Comparison of Antibacterial Properties of an Orthodontic Composite Containing Silver and Amor-phous Tricalcium Phosphate Nanoparticles against Streptococcus mutans: An In Vitro Study

Formation of white spot lesions, due to plaque accumulation and bacterial biofilm growth, is a common complication in orthodontic treatment. The present study aimed to compare the antibacterial properties of an orthodontic composite containing silver (Ag) and amorphous tricalcium phosphate (ATCP) nanoparticles against Streptococcus mutans (S. mutans).  

In this in vitro study, 0.3% w/w Ag nanoparticles and 3% w/w ATCP nanoparticles were added to Transbond XT orthodontic composite. Totally, 48 composite discs were fabricated in three groups) n=16). The experimental groups included composite specimens containing nanoparticles and the control group included composite specimens without nanoparticles. The antibacterial effects of composite discs with and without nanoparticles against S. mutans (ATCC 35668) in the three groups were assessed by the direct contact test after 24 hours and 30 days. The number of bacterial colonies was visually counted in the three groups and compared. Data were analyzed by one-way ANOVA and Duncan's multiple comparisons test. P-values under 0.05 were considered significant.

The antibacterial properties of nano-composites significantly increased in both experimental groups of composites containing Ag and ATCP nanoparticles, compared to the control group (P<0.001). The highest antibacterial activity was observed in the orthodontic composite containing ATCP nanoparticles.

Addition of Ag and ATCP nanoparticles to orthodontic light-cure composite increases its antibacterial activity against S. mutans.