RESUMO
AIM: To test the hypothesis that polyacrylic acid-based and calcium silicate materials are able to increase mineral density of artificially demineralized dentine produced by a microcosm model for caries formation. METHODOLOGY: Forty-five dentine cavities were prepared in nine sound human third molars (five in each tooth). Specimens received a bacterial inoculum and were incubated in BHI plus 5% of sucrose for 96 h to allow biofilm formation. After that, the specimens were scanned in a high energy micro-CT (baseline stack) and then, each cavity was filled with different cements: zinc polycarboxylate (Poly Zinc™, Prevest DenPro, Jammu, India), conventional glass-ionomer (Ketac Molar, 3M ESPE, Seefeld, Germany) and two calcium silicate-based materials (MTA, Angelus, Londrina, Brazil and Biodentine™, Septodont, Saint Maur des Fosses, France) whilst the central cavity was filled with utility wax (negative control). Specimens were kept for 45 days under simulated intrapulpal pressure using simulated body fluid and after, they were again scanned (treated stacks). Reconstruction of the acquired projections was accomplished using standardized parameters, and the percentage mineral density change was calculated around each cavity. Data were tested for normality using the Shapiro-Wilk test, followed by nonparametric methods. RESULTS: A microcosm artificial caries model was able to cause dentine demineralization (±90% related to sound dentine). Significant increases in dentine mineral density were achieved using MTA or Poly Zinc™ (43.56% and 41.64% remineralization), followed by Biodentine™ (36.40%) and Ketac Molar (32.54%), P < 0.05. CONCLUSION: All cements increased mineral density in demineralized dentine, but zinc polycarboxylate cement and MTA had greater bioactive potential. Micro-CT proved to be an effective method to evaluate changes in mineral density within dentine in contact with bioactive materials.