Evaluation of the Preventive Effect of Composites Containing Silver and TiO₂ Nanoparticles on Demineralization around...

The aim of this study was to investigate the antidemineralization effect of composites containing silver and titanium dioxide (TiO₂) nanoparticles used for bonding brackets to tooth specimens.

A total of 75 freshly extracted teeth were etched and primed and then randomly assigned to three adhesive groups: (1) conventional orthodontic adhesive, (2) conventional adhesive mixed with TiO₂ nanoparticles, and (3) conventional adhesive mixed with silver nanoparticles. In each group, brackets were bonded with the pertinent adhesive. Teeth were painted with varnish on all surfaces except a 2-mm rim around brackets. Specimens were subjected to a cariogenic process in a circulating microbial model inoculated with Streptococcus mutans and Lactobacillus casei for 12 days and subsequently sectioned for cross-sectional microhardness testing. In each specimen, enamel microhardness was determined in three locations: 25-30 μm and 1.5 mm away from the bracket and under the varnish-protected enamel. Hardness of enamel in the first two locations was reported as a percentage of the protected enamel hardness.

Enamel hardness was higher at 25-30 μm away from brackets in both the experimental groups (p value < 0.05), and the nanoparticles acted similarly in this location (p value = 0.992). At 1.5 mm away from the brackets, there was no difference between experimental and control groups (p value > 0.05); the effect of TiO₂ attenuated in this location while silver remained as potent.

Both nanoparticles resulted in decreased demineralization at 25-30 μm from the bracket but farther away the effect of TiO₂ was diminished.

According to the results of this study, composites containing silver and TiO₂ nanoparticles can be suggested as anti-demineralization adhesives in case their biocompatibility is proved.