The objective of this study was firstly to assess the demineralization inhibitory effect of ion-releasing restorations in enamel adjacent to restoration using a biofilm caries model and secondly to compare the effect to that in a chemical caries model. Fifty-six bovine incisors were filled with either Surefil one (SuO), Cention N (CN) (both ion-releasing materials), Ketac-Molar (GIC) or Powerfill resin composite (RC). The restored teeth were then randomly divided into 2 groups according to the used caries model (biofilm or chemical caries model). The micro-computed tomography (MicroCt) and optical coherence tomography (OCT) outcome measures used to evaluate demineralization inhibition effects were lesion depth, LD and increase in OCT integrated reflectivity, ΔIR, at five different depths. It was observed that all outcome measures of CN were statistically the same as those of GIC and conversely with those of RC. This was also the case for SuO except for LD, which was statistically the same as RC. When comparing the two caries models, LD of the biofilm model was statistically deeper (p < 0.05) than the chemical model for all four materials. In conclusion, CN and SuO have similar demineralization inhibitory effects as GIC, and the biofilm caries model is more discriminatory in differentiating demineralization inhibitory effects of ion-releasing restorative material.

Background: Reliable bonding to dentin in high C-factor cavities remains a clinical challenge due to polymerization stress. Bulk-fill composites, including self- and dual-cured systems, aim to simplify placement and improve adaptation in deep cavities. However, limited data exist on how different dentin surface treatments affect their bond strength. Materials and methods: Sixty extracted human molars with standardized Class I cavities were randomly assigned to six groups based on restorative system (self-curing bulk-fill, and a dual-cured bioactive composite system) and dentin treatment (self-etch, short 3-second etch, conventional etch-and-rinse). µTBS was evaluated after one month of water storage. Two-way ANOVA was used to assess the effects of material and dentin treatment, and failure modes were analyzed descriptively using Chi-square test. Results: Dentin treatment significantly affected µTBS ( p < 0.001), whereas the restorative system did not ( p = 0.56). The highest µTBS was observed in the etch-and-rinse groups for both the self-cure (26.4 MPa) and the dual-cure systems (26.0 MPa), while the lowest values occurred in self-etch groups (self-cure: 18.0 MPa; dual-cure: 19.5 MPa). Failure mode analysis showed predominantly adhesive failures in self-etch groups and mixed failures in etch-and-rinse groups. Conclusion: Within the limitations of this study, etch-and-rinse dentin treatment appears to provide higher µTBS than self-etch. While short dentin etching could potentially offer a practical compromise, particularly for the self-curing bulk-fill composite. Clinical significance: A short 3-second etch may improve bond strength over self-etch protocols, especially for the self-cure restorative system (Stela, SDI), suggesting a simple strategy to optimize adhesion while minimizing potential over-etching.