Effects of Different Dentin Surface Cleaning Protocols on Bond Strength of Dual-Cure Resin Cement Following Temporary Cementation.

Objective:  The aim of this study was to compare the effectiveness of various cleaning protocols on the bond strength of dual-cure resin cement following temporary cementation.

Materials And Methods:  Fifty-two human third molars were sectioned to expose superficial dentin and divided into four groups: (1) fresh, noncontaminated dentin (control); (2) pumice cleaning; (3) pumice + sodium bicarbonate air polishing; and (4) pumice + 10-methacryloyloxydecyl dihydrogen phosphate (MDP) based cleaner. Groups 2, 3, and 4 were treated with noneugenol zinc oxide temporary cement, followed by their respective cleaning protocols. After the teeth were cleaned, the restorative procedure was performed. All dentin surfaces were then bonded with a composite restoration using dual-cure resin cement. Shear bond strength was tested using a universal testing machine until failure. Surface morphology was assessed using a scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) was used to analyze the residual elements on the dentin surface.

Statistical Analysis:  Group differences were analyzed using one-way analysis of variance (ANOVA), followed by Tamhane's post hoc test. Chi-squared tests were used to assess the differences in failure mode proportions among groups. All statistical analyses were conducted at a significance level of  < 0.05.

Results:  ANOVA revealed significant differences in bond strength among the groups ( < 0.001). Post hoc analysis showed no significant difference in bond strength between the control group and the sodium bicarbonate air polishing or MDP-based cleaner groups. However, the pumice polishing group exhibited a significantly lower bond strength compared to all other groups ( < 0.001). SEM-EDS analysis confirmed incomplete removal of temporary cement with pumice polishing, as evidenced by residual cement and elevated levels of zinc and oxygen ions.

Conclusion:  Pumice polishing alone was insufficient for removing temporary cement, resulting in reduced bond strength of the subsequently applied resin cement. This study demonstrated that combining pumice with sodium bicarbonate air polishing or MDP-based cleaner effectively removed cement and restored bond strength to levels comparable to fresh, noncontaminated dentin.