Effect of an Organogelator on the Properties of Dental Composites

Bioactive dental composites containing amorphous calcium phosphate have the potential to remineralize caries lesions and white spots, but their applications are limited by the inherent weakness of calcium phosphate as a filler material. To extend the possible uses of these materials, it is necessary to develop stable composites that exhibit strong mechanical properties and sustained ion release. Dibenzylidene sorbitol (DBS) is an organic molecule capable of inducing physical gelation in a variety of organic solvents, monomers, and polymers by forming self-assembled networks. Recent efforts have revealed that DBS is capable of gelation in a wide variety of dental monomers including an ethoxylated bisphenol A dimethacrylate (EBPADMA). This research was aimed at determining the effect of DBS networks on vinyl conversion, polymerization shrinkage, mechanical properties, and ion release potential of bioactive dental composites consisting of zirconia-modified amorphous calcium phosphate (Zr-ACP) as the primary filler phase and EBPADMA as the resin matrix phase. Although DBS had little effect on the vinyl conversion of EBPADMA/Zr-ACP composites, it significantly (1) reduced the volumetric shrinkage and associated shrinkage stress, and (2) increased the biaxial flexural strength and hardness of dry specimens. However, ion release studies suggest that DBS inhibits the release of calcium and phosphate ions.