Objectives: To evaluate effects of a novel auxiliary irrigation strategy, proanthocyanidin (PA) + carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) nanocomplexes, on maintaining the organic-inorganic structural integrity and hence optimizing the adhesion strength of root dentin.
Materials and methods: Dentin specimens (n = 150) were prepared and subjected to the classical irrigating strategy with or without PA and CMC/ACP. The ultrastructure and biomechanical behaviour of dentin were characterized by scanning electron microscopy and atomic force microscope, respectively. Forty single root-canal premolars were employed for push-out bond strength testing. Besides, the antibacterial effects against Enterococcus faecalis were evaluated with confocal laser scanning microscopy. Statistical differences were verified with one-way ANOVA and Tukey's post-tests.
Results: The organic-inorganic structural integrity of root dentin was repaired with the synergetic use of PA and CMC/ACP. Correspondingly, the bond stability between the root canal wall and the AH-Plus sealer was significantly reinforced (P < 0.05). Meanwhile, the tissue biomechanical properties and antibacterial behaviour were enhanced compared to that of control group (P < 0.05).
Conclusions: The synergistic utilization of PA and CMC/ACP can preserve the structural integrity of root dentin, contributing to optimizing the sealing effects of root canal. Moreover, the novel irrigation strategy demonstrated a favourable antimicrobial activity.
Clinical relevance: The combination of PA and CMC/ACP can serve as a promising auxiliary irrigation strategy to optimize the outcomes of chemical preparation, enhance the sealing effects of root canal and hence improve the success rate of treatment.
Keywords: Bond strength; Carboxymethyl chitosan/amorphous calcium phosphate; Chemical irrigation; Proanthocyanidin; Root dentin.
© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.