Re: Efficacy of three hygienic protocols in reducing biofilm adherence to removable thermoplastic appliance. The Angle Orthodontist 2014(1) 161–170

To: Editor, The Angle Orthodontist

We read this paper with great interest. Thank you for examining the performance of removable thermoplastic appliances (RTA) evaluating different hygiene protocols.

In the in vivo part of the study, the patients were each assigned the same three stage protocol: only brushing for 4 weeks, followed by brushing and chlorhexidine immersion (CHX) for 10 weeks, followed by a vibrating bath solution (VBC) for 10 weeks. Since patients' oral hygiene has been shown to change over the course of treatment with most getting worse over time and some better with more instruction, perhaps this would affect the bacterial adherence to the aligners. Patient hygiene could affect the bacteria adhering to the aligners. It may have been better to use a crossover design where patients went from CHX to VBC and back to CHX to test for this effect scientifically. Also, is the first 4 weeks of treatment the best time to establish a baseline?

In addition, we were interested to know if there were any differences observed between males and females during the study. Lastly, since the VBC had no antibacterial component that was effective against the bacteria tested, would the result still have been excellent if the patients used a vibrating bath with another liquid such as water?

Thank you once again for publishing this interesting study.