MARGINAL SEAL AND BIOCOMPATIBILITY OF A 4TH-GENERATION BONDING AGENT

Objectives. The pulpal reaction and the marginal sealing of in vivo re stored samples using resin composite and Scotchbond Multi-Purpose adhe sive system (3M Dental Products) were analyzed in this study. Methods. Twelve Class I non-exposed cavity preparations were placed on premola rs to be removed for orthodontic reasons. They were restored and obser ved at 7 d and 28 d. Results. The examination of the resin-dentin inte rface under the scanning electron microscope (SEM) revealed: 1) a gap- free attachment between adhesive resin and dentinal surface in 80% of the areas studied, 2) penetration of resin tags into the dentinal tubu les, and 3) formation of a 3-5 mu m thick acid-resistant hybrid layer. Microfissures measuring about 10 mu m were observed in only 20% of th e areas studied, these were located along the walls of the cavities, e specially near the enamel in zones where there was a lower concentrati on of dentinal tubules. The histological analysis, carried out 7 d aft er preparation of the restoration, did not show any alteration of the pulp. After 4 wk, reparative dentin was produced in the pulpal areas c orresponding to the restored cavities. Significance. The quantity of n ewly formed dentin is correlated with the distance from the cavity to the pulp. The results indicate that acid-etching of vital dentin using 10% maleic acid does not impair pulpal healing in deep Class I caviti es and that the Scotchbond Multi-Purpose adhesive system is able to pr eserve the morphological and biological integrity of the pulpo-dentina l complex.