Mechanical and chemical analysis of experimental adhesive containing drug-loaded mesoporous silica nanoparticles

Tooth-colored restorations have been widely used in dental offices around the world since they were introduced to the market about 50 years ago. However, dentists still encounter many failed cases mainly due to the formation of tooth decay at the filling-tooth interface where the restoration's primer and adhesive are placed. Such failures typically warrant replacement or repair which is time-consuming and costly. To increase the lifespan of such restorations, techniques utilizing natural compounds such as grape seed extracts (GSE) that are rich in proanthocyanidins (PACs) were suggested. PACs' application to tooth structure was reported in the literature to enhance adhesion to tooth-colored restorations.

In a previous study in our lab, PACs were successfully loaded onto nano-sized drug carriers and further incorporated into resin dental adhesive primers to enhance tooth colored restoration longevity. The use of these therapeutic dental primers demonstrated better adhesion to tooth structure than when neat primers were utilized. In this study, we tested the chemical and mechanical changes to the resin network when these PACs-loaded nano-carriers are added. Results showed that the PAC-containing samples were not significantly different from neat resin samples in terms of chemical transformation from monomers to polymers when light-cured. Further, PACs’ introduction to the resinous systems generally reduced their mechanical properties, mainly when loading was performed prior to surface modification of the nano-carriers. Future research may focus on optimizing surface treatment of the nanocarriers and investigate further the composition of GSE.