In vitro remineralization by various ion-releasing materials of artificially demineralized dentin: A micro-CT study

Objective: The aim of this study was to evaluate the remineralizing properties of ion-releasing restorative materials on pH cycling-induced carious dentin. Methods: Fifty sound molars were freshly extracted. The occlusal surfaces were abraded using water-cooled sandpaper (800 grit). The residual crowns were embedded in self-cured acrylic resin with the flat dentin surface exposed. A mesio-distal trench was created using a calibrated 0.5 mm deep occlusal reduction burr, and artificial dentin caries were generated by pH cycling. Then, teeth were randomly assigned to five groups according to the ion-releasing material used. For each sample, micro-CT acquisitions were performed at various intervals. Remineralization was assessed by mean gray value (MGV) measurements after registration and segmentation of the region of interest with 3D Slicer software. One-way repeated-measures ANOVA followed by Tukey's post hoc test was used to investigate the difference in MGVs among the various groups. Results: Only Cention Forte showed significantly increased MGVs after 4 weeks compared to demineralized dentin. MGVs were higher, but not significantly, after placement of the restorative materials, including in the resin composite control group. These results can be explained by the radiopacity of the materials. Significance: Cention Forte, the material with the highest radiopacity, showed a significant increase in the MGVs of artificially carious dentin after 4 weeks. However, the study of dentin remineralization by micro-CT could be impacted by the radiopacity of the restorative materials used. The relevance of this examination for the study of dentinal remineralization should be investigated.