Evaluation of antimicrobial and shear bond strength of orthodontic primers containing three Antimicrobial agents – “an invitro study”

Background: Orthodontic treatment make oral hygiene maintenance difficult, there by creating a favourable environment for bacterial accumulation. Acid produced by the oral bacteria can demineralise the tooth leading to white spot lesions. Antimicrobial agents are recommended to reduce the bacterial growth. The aim of this study to compare the antimicrobial properties of primer containing Chlorhexidine, Cetyl Pyridinium Chloride, Triclosan and conventional primer using planktonic and biofilm model of Streptococcus mutans and to compare physical properties of primers by analyzing shear bond strength and bond failure pattern. Methodology: Three antimicrobial agents were incorporated respectively to Transbond XT primer. MIC and MBC values of newly prepared primers were determined. Antibacterial activity of four primers (TX, TX-CHX, TX-CPC and TX-Triclosan) against growth of Streptococcus mutans in both planktonic and biofilm model was analysed by performing growth and biofilm assay. These antimicrobial agents added primers were used for bonding brackets on to the tooth. The shear bond strength of conventional and newly prepared primers were tested using universal testing mechine. Result: TX-CHX had stronger antimicrobial activity against S. mutans in the planktonic and biofilm phases than TX, TX-CPC and TX-Triclosan. The antimicrobial activity of TX-CHX was maintained after thermocycling. Chlorhexidine incorporated with XT primer shows better Shear bond strength than Triclosan and Cetyl pyridenium chloride incorporated primers but less than XT primer. Conclusion: TX-CHX has better antibacterial property than TX-CPC, TX-Triclosan and TX. Antibacterial agents added primers has sufficient bond strength to withstand orthodontic force. TX-CHX has better shear bond strength than TX-CPC and TX-Triclosan but less than XTprimer