15 May 1997 Debris screening and heat diffusion in Er:YAG drilling of hard dental tissues
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Proceedings Volume 2973, Lasers in Dentistry III; (1997) https://doi.org/10.1117/12.273593
Event: BiOS '97, Part of Photonics West, 1997, San Jose, CA, United States
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.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Boris Majaron, Dusan Sustercic, Matjaz Lukac, "Debris screening and heat diffusion in Er:YAG drilling of hard dental tissues", Proc. SPIE 2973, Lasers in Dentistry III, (15 May 1997); doi: 10.1117/12.273593; https://doi.org/10.1117/12.273593
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