EFFECT OF HEMA-CONTAINING DENTIN DESENSITIZERS ON SHEAR BOND STRENGTHOF A RESIN CEMENT

Purpose: To determine whether the use of two HEMA-containing dentin de sensitizing agents [Health-Dent Desensitizer with fluoride (H) or Glum a Desensitizer (G)], when applied at simulated ''cavity preparation'' and ''cementation'' appointments, affects the bond strength of lab pro cessed 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 t o 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 appoi ntment (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 w ere used according to manufacturers' instructions to cement pre-polyme rized 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 Tuk ey'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 significant ly higher than all groups except for GG. Results of this in vitro stud y indicate that the use of desensitizers at the preparation and/or cem entation appointment does not interfere with bond strengths of resin c ement to dentin.