(1) Dye-stain 1 (excavated until stain free)
(2) Dye-stain 2 (excavated until pale-pink-stained)
(3) Probing (excavated until hard to a sharp probe)
(4) Control (pulpal dentin walls were polished flat)
On dye-stained groups, infected dentin stained with Caries Detector solution (Kuraray Medical, Japan) was removed with a water-cooled low-speed steel round bur. On probing group, infected dentin was removed by bur excavation until the dentin surface became hard to a sharp probe. Prepared dentin was bonded with Clearfil Mega Bond (Kuraray Medical, Japan). Composite build-up was performed with Cleafil DC Core automix (Kuraray Medical, Japan). All specimens were stored in water at 37 °C for 24 hours in darkness and specimen was shaped hourglass configuration with a cross-sectional area of approximately 1mm2 for microtensile testing. The specimens were loaded in a microtensile testing device (AUTOGRAPH AGS-H, Shimadzu, Japan) at a crosshead speed of 1.0 mm/min. Data were analyzed by one-way ANOVA and Tukey's HSD test (p<0.05). Results: Microtensile bond strength was following (MPa):
Dye-stain 1: 47.7±6.4 a
Dye-stain 2: 52.3±5.9 a
Probing: 71.1±9.8 b
Control: 71.9±8.2 b
Different letters indicate statistically significant difference.
Conclusion: The caries removal technique affected the microtensile bond strength. Probing group showed higher tensile strength than used the solution group.