Microtensile bond strength of resin composite to dentin treated with Er:YAG laser of bleached teeth.
The objective of this study was to evaluate the influence of Er:YAG laser (λ = 2.94 μm) on microtensile bond strength (μTBS) and superficial morphology of bovine dentin bleached with 16% carbamide peroxide. Forty bovine teeth blocks (7 × 3 × 3 mm(3)) were randomly assigned to four groups: G1- bleaching and Er:YAG irradiation with energy density of 25.56 J/cm(2) (focused mode); G2 - bleaching; G3 - no-bleaching and Er:YAG irradiation (25.56 J/cm(2)); G4 - control, non-treated. G1 and G2 were bleached with 16% carbamide peroxide for 6 h during 21 days. Afterwards, all blocks were abraded with 320 to 600-grit abrasive papers to obtain flat standardized dentin surfaces. G1 and G3 were Er:YAG irradiated. Blocks were immediately restored with 4-mm-high composite resin (Adper Single Bond 2, Z-250-3 M/ESPE). After 24 h, the restored blocks (n = 9) were serially sectioned and trimmed to an hour-glass shape of approximately 1 mm(2) at the bonded interface area, and tested in tension in a universal testing machine (1 mm/ min). Failure mode was determined at a magnification of 100× using a stereomicroscope. One block of each group was selected for scanning electron microscope (SEM) analysis. μTBS data was analyzed by two-way ANOVA and Tukey test (α = 0.05). Mean bond strengths (SD) in MPa were: G1- 32.7 (5.9)(A); G2- 31.1 (6.3)(A); G3- 25.2 (8.3)(B); G4- 36.7 (9.9).(A) Groups with different uppercase letters were significantly different from each other (p < .05). Enamel bleaching procedure did not affect μTBS values for dentin adhesion. Er:YAG laser irradiation with 25.56 J/cm(2) prior to adhesive procedure of bleached teeth did not affect μTBS at dentin and promoted a dentin surface with no smear layer and opened dentin tubules observed under SEM. On the other hand, Er:YAG laser irradiation prior to adhesive procedure of non-bleached surface impaired μTBS compared to the control group.
Leonetti
Eduardo dos Santos
Edos S
Department of Restorative Dentistry, School of Dentistry, Guarulhos University, Praça Teresa Cristina, Guarulhos, SP, Brazil.
Rodrigues
José Augusto
JA
Reis
André Figueiredo
AF
Navarro
Ricardo Scarparo
RS
Aranha
Ana Cecília Correa
AC
Cassoni
Alessandra
A
D000818:Animals; D000077463:Carbamide Peroxide; D002417:Cattle; D003188:Composite Resins / Q000528:radiation effects*; D001840:Dental Bonding; D003743:Dental Enamel / Q000187:drug effects / Q000528:radiation effects; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D010545:Peroxides / Q000494:pharmacology; D019279:Resin Cements / Q000528:radiation effects; D013718:Tensile Strength; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology
D003188:Composite Resins; D010545:Peroxides; D019279:Resin Cements; D000077463:Carbamide Peroxide; D014508:Urea