Com o objetivo de avaliar a capacidade de reparação e formação de ponte de dentina de polpas mecanicamente expostas capeadas com o sistema adesivo All Bond 2 (AB-2 - grupo experimental) e o cimento de óxido de zinco e eugenol (OZE - grupo controle), quarenta dentes de ratos tiveram o tecido pulpar capeado com ambos os materiais. Decorridos 7, 15, 30 e 60 dias, as maxilas foram removidas e cortes histológicos com 5pm de espessura foram obtidos e corados com H/E e Brown e Brenn. Foi possível observar que o AB-2 provocou necrose tecidual limitada ao corno pulpar relacionado com a exposição da polpa aos 7 dias. Com o decorrer dos períodos, a área de necrose aumentou, e aos 60 dias a necrose pulpar era total. Quando havia contaminação bacteriana, o quadro reacional era exacerbado com desenvolvimento de lesões periapicais e gangrena tecidual. No grupo controle houve formação de ponte de dentina, iniciada aos 7 dias e completada aos 60 dias. Concluiu-se que o sistema adesivo AB-2 foi diretamente responsável pela degeneração e necrose do tecido pulpar, além da não-formação de ponte de dentina, mesmo na ausência de contaminação bacteriana.

This study was designed to observe the healing and bridging capacity of mechanically exposed pulps that were capped with adhesive resin system All Bond 2 (AB-2 experimental group) or zinc-oxide eugenol cement (OZE-control group) and the cavities were restored with Z100 resin. In twenty rats, 40 class I occlusal cavities with pulpal exposures were directly capped, 20 with AB-2 system and 20 with ZOE. The animals were sacrificed after intervals of 7, 15, 30 and 60 days. At 7 days the pulps capped with AB-2 showed pulpal necrosis in the horn next the exposures. At 60 days all pulp sh owed necrosis. When bacterial contamination wasn't provided, was observed periapical lesions and gangrena. The pulps capped with ZOE showed dentinal matrix deposition, that to began at 7 days and completed its formation at 60 days postoperative. This study indicates that pulp processes an inherent healing capacity for cell reorganization and bridge formation when a bacterial seal is provided. But the dentinal adhesive resin system All Bond 2 was directly responsible for pulpal degeneration or necrosis and absence of bridge formation.