Effect of Simulated Gastric Acid on Various Esthetic CAD-CAM Materials

Objectives: This study aimed to investigate the effect of coffee and fruit juice on color and microhardness of various esthetic ceramic materials following simulated gastric acid exposure.
Methods: A glass-ceramic material (IPS E-max), polymer infiltrated ceramic material (Vita Enamic) and a nano hybrid ceramic material (Cerasmart) were selected for this study (n=32 per group). Following polishing with metallographic SiC papers, all of the samples were immersed into artificial saliva for 21 days. Half of the samples were separated as the control group and were only exposed to artificial saliva (ph: 7.3). Remaining 16 samples were exposed to saliva and simulated gastric acid, respectively. The simulated gastric acid was lacked of pepsin and comprised of a 0.06 M and 0. 113 % HCl (pH 1.2 ± 0.2) acid solution in distilled water. 16 samples from each group were exposed to gastric acid 3 times a day for 30 seconds. With this procedure, an attempt was made to imitate the 21-day oral conditions of a patient with bulimia. Then, the color and the Vickers microhardness measurements were performed. Following these procedures, samples were exposed to coffee and orange juice (n=8/per group). The samples were exposed to the solutions for 16 hours and 48 minutes to simulate 21 days of consumption. Then, second measurements (color and hardness) were performed. Statistical significance was determined by ANOVA followed by Tukey’s post hoc test.
Results: Two-way ANOVA showed that there was a statistically significant difference between the colors of the materials following various media insertion (p< 0.001). In addition, the results of the hardness evaluation showed that significant differences were observed based on the type of restoration material and solutions (p< 0.001).
Conclusions: The exposure to different immersion beverages could affect the microhardness and color stability characteristics of ceramic materials.