Shear Bond Strength of Two RMGICs to Enamel and Dentin

Abstract

Objective: To evaluate the effect of different surface treatments on the shear bond strength (SBS) of two resin-modified glass-ionomer cements (RMGIC) to enamel and dentin. Method: Two hundred bovine anterior teeth were used in this study. Subsequent to teeth gringing and creation of the smear layer, the cervical thirds of the teeth were randomly divided into 20 groups (n=10) according to: 1- Tooth substrate; enamel or dentin, 2- RMGIC; Ionoseal (VOCO, Germany) and Fuji II LC (GC Europe, Belgium) and 3- Surface treatment; no treatment (NT), 25%poly acrylic acid (PAA) 10s, washed 10s and blot dried (3M-ESPE, USA), 37% phosphoric acid (AE) 15s, washed 20s and blot dried (Pentron Clinical, USA), Scotchbond universal (SBU, 3M-ESPE, USA), G-aenial bond (GB, GC Europe, Belgium). Both adhesives were applied in self-etching mode according to manufacturer instructions and light cured (10s). One RMGIC cylinder (2mmx1mm) was bonded per each tooth and light cured (20s). Specimens were stored in distilled water (37ºC/24h). SBS test was run at a crosshead speed of 0.5 mm/minute. Statistical analysis was performed using Three-Way ANOVA, Tukey HSD test and t-test, p=0.05. Failure mode analysis was evaluated using stereomicroscope at 40X magnification.

Result:

Three-way ANOVA revealed significant effects of substrate, RMGIC, surface treatment and interactions, p=0.0001. The average means of the substrate were: dentin 10.4±6.2 MPa = enamel 8.7±4.1 MPa. The average means of the RMGIC were: Fuji II LC 10.5±4.8 MPa > Ionoseal 8.5±5.6 MPa. Average means of surface treatment were: SBU 15.5±4.4 MPa > AE 10.2±4.7 MPa = GB 9.3±2.6 MPa > PAA 5.7±4.2 MPa = NT 4.8±2.3 MPa. Adhesive failure represents 76%, mixed represents 14% and cohesive represents 10%.

Conclusion: Based on the results of the current study, the application of Scotcbond Universal improves the SBS of RMGICs to both enamel and dentin