Fig. (1) SEM images of different failure modes. (1) -Scotchbond multi-purpose. Interfacial failure: A – adhesive; D – dentin. (2) -Scotchbond universal applied in the etch-and-rinse mode. Mixed failure (interfacial + cohesive in composite resin): CR – composite resin; D – dentin; A – adhesive. (3) -Scotchbond universal applied in the etch-and-rinse mode. Mixed failure (cohesive in adhesive + cohesive in composite resin): A - adhesive; CR – composite resin.