title: CO2 laser irradiation enhances CaF2 formation and inhibits lesion progression on demineralized dental enamel-in vitro study.
abstract: This study evaluated if Carbon dioxide (CO2) (λ 10.6 μm) laser irradiation combined with acidulated phosphate fluoride gel application (APF gel) enhances "CaF2" uptake by demineralized enamel specimens (DES) and inhibits enamel lesion progression. Thus, two studies were conducted and DES were subjected to APF gel combined or not with CO2 laser irradiation (11.3 or 20.0 J/cm(2), 0.4 or 0.7 W) performed before, during, or after APF gel application. In study 1, 165 DES were allocated to 11 groups. Fluoride as "CaF2 like material" formed on enamel was determined in 100 DES (n = 10/group), and the surface morphologies of 50 specimens were evaluated by scanning electron microscopy (SEM) before and after "CaF2" extraction. In study 2, 165 DES (11 groups, n = 15), subjected to the same treatments as in study 1, were further subjected to a pH-cycling model to simulate a high cariogenic challenge. The progression of demineralization in DES was evaluated by cross-sectional microhardness and polarized light microscopy analyses. Laser at 11.3 J/cm(2) applied during APF gel application increased "CaF2" uptake on enamel surface. Laser irradiation and APF gel alone arrested the lesion progression compared with the control (p < 0.05). Areas of melting, fusion, and cracks were observed. CO2 laser irradiation, combined with a single APF application enhanced "CaF2" uptake on enamel surface and a synergistic effect was found. However, regarding the inhibition of caries lesion progression, no synergistic effect could be demonstrated. In conclusion, the results have shown that irradiation with specific laser parameters significantly enhanced CaF2 uptake by demineralized enamel and inhibited lesion progression.
authors.affiliation: Department of Pediatric Dentistry-Piracicaba Dental School, University of Campinas (UNICAMP), Av. Limeira 901, Piracicaba, São Paulo, 13414-903, Brazil.
authors.forename: Bruna R
authors.initials: BR
authors.lastname: Zancopé
authors.affiliation: Department of Pediatric Dentistry-Piracicaba Dental School, University of Campinas (UNICAMP), Av. Limeira 901, Piracicaba, São Paulo, 13414-903, Brazil.
authors.forename: Lívia P
authors.initials: LP
authors.lastname: Rodrigues
authors.affiliation: Department of Pediatric Dentistry-Piracicaba Dental School, University of Campinas (UNICAMP), Av. Limeira 901, Piracicaba, São Paulo, 13414-903, Brazil.
authors.forename: Thais M
authors.initials: TM
authors.lastname: Parisotto
authors.affiliation: Department of Pediatric Dentistry-Piracicaba Dental School, University of Campinas (UNICAMP), Av. Limeira 901, Piracicaba, São Paulo, 13414-903, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Steiner-Oliveira
authors.affiliation: Faculty of Pharmacy, Dentistry and Nursing-Federal University of Ceará, Rua Alexandre Baraúna 949, Fortaleza, 60430-160, Ceará, Brazil.
authors.forename: Lidiany K A
authors.initials: LK
authors.lastname: Rodrigues
authors.affiliation: Department of Pediatric Dentistry-Piracicaba Dental School, University of Campinas (UNICAMP), Av. Limeira 901, Piracicaba, São Paulo, 13414-903, Brazil. nobre@fop.unicamp.br.
authors.forename: Marinês
authors.initials: M
authors.lastname: Nobre-dos-Santos
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000494:pharmacology; D002124:Calcium Fluoride / Q000378:metabolism* / Q000494:pharmacology; D059248:Chemoradiotherapy; D003731:Dental Caries / Q000628:therapy*; D003743:Dental Enamel / Q000187:drug effects / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D005782:Gels; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000187:drug effects / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D017001:Tooth Demineralization / Q000628:therapy*
chemical_list: D005782:Gels; D000149:Acidulated Phosphate Fluoride; D002124:Calcium Fluoride
keywords: Acidulated phosphate fluoride; CO2 laser; Dental caries; Dental enamel