In Vitro Assessment of Mechanical and Optical Performance of Advanced Lithium Disilicate Ceramics Before and After Immersion in Different pH Media

Document Type : Original Article

Authors

Lecturer of Fixed Prosthodontics, Faculty of Dentistry, Cairo University, Cairo, Egypt.

10.21608/edj.2025.406268.3563

Abstract

Purpose: This study was conducted to assess the impact of different immersion solutions on hardness, fracture toughness and color stability of advanced lithium disilicate (ALD) ceramics.
Methods: Forty-four plates of ALDS ceramic were randomly divided into 4 groups (n=11) according to the immersion solution; Artificial saliva (AS), Soft Drink (SD), Energy Drink (ED) and Mouthwash (MW). Each plate was immersed in a tightly sealed container filled with 5 ml of solution inside an incubator at 37oc for 12 days simulating one year of intraoral use. The solutions were renewed every 12 hours to obtain freshly solutions. Vickers microhardness was measured followed by fracture toughness calculation using the indentation technique. While color stability was measured using a spectrophotometer. All outcomes were obtained before immersion as baseline readings and after immersion. Data were statistically analyzed using One Way ANOVA test followed by Tukey’s Post Hoc test and Paired t test with the significance level set at p ≤ 0.05 .
Results: Regarding hardness, only group MW exhibited a statistically significant reduction in hardness. Regarding fracture toughness, there was a highly statistically significant decrease in fracture toughness values in SD, ED and MW groups. Regarding color stability, group ED recorded the highest ΔE followed by group SD, group MW while the lowest color change was recorded in group AS.
Conclusions: Acidic media have negative effect on fracture toughness of ALDS ceramics. Meanwhile mouthwash has a deteriorating effect on their hardness. ALDS ceramics are susceptible to color change after being subjected to acidic media.

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