MATERIALS RESEARCH INNOVATIONS, vol.15, no.3, pp.202-207, 2011 (SCI-Expanded)
The aim of this study is to investigate the effect of different procedures applied to the dentine surface on the cement bonding strength of various resins. Improving the bonding strength between dentine and composite resin usually requires increased surface roughness to promote mechanical interlocking. Ninety-six extracted human non-carious incisor teeth were used. Teeth were separated into six groups. In group I, the dentine surfaces were roughened with a diamond bur in a high speed handpiece at 200 000 rev min(-1) with air/water coolant. In group II, the dentine surfaces were etched with 37% phosphoric acid gel for 10 s. In group III, the dentine surfaces were air abraded for 7 s with 30 mm aluminium trioxide particles at 3 bar pressure. In group IV, the dentine surfaces were sandblasted with 50 mu m aluminium oxide powder using an intraoral sandblasting device. In group V, the samples were irradiated with an Er:YAG laser with a continuous wavelength of 2940 nm. In group VI, the group served as control. The teeth were then bonded with one of the two resin cements according to each manufacturer's instructions and stored in distilled water at 37 degrees C for 24 h. The specimens in each group were tested in shear mode in a screw driven universal testing machine at a crosshead speed of 0.5 mm min(-1). The treated dentine surfaces were photographed with a scanning electron microscope. Analysis of variance showed that the interaction between surface procedures applied to dentine, resin cement type and resin cement type surface procedure was statistically significant (p<0.001). The lowest bonding resistance was determined in the control group and the highest in the specimens abraded using a bur and cemented with Clearfil SA cement, while similar resistances were determined in the other group specimens. Bur abrasion led to the greatest increase in bonding value, while the best bonding effectiveness was obtained in specimens cemented with Clearfil SA cement.