Pulpal Reactions and in vivo Bonding Interface of Antibacterial Self-etching System Incorporating MDPB

Abstract

This study examined the pulpal reactions to adhesive systems that employ a self-etching primer containing the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB), and evaluated its in vivo bonding ability by animal tests. Class V cavities were prepared on the buccal surfaces of the anterior teeth of beagle dogs and composite filling was performed using the self-etching primer containing 5% MDPB in combination with experimental fluoride-releasing bonding resin or commercial bonding resin. After 7, 30 or 75 days, the teeth were extracted and serial thin sections were prepared following fixation, demineralization, and resin-embedding. The sections were stained with hematoxylin and eosin, and the pulp response was histopathologically examined according to the criteria of ISO7405. In addition, after 7 days, the crown of the canine tooth restored with composites using 5 % MDPB-containing primer and experimental bonding resin was cut, and the ultrastructure of the resin-dentin interface was observed by transmission electron microscopy (TEM). Restoration with MDPB-containing primer either with experimental or commercial bonding resin resulted in no pulpal inflammation for all periods. TEM observation demonstrated integrity of the resindentin interface with the production of a 0.5-1 μm thick hybridized layer and obturation of dential tubules with resin. The results indicate that the self-etching system employing the antibacterial primer containing MDPB, which is utilized for commercial version Clearfil Mega Bond FA, shows excellent biocompatibility and produces an effective bond under in vivo conditions.