Effect of Three Different Denture Cleansers on the Impact Strength of Heat-Cure Polymethylmethacrylate and Polyamide Denture Base Resin: An In Vitro Study

Background This in vitro study aimed to evaluate and compare the effects of three commercially available denture cleansers on the impact strength of two common denture base resins, namely, heat-polymerized polymethylmethacrylate (PMMA) and polyamide. The cleansers used in the study included Valclean (acidic), Polident (neutral), and Clinsodent (alkaline). Methodology A total of 112 specimens from two groups (Group A and B) with 14 specimens in eight subgroups were made as per ISO 1567:1999/Amd. 1:2003(E). Group A consisted of 56 PMMA (Acryton H) specimens, while Group B consisted of 56 polyamide (Valplast) specimens. Each primary group was categorized into the following four subgroups: distilled water - control (A1 and B1), Valclean (A2 and B2), Polident (A3 and B3), and Clinsodent (A4 and B4). All specimens underwent a six-month immersion schedule, alternating between distilled water and the cleanser solutions. A Charpy-type digital impact testing machine was used to measure the impact strength, and statistical analysis was conducted. Quantitative parameters were compared among the categories using a one-way analysis of variance (F test). Results Both heat-polymerized PMMA (Acryton H) and polyamide (Valplast) showed a statistically significant reduction in impact strength following immersion in the denture cleansers used in this study (p < 0.01). The reduction in strength was progressively evident across cleanser groups, indicating that prolonged cleanser exposure can significantly alter the mechanical integrity of denture base resins. Conclusions The impact strength of both PMMA and polyamide resins was affected by immersion in denture cleaners. Cleansers with extreme pH levels, both acidic and alkaline, led to greater material degradation, while the neutral cleanser (Polident) caused minimal changes. These findings underscore the significance of selecting denture cleansers carefully, especially for prolonged use.