Evaluation of microhardness and surface roughness of two bioactive restorative materials submitted to erosive challenge of simulated gastric acid

Abstract Background Within dentistry, there has been a growing concern associated with dental erosion, which is described as ‘the irreversible loss of dental hard tissue due to chemical processes not involving bacteria.’ Depending on the individual’s medical condition, factors such as bulimia nervosa, gastroesophageal reflux disease, or having excess contact with acidic drinks and food can exacerbate this condition. Objective This study aims to evaluate and compare the microhardness and surface roughness of two bioactive restorative materials—Cention Forte and Beautifil II—after repeated exposure to simulated gastric acid, emulating the oral environment of patients at an increased risk of dental erosion, like those with gastroesophageal reflux disease or bulimia nervosa. Patients and methods To test the identified research problem, 36 disc-shaped specimens (18 from each material) following the manufacturer’s instructions were prepared into three subgroups: control (no acid exposure), moderate acid exposure (three times per week), and severe acid exposure (14 times per week). Specimens were cyclically immersed in artificial saliva and subjected to simulated gastric acid (pH 1.2) to mimic clinical scenarios. Surface roughness was acquired with a three-dimensional optical profilometer while microhardness measurements were taken with the Vickers microhardness tester. One-way ANOVA, Tukey’s post hoc test, and Pearson’s correlation were used to analyze data for surface roughness, microhardness, and the correlation between them. Results Both restorative materials demonstrated statistically significant changes with an increase in surface roughness and a decline in microhardness with more frequent acid exposure ( P < 0.05). Cention Forte microhardness values were low while surface roughnesses were higher than those of Beautifil II across all subgroups. There was a high negative correlation between surface roughness and microhardness for both materials. Conclusion Repeated exposure to simulated gastric acid negatively impacts the surface characteristics and mechanical strength of bioactive restorative materials. Beautifil II performed better than Cention Forte in resisting erosive challenges so that Beautifil II might be suitable for patients with high intrinsic acid exposure. These results will help clinicians make better choices when selecting restorative materials for patients with dental erosion, achieving better long-term clinical outcomes.