antimicrobial properties and shear bond strength of composite used in orthodontics following the addition of curcumin-reduced nanographene oxide

Background: composites used in the direct bonding of brackets in fixed orthodontics are considered a suitable environment for the multiplication of cariogenic bacteria and the establishment of microbial plaques by creating a distance between the bracket, tooth surface, and surface properties such as porosity. in the present study, we decided to combine curcumin-reduced nano-graphene oxide (rgo-ncur) with a composite resin used in orthodontics to achieve a composite with optimal shear bond strength (sbs) and antimicrobial properties against streptococcus mutans as a main cariogenic bacterium. methods: in the present study, nanoparticle of graphene oxide (ngo) was synthesized by the modified hummers’ method using graphite powder and reacted by ncur to regenerate reduced-ngo (rgo-ncur). scanning electron microscopy (sem) was used to confirm the synthesis of ngo, ncur, and rgo-ncur. sbs and antimicrobial activity of transbond xt composite containing 5% rgo-ncur were performed against s. mutans biofilms. spss software, one-way anova test, and tukey post hoc test with a significance level equal to or less than 0.05 were used to analyze the data. results: the synthesis of ngo, ncur, and rgo-ncur in nanoscale was confirmed by sem. the amount of sbs in the composite sample with 5% w/w rgo-ncur was 12.30 ± 0.65 mpa. the optical density of s. mutans in the biofilm structure formed on composite containing 5% w/w rgo-ncur was significantly reduced (62.10%) compared with the control group, namely, original composites used in orthodontics (p < 0.05). conclusions: based on the data of the present study, it can be concluded that composite containing 5% w/w rgo-cur, without adverse effect on the physical-mechanical properties of composites, can be used as an antimicrobial additive of composites used in orthodontics to control biofilm formation and caries around orthodontic brackets.