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Proceedings Paper

Thermal and acoustic problems on root canal treatment with different lasers
Author(s): Thomas P. Ertl; Hartmut Benthin; Gerhard J. Mueller
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Paper Abstract

Side effects of root canal preparation with lasers such as the generation of acoustic shockwaves and heat transfer were investigated. Shockwaves may cause disintegration of root hard substance and too high temperatures may damage the periodontium. Three types of pulsed lasers with different ablation characteristics were chosen for the study. (1) Excimer laser 308 nm/120 ns. (2) Er:YSGG laser 2.78 micrometers /500 microsecond(s) . (3) Nd:YAG laser 1.06 micrometers /180 microsecond(s) . Delivery systems for all lasers were quartz fibers with 400 micrometers core diameter. Canals were pretreated up to size 40 to obtain a comparable root canal shape. The teeth were positioned with the root in chicken egg protein as a heatsink during the laser operation. Shockwaves were measured with a needle hydrophone and visualization of the ablation process was made with high speed flashlamp photography. Temperatures were measured with a fiberoptic device. Results show that lasers with medium pulse length, operating at wavelength highly absorbed by hard and soft tissue, caused minimum side effects. The ablation process with lasers emitting at a low absorbed wavelength rapidly shifts from an initial heat transfer at the beginning of preparation to a noncontrollable ablation and temperature rise when carbonization occurs in the canal. Very short pulsed lasers such as excimer lasers cause stronger shock waves than lasers with a pulse length in the microsecond(s) region. One can conclude that Er:YSGG lasers offer the best ratio between efficiency and side effects.

Paper Details

Date Published: 23 December 1994
PDF: 11 pages
Proc. SPIE 2327, Medical Applications of Lasers II, (23 December 1994); doi: 10.1117/12.197597
Show Author Affiliations
Thomas P. Ertl, Freie Univ. Berlin (Germany)
Hartmut Benthin, Laser-Medizin-Zentrum GmbH (Germany)
Gerhard J. Mueller, Freie Univ. Berlin and Laser-Medizin-Zentrum GmbH (Germany)

Published in SPIE Proceedings Vol. 2327:
Medical Applications of Lasers II
Stephen G. Bown; J. Escourrou; Frank Frank; Herbert J. Geschwind M.D.; Guilhem Godlewski M.D.; Frederic Laffitte; Hans H. Scherer M.D., Editor(s)

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