Does Bonding Approach Influence the Bond Strength of Universal Adhesive to Dentin of Primary Teeth?

To evaluate the effect of bonding strategy on microtensile bond strength (μTBS) of a new universal adhesive system to primary tooth dentin.

Flat dentin surfaces from 25 primary molars were assigned to 5 groups according to the adhesive and bonding approach: Adper Single Bond 2 (two-step etch-and-rinse adhesive) and Clearfil SE Bond (two-step self-etch system), as controls; Scotchbond Universal Adhesive-self-etch, dry or wet-bonding etch-and-rinse strategies. Composite buildups were constructed and the teeth were sectioned to obtain bonded sticks (0.8 mm²) to be tested under tension at 1mm/min. The μTBS means were analyzed by one-way ANOVA and Tukey's tests (α = 0.05). Failure mode was evaluated using a stereomicroscope (400×).

Universal adhesive applied following both dry and wet-bonding etch-and-rinse strategies showed similar bond strength compared with control adhesive systems. Self-etch approach resulted in the lowest μTBS values. For all groups, adhesive/mixed failure prevailed. The percentage of premature debonded specimens was higher when the universal adhesive was used as self-etch mode.

The universal adhesive does not share the same versatility of being used in the etch-and-rinse and self-etch approaches; however, the use of the new adhesive following either wet or dry-bonding may be a suitable option as alternative to two-step etch-and-rinse adhesive protocol.