Effect of HEMA-containing dentin desensitizers on shear bond strength of a resin cement

Purpose: To determine whether the use of two HEMA-containing dentin desensitizing agents [Health-Dent Desensitizer with fluoride (H) or Gluma Desensitizer (G)], when applied at simulated ''cavity preparation'' and ''cementation'' appointments, affects the bond strength of lab processed resin composite restorations cemented to dentin. Materials and Methods: The occlusal surfaces of 70 teeth were ground flat to expose dentin and polished to 600 grit. Teeth were randomly assigned to seven groups (n=10). The treatments were applied in two sessions in order to simulate cavity preparation and cementation appointments. Water (W) was applied as a control instead of a desensitizing agent. H or G were applied for 30 seconds with a rubbing motion (1) at preparation appointment (HW and GW), or (2) at cementation appointment, after etching (WH and WG), or (3) at both sessions (HH and GG). In the control group, water was applied at both sessions (WW). All-Bond 2 and Dual Cement were used according to manufacturers' instructions to cement pre-polymerized resin composite cylinders (4 mm diameter) to the dentin surfaces using a force of 1.0 MPa. Specimens were thermocycled 300x and tested in shear until failure. Data was analyzed using one-way ANOVA and Tukey's HSD test at alpha=0.05. Results: Mean bond strength and standard deviations are reported in MPa: GW=7.4 +/- 6.0; WW=7.7 +/- 5.8; HW=8.2 +/- 4.3; WH=10.8 +/- 6.2; GG=13.5 +/- 6.0; HH=13.8 +/- 7.1; WG=19.9 +/- 8.8. There were no significant differences in bond strengths for GW, WW, HW, WH and GG. Shear bond strength for WG and HH was significantly higher than all groups except for GG. Results of this in vitro study indicate that the use of desensitizers at the preparation and/or cementation appointment does not interfere with bond strengths of resin cement to dentin.