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 × 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 (ΔE) of the ceramic samples stored in a coffee solution at 37°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 ΔE values to conventionally glazed specimens for the tested ceramics (P > .05). Polished specimens showed higher ΔE 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.