1428 Effect of Home-bleaching on Shear Bond Strength to Enamel

G.C. LOPES, T. MICHELON, L.C.C. VIEIRA, and L.N. BARATIERI, Universidade Federal de Santa Catarina, Florianópolis SC, Brazil

Objective: The purpose of this in vitro study was to evaluate shear bond strengths of a total-etch one-bottle adhesive system to enamel submitted to home-bleaching with three differents agents.

Methods: Forty human molars were mounted, polished to 600-grid and randomly assigned to 4 groups (n=10) according to home-bleaching agent: 10% carbamide peroxide (RE.Rembrandt, Den-Mat), oxygen-free hidroxilite-based agent (HL.Hi-Lite II, Shofu) and polyethylene-strip whitening system containing 5.3% hydrogen peroxide (HP.Whitestrips, Procter&Gamble). The control group was kept in artificial saliva (control). Bleaching procedure was performed 8-hours day (except for HP, in which it was performed 30'a.m. and 30'p.m) for 2 weeks. After bleaching diary time, the specimens were rinsed and maintained in fresh artificial saliva, changed daily. After bleaching, a total-etch one-bottle adhesives system (SingleBond, 3M ESPE)] was applied on the enamel surfaces, the hybrid resin (FiltekZ-250, 3M ESPE) inserted in a #5 gelatin capsule and ligth-cured. After 24 h, the shear bond strength was performed with an Instron at 5mm/min. The data were analyzed with one-way ANOVA and Duncan Post hoc.

Results: The SBS were [mean (±SD)]: RE=28.0±10.6ab; HL=27.6±9.0ab; HP=23.6±7.2b ; control=31.4±4.5a . Superscript letters indicate Duncan's homogeneous subsets.

Conclusion: Bleaching with 10% Carbamide Peroxide and an oxygen-free agent had no effect on SBS to enamel. On the other hand, bleaching with 5.3% hydrogen peroxide strip resulted in reduced SBS to enamel.

Seq #154 - Technical/Environmental/Surface Conditioning Effects 11:00 AM-12:15 PM, Friday, 27 June 2003 Svenska Massan Exhibition Hall B