How could mouthwashes affect the color stability and translucency of various types of monolithic zirconia? An in-vitro study

OBJECTIVES: This study aimed to evaluate the color stability and translucency of various types of monolithic zirconia after immersion in chlorhexidine and Listerine mouthwashes. MATERIALS AND METHODS: This experimental study was performed on 36 disk-shaped specimens fabricated from low-translucent, high-translucent, and multilayered monolithic zirconia (n = 12 per group). Each group was equally divided and immersed in either 2% chlorhexidine (CHX) or Listerine mouthwash for 2 min daily over 7 days. Changes in color (ΔE) and the translucency parameter (ΔTP) were evaluated and compared. The data were analyzed with one-way ANOVA followed by Tukey’s post-hoc tests (α = 0.05). RESULTS: Chlorhexidine caused a significantly lower ΔE and a significantly higher ΔTP in multilayered zirconia compared to the low-translucency (ΔE: P = 0.0027, ΔTP: P<0.001) and the high-translucency zirconia group (ΔE: P<0.001, ΔTP: P = 0.022). Listerine caused a significantly higher ΔE in the high-translucency zirconia group compared to the multilayered zirconia group (P = 0.0165). It also resulted in a significantly higher mean ΔTP in the multilayered zirconia group compared to the low-translucency (P = 0.0003) and high-translucency zirconia groups (P = 0.019). CONCLUSIONS: In both mouthwashes, multilayered monolithic zirconia exhibited the highest color stability among the tested materials; albeit with the most pronounced changes in translucency. Meanwhile, high-translucency monolithic zirconia was more prone to discoloration when exposed to both mouthwashes.