Dentinal tubule anastomosis: a potential factor in adhesive bonding?

This study investigated adhesive tag formation within dentinal tubules and the anastomosing of lateral canals observable with scanning electron microscopy. This mechanism of micromechanical bonding had not been studied previously. The following brands of adhesives were applied to the prepared dentin surface of unerupted human third molars: Scotchbond Multipurpose, C&B Metabond, All-Bond 2, both etched and unetched, Tenure Solution, and XR-Bond. The experimental specimens were decalcified and prepared for SEM examination. Many tubule resin tags with lateral branching were observed. The resin branches were the result of primer, adhesive, or both entering lateral canals and communicating with adjacent tubules. The polymerization of adhesive in lateral canals was more prevalent with Scotchbond Multipurpose, C & B Metabond, and etched All-Bond 2 adhesives. The network of interconnected adhesive tags formed with these materials may be fundamental to the development of a stronger dentin/resin bond.