Physical, antimicrobial, and release profiles of orthodontic adhesives modified with chlorhexidine and cetylpyridinium chloride

The aim of the present study was to evaluate the properties (physical, antimicrobial, and release profiles) by using modified orthodontic adhesives on extracted teeth. Three primers, Transbond (Tx), Transbond-Chlorhexidine (Tx-CHx), and Transbond-Cetylpyridinium chloride (Tx-CTP), containing antibacterial agents CHx and CTP, were tested against Streptococcus mutans (Sm) in planktonic and biofilm phases. Their antimicrobial activities (biofilm and growth assays), affected by water aging, were analyzed along with shear bond strength and mode of fracture after bonding brackets onto bovine incisors. Tx-CHx demonstrated superior antimicrobial activity against in both planktonic and biofilm states, completely inhibiting their growth and biofilm formation. This effectiveness persisted after thermocycling. Conversely, Tx-CTP showed a positive outcome against microbial activity compared to Tx. Shear bond strength (SBS) (Tx–11.21±1.72; Tx-CTP–12.48±2.50; Tx-CHx–11.57±2.28) and bond failure interface showed no significant differences among the three primers. Adding CHx and CTP to an orthodontic primer could potentially safeguard enamel from demineralization without negatively impacting its structural characteristics.