Optical stability of restorative materials following exposure to food-simulating liquids: an in vitro study

The optical stability of restorative materials plays an important role in the long-term esthetic success of dental restorations. This in vitro study investigated the effects of food-simulating liquids on the color stability and surface gloss loss of restorative materials with different material characteristics.

A total of 200 disc-shaped specimens were prepared from five restorative materials: Cention N, Beautifil II, Admira Fusion, G-ænial A'Chord, and Gradia Plus. The specimens were immersed in artificial saliva, heptane, ethanol, or citric acid for 7 days at 37 °C. Color measurements were performed using a spectrophotometer, and color changes were calculated according to the CIEDE2000 formula (ΔE₀₀). Surface gloss was evaluated using a glossmeter and expressed as percentage gloss loss. Data were analyzed using two-way robust ANOVA and percentile bootstrap-based pairwise comparisons.

Material type significantly affected both ΔE₀₀ and gloss loss values. Although the main effect of solution type on ΔE₀₀ was not significant, a significant material-solution interaction was observed. For gloss loss, both material type and solution type showed significant effects, whereas their interaction was not significant. Cention N generally demonstrated greater optical alterations, while G-ænial A'Chord and Gradia Plus exhibited relatively stable optical behavior. Among the tested solutions, citric acid resulted in the highest gloss loss values, whereas heptane showed the lowest effect.

The optical behavior of restorative materials following chemical exposure appears to be influenced by both material composition and the type of food-simulating liquid. Cention N showed greater susceptibility to optical alterations, whereas G-ænial A'Chord and Gradia Plus demonstrated more stable optical performance. These findings suggest that chemical stability should be taken into consideration during restorative material selection, particularly in patients with frequent exposure to acidic dietary conditions.