Could Microwave Glazing Be Considered as an Alternative to Conventional Surface Finishing Methods of Ceramic Materials in Terms of Color Stability?

PURPOSE: To examine microwave heating for the purpose of ceramic glazing as an alternative to conventional methods in terms of color stability. MATERIALS AND METHODS: Thirty disk-shaped specimens (11 x 2 mm) of VITA VM 9, VITA VM 13, VITA VMK 95, and IPS e.max Ceram veneers were prepared (n = 30 each). The specimens were further divided into three subgroups according to surface finishing procedure (polishing, conventional oven glazing, or microwave glazing [n = 10 each]). The related surface finishing procedure was applied according to the manufacturers' instructions. Color differences (DeltaE) of the ceramic samples stored in a coffee solution at 37 degrees C for 168 hours were determined using spectrophotometry. Data were analyzed using two-way ANOVA. The group differences were analyzed using Tukey HSD test. RESULTS: Microwave-glazed specimens showed similar DeltaE values to conventionally glazed specimens for the tested ceramics (P > .05). Polished specimens showed higher DeltaE values than glazed specimens for the investigated ceramic materials, and the difference was significant for VITA VMK 95 and Vita VM9 (P </= .05). CONCLUSION: Microwave glazing has the advantage of decreasing glazing time to a few minutes and could be considered as an alternative method to conventional oven glazing and polishing with respect to color stability.