IMPACT OF DENTIN CONDITIONING ON SHEAR BOND STRENGTH OF SELF-ADHESIVE RESIN CEMENT

Statement of the Problem: The clinical success of fixed dental prosthesis depends on the bond strength between the prepared tooth and the luting cement.
Purpose: To estimate the bond strength of self-adhesive resin cement to dentin of prepared teeth using different conditioning methods.
Materials and Methods: Mandibular first molars (n=32) periodontally compromised and indicated for extraction were collected after patient consent from oral surgery department, Faculty of Dentistry, Mansoura University. Flat dentin surfaces were prepared and treated as follows: (1) no pretreatment of dentin (T-NT) control group; (2) self-etching bonding agent (T-SEB); (3) Dentin conditioning agent (polyacrylic acid) (T-PA) (4) Ethylenediaminetetraacetic acid (EDTA) (T-ED). Self-adhesive resin cement (SuperCem), was used to lute discs of composite on conditioned prepared teeth surfaces. Specimens were stored in distilled water at 37˚C for 24 hours after that thermal cycling was performed between 5°C and 50°C in distilled water with a dwell time of 1 minute (Theromocycler, Robota, Alexandria, Egypt) for 10.000 cycles. Shear bond strength (SBS) was measured in MPa using a universal testing machine at a crosshead speed of 0.5 mm/min. Scanning electron microscope (SEM) was used for failure modes examination.
Results: SPSS (22) was used for statistical analysis. One-way ANOVA and Tukey tests were used for comparing data at (p=0.001). The highest mean SBS (MPa) was reported for group T-SEB (3.9 MPa), while the lowest mean SBS value was observed for group T-NT (2 MPa). There was no statistically significant difference between group T-SEB (3.9 MPa) and group T-PA (3.3 MPa). Also there was no statistically significant difference between the other two test groups (T-NT=2 MPa, T-ED=2.6 MPa) (P>0.05). On the other hand there was statistically significant difference between group T-NT (2 MPa) and groups T-SE and T-PA groups (P<0.05).
Conclusion: Conditioning of prepared dentin using self-etching adhesive or polyacrylic acid significantly increased the bond strength of self-adhesive resin cement.