Resumo

BENGTSON, Camilla Regina Galvão; AZEVEDO, Daniel Silva  e  TURBINO, Miriam Lacalle. Influence of resin increment thickness on microtensile bond strength to bovine enamel. RPG, Rev. pós-grad. [online]. 2010, vol.17, n.3, pp. 138-142. ISSN 0104-5695.

The purpose of this study was to investigate the relationship between microtensile bond strength to enamel and increment thickness. Thirty bovine incisors (n=10) were used for this investigation. Enamel surfaces were flattened with decreasing grit silicon carbide papers. They were sectioned in 10 mm x 8 mm specimens. Each dental fragment was included in acrylic resin before microtensile bond strength tests. The enamel surfaces were bonded with a total-etching adhesive system and composite resin blocks were built up over treated surfaces, according the groups. Group 1: 4 increments of 1mm light activated for 40 seconds each increment; Group 2: 2 increments of 2 mm light activated for 80 seconds each increment and Group 3: 1 increment light activated for 160 seconds. Samples were vertically sectioned, obtaining specimens with 1.0 mm² cross-sectional area. Specimens were stressed in tension at 0.5 mm/min crosshead speed. Bond strength results were evaluated using ANOVA (p<0.05). No statistically significant differences of bond strength values were found between groups (p=0,9831 e f=0,0180). We concluded that the difference in increment thickness of composite resin and the probably difference in degree of conversion did not influence tensile bond strength values in 1, 2 and 3 mm thickness when used the same total time of light curing.

Palavras-chave : Adhesiveness; Dentin-bonding agents; Composite resins.