Novel evaluation method of dentin repair by direct pulp capping using high-resolution micro-computed tomography

  • Motoki Okamoto
  • Yusuke Takahashi
  • Shungo Komichi
  • Manahil Ali
  • Naomichi Yoneda
  • Takuya Ishimoto
  • Takayoshi Nakano
  • Mikako Hayashi
Original Article



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.

Clinical relevance

These multifaceted approaches to evaluate pulp capping materials may accelerate review processes, ultimately improving vital pulp therapy.


Micro-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.

Ethical approval

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.

Informed consent

For this type of study, formal consent is not required.

Supplementary material

784_2018_2374_MOESM1_ESM.docx (1.2 mb)
ESM 1 (DOCX 1.15 mb).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Motoki Okamoto
    • 1
  • Yusuke Takahashi
    • 1
  • Shungo Komichi
    • 1
  • Manahil Ali
    • 1
  • Naomichi Yoneda
    • 1
  • Takuya Ishimoto
    • 2
  • Takayoshi Nakano
    • 2
  • Mikako Hayashi
    • 1
  1. 1.Department of Restorative Dentistry and EndodontologyOsaka University Graduate School of DentistryOsakaJapan
  2. 2.Division of Materials and Manufacturing ScienceOsaka University Graduate School of EngineeringOsakaJapan

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