Objectives: This study was conducted to evaluate the effect of sodium hypochlorite pre-treatment on dentin bond strength of two one-bottle etch&rinse adhesives. Methods: Two dental adhesives were selected: Prime&Bond NT (PBNT) and XP Bond (XP). 6% sodium hypochlorite (NaOCl) and 10-15% sodium hypochlotrite were used. Extracted human molars were wet ground to expose flat surfaces using 320 and 600 grit abrasive paper. After acid-etch and rinse, dentin was treated with sodium hypochlorite solution for various duration and then rinsed for 30”. Adhesives were applied and light-cured per manufacturers' instructions. TPH3 composite was loaded to gelatin capsule, placed onto tooth surface and light-cured. Specimens were stored in 37°C water for 24-hr. Shear bond strength (SBS) was obtained with Instron 4400 at crosshead speed of 1 mm/min. The data was analyzed with ANOVA (n=6, a=0.05, Tukey HSD test). Results: Mean values for SBS (MPa) with standard deviations are listed below:
Time (s) | 0 | 15 | 30 | 60 | 120 | 300 | |
6% NaOCl | PBNT | 15.4± 2.3A | 4.1±1.3B | 4.8±1.1B | 5.6±1.1B | 15.6±2.8A | 16.7±3.0A |
XP | 16.3±2.9A | 8±4.1B | 10.2±2.1B | 5.9±1.4B | 4.7±0.6B | 16.9±4.7A | |
10-15% NaOCl | PBNT | 15.4±2.3B | 20.1±2.9A | 15.7±3.0B | 20±1.6A | 10.4±2.0C | 8.6±1.3C |
XP | 16.3±2.9A | 11.6±3.7B | 8.6±3.4BC | 13.1±1.3AB | 6.9±1.9C | 6.8±1.1C | |
*Within the same row, groups connected by the same letter are not significantly different.
Conclusion: In general, treatment of demineralized dentin with NaOCl may significantly affect bond strength. The actual effect is dependent on adhesive systems, concentrations of NaOCl and duration of treatment.