CAD/CAM Polymer Durability: Thermal Aging Impact on Provisional Restorations

Objectives: The success of provisional restorative materials depends significantly on their clinical longevity. This research focused on assessing and comparing the impact of thermal aging on the color stability and mechanical properties of CAD/CAM polymers used for long-term provisional restorations.
Methods: Three CAD/CAM polymers were included CAD-Temp (CAT), Everest C-Temp (CT), and PEEK (PK). Forty specimens of each CAD/CAM material were produced by sectioning the CAD/CAM block. The specimens were distributed randomly into two subgroups: Subgroup A (control group): specimens were submerged in distilled water for 24 hours, whereas subgroup B underwent 5000 thermocycles at temperatures between 5 and 55 °C for 30 seconds. The color stability, flexural strength, survival probability, and microstructures were evaluated following thermocycling. The analysis of the data was conducted utilizing two-way ANOVA along with Tukey’s test. The threshold for statistical significance was established at p < 0.05. An assessment of the flexural strength data was performed using Weibull analysis.
Results: The CAT (3.74 ± 0.39) and CT (3.51 ± 0.54) groups exhibited the highest color variations, while PEEK (2.95 ± 0.45) showed the lowest color change. The baseline groups showed that the CT group had the highest flexural strength value (p < .05). Following thermocycling, both the CAT and CT groups showed a significant decrease in flexural strength values (p < .05). The Pk group did not exhibit a significant reduction in FS after thermocycling (p=.16). The characteristic flexural strength was significantly reduced for the CAT group than for other groups.
Conclusions: The color measurement and flexural strength outcomes were significantly influenced by the different CAD/CAM materials and the aging process. The CT group exhibited higher flexural strength than the other groups, both pre- and post-thermocycling. PK group shows the lowest color change compared to other groups. Regardless of aging condition, C-Temp and PEEK materials recorded the highest survival probability, a 95% significance level compared to CAD-Temp.