Adhesive/Cements Bond Strength in Self/Total-etch Modes With Light/Auto-polymerization to Dentin/Enamel

Objectives: To measure the shear bond strength of adhesive/cements in self-etch and total-etch modes with light- and auto-polymerization to dentin and enamel.
Methods: Human molars were ground to midcoronal dentin or superficial enamel with 320-grit SiC abrasive. Teeth were divided among 24 groups (n=10) for 4 different adhesive/cement combinations which were used in self-etch and total-etch (when indicated) modes with light- and auto-polymerization to dentin and enamel (see table for groups). Etched groups were etched with 37% phosphoric acid for 20s. Each adhesive was applied onto the tooth with agitation and air thinning. For light-polymerized groups, adhesive was light-polymerized with a curing light (Bluephase; 1200mW/cm2) according to IFU. A Tygon tube (ID=1.5mm) was filled with the corresponding cement and affixed to the surface of each specimen. The specimens were stored in a dark room and the cement was allowed to auto-cure for up to 15 minutes prior to being placed in an incubator (24hr,37°C). The specimens were then tested in a universal testing machine in shear at a crosshead speed of 1mm/min. Shear bond strength was compared by a 3-way ANOVA (“material”, “etch”, and “light”) and Tukey-post hoc analyses (alpha=0.05). Enamel and dentin substrates were analyzed separately.
Results: All factors were significant with dentin and factors “material” and “etch” were significant with enamel.

Conclusions: For dentin: Self-etching provides slightly higher bond than total-etching when light-curing; Total-etching provides slightly higher bond than self-etching when auto-curing(p=.01). For enamel: Total-etching provides higher bond than self-etching(p<.01).