Biofilm-resistant zwitterionic resin-based adhesive for orthodontic bracket-tooth interfaces: an in vitro evaluation.

Objectives: An in vitro study to verify the potential effectiveness of an orthodontic adhesive incorporating a polybetaine zwitterionic mixture in preventing biofilm formation.

Materials and methods: 2-methacryloyloxyethyl phosphorylcholine (MPC) and sulfobetaine methacrylate (SBMA), were added to An adhesive at 1 wt% (MS1) And 3 wt% (MS3). The MS0 group had no zwitterions. Flowability measurement, shear bond strength (SBS), the adhesive remnant index (ARI), and the contact angle were assessed. Bracket bonding was performed, and cross-sections were examined using scanning electron microscopy (SEM). Biofilm formation was analyzed using confocal laser scanning microscopy. Statistical analyses were conducted using R software. Wilcoxon tests with the Holm correction were used for non-parametric data, and pairwise t-tests with the Bonferroni correction were used for parametric data. Significance was set at P < 0.0001.

Results: Flow analysis showed no significant differences in the experimental groups compared to the MS0 group (P > 0.05). The SEM images confirmed uniform bonding in all groups. SBS decreased significantly with higher MS content (P < 0.0001), And ARI scores shifted with the addition of zwitterionic mixtures, increasing scores to 1 And 2. MS3 showed a significantly lower contact angle compared to MS0 (P < 0.05). MS3 exhibited reduced biofilm formation and lower fluorescence intensity (P < 0.05).

Conclusions: Despite reductions in SBS, all adhesives remained at minimum acceptable levels. The 3 wt% zwitterionic adhesive effectively suppressed biofilm formation and may help prevent demineralization.

Clinical relevance: An orthodontic adhesive containing a zwitterionic mixture can satisfy clinical properties and prevent side effects due to biofilm formation.