Premium
Non‐destructive assessment of inhibition of demineralization in dental enamel irradiated by a λ = 9.3‐µm CO 2 laser at ablative irradiation intensities with PS‐OCT
Author(s) -
Can Anna M.,
Darling Cynthia L.,
Ho Chi,
Fried Daniel
Publication year - 2008
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.20633
Subject(s) - demineralization , enamel paint , laser , materials science , fluoride , irradiation , fluence , optical coherence tomography , optics , chemistry , composite material , physics , nuclear physics , inorganic chemistry
Background and Objective Polarization sensitive optical coherence tomography (PS‐OCT) has great promise for the non‐destructive assessment of the efficacy of anti‐caries agents such as fluoride and thermal laser treatments on enamel surfaces. The purpose of this study was to demonstrate that PS‐OCT can be used to measure demineralization in craters/incisions prepared in enamel by a CO 2 laser operating at the high irradiation intensities required for cavity preparations. Materials and Methods Incisions in bovine enamel surfaces were produced by a CO 2 laser used with a water spray. The laser was operated at λ = 9.3 µm with a pulse duration of 15 µs and an incident fluence of 20 J/cm 2 . The laser treatments were also combined with topical fluoride treatments. A PS‐OCT system operating at 1,310 nm was used to acquire polarization resolved images of six areas including sound and laser‐ablated+topical fluoride treated zones on each sample. After imaging the teeth, they were sectioned and the thin sections were examined with polarized light microscopy (PLM) and transverse microradiography (TMR). The integrated reflectivity and lesion depth derived from the PS‐OCT scans, the integrated mineral loss and depth measured using TMR and the lesion depth measured with PLM were acquired for each area on the fifteen samples for comparison. Results The integrated reflectivity and depth in the areas treated by the laser and fluoride were significantly lower ( P <0.05) than for the untreated enamel. Similar results were observed for TMR and PLM. Conclusions These results suggest that PS‐OCT has great potential for the non‐destructive “in vivo” assessment of the inhibition of demineralization by lasers at ablative irradiation intensities with and without topical fluoride application. Lesers Surg. Med. 40:342–349, 2008. © 2008 Wiley‐Liss, Inc.