title: Shear strength of the bond to primary dentin: influence of Er:YAG laser irradiation distance.
abstract: The aim of this study was to assess in vitro the influence of Er:YAG laser irradiation distance on the shear strength of the bond between an adhesive restorative system and primary dentin. A total of 60 crowns of primary molars were embedded in acrylic resin and mechanically ground to expose a flat dentin surface and were randomly assigned to six groups (n = 10). The control group was etched with 37% phosphoric acid. The remaining five groups were irradiated (80 mJ, 2 Hz) at different irradiation distances (11, 12, 16, 17 and 20 mm), followed by acid etching. An adhesive agent (Single Bond) was applied to the bonding sites, and resin cylinders (Filtek Z250) were prepared. The shear bond strength tests were performed in a universal testing machine (0.5 mm/min). Data were submitted to statistical analysis using one-way ANOVA and the Kruskal-Wallis test (p<0.05). The mean shear bond strengths were: 7.32 ± 3.83, 5.07 ± 2.62, 6.49 ± 1.64, 7.71 ± 0.66, 7.33 ± 0.02, and 9.65 ± 2.41 MPa in the control group and the groups irradiated at 11, 12, 16, 17, and 20 mm, respectively. The differences between the bond strengths in groups II and IV and between the bond strengths in groups II and VI were statistically significant (p<0.05). Increasing the laser irradiation distance resulted in increasing shear strength of the bond to primary dentin.
authors.affiliation: Department of Pediatric Clinics, Preventive and Social Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, S/N, Monte Alegre, CEP: 14040-904, Ribeirão Preto, SP, Brasil.
authors.forename: Camila
authors.initials: C
authors.lastname: Scatena
authors.forename: Carolina Paes
authors.initials: CP
authors.lastname: Torres
authors.forename: Jaciara Miranda
authors.initials: JM
authors.lastname: Gomes-Silva
authors.forename: Marta Maria Martins Giamatei
authors.initials: MM
authors.lastname: Contente
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Regina Guenka
authors.initials: RG
authors.lastname: Palma-Dibb
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Borsatto
mesh_terms: D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D003804:Dentin / Q000502:physiology* / Q000528:radiation effects*; D017220:Dentin-Bonding Agents; D006801:Humans; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008422:Materials Testing; D008963:Molar / Q000502:physiology / Q000528:radiation effects; D033081:Shear Strength
chemical_list: D017220:Dentin-Bonding Agents