Impact of Simulated Gastric Acid on Tensile Bond Strength of Class II Inlay Indirect Restorations

Abstract: The current study aimed to determine the impact of using hydrochloric acid (HCl) on the tensile bond strength of four distinct restorative materials. By doing so, we sought to provide valuable insights into the durability and resilience of these materials in the face of gastric acid exposure. Material and Methods: Eighty sound maxillary first premolars were included in this study; Teeth were randomly assigned into four groups (n=20) according to the restorative materials. The first group was restored using Filtek Bulk Fill Posterior Restorative (3MTM). The second group was restored with EverX Posterior Fiber Reinforced Dental Composite (GCTM). The third group was restored with multilayer high-strength cubeX zirconia (Dental Direkt TM), and the fourth group was restored with IPS e-max press (Ivoclar/VivadentTM). The samples in the four main categories were further classified into two subgroups (n = 10) based on their immersion in either artificial saliva or simulated gastric acid solution (SGAS). The specimens underwent a tensile bond strength assessment utilizing a universal testing apparatus. The data were examined utilizing Two-Way ANOVA and the Friedman test. The threshold for statistical significance was established at p < 0.05. Results: The impact of HCl was evident on all tested materials, with a significant difference observed between groups after immersion in HCl (p0.000). The lithium disilicate group demonstrated the greatest tensile bond strength, whereas the cubeX zirconia group exhibited the least. All samples showed a notable decline in tensile bond strength following exposure to simulated gastric acid. However, the extent of tensile bond reduction differed throughout the tested groups. Conclusion: The simulated gastric acid, regardless of its type, significantly reduces the tensile bond strength of the tested materials. This underscores the need for further research and the development of more acid-resistant restorative materials.