DIFERENTES ÁREAS ADESIVAS AFETAM A RESISTÊNCIA DE UNIÃO AO MICROCISALHAMENTO

The smaller the surface area, the greater is the resistance. Specimens with small surface area have a better stress distribution and a reduction in the number of internal faults. Bonding resistance to micro-shearing of specimens with two different diameters, 0.55 mm and 0.76 mm, were analyzed. Forty Suprinity ceramic slices, 1.3 mm thick, polished by file #600, were randomly divided into two groups (n=20). Four adhesive areas in each slice were delimited by adhesive tape and fixed to circular matrixes. Specimens were conditioned with hydrofluoric acid 5% (FGM) for 20 s, washed, dried, silanized (RelyX Ceramic Primer - 3M ESPE) and dried by air jet. Matrixes were filled with resinous cement RelyX U200 3M ESPE and photopolymerized for 100 s. After 24 h in de-ionized water at 37o C, the specimens underwent micro-shearing test at 0.5 mm/min. Normal and homogeneous data were submitted to ANOVA for totally randomized assay, with no significant difference (p=0.62) between the two areas under analysis – 23.74±4.49 and 24.85±4.41, respectively for areas 0.55 and 0.76 mm. Results show that no bonding resistance to micro-shearing exists when different adhesive areas are employed.