Novel antibacterial orthodontic elastomeric ligature with oral biofilm-regulatory ability to prevent enamel demineralization

Objectives

To synthesize a novel antibacterial orthodontic elastomeric ligature incorporating dimethylaminohexadecyl methacrylate (DMAHDM) for the first time to prevent enamel demineralization during orthodontic therapy.

Methods

Various mass fractions of DMAHDM (ranging from 0 % to 20 %) were grafted onto commercial elastomeric ligatures using an ultraviolet photochemical grafting method and were characterized. The optimal DMAHDM concentration was determined based on biocompatibility and mechanical properties, and the antibacterial efficacy was evaluated in a whole-plaque biofilm model. TaqMan real-time polymerase chain reaction and fluorescence in situ hybridization were used to assess the microbial regulatory ability of the multispecies biofilms. Furthermore, an in vitro tooth demineralization model was established to explore its preventive effects on enamel demineralization. Statistical analysis involved a one-way analysis of variance and LSD post hoc tests at a significance level of 0.05.

Results

The elastomeric ligature containing 2 % mass fraction of DMAHDM exhibited excellent mechanical properties, favorable biocompatibility, and the most effective antibacterial ability against microorganisms, which decreased by almost two logarithms (P < 0.05). It significantly reduced the proportion of Streptococcus mutans in the multispecies plaque biofilm by 25 % at 72 h, leading to an enhanced biofilm microenvironment. Moreover, the novel elastomeric ligature demonstrated an obvious preventive effect on enamel demineralization, with an elastic modulus 30 % higher and hardness 62 % higher than those of the control group within 3 months (P < 0.05).

Significance

The integration of DMAHDM with an elastomeric ligature holds significant promise for regulating biofilms and preventing enamel demineralization in orthodontic applications.