Mechanical strength and inhibition of plaque biofilm activity of a novel antibacterial Hawley retainer

Abstract

Objectives The purposes of this study were to evaluate the long-term mechanical property, bacteria-killing ability, protein resistance and cytotoxicity of a novel antibacterial methyl methacrylate (MMA) resin. Methods The 2-methacryloyloxyethyl phosphorylcholine (MPC) has been added into the MMA used for making Hawley orthodontic retener according to the mass percentage 0% (control group), 1.5%, 2.25%, 3%, 4.5% and 6%. Specimens from the control group and MPC group were water-aged for 1 d, 90 d and 180 d, and then the universal material testing machine was used to investigate the long-term mechanical properties of the modified MMA specimens in the oral environment. The biofilm metabolic activity, colony-forming unit (CFU) and live/dead staining assay of the biofilms in the control group and MPC group in the oral environment were tested using the dental plaque biofilm model. The micro-bicinchoninic acid (BCA) method was used to determine the amount of protein adsorbed on the specimens. The MTT method was used to evaluate the cytotoxicity of the control group and MPC group. Results In the simulated oral environment, the addition of 0% to 3% MPC had no significant effect on the mechanical properties of the MMA specimen (P > 0.05). The control group and the modified MMA specimens with 3%MPC were statistically significant in time and the interaction effects between the two groups (P 0.05). Conclusions The addition of MPC into the MMA resin did not compromise the mechanical properties of the resin and exhibited long-lasting antibacterial and protein-repellent effects.

Keywords

• polymethyl methacrylate resin
• hawley retainer
• 2-methacryloyloxyethyl phosphorylcholine
• orthodontics
• simulated oral environment
• antibacterial properties
• protein-repellent effects