Evaluation of Streptococcus Mutans Biofilm Retention by Three Different Types of Ligations on Orthodontic Brackets: An InVitro Scanning Electron Microscopic Study

Abstract

Introduction - The aim of the study was to evaluate Streptococcus mutansMTCC 890 biofilm retention on the orthodontic brackets with 3 different techniques of ligation using scanning electron microscopic analysis. Methods and Materials - The extracted premolars for orthodontic purpose were taken and were stored in normal saline solution. The 60 extracted premolars were divided into 3 groups:Group - A - Conventional PEA metal brackets with .022 in slot with elastomeric or rubber module (n=20), Group -B - Conventional PEA metal brackets with .022 in slot with steel wire ligatures (n=20) and Group - C - Self ligating brackets (SLB) with .022 in slot for straight arch technique (n=20). The tooth samples were immersed in Brain-Heart Infusion Broth (BHIB) containing S.mutans and incubated aerobically for 72 hours at 37◦C to allow biofilm formation. The formation of biofilm and its retention to the brackets was confirmed by Scanning Electron Microscopy (SEM). Results - The SEM images showed significant statistical difference (p< 0.05) in biofilm retention between the three groups of ligating method. Brackets ligated with elastomeric modules and SLB had more biofilm retention when compared to steel wire ligature group. Conclusion - Fixed orthodontic appliances significantly increase the retention of biofilm regardless the type of bracket system chosen. The result of the present study indicates that steel ligature had least amount of biofilm retention when compared to elastomeric module and self-ligating bracket.