Microbial evaluation of the effectiveness of different methods for cleansing clear orthodontic retainers: A randomized clinical trial

Abstract

Objective: To compare effectiveness of brushing an Essix retainer with water only and brushing followed by soaking in one of three commercial cleansing tablets. Materials and Methods: A double-blind, parallel, randomized clinical trial with a split-mouth design was completed with 60 volunteers with specific eligibility criteria assigned to three groups to compare the cleansing effectiveness of brushing an Essix retainer with water only, followed by soaking in one of three alkaline peroxide-based commercial cleansing tablets (Retainer Britet, Kukist, and Coregat). Each participant wore an upper Essix retainer (with an electronic microsensor) on a full-time basis for 14 days and used one of the three products on one side of the retainer for 15 min/d. The effectiveness of the cleansing tablets was tested by the scanning electron microscopy, bacterial identification, bacterial quantification, and disk diffusion methods. Results: Bacterial quantification tests demonstrated nonsignificant statistical differences between the control and test sides of the three cleansing tablets: Retainer Britet, Kukist, and Coregat (Mann-Whitney test P-values were .6, .37, and .5, respectively). A Kruskal-Wallis test also showed nonstatistical difference in the bacterial counts between the three groups (P-value = .5). In vitro tests showed a minimal inhibition zone of Staphylococcus epidermidis only with Coregat tablets. Conclusions: Using chemical cleansing tablets after mechanical cleansing did not significantly reduce the bacterial count in Essix retainers when compared to use of mechanical cleansing alone. However, the tablets seem to be effective against "cocci" bacterial species.