Chlorhexidine Antimicrobial Activity in Self-ligating and Conventional Orthodontic Brackets Infected with Porphyromonas Gingivalis Biofilm

Objectives: The formation of biofilms on orthodontic brackets is still problematic in orthodontic patients. Among the many types of available orthodontic brackets, self-ligating (SL) brackets are claimed to be more effective than conventional ligating (CL) brackets in maintaining oral hygiene. The present study was conducted to evaluate the adhesion of Porphyrmonas gingivalis (P.gingivalis ) biofilms formed on SL and CL brackets and their bacterial viability after treatment with 0.12% chlorhexidine (CHX) mouthwash. Materials and Methods In this experimental study, 48 commercial metal brackets were divided into two equal groups based on their types (CL with elastomeric ligature and SL). The brackets were first coated with saliva, then placed in the suspension of P.gingivalis for 3 days to grow bacterial biofilms on their surfaces. Half of the brackets in each group were randomly treated with CHX mouthwash or phosphate-buffered saline (PBS) for one minute. Quantitative analysis was performed by counting the number of colony-forming units (CFUs). Data were analyzed using ANOVA and Tukey test (α = 0.05). Results There was a statistically significant difference between the two types of brackets in biofilm formation; SL brackets were colonized more than CL brackets (P < 0.024). In both groups, CHX-treated brackets exhibited a significant reduction in P.gingivalis viability compared to PBS-treated brackets (P < 0.001). Comparison of antimicrobial activity of CHX in two types of brackets showed that more bacteria were survived on the surface of SL brackets (P < 0.001). Conclusion Seemingly, bracket design can have a significant effect on the adhesion and viability of potential periopathogens. Clinical Relevance: Use of CL brackets is preferred over SL brackets and is recommended to use SL brackets with caution in people who have poor oral health or are prone to periodontal disease.