Plastic deformation evaluation of clear aligners exposed to different cleaning solutions.

Objectives: To evaluate the effect of different antimicrobial solutions on the mechanical properties of aligners (Invisalign, Align Technology Inc., San Jose, CA, USA). Material and Methods: Invisalign aligners were used, originating from an orthodontic treatment sequence to correct malocclusion in the upper arch. Specimens were obtained from the buccal surfaces extending from the upper right canine to the second molar and used for mechanical testing (n = 60). The test specimens were divided into seven groups: 0.5% sodium hypochlorite (HYP); sodium bicarbonate (BIC); neutral detergent (DET); 0.12% chlorhexidine digluconate (CX); white vinegar (VIN); Corega tabs (COR) and distilled water (DW) (control). Results: After 7 days, significant intergroup differences in Young's modulus were observed, with HYP differing from DW and DET (P < .05). After 14 days, a significant difference was observed between CX and COR (P < .05). Significant changes related to immersion time were detected for DET, CX, and COR between 7 and 14 days (P < .05). No statistically significant differences were found in the maximum deformation values for any solution (P > .05). Conclusions: Stiffness of the materials was influenced by immersion in different solutions, with specific intergroup differences observed after 7 and 14 days. Significant changes over time were detected for DET, CX, and COR. However, immersion in the evaluated solutions did not significantly affect maximum deformation of the material.