International Association for Dental Research (IADR), Barcelona, Spain, 14 - 17 July 2010, pp.797
METHOD: Ten disc shaped specimen (10 mm diameter, 2 mm thickness) were prepared by using two autopolymerizing relining materials; UfiGel Hard (UGH), Truliner (T), a thermoplastic nylon; Flexiplast (FP) and an autopolymerizing acrylic; QC 20 (QC) according to the manufacturer's recommendations. Total of forty specimens were subjected to thermocycling for 4000-12000 cycles between 5-55° C in water. Color measurements were made immediately after deflasking and thermocycling processes (4000-12000). Color changes (ÄE) were calculated by using colorimeter. To assess the effect of material type and cycling period on ÄE values, a two-way analysis of variance (ANOVA) is carried out followed by the Fisher's LSD test (á=0.05).
RESULTS: Statistical analysis revealed that material type and cycling period has significant effect on ÄE values. It is seen that while UGH displays largest changes in ÄE values compared to the other materials, FP and QC exhibits the smallest changes in ÄE values. Furthermore, the difference between the ÄE values of FP and QC exhibits is found statistically no significant, which means that two material performances are nearly the same in terms of ÄE values.
CONCLUSION: Within the limitations of this study, denture base materials showed better tolerance to the thermocyling process than relining materials, but all demonstrated clinically acceptable color stability values.