Effect of Addition of Nano-TiO(2), Nano-SiO(2), and a Combination of Both, on Antimicrobial Activity of an Orthodontic Composite.

AIM: This study aimed to assess the effect of addition of nano-titanium oxide (nano-TiO(2)), nano-silicon dioxide (nano-SiO(2)), and a combination of both, on antimicrobial activity of an orthodontic composite. MATERIALS AND METHODS: Molds measuring 0.64 x 0.5 mm were used for the fabrication of composite disks. For this purpose, 0.5% and 1% nano-TiO(2), nano-SiO(2), and a combination of both (0.5% nano-TiO(2) and 0.5% nano-SiO(2)), were mixed with Transbond XT composite (3M Unitek). A total of 180 composite disks were fabricated for eluted component, disk agar diffusion (DAD), and biofilm inhibition tests. The colony counts of Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), and Lactobacillus acidophilus (L. acidophilus) and the diameters of growth inhibition zones were measured at 3, 15, and 30 days after exposure to the materials. Data were analyzed using one-way ANOVA and a post hoc test. RESULTS: None of the nano-TiO(2) and nano-SiO(2) concentrations had any significant effect on the growth inhibition zone. All tested concentrations of nano-TiO(2) and nano-SiO(2) decreased the colony count of all bacteria. The composite sample containing both nano-TiO(2) and nano-SiO(2) had the greatest efficacy for reduction of S. mutans and S. sanguinis colony counts at all three time points. Also, 1% nano-TiO(2) and 1% nano-SiO(2) had similar effects on L. acidophilus in eluted component test. CONCLUSION: Addition of TiO(2) and SiO(2) nanoparticles conferred antimicrobial property to the tested orthodontic composite. CLINICAL SIGNIFICANCE: Using orthodontic composite containing nonoparticles with antibacterial activity may prevent dental caries.