Pilot study of response of human dental pulp to direct pulp capping with polymeric nanoparticles loaded with brazilian red propolis

Direct pulp capping helps to regenerate and repair damaged dentin, preserving tooth vitality. Despite being a widely recognized method, the authors investigated the use of a natural product with significant biological activity for this purpose. Thus, the aim of this study was to evaluate the human dental pulp response to direct pulp capping with polymeric nanoparticles loaded with Brazilian red propolis (BRP) compared to mineral trioxide aggregate (MTA). Following the synthesis, the nanoparticles loaded with 50μg of BRP (NPP50) and 100μg of BRP (NPP100) were analyzed by infrared spectroscopy (FTIR) and the cytotoxicity of all materials was tested. The dental pulp of 60 healthy third molars was mechanically exposed. Then, the teeth were pulp-capped with NPP50; NPP100; MTA + NPP50; MTA + NPP100; pure MTA (control). After experimental periods (15, 45, and 60 days) the teeth were extracted and processed for histological analysis. Inflammatory cell response, pulp tissue organization, hard tissue formation and the presence of bacteria was accessed. Data were analyzed by one-way ANOVA followed by Dunnett’s post-hoc test (cytotoxicity) or Kruskal-Wallis’ test followed by Kruskal-Wallis multiple comparison test (a = 0.05). FTIR spectra of nanoparticles showed typical bands of major compounds present in BRP. All materials exhibited no-cytotoxicity. Regarding inflammatory pulp response and organization of the pulp tissue, there was no significant difference between the materials in any of the periods of evaluation (p>0.05). The direct pulp capping agents containing BRP induced mineralized tissue formation like MTA with no cytotoxicity indicating promising regenerative potential for dental pulp tissue.