In vitro study of the antibacterial effect of plasma surface treatment using Argon gas on orthodontic stainless steel brackets against Streptococcus mutans and Lactobacillus acidophilus

Abstract

Orthodontic treatment improves dental aesthetics. However, the prolonged duration of treatment and patient's oral hygiene results in more significant biofilm buildup and boosting concentrations of acidogenic bacteria, resulting in enamel demineralization. Plasma treatment technology has developed an interest in enhancing appliances' surface properties. The present study aimed to investigate cytotoxicity and antibacterial activity represented by anti-adhesion and anti-biofilm formation of Argon plasma treatment on orthodontic brackets against Streptococcus mutans and Lactobacillus acidophilus and evaluation the effect of change in plasma exposure duration on these properties in vitro. The study included three groups, group 1: untreated stainless steel brackets, group 2: brackets treated for 15 min, and group 3: brackets treated for 30 min. S.mutans and L.acidophilus were isolated from patients undergoing fixed orthodontic treatment. Microbiological tests included adhesion assay using plate counting method and biofilm formation assay using ELISA plate reader. S. mutans& L. acidophilus were cultivated in three groups, and their adherence and biofilm formation were measured and compared. The biocompatibility of treated stainless steel brackets was evaluated by MTT assay. Results showed that groups 2 & 3 had better anti-adhesion and anti-biofilm activity when compared with group 1, with a significant difference between group 1 &group 3, in which group 3 recorded the lowest biofilm formation and the highest anti- anti-A adhesion activity. MTT showed that groups 2 and 3 exhibited more than 80% cell viability after 24, 48, and 72 hours. Plasma surface treatment of metal brackets possesses antibacterial activity against S.mutans and L.acidophilus; alteration exposure time impacts the development of these properties. Keywords. Plasma treatment, Argon gas, orthodontic brackets, biofilm, antimicrobial.