Contribution of Root Canal Treatment to the Fracture Resistance of Dentin


      • The properties of root dentin from unrestored teeth were compared to those of endodontically-restored teeth.
      • Dentin from teeth that received endodontic treatment had significantly lower flexure strength than that of the unrestored group.
      • Dentin from endodontically-treated teeth exhibited a higher collagen cross-linking ratio and a lower occlusion ratio and lower tubule occlusion.



      Although the strength and toughness of dentin decrease with age, no study has explored if restorative treatments are a contributing factor.


      Multiple extracted teeth were obtained from randomly selected donors and categorized according to donor age and prior root canal treatment. The microstructure and chemical composition of radicular dentin were evaluated using scanning electron microscopy and Raman spectroscopy, respectively, and the strength was evaluated in 4-point flexure to failure. Data were compared using the Student t test.


      Dentin from the root canal–restored teeth exhibited significantly lower strength (P < .05) than tissue from age- and donor-matched unrestored tooth pairs. Although there was no significant difference in the mineral-to-collagen ratio between the 2 groups, dentin obtained from the root canal–treated teeth exhibited more extensive collagen cross-linking and lower tubule occlusion ratios than the unrestored tooth pairs.


      There is a decrease in the strength of radicular dentin with aging, but prior root canal treatment increases the extent of degradation.

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