EFFECTS OF DIFFERENT GLAZE TREATMENTS ON THE OPTICAL PROPERTIES AND ROUGHNESS OF LITHIUM DISILICATE CERAMICS

Abstract

Objectives: To investigate effects of different glaze procedures on the colour,translucency, and roughness of lithium disilicate (LDS) ceramics after short-termageing.Materials and Methods: Eighteen LDS specimens (thickness: 0.6 mm) weredivided into three groups (paste (EP), spray (ES), and powder–liquid glaze (EL))based on the type of glaze treatment (n=6). After glaze firings, specimens werethermally aged (5000 cycles). Before and after thermocycling, the colour,translucency, and roughness values of the specimens were measured. Before andafter thermocycling, the translucency and roughness data were analysed using aone-way analysis of variance (ANOVA) and compared using a Wilcoxon signedrank test. Changes in colour, translucency, and roughness data were analysedusing one-way ANOVA, and the correlations between them were analysed usingSpearman’s correlation analysis (p=.05).Results: The EL group showed the highest and clinically unacceptable colourchange value (p≤.005). Before and after ageing, the EL group exhibited highertranslucency than the other groups (p<.001), and the EL and EP groups exhibitedhigher roughness values than the ES group (p≤.001). Wilcoxon signed-rank testresults showed that although a significant difference between the initial and finaltranslucency values was observed in the EL group (p=.028), no significantdifferences between the initial and final roughness values were observed in eachgroup. Only in the EL group, a significant correlation was found between thecolour and translucency change values (r=.943, p=.005).Conclusions: After short-term ageing, based on the evaluation of the LDSceramics' colour and translucency changes, ES and EP treatments are preferablefor glazing. When dentists select a material (EP, EL, ES) for glazing LDSceramics, they should consider the effects of this material on the optical propertiesand surface roughness of LDS ceramics.