title: Effect of CO2 laser on root caries inhibition around composite restorations: an in vitro study.
abstract: The aim of the present study was to investigate the in vitro effect of CO2 laser on the inhibition of root surface demineralization around composite resin restorations. For this purpose, 30 blocks obtained from human molar roots were divided into three groups: group 1 (negative control), cavity prepared with cylindrical diamond bur + acid etching + adhesive + composite resin restoration; group 2, cavity prepared with cylindrical diamond bur + CO2 laser (5.0 J/cm(2)) + acid etching + adhesive + composite resin; and group 3, cavity prepared with cylindrical diamond bur + CO2 laser (6.0 J/cm(2)) + acid etching + adhesive + composite resin. After this procedure, the blocks were submitted to thermal and pH cycling. Root surface demineralization around the restorations was measured by microhardness analysis. The hardness results of the longitudinally sectioned root surface were converted into percentage of mineral volume, which was used to calculate the mineral loss delta Z (ΔZ). The percentage of mineral volume, ΔZ, and the percentage of demineralization inhibition of the groups were statistically analyzed by using analysis of variance and Tukey-Kramer test. The percentage of mineral volume was higher in the irradiated groups up to 80 μm deep. The ΔZ was significantly lower in the irradiated groups than in the control group. The percentage of reduction in demineralization ranged from 19.73 to 29.21 in position 1 (50 μm), and from 24.76 to 26.73 in position 2 (100 μm), when using 6 and 5 J/cm(2), respectively. The CO2 laser was effective in inhibiting root demineralization around composite resin restorations.
authors.affiliation: School of Dentistry, Cruzeiro do Sul University (UNICSUL), Av. Dr. Ussiel Cirilo, 225, 08060-070, São Paulo, Brazil.
authors.forename: Jociana Bandeira
authors.initials: JB
authors.lastname: de Melo
authors.forename: Fernando Seishim
authors.initials: FS
authors.lastname: Hanashiro
authors.forename: Washington
authors.initials: W
authors.lastname: Steagall
authors.forename: Miriam Lacalle
authors.initials: ML
authors.lastname: Turbino
authors.forename: Marinês
authors.initials: M
authors.lastname: Nobre-dos-Santos
authors.forename: Michel Nicolau
authors.initials: MN
authors.lastname: Youssef
authors.forename: Wanessa Christine
authors.initials: WC
authors.lastname: de Souza-Zaroni
mesh_terms: D003188:Composite Resins; D003793:Dental Restoration, Permanent / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D054020:Lasers, Gas / Q000627:therapeutic use*; D008903:Minerals / Q000032:analysis; D008963:Molar; D017213:Root Caries / Q000517:prevention & control* / Q000532:radiotherapy
chemical_list: D003188:Composite Resins; D008903:Minerals