Discoloration of polymethylmethacrylate (PMMA) and nylon base polymers in coffee, tea and cola-an invitro study

Abstract

Color stability is an important property of denture base material .This study evaluated the color stability of one heat cured denture base acrylic resin (Triplex)and one nylon base denture (Flexiplast)after immersion in four solutions. Materials and methods: Twenty specimens from each type of test material were prepared (10mm diameter, 2mm thickness) and stored in distilled water for 24hours at 37c in a dark environment. During that time (T0),the color of all specimens was spectrophotometrically measured. Each specimen was immersed in coffee, tea, cola, and saliva (as a means of control) solutions. After 7-day (t1) and 30-day (t2) periods of immersion, the color of the specimens was measured again. The CIE (commission Internationale del Eclairage) l*a*b*compared statistically with Tukey test. results: In ET0T1 a significant color shifts accrued in coffee in Flexiplast and triplex materials (p<0.01). Tea and cola were the second-most staining beverages for each of the both tested material. Flexiplast produced larger color changes in beverages in comparison with triplex (p<0.01). In ET1T2were not significant staining differences among the test material groups in four solutions. Conclusions: The effect of staining solutions on the color of each test material in each session was perceivable by the human eye (E>1), however, the color shifts of two test materials were clinically acceptable (E<3.7) except for coffee. Therefore, minimizing drinking of such beverages may be advantageous for denture wearers for long-term color stability.