Effect of Denture Cleansers on Surface Roughness and Flexural Strength of Heat Cure Denture Base Resin-An In vitro Study.

Introduction: Denture cleansing is essential for maintaining the prosthesis and oral health, so choosing an appropriate cleanser which is not only efficient but also not adversely affects the properties of denture base resin itself with prolonged use is important. Hence, the present study was undertaken.

Aim: To evaluate the effect of different chemical cleansers on surface roughness and flexural strength of heat cure denture base resin when used daily for three months.

Materials And Methods: A total of 40 rectangular specimens (65 mm x 10 mm x 2.5 mm) and 32 disc shaped specimens (10 mm x 2 mm) were fabricated from heat cure denture base resin (DPI Heat Cure) for evaluation of flexural strength and surface roughness respectively. The specimens not subjected to cleansing served as control whereas other specimens were subjected to daily cleansing with one of the three cleansers (1% sodium hypochlorite, fittydent tablets, 100% vinegar) daily and stored in distilled water for three months. Surface analyser (Surftest SJ-210, Mitutoyo, USA) was used to evaluate change in surface roughness of the specimens (ΔRa) before and after cleansing. Also, flexural strength (S) of specimens after cleansing was evaluated by subjecting the specimens to load of 50 kgf at a crosshead speed of 5 mm/min in universal testing machine (INSTRON). Data obtained by testing was compiled and analysed using statistical software SPSS version 17.5. ANOVA and Post-hoc Tukey's tests were used and p-value <0.05 was considered significant in all tests.

Results: Results showed that the surface roughness of the specimens was significantly increased and flexural strength significantly decreased after immersion in 1% sodium hypochlorite solution for three months (p<0.05). No statistically significant difference were observed in flexural strength and surface roughness of the specimens cleaned with fittydent and 100% vinegar for three months (p>0.05).

Conclusion: Within the limitations of this in vitro study, it was concluded that immersion in 1% sodium hypochlorite solutions for three months influences the surface roughness and flexural strength of heat cure denture base resin; hence it should be used with caution when used for long period. Fittydent and 100% vinegar can be recommended as a routine chemical cleansing agent for long term use.