Effect of beverages on surface roughness of different denture base materials

Objectives: To evaluate the surface roughness of different denture base materials (DBM) after exposure to beverages for different storage durations (1 day, 1 week and 1 month).
Methods: Three selected coffee types were prepared and used as a storage medium; Arabic Coffee (Group A), Schoko Cappuccino (Group B), and Turkish Coffee (Group C), while distilled water used as a control (Group D). The (DBM) were Heat-cure (Major, Italy), Cold-cure (BMS, Italy), Cold-cure (Vertex Castavaria, Netherlands), and polyamide-based, injection-molded (DBM) (Deflex, Argentina). Forty cylindrical specimens measuring 20mm in diameter and 3mm height were prepared for each (DBM) according to manufacturers' instructions (ten specimens for each medium). Polished specimens were then stored in storage mediums at a temperature of 37 ^oC. Surface roughness measurements were performed with Optical Profilometer Contour GT (Bruker, USA). The surface parameter R_a (the arithmetical mean roughness of all the values of R profile within the measuring length) was measured for each specimen before and after storage for the specific time. Surface roughness difference ΔR_a was calculated. The mean data obtained were statistically analyzed using One-Way ANOVA and multiple comparisons (Tukey test).
Results: All test materials exhibited changes in the R_a values in varying degrees during the three durations of storage (one day, one week and one month). The results from this study showed that there were highly significant statistical differences (P<0.000) in the mean ΔR_a between the tested acrylic resin materials after one day, one week and one month of storage in each storage condition.
Conclusions: The results obtained in this investigation revealed that, type of storage medium, in addition, to time of immersion were found to be significant factors that influence the surface roughness properties of tested (DBM).