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Journal of Biomedical Optics • Open Access

Pulsed laser ablation of dental calculus in the near ultraviolet

Paper Abstract

Pulsed lasers emitting wavelengths near 400 nm can selectively ablate dental calculus without damaging underlying and surrounding sound dental hard tissue. Our results indicate that calculus ablation at this wavelength relies on the absorption of porphyrins endogenous to oral bacteria commonly found in calculus. Sub- and supragingival calculus on extracted human teeth, irradiated with 400-nm, 60-ns laser pulses at ≤8  J/cm 2 , exhibits a photobleached surface layer. Blue-light microscopy indicates this layer highly scatters 400-nm photons, whereas fluorescence spectroscopy indicates that bacterial porphyrins are permanently photobleached. A modified blow-off model for ablation is proposed that is based upon these observations and also reproduces our calculus ablation rates measured from laser profilometry. Tissue scattering and a stratified layering of absorbers within the calculus medium explain the gradual decrease in ablation rate from successive pulses. Depending on the calculus thickness, ablation stalling may occur at <5  J/cm 2 but has not been observed above this fluence.

Paper Details

Date Published: 18 February 2014
PDF: 9 pages
J. Biomed. Opt. 19(2) 028003 doi: 10.1117/1.JBO.19.2.028003
Published in: Journal of Biomedical Optics Volume 19, Issue 2
Show Author Affiliations
Joshua E. Schoenly, Univ. of Rochester (United States)
Wolf D. Seka, Univ. of Rochester (United States)
Peter Rechmann, Univ. of California, San Francisco (United States)

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