Comparison of the Effect of Simulated Gastric Juice on Surface Roughness and Flexural Strength of Three Different Computer Aided Designing Computer Aided Manufacturing Blocks: An In Vitro Study.

Purpose: To evaluate the effect of simulated gastric juice on surface roughness and flexural strength of three different CAD/CAM blocks. Materials and Methods: Resin based ceramic (RBC Group), High impact polymer composite (HIPC Group) and Zirconia (Z Group) as 3 groups were considered for the study (90 samples, 30 samples per group). In each group, 10 samples were evaluated without immersion in gastric juice (Baseline). Remaining 20 samples were immersed for total of 24 hours in simulated gastric juice (pH 1.2). The surface roughness and flexural strength of samples was evaluated at the end of 6 hours and 24 hours. This was repeated for all groups. The data obtained was subjected to One way and Multivariate ANOVA and Tukey HSD tests. The significance level was fixed at 5% (p<0.05) Results: One way ANOVA showed surface roughness of Z group decreased significantly after acid immersion whereas RBC group and HIPC group showed significant increase in the surface roughness after acid immersion. One way multivariate ANOVA revealed statistically significant differences between the groups. Tukey HSD revealed a significant difference from base line to 24 hours across all groups. The surface changes were not significant between 6 hours to 24 hours in Z (p=0.261), RBC (p=0.797), HIPC (p=0.401) and baseline to 6 hours in HIPC group (p=0.397). The flexural strength of all the groups decreased significantly after acid immersion. The change in flexural strength from baseline to 6 hours was not significant in RBC (p=0.123) and HIPC groups (p=0.126) and 6 hours to 24 hours in RBC group (p=0.096). Z group showed a significant reduction from baseline to 6, 6 to 24 and baseline to 24 hrs. RBC and HIPC showed significant reduction from baseline to 24 hrs; and HIPC from 6 to 24 hrs Conclusion: Resin based ceramic is a suitable material in terms of flexural strength and surface roughness in gastric acid regurgitation, followed by Zirconia as the surface roughness does not increase from the baseline. High impact polymer composite can be a suitable restorative material in severe abrasion and erosion cases as it is least affected by acid in terms of roughness. [ABSTRACT FROM AUTHOR]