ABSTRACT Introduction: Thermoplastic materials used for retainers, aligners, and occlusal splints may degrade when exposed to common beverages and mouthwashes, affecting mechanical properties and aesthetics. Objective: To evaluate the effects of carbonated drinks, alcoholic beverages (brandy), and mouthwashes on the mechanical properties and colour stability of various orthodontic thermoplastics. Material and Methods: A total of 144 samples from six thermoplastic materials (Erkodur, Duran, Erkodur-Al, CA Pro+, Erkoflex, Bioplast) were immersed daily for 10 minutes over 14 days in artificial saliva, brandy, carbonated drink, or chlorhexidine mouthwash. Mechanical properties (yield strength, stiffness, elastic modulus) were measured via universal testing machine; colour changes (ΔE) were assessed with a colorimeter. One-way ANOVA was used for statistical analysis (p < 0.05). Results: Retainers immersed in saliva exhibited highest yield strength (Erkodur: 61.95 ± 4.21; Duran: 59.25 ± 3.12) and stiffness (Erkodur: 2.12 ± 0.19; Duran: 2.12 ± 0.23), with lowest values in carbonated drinks (Erkodur: 48.88 ± 3.32 ; Duran: 48.45 ± 5.77). Aligners and occlusal splints followed similar trends; Bioplast splints performed best mechanically (saliva: 63.05 ± 4.36 ; stiffness: 1.98 ± 0.13). Colour changes were greatest in alcoholic beverages, notably Duran (ΔE: 0.978 ± 0.21, p = 0.010) and Erkoflex (ΔE: 1.21 ± 0.06, p = 0.003); aligners and Bioplast showed minimal ΔE differences. Conclusion: Acidic and alcoholic beverages significantly reduce mechanical strength and compromise aesthetics of thermoplastic orthodontic appliances. Bioplast exhibited superior mechanical performance among splints, while aligners demonstrated minimal discoloration. Patient education on limiting exposure to such beverages is crucial to maintain appliance durability and optimal treatment outcomes.
NIHARIKA et al. (Thu,) studied this question.