Disinfection Effects on Orthodontic Elastomers: Mechanical Performance and Surface Wettability Considerations

Background: Various infection control procedures for orthodontic elastomers, including the use of disinfectant solutions and antibacterial mouthwashes, are currently being evaluated to prevent cross-contamination. Objective: This study aimed to compare the effects of ethanol- and glutaraldehyde-based disinfection on the mechanical properties and surface wettability of selected orthodontic elastomeric materials. Methods: Three categories of polyurethane orthodontic elastomers were evaluated: ligatures (white and navy blue), power chains, and elastomeric thread. Specimens were assigned to control and disinfection groups. Disinfection was performed by immersion in 99.98% ethanol or 10% glutaraldehyde for 30 min. Three sets of specimens were prepared for each product type (n = 5 per group for tensile testing; contact angle measurements were performed using 10 droplets per experimental condition). Following disinfection, specimens were dried and stored under laboratory conditions for 8 days before testing. Surface wettability was assessed using the sessile drop contact angle method, and mechanical properties were evaluated by static tensile testing. Statistical analysis was performed using Welch’s t-test (p ≤ 0.05). Results: The effects of disinfection were product-type-dependent. Significant increases in contact angle were observed for white ligatures, power chains, and elastomeric thread, indicating reduced surface wettability after exposure to the disinfectants. Glutaraldehyde generally produced larger wettability changes than ethanol. Tensile testing revealed significant reductions in maximum tensile force for power chains after both disinfection protocols, whereas navy-blue ligatures showed no significant changes. The response of elastomeric thread differed from that of the other materials, with glutaraldehyde increasing the maximum tensile force. Conclusions: Exposure to ethanol and glutaraldehyde may modify the mechanical and surface properties of orthodontic elastomers; however, the magnitude and direction of these changes depend on the specific product. The findings improve understanding of elastomer behavior following disinfectant exposure under laboratory conditions. Further studies incorporating microbiological assessment, aging procedures, and clinically relevant conditions are needed before definitive recommendations regarding orthodontic disinfection protocols can be established.