Effects of Denture Cleansers on the Flexural Strength of Two Flexible Denture Materials

Objectives: Clinical observations of flexible partial removable dental prostheses (FPRDP) indicate deteriorating physical properties requiring replacement. Patients are advised to cleanse FPRDPs daily with denture cleansers. The objective of this study was to investigate denture cleansing effects on flexural strength of FPRDP.
Methods: Rectangular shaped (2x10x35mm) specimens were prepared by a dental laboratory as clinical FPRDPs from DuraFlex™ and Valplast™. Specimens were divided into fourteen experimental groups (n=8/gp) by material, treatments, and storage methods. Treatments consisted of thermocycling (55°C and 5°C) for 5,000 cycles in water with storage in water, Efferdent™, Polident™, non-thermocycling with water storage, Efferdent, Polident, and 37°C water. All specimen storage was maintained at 22°C except the 37°C water group. Efferdent and Polident solutions were prepared as one measure of cleanser/100ml water. Flexural strength was measured using three-point bending test in a universal testing machine. Data were analyzed with three-way ANOVA and SNK post-hoc test (α-0.05) between baseline and 5,000 cycles.
Results: Significant differences in flexibility between DuraFlex and Valplast occurred at baseline (p=0.027). Valplast specimens became significantly more flexible in all treatment groups (p<0.001). DuraFlex experienced no significant change for flexural strength among any groups.
Conclusions: Decreased flexural strength in Valplast is perhaps related to water absorption. This study may help improve clinical recommendation for home cleansing advice to patients, FPRDP performance, and appearance.