Remineralization of Dentin with Cerium Oxide and Its Potential Use for Root Canal Disinfection

Abstract

Objective

This study was to investigate a novel antibacterial biomimetic mineralization strategy for exploring its potential application for root canal disinfection when stabilized cerium oxide was used.

Material and Methods

A biomimetic mineralization solution (BMS) consisting of cerium nitrate and dextran was prepared. Single-layer collagen fibrils, collagen membranes, demineralized dentin, and root canal system were treated with the BMS for mineralization. The mineralized samples underwent comprehensive characterization using various techniques, including transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared spectroscopy (FTIR), scanning transmission electron microscopy (STEM), selected-area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and micro-CT. Additionally, the antimicrobial properties of the BMS and the remineralized dentin were also analyzed with broth microdilution method, live/dead staining, and SEM.

Results

Cerium ions in the BMS underwent a transformation into cerium oxide nanoparticles, which were deposited in the inter- and intra-fibrillar collagen spaces through a meticulous bottom-up process. XPS analysis disclosed the presence of both Ce (III) and Ce (IV) of the generated cerium oxides. A comprehensive examination utilizing SEM and micro-CT identified the presence of cerium oxide nanoparticles deposited within the dentinal tubules and lateral canals of the root canal system. The BMS and remineralized dentin exhibited substantial antibacterial efficacy against E. faecalis, as substantiated by assessments involving the broth dilution method and live/dead staining technique. The SEM findings revealed the cell morphological changes of deceased E. faecalis.

Conclusion

This study successfully demonstrated antibacterial biomimetic mineralization as well as sealing dentinal tubules and lateral branches of root canals using cerium nitrate and dextran. This novel biomimetic mineralization could be used as an alternative strategy for root canal disinfection.

Keywords:

• cerium oxide
• dextran
• biomimetic mineralization
• root canal disinfection

Acknowledgment

This work was supported by the National Natural Science Foundation of China (No. 81970982), Natural Scientific Research Fund of the Zhejiang Province, China (No. LGF20H140009) and Fujian Provincial Engineering Research Center of Oral Biomaterial, School and Hospital of Stomatology, Fujian Medical University (Grant No. 2023GC-A02). We thank Xiaomin Zhang, Xiaohuan Zhao and Nianhang Rong in the Analysis Center of Agrobiology and Environmental Sciences, Faculty of Agriculture, Life and Environment Sciences, Zhejiang University. We thank Zhemin Wu in the Center of Electron Microscopy, Zhejiang University, China, for technical assistance with STEM. We also thank Xiaoli Hong from the Core Facilities, Zhejiang University School of Medicine for the technical support.

Disclosure

The authors declare that they have no potential conflicts of interest with respect to the authorship and/or publication of this article.