simple method of testing polymer leaching from thermoplastic sheets used for clear aligner

Objective: With the increasing popularity of clear aligners, newer materials are introduced in the form of thermoplastic sheets. Long-term studies testing the biocompatibility of these sheets are not available. The purpose of this study is to provide a simple, yet effective method to evaluate their leaching potential. Materials and Methods: Using the oxidation reduction reaction taking place in the presence of two different concentrations of potassium permanganate, five different samples were tested. The sequence of colour change from purple to red to brown to yellow to clear was used to determine the amount of leaching. This is the result of a stoichiometric relation between the oxidizing agent and the reducing sample. Color changes were observed through naked eyes over a period of 24 h. Photographs were taken at 15 min, 8 h and 24 h using D-SLR1000 Canon camera. Photos were evaluated separately. Result: Diluted solution showed faster change in color, due to the lesser amount of reagent. 3A Medes (Korea) was the first to leach, followed by CA (Scheu, Germany) EVA (Endent Private Limited, Delhi, India), Ultradent (United States) and Avac R (Jaypee, Kerela, India). Conclusion: "Do it yourself" test is a repeatable and reproducible method that can be modified and used in clinical practice as a chair side method.