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Proceedings Paper

Infrared laser ablation of dental enamel: influence of an applied water layer on ablation rate and peripheral damage
Author(s): Nahal Ashouri; Ramesh K. Shori; Jason M. Cheung; Daniel Fried
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Paper Abstract

Studies have shown that a water spray may augment the laser ablation rate of dental hard tissues in addition to reducing heat accumulation. However, the mechanism of augmentation is controversial and poorly understood. The influence of an optically thick applied water layer on the ablation rate was investigated at wavelengths in which water is a primary absorber and the magnitude of absorption varies markedly. Water was manually applied with a pipette and troughs were cut in enamel blocks using a laser scanning system. Q- switched and free running Er:YSGG and Er:YAG, free running Ho:YAG and 9.6 micrometers TEA CO2 laser systems were investigated. The addition of water increased the rate of ablation and produced a more desirable surface morphology during enamel ablation with all the erbium systems. Ablation was markedly more efficient for the Q-switched erbium lasers than for the longer free-running laser systems when a water layer was added. Although, the addition of a thick water layer reduced the rate of ablation during CO2 laser ablation, the addition of the water removed undesirable deposits of non-apatite mineral phases from the crater surface. There was extensive peripheral damage after irradiation with the Ho:YAG laser with and without added water without effective ablation of enamel. The results of this study suggest that water augments the ablation of dental enamel by aiding in the removal of loosely attached deposits of non-apatite mineral phase from the crater surface, thus producing a more desirable crater surface morphology. The non-apatite mineral phase interfere with subsequent laser pulses during erbium laser irradiation reducing the rate of ablation and their removal aids in maintaining efficient ablation during multiple pulses irradiation.

Paper Details

Date Published: 27 April 2001
PDF: 7 pages
Proc. SPIE 4249, Lasers in Dentistry VII, (27 April 2001); doi: 10.1117/12.424498
Show Author Affiliations
Nahal Ashouri, Univ. of California/San Francisco (United States)
Ramesh K. Shori, Univ. of California/Los Angeles (United States)
Jason M. Cheung, Univ. of California/San Francisco (United States)
Daniel Fried, Univ. of California/San Francisco (United States)

Published in SPIE Proceedings Vol. 4249:
Lasers in Dentistry VII
Peter Rechmann D.D.S.; Daniel Fried; Thomas Hennig, Editor(s)

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