Tooth Dentin Porosity

Characterize the cellular porosity network and its functional impact

This project started in 2012 in collaboration with Elsa Vennat from CentraleSupélec, University Paris-Saclay, France.

Keywords: Tooth dentin, cellular porosity, odontoblasts, sentivity, biomechanics.

Our goal is to characterize dentinal porosity at the whole tooth level and understand its biomechanical impact and role in biomechanics and teeth sensitivy.

Origin of the project This project started with the observation of dentinal porosity close to the dentin-enamel junction (DEJ) using confocal fluorescence microscopy. Visualizing a dense 3D distribution of fine branches stemming out from the main tubules and performing finite element modeling (FEM) on idealized porosity representations, we got a first hint that dentinal porosity could clearly affect mechanical properties, with effects mittigated by the presence of a pertitubular collar (Vennat et al., 2017). In doing so, we realized that there was only limited knowledge about the porosity topology and connectivity, and even less about its precise functional role.

Optimizing optical fluorescence microscopy of dentinal porosity The first step to characterizing dentinal porosity is to be able to obtain statistically accurate 3D visalizations. This is the current objectif of SeungHwan Lee’s PhD.

The use of autofluorescence arrizing from endogenous fluorophores is another way to futher characterize dentin tissue. It allows overcoming situations where the porosity cannot be stained with a dye, e.g. when occluded by mineral, which frequently happens with ageing. In addition, it allows visualizing structural features that would require specific staining or complementary correlated measurements. A complete account can be found in: (Lee et al., 2022).

Characterization of the porosity network While tubules radiating from the pulp to the enamel are well-known porosity features, the distribution of secondary branches is much less clear from the littearture. During his PhD, Lucas Chatelain used graph analysis to show how those secondary branches mostly connect neighbouring tubules up to 1 mm away from the DEJ, thus forming a densely interconnected network (Chatelain et al., 2025). Following an in-depth quantification of errors, he also demonstrated that network characteristics strongly fluctuate in space, which may provide valuable histological indications of specific dentinogenesis events in healthy or pathological states.

Towards dentinal porosity imaging at the whole tooth level The studies perform so far clearly show that there is a strong need for extended imaging of dentinal porosity at the tooth level to be able to understand global function and possible pathological alterations. This is goal is currently persued by Lauren Anderson’s PhD.

References

2025

PLOSOne
Cellular porosity in dentin exhibits complex network characteristics with spatio-temporal fluctuations

Lucas Chatelain, Nicolas Tremblay, Elsa Vennat, and 3 more authors

PLoS One, 2025

Abs DOI Bib HTML

According to the current hydrodynamic theory, teeth sensitivity is mediated by odontoblast cell processes which can be activated by fluid flow in the pericellular space of bulk dentin. To better understand the possible spatial extent of such phenomena, we investigated the topology and connectivity of dentinal porosity of a healthy human tooth. Using confocal fluorescence microscopy, we modeled the porosity as a spatial graph with edges representing dentinal tubules or lateral branches and nodes defining their connections. A large fraction of porosity channels in crown dentin was found to be interconnected, with 47% of nodes linked in a single component over a millimetric distance from the dentin-enamel junction (DEJ). However, significant differences in network topology were also observed. A sharp transition in connectivity from 83% to 43% occurred at 300 µm from the DEJ, which corresponds to an early stage of tooth formation. This was reflected in all graph metrics investigated, in particular the network resilience which dropped by a factor 2. To test the robustness of our observations, an in-depth analysis of potential remaining biases of the graph extraction was conducted. Most graph metrics considered were found to be within a 10% precision range from a manually annotated ground truth. However, path metrics, which characterize transport properties, proved very sensitive to network defects. Residual errors were classified in 4 topological classes related to fluorescence staining and confocal detection efficiency, instrumental resolution and image processing. Their relative importance was estimated using statistical and physical graph attack simulations in a broad experimental range. Our modeling thus provides a practical framework to estimate the interpretability of calculated graph metrics for a given experimental microscopy setup and image processing pipeline. Overall, this study shows that dentin porosity exhibits typical characteristics of a complex network and quantitatively emphasize the importance of the smallest lateral branches. Our results could be used to model fluid flow more accurately in order to better understand mechanosensing by odontoblasts in dentin.
@article{chatelain2025cellular, title = {Cellular porosity in dentin exhibits complex network characteristics with spatio-temporal fluctuations}, author = {Chatelain, Lucas and Tremblay, Nicolas and Vennat, Elsa and Dursun, Elisabeth and Rousseau, David and Gourrier, Aur{\'e}lien}, journal = {PLoS One}, volume = {20}, number = {7}, pages = {e0327030}, year = {2025}, publisher = {Public Library of Science San Francisco, CA USA}, url = {https://doi.org/10.1371/journal.pone.0327030}, doi = {10.1371/journal.pone.0327030}, }

2022

Autofluorescence Loss in Photobleaching for Human Dentin ex vivo

Seunghwan Goldmund Lee, Minwoo Kim, Sunghee Jeong, and 5 more authors

Current Optics and Photonics, 2022

DOI Bib HTML

@article{lee2022autofluorescence,
  title = {Autofluorescence Loss in Photobleaching for Human Dentin ex vivo},
  author = {Lee, Seunghwan Goldmund and Kim, Minwoo and Jeong, Sunghee and Hwang, Jaejoon and Kim, Jisu and Gourrier, Aur{\'e}lien and Vial, Jean Claude and Kyhm, Kwangseuk},
  journal = {Current Optics and Photonics},
  volume = {6},
  number = {1},
  pages = {86--91},
  year = {2022},
  publisher = {Optical Society of Korea},
  url = {https://doi.org/10.3807/COPP.2022.6.1.086},
  doi = {10.3807/COPP.2022.6.1.086}
}

2017

ActaBiomater
Mesoscale porosity at the dentin-enamel junction could affect the biomechanical properties of teeth

Elsa Vennat, Wenlong Wang, Rachel Genthial, and 3 more authors

Acta biomaterialia, 2017

Abs DOI Bib HTML

In this paper, the 3D-morphology of the porosity in dentin is investigated within the first 350 lm from the dentin-enamel junction (DEJ) by fluorescence confocal laser scanning microscopy (CLSM). We found that the porous microstructure exhibits a much more complex geometry than classically described, which may impact our fundamental understanding of the mechanical behavior of teeth and could have practical consequences for dental surgery. Our 3D observations reveal numerous fine branches stemming from the tubules which may play a role in cellular communication or mechanosensing during the early stages of dentinogenesis. The effect of this highly branched microstructure on the local mechanical properties is investigated by means of numerical simulations. Under simplified assumptions on the surrounding tissue characteristics, we find that the presence of fine branches negatively affects the mechanical properties by creating local stress concentrations. However, this effect is reduced by the presence of peritubular dentin surrounding the tubules. The porosity was also quantified using the CSLM data and compared to this derived from SEM imaging. A bimodal distribution of channel diameters was found near the DEJ with a mean value of 1.5–2 lm for the tubules and 0.3–0.5 lm for the fine branches which contribute to 30% of the total porosity (1.2%). A gradient in the branching density was observed from the DEJ towards the pulp, independently of the anatomical location. Our work constitutes an incentive towards more elaborate multiscale studies of dentin microstructure to better assess the effect of aging and for the design of biomaterials used in dentistry, e.g. to ensure more efficient bonding to dentin. Finally, our analysis of the tubular network structure provides valuable data to improve current numerical models.
@article{vennat2017mesoscale, title = {Mesoscale porosity at the dentin-enamel junction could affect the biomechanical properties of teeth}, author = {Vennat, Elsa and Wang, Wenlong and Genthial, Rachel and David, Bertrand and Dursun, Elisabeth and Gourrier, Aur{\'e}lien}, journal = {Acta biomaterialia}, volume = {51}, pages = {418--432}, year = {2017}, publisher = {Elsevier}, url = {http://dx.doi.org/10.1016/j.actbio.2017.01.052}, doi = {10.1016/j.actbio.2017.01.052} }