β-TCP nanoparticles doped with antimicrobial agents as an orthodontic adhesive component

Abstract Objective This study sought to evaluate the caries inhibition effect, and physical-chemical properties reached by the addition of β-TCP nanoparticles doped with antimicrobial agents to orthodontic adhesive bonding brackets. Design A commercially available orthodontic bonding adhesive, YSticker Ortho (YO - Yller Biomateriais) was modified by adding β-TCP nanoparticles doped with antimicrobial agents at 10% by weight. The experimental groups were: TB (Transbond XT -unmodified orthodontic bonding adhesive, control), YO (YSticker Ortho modified with β-TCP), YOβ-TCP@AgNP (YO modified with β-TCP + Silver nanoparticles), YOβ-TCP@TRI (YO modified with β-TCP + triclosan), YOβ-TCP@CHX (YO modified with β- TCP + chlorhexidine gluconate) and YOβ- TCP@BAC (YO modified with β-TCP + benzalkonium chloride). Bonded brackets were submitted to antimicrobial evaluation by modified direct contact test using Streptococcus mutans, and the antibiofilm effect in a microcosm model followed by shear bond strength test. Changes in the integrated mineral loss (ΔS), in situ degree of conversion, water sorption, and solubility, were also evaluated. Statistical comparisons were conducted at a 5% significance level. Results All experimental groups containing β-TCP nanoparticles doped with antimicrobial agents significantly inhibited bacterial growth. For bond strength, no difference was observed between TB and YO groups except for YOβ- TCP@CHX which resulted in the lowest values of bond strength. The orthodontic adhesive type did not dramatically affect the in situ degree of conversion, (ΔS), water sorption, and water solubility. Conclusion β-TCP nanoparticles doped with antimicrobial agents addition hold promise as a novel orthodontic adhesive bonding bracket. Possessing great caries inhibition potential with good mechanical properties.