, Jozef Stefan Institute/Univ. of Ljubljana (Slovenia)


Published in SPIE Proceedings Vol. 2973:
Lasers in Dentistry III
Harvey A. Wigdor; John D. B. Featherstone; Peter Rechmann, Editor(s)

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