Novel evaluation method of dentin repair by direct pulp capping using high-resolution micro-computed tomography
We evaluated a novel micro-computed tomography (micro-CT) assessment for quality and quantity of dentin repair, which is difficult to visualize by histological analysis, after direct pulp capping under standardized cavity preparation.
Materials and methods
Standardized cavities were prepared on Wistar rats and direct pulp capping was performed using two commercial bioceramics, ProRoot MTA, and iRoot BP Plus. After 2 or 4 weeks, quality and quantity of tertiary dentin formation were evaluated using high-resolution micro-CT analyses including dentin mineral density, dentin mineral contents, compactness and integrity of tertiary dentin, and dentin volume with/without void space. Reproducibility of micro-CT analyses was confirmed by histological evaluation of the same specimen.
The exposed pulp area sizes were similar between iRoot BP Plus and ProRoot MTA. Micro-CT analysis of 2-week samples showing compactness of tertiary dentin was significantly higher in iRoot BP Plus than ProRoot MTA (p < 0.05). Tertiary dentin volume without void space, dentin mineral contents, and density were not significantly different between the groups. In 4-week samples, a significant increase was observed in dentin mineral density, compactness, and dentin volume with/without void space induced by iRoot BP Plus (p < 0.05). Micro-CT analysis of tertiary dentin integrity demonstrated that some ProRoot MTA specimens had small defects and lacked continuity (6/512 images). No defects were observed with iRoot BP Plus.
Micro-CT analysis was confirmed as an accurate, objective, and inclusive approach for evaluating quality and quantity of dentin repair.
These multifaceted approaches to evaluate pulp capping materials may accelerate review processes, ultimately improving vital pulp therapy.
KeywordsMicro-computed tomography evaluation Direct pulp capping iRoot BP Plus Mineral trioxide aggregate
This work was supported by JSPS KAKENHI (grant numbers JP16K20453, 17H06848, and 17K11704).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
The animal experimental protocol in this study was approved by the Ethical Guidelines Committee for Animal Care of Osaka University Graduate School of Dentistry (no. 23-005-1). All surgeries were performed under general anesthesia and efforts were made to minimize suffering.
For this type of study, formal consent is not required.
- 3.Ominsky MS, Boyd SK, Varela A, Jolette J, Felx M, Doyle N, Mellal N, Smith SY, Locher K, Buntich S, Pyrah I, Boyce RW (2017) Romosozumab improves bone mass and strength while maintaining bone quality in ovariectomized cynomolgus monkeys. J Bone Miner Res 32(4):788–801. https://doi.org/10.1002/jbmr.3036 CrossRefPubMedGoogle Scholar
- 5.Ishimoto K, Hayano S, Yanagita T, Kurosaka H, Kawanabe N, Itoh S, Ono M, Kuboki T, Kamioka H, Yamashiro T (2015) Topical application of lithium chloride on the pulp induces dentin regeneration. PLoS One 10(3):e0121938. https://doi.org/10.1371/journal.pone.0121938 CrossRefPubMedPubMedCentralGoogle Scholar
- 11.Min KS, Park HJ, Lee SK, Park SH, Hong CU, Kim HW, Lee HH, Kim EC (2008) Effect of mineral trioxide aggregate on dentin bridge formation and expression of dentin sialoprotein and heme-oxygenase-1 in human dental pulp. J Endod 34(6):666–670. https://doi.org/10.1016/j.joen.2008.03.009 CrossRefPubMedGoogle Scholar
- 16.Zhou W, Zheng Q, Tan X, Song D, Zhang L, Huang D (2017) Comparison of mineral trioxide aggregate and iRoot BP plus root repair material as root-end filling materials in endodontic microsurgery: a prospective randomized controlled study. J Endod 43(1):1–6. https://doi.org/10.1016/j.joen.2016.10.010 CrossRefPubMedGoogle Scholar
- 22.Suzuki M, Taira Y, Kato C, Shinkai K, Katoh Y (2016) Histological evaluation of direct pulp capping of rat pulp with experimentally developed low-viscosity adhesives containing reparative dentin-promoting agents. J Dent 44:27–36. https://doi.org/10.1016/j.jdent.2015.11.005 CrossRefPubMedGoogle Scholar