Abstract

VIEGAS MONTENEGRO, Robinsom et al. Analisis comparativo entre los experimentos mecanicos de cizallamiento y microcizallamiento. Acta odontol. venez [online]. 2008, vol.46, n.4, pp.416-422. ISSN 0001-6365.

The aim of this study was to evaluate comparatively the methodology of micro-shear and shear bond strength using the two available bonding strategies self etching and total etching techniques. Forty bovine incisors were cut and embedded in PVC tubes with acrylic resin. The buccal surfaces were flattened and exposed with SiC paper. For the shear bond strength test, an area of 4mm in diameter was delimited and the adhesive systems were applied according to the manufacturer's instructions. A composite cylinder (Filtek-Z250 - 3M ESPE) of 4mm diameter and 5mm height were built in the area. The samples for microshear were made use of Tygon tubes with 0,7mm in internal diameter in 0,5mm height, using the same composite. Loading were carried out at crosshead speed of 1,0mm/min using an orthodontic wire loop of 0,3mm diameter. The results showed that for shear test the Adper Single Bond presented higher values with statistical significance to Clearfil SE Bond (p=0,037). For the micro-shear test statistical difference was not observed (p=0,780). The samples were submitted to SEM for a fracture pattern classification. For the shear bond test were observed adhesive and dentin cohesive failures for both adhesive systems. For micro-shear bond test were observed a high prevalence of adhesive failures. According to the results it was possible to conclude that micro-shear bond test was more appropriated to evaluate the resistance of bond strength in interface composite/dentin.

Keywords : Resistencia al cizallamiento; Adhesivos Dentinarios; Estudio Comparativo.