title: Chemical, morphological and thermal effects of 10.6-microm CO2 laser on the inhibition of enamel demineralization.
abstract: Studies have shown that enamel can be modified by pulsed CO2 laser to form a more acid-resistant substrate. This study evaluated the effects of a 10.6-microm CO2 laser on enamel surface morphology and chemical composition as well as monitored intrapulpal temperature changes during irradiation. Human teeth were irradiated with fluences of 1.5-11.5 J/cm2, and pulpal thermal as well as chemical and morphological modifications on enamel were assessed. The teeth were submitted to a pH-cycling model, and the mineral loss was determined by means of cross-sectional microhardness. For all irradiated groups, intrapulpal temperature changes were below 3 degrees C. FT-Raman spectroscopy and scanning electron microscopy indicated that fluences as low as 6.0 J/cm2 were sufficient to induce chemical and morphological changes in enamel. Then, for fluences reaching or exceeding 10.0 J/cm2, laser-induced inhibitory effects on demineralization were observed. It was thus concluded that laser energy density in the range of 10.0 and 11.5 J/cm2 could be applied to dental enamel in order to produce chemical and morphological changes and reduce the acid reactivity of enamel without compromising the pulp vitality.
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry of Piracicaba, State University of Campinas, São Paulo, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Steiner-Oliveira
authors.forename: Lidiany K A
authors.initials: LK
authors.lastname: Rodrigues
authors.forename: Luís E S
authors.initials: LE
authors.lastname: Soares
authors.forename: Airton A
authors.initials: AA
authors.lastname: Martin
authors.forename: Denise M
authors.initials: DM
authors.lastname: Zezell
authors.forename: Marinês
authors.initials: M
authors.lastname: Nobre-dos-Santos
mesh_terms: D000704:Analysis of Variance; D002245:Carbon Dioxide; D003743:Dental Enamel / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure; D006244:Hardness; D006358:Hot Temperature / Q000627:therapeutic use; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053685:Laser Therapy; D013059:Spectrum Analysis, Raman / Q000379:methods; D018709:Statistics, Nonparametric; D017001:Tooth Demineralization / Q000517:prevention & control*
chemical_list: D002245:Carbon Dioxide