This study examined the color changes of a resin composite with different shades upon exposure to water with different pH.
Nanohybrid resin composites (Filtek Z350XT, 3M ESPE) with four different shades (A2, A3, B1, and B2) were immersed in water with three different pH (pH 3, 6, and 9) for 14 day. The CIE
The resulting change of color of the tested specimens did not appear to be clinically problematic because the color difference was < 1.6 in the acidic, neutral, and alkaline solutions regardless of the resin shade, i.e., the color change was imperceptible.
The purpose of this study was to evaluate the effect of multiple application of all-in-one dentin adhesive system on microtensile bond strength to caries-affected dentin.
Twenty one extracted human molars with occlusal caries extending into mid-dentin were prepared by grinding the occlusal surface flat. The carious lesions were excavated with the aid of caries detector dye. The following adhesives were applied to caries-affected dentin according to manufacturer's directions; Scotchbond™ Multi-Purpose in SM group, Adper Prompt L-Pop™ 1 coat in LP1 group, 2 coats in LP2 group, 3 coats in LP3 group, Xeno® III 1 coat in XN1 group, 2 coats in XN2 group, and 3 coats in XN3 group. After application of the adhesives, a cylinder of resin-based composite was built up on the occlusal surface. Each tooth was sectioned vertically to obtain the 1 × 1 mm2 sticks. The microtensile bond strength was determined. Each specimen was observed under SEM to examine the failure mode. Data were analyzed with one-way ANOVA.
The results of this study were as follows;
1. The microtensile bond strength values were; SM (14.38 ± 2.01 MPa), LP1 (9.15 ± 1.81 MPa), LP2 (14.08 ± 1.75 MPa), LP3 (14.06 ± 1.45 MPa), XN1 (13.65 ± 1.95 MPa), XN2 (13.98 ± 1.60 MPa), XN3 (13.88 ± 1.66 MPa). LP1 was significantly lower than the other groups in bond strength (p < 0.05). All groups except LP1 were not significantly different in bond strength (p > 0.05).
2. In LP1, there were a higher number of specimens showing adhesive failure. Most specimens of all groups except LP1 showed mixed failure.