Shear Bond Strength and Ease of Use of Adhesive Resin Cements

Objectives: There are many esthetic adhesive cements available, differing in the number of components and steps needed for cementation. In this study, it was determined whether the ease of use provided by less components and steps would come at the expense of shear bond strength to bovine teeth before and after artificial aging.
Methods: 3 adhesive resin cement systems were tested: Experimental Cement (EXP-C, 3M™) with Experimental Adhesive (EXP-A, 3M™), Multilink® Automix (MLA, Ivoclar™) with Primer A and Primer B (PAB, Ivoclar™), and Variolink® Esthetic (VLE, Ivoclar™) with Adhese® Universal (ADU, Ivoclar™). All cements and adhesives were used according to manufacturers’ instructions. Bovine teeth were ground flat to expose dentin or enamel, polished (grit 320 sandpaper), water-rinsed, and gently air-dried. Stainless steel rods (diameter=4mm) were sandpapered, sandblasted, and silanized (ESPE™ Sil, 3M™ ESPE). Adhesives were applied as follows: EXP-A and PAB were not light-cured whereas ADU had to be light-cured (Elipar™ S10, 3M™ ESPE) for 10s prior to cementation. Stainless steel rods were cemented (n=6) under standardized pressure (20g/mm²). After excess removal, the cement was irradiated from 4 sides (10s each; Elipar™ S10, 3M™ ESPE). The specimens were stored for 10min under pressure (36°C) followed by additional 24h (36°C; 100% relative humidity) without pressure. Part of the specimens was subjected to artificial aging (thermocycling: 5000 cycles, 5°C-55°C) before shear bond strength testing (Zwick Z010; n=6; speed=0.75mm/min). Data analysis was performed using One-Way ANOVA (Tukey; p<0.05).
Results: see table.
Conclusions: In general, the Experimental Cement & Adhesive deliver at least statistically identical shear bond strength to Multilink® Automix & Primer A+B and Variolink® Esthetic & Adhese® Universal. The Experimental Cement & Adhesive have less steps than Variolink® Esthetic & Adhese® Universal due to the absence of a mandatory light-curing step of the Experimental Adhesive. Furthermore, the Experimental Cement & Adhesive (2 components) consist of less components than Multilink® Automix & Primer A+B (3 components). The data suggests that workflow simplification by less steps/components with the Experimental Cement & Adhesive does not come at the expense of bond strength.