Effect of bioceramic fillers on antibiofilm and remineralization properties of flowable composite used as clear aligner attachments

Clear aligners, while offering a more hygienic alternative to fixed appliances, are still associated with challenges including plaque accumulation and enamel demineralization. The purpose of the present study was to evaluate the antibiofilm and remineralization effectiveness of innovative flowable composite attachments containing bioceramic micro-fillers. Four experimental attachments were formulated and bonded to human enamel specimens: 3M Filtek Supreme flowable composite (Filtek SF) + 10% bioactive glass 45S5 (BAG), Filtek SF + 30% BAG, Filtek SF + 10% Bredigite (BRT), Filtek SF + 30% BRT. The attachment with no micro-fillers (Filtek SF) was used as control group. Plaque biofilms were grown on the attachment bonded enamel using a standardized protocol and the biofilm-killing effect was assessed by confocal laser scanning microscopy and viability staining. Attachments with bioceramic mico-fillers significantly inhibited plaque biofilm growth in 3 weeks on enamel, contributing over 20% bacterial cell killing in 10% micro-filler groups and over 30% killing in 30% micro-filler groups. Vickers microhardness was measured to assess the remineralization effect of the attachments containing bioceramic fillers after acid challenge. All four experimental groups demonstrated significantly higher microhardness values than the control group without fillers on the attachment side. Shear bond test was performed using a Universal Testing Machine. The shear bonding strength was not compromised in the attachments containing micro-fillers. In conclusion, proper incorporation of bioceramic micro-fillers in clear aligner attachments provides an innovative approach for clear aligner therapy with reinforced antibiofilm and remineralization effects without weakening their shear bonding strength.