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Journal of Biomedical Optics • Open Access

Femtosecond laser ablation of enamel
Author(s): Quang-Tri Le; Caroline Bertrand; Rui Vilar

Paper Abstract

The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14  J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14  J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3(PO4)2, at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel’s hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

Paper Details

Date Published: 22 June 2016
PDF: 8 pages
J. Biomed. Opt. 21(6) 065005 doi: 10.1117/1.JBO.21.6.065005
Published in: Journal of Biomedical Optics Volume 21, Issue 6
Show Author Affiliations
Quang-Tri Le, Instituto Superior Técnico (Portugal)
Institut de Chimie de la Matière Condensée de Bordeaux (France)
Caroline Bertrand, Institut de Chimie de la Matière Condensée de Bordeaux (France)
Rui Vilar, Instituto Superior Técnico (Portugal)

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