Method: Forty extracted human molars were used. The crowns were separated from the roots 1mm below cervical line, then crowns were cut in a buccolingual direction, so eighty samples were obtained. The samples were divided into four groups (20 each): sodium hypochlorite, chlorhexidine, combination between sodium hypochlorite and sodium ascorbate and the control group (no irrigation). Each group was subdivided into two subgroups (10 each), where the universal single bond was applied as total etching adhesive technique and self etching adhesive technique. The composite resin was cured, the samples were stored for 24h at 37c and the shear bond test was performed by universal testing machine.
Result: The results showed that, the self-etch with NaOCl had the statistically significantly highest mean shear bond strength (P <0.05), while total-etch with NaOCl + sodium ascorbate showed the statistically significantly lowest mean shear bond strength.
Conclusion:
Dentin pretreatment with sodium hypochlorite improved the shear bond strength of self etch technique of universal single bond. Using sodium ascorbate after sodium hypochlorite adversely affects the shear bond strength on using the total etch technique of universal single bond.