Microbiological evaluation in invisible aligner chemical cleaning methods against Candida albicans and Streptococcus mutans

Introduction: This study aimed to assess the efficacy of chemical agents in removing Candida albicans and Strep-tococcus mutans biofilm from invisible aligners. Methods: The samples were made of EX30 Invisalign trays, biofilm was cultured by standardized suspensions of C. albicans ATCC strain and S. mutans clinical strain on the sample. The treatments used were 0.5% sodium hypochlorite (NaClO) (20 minutes), 1% NaClO (10 minutes), chlorhexidine (5 minutes), peroxide (15 minutes), and orthophosphoric acid (15 seconds). The control group received phosphate-buffered saline for 10 minutes. The colony-forming units per milliliter of each microorganism were determined by serial dilutions seeded in plates with selective culture mediums for each one. Data were analyzed by the Kruskal-Wallis and Conover-Iman tests at an a of 0.05. Results: For the C. albicans biofilm group, the control group had 9.7 Log10 of microorganism growth, and all treatment groups had statistically significant bio -film reduction, in which chlorhexidine presented the highest inhibition of 3 Log10, followed by alkaline peroxide and orthophosphoric acid both with 2.6 Log10, 1% NaClO (2.5 Log10), and 0.5% NaClO (2 Log10). As for S. mutans, the control group had 8.9 Log10 of growth, and a total microorganism inhibition was reached by chlorhexidine, 1% NaClO, and orthophosphoric acid, whereas alkaline peroxide inhibited growth to 7.9 Log10 and 0.5% NaClO 5.1 Log10. Conclusions: Within the limitations, chlorhexidine and orthophosphoric acid had greater efficacy in both biofilms. In addition, 1% NaClO and alkaline peroxide also had significant effects; therefore, their incorporation aligners disinfection protocols are valid.

Automated summary

This study aimed to evaluate the efficacy of chemical agents in removing biofilms of Candida albicans and Streptococcus mutans from invisible aligners. The results showed that chlorhexidine and orthophosphoric acid had higher antibacterial effects, while 1% sodium hypochlorite and alkaline peroxide also had significant effects. Therefore, these chemical agents can be used for disinfection of invisible aligners.