IADR Abstract Archives
Resin Composite Thickness Affects Resin Cement Adhesion Performance to Dentin
Objectives: To evaluate the effect of resin composite material thickness on shear bond strength (SBS) and nanoleakage (NL) of a chemically-cured self-etching adhesive/dual-cured resin cement system.
Methods: For SBS, 100-bovine permanent anterior teeth were used. Subsequent to teeth grinding and creation of standardized dentin smear layer, teeth were randomly divided into four experimental groups (n=25 teeth/group). For groups 1, 2 and 3 (light curing groups), seventy-five pre-cured resin composite cylinders (CeramX SphereTEC, Dentsply Sirona, Germany) of 4mm diameter x 2mm, 4mm and 6mm thicknesses respectively were cemented to dentin using a chemically-cured self-etching adhesive/dual-cured resin cement system (Tokuyama Universal Bond/Estecem II, Tokuyama Dental Corp. Japan) and light cured (40s/each cylinder) from their top surfaces using LED unit (1600mW/cm2, Radii Plus, SDI, Australia). In group 4 (co-cure group), twenty-five pre-cured cylinders (4mmx2mm) were cemented and left to cure chemically (10min) under 500g load. Specimens were stored (48h) in 100% relative humidity. The SBS test was run at a crosshead speed of 0.5 mm/min. Failure modes were examined under Stereomicroscope (16x, SMZ 745T, Nikon, Japan). For NL, 12 bovine teeth were randomly divided into 4 groups (n=3 teeth/group) as for SBS. For light curing groups, 9 pre-cured resin composite discs of 7mmx2mm, 7mmx4mm, 7mmx6mm were cemented to dentin and light cured (40s/each disc). For co-curing group, 3 pre-cured cylinders (7mmx2mm) were cemented and left to cure chemically (10min) under 500g load. After storage (48h), specimens were immersed in silver nitrate/developer solution and were examined using SEM (ESEM, Quanta 250 FEG, FEI company, Netherlands). Statistical analysis was performed using One-Way ANOVA/Turkey’s HSD test for comparison (P=0.05).
Results: For SBS, 2mm(10.5±4.5 MPa)=4mm(11.6±4.4MPa)=6mm(9.4±3.8MPa)>co-cure(5.3±4.2MPa). Cohesive failure (0%), adhesive failure (72%) and mixed failure (28%). For NL, 2mm(0.0±0.0%)Conclusions: Light curing was crucial to achieve high SBS values regardless to material thickness. Decrease material thickness improved the integrity of adhesive/resin cement/dentin interface.
Methods: For SBS, 100-bovine permanent anterior teeth were used. Subsequent to teeth grinding and creation of standardized dentin smear layer, teeth were randomly divided into four experimental groups (n=25 teeth/group). For groups 1, 2 and 3 (light curing groups), seventy-five pre-cured resin composite cylinders (CeramX SphereTEC, Dentsply Sirona, Germany) of 4mm diameter x 2mm, 4mm and 6mm thicknesses respectively were cemented to dentin using a chemically-cured self-etching adhesive/dual-cured resin cement system (Tokuyama Universal Bond/Estecem II, Tokuyama Dental Corp. Japan) and light cured (40s/each cylinder) from their top surfaces using LED unit (1600mW/cm2, Radii Plus, SDI, Australia). In group 4 (co-cure group), twenty-five pre-cured cylinders (4mmx2mm) were cemented and left to cure chemically (10min) under 500g load. Specimens were stored (48h) in 100% relative humidity. The SBS test was run at a crosshead speed of 0.5 mm/min. Failure modes were examined under Stereomicroscope (16x, SMZ 745T, Nikon, Japan). For NL, 12 bovine teeth were randomly divided into 4 groups (n=3 teeth/group) as for SBS. For light curing groups, 9 pre-cured resin composite discs of 7mmx2mm, 7mmx4mm, 7mmx6mm were cemented to dentin and light cured (40s/each disc). For co-curing group, 3 pre-cured cylinders (7mmx2mm) were cemented and left to cure chemically (10min) under 500g load. After storage (48h), specimens were immersed in silver nitrate/developer solution and were examined using SEM (ESEM, Quanta 250 FEG, FEI company, Netherlands). Statistical analysis was performed using One-Way ANOVA/Turkey’s HSD test for comparison (P=0.05).
Results: For SBS, 2mm(10.5±4.5 MPa)=4mm(11.6±4.4MPa)=6mm(9.4±3.8MPa)>co-cure(5.3±4.2MPa). Cohesive failure (0%), adhesive failure (72%) and mixed failure (28%). For NL, 2mm(0.0±0.0%)