title: Shear bond strength of repairs in porcelain conditioned with laser.
abstract: The aim of this study was to evaluate the shear bond strength of repairs in porcelain conditioned with laser. Sixty porcelain discs were made and six groups were formed (n = 10): G1: conditioning with laser with potency 760 mW; G2: conditioning with laser with potency 760 mW and application of 37% phosphoric acid for 15 s; G3: conditioning with laser with potency 900 mW; G4: conditioning with laser with potency 900 mW and application of 37% phosphoric acid for 15 s; G5: application of 37% phosphoric acid for 15 s (group control) and G6: application of 10% hydrofluoric acid for 2 min. The composite resin was insert of incremental layers at the porcelain surface aided with a metal matrix, and photoactivation for 20 s each increment. The specimens were submitted to a thermal cycling by 1000 cycles of 30 s in each bath with temperature between 5 and 55°C. After the thermal cycling, specimens were submitted to the shear bond strength. The results were evaluated statistically through analysis of variance and Tukey's tests with 5% significance. The averages and standard deviation founded were: G1, 11.25 (±3.10); G2, 12.32 (±2.65); G3, 14.02 (±2.38); G4, 13.44 (±2,07); G5, 9.91 (±2,18); G6, 12.74 (±2.67). The results showed that the femtosecond laser produced a shear bond strength of repairs in porcelain equal to the hydrofluoric acid and significantly superior to the use of phosphoric acid.
authors.affiliation: Department of Dental Materials and Prostheses, Ribeirão Preto School of Dentistry, University of São Paulo, São Paulo, Brazil. hamilton@forp.usp.br
authors.forename: Hamilton
authors.initials: H
authors.lastname: Pedrazzi
authors.forename: Cristina Yoshie Garcia
authors.initials: CY
authors.lastname: Takeuchi
authors.forename: Sabrina Spinelli
authors.initials: SS
authors.lastname: Cioffi
authors.forename: Marília Regalado
authors.initials: MR
authors.lastname: Galvão
authors.forename: Marcelo Ferrarezi
authors.initials: MF
authors.lastname: De Andrade
authors.forename: Osvaldo Luiz
authors.initials: OL
authors.lastname: Bezzon