Effect of mouth rinses on the stainability of monolithic lithium disilicate glass-ceramics with different surface treatments: An in vitro study

Abstract

Statement of problem: Mouth rinses have been reported to cause tooth surface discoloration. However, information regarding their effect on the stainability of monolithic glass-ceramics with different surface treatments is lacking.

Purpose: The purpose of this in vitro study was to assess the effect of mouth rinses on the color change of milled and pressed monolithic lithium disilicate glass-ceramics with different surface treatments.

Material and methods: Fifty-six Ø12×1.5-mm disk specimens were fabricated using 2 different processing techniques: milling and pressing. Each group was subdivided into 2 subgroups according to surface treatments: glazed and polished. Specimens were then immersed in 2 different types of mouth rinse (n=7): chlorhexidine (CHX) and Listerine (LST). Color parameters were assessed using a digital spectrophotometer. Color difference (ΔE₀₀) was calculated and compared with perceptibility (ΔE₀₀=0.8) and acceptability (ΔE₀₀=1.8) thresholds. The data were analyzed using ANOVA and Tukey post hoc tests (α=.05).

Results: The color difference (ΔE₀₀) was significantly affected by the type of processing technique, surface treatment, and mouth rinse (P<.001) and their interaction (P=.008). All ΔE₀₀ values were below the selected clinical acceptability threshold (ΔE₀₀=1.8). Milled groups (ΔE₀₀=1.13) showed greater discoloration than pressed groups (ΔE₀₀=0.86). Glazed specimens (ΔE₀₀=0.70) were more resistant to discoloration than polished specimens (ΔE₀₀=1.28) and immersion in CHX (ΔE₀₀=1.09) led to more discoloration than immersion in LST (ΔE₀₀=0.89).

Conclusions: The color of milled and pressed monolithic lithium disilicate glass-ceramics with different surface treatments was affected by using CHX and LST mouth rinses. Glazed lithium disilicate glass-ceramics showed less staining compared with those that were polished. Specimens immersed in CHX showed more discoloration than those immersed in LST.