Morphological evaluation of maxillary second molars with fused roots: a micro-CT study

R. Ordinola-Zapata, J. N.R. Martins, C. M. Bramante, M. H. Villas-Boas, M. H. Duarte, M. A. Versiani

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40 Scopus citations


Aim: To evaluate the internal and external morphologies of fused-rooted maxillary second molars by means of micro-computed tomography (micro-CT) analysis. Methodology: A total of 100 fused-rooted maxillary second molars from a Brazilian subpopulation were divided into six groups according to the root morphology. The samples were scanned at a resolution of 19.6 μm and evaluated with regard to the external morphology of the roots, the root canal configuration, the percentage frequency of C-shaped canals and isthmuses, as well as the morphology of the root canal system at 1, 2 and 3 mm from the anatomical apex of the fused roots. Results: The most prevalent root canal fusions were type 1, mesiobuccal root fused with distobuccal root (32%), followed by type 3, DB root fused with P root (27%), and type 4, MB root fused with DB root, and P root fused with MB or DB roots (21%). The prevalence of C-shaped root canal systems were 22%. Depending on the type of root fusion, the percentage frequency of isthmuses in the apical level varied from 9.3% to 42.8%, whilst the presence of apical deltas ranged from 18.5% to 57.1% of teeth. Conclusions: The root canal system of maxillary second molars with fused roots may have a high incidence of merging canals, isthmuses, apical deltas and C-shaped configurations.

Original languageEnglish (US)
Pages (from-to)1192-1200
Number of pages9
JournalInternational Endodontic Journal
Issue number12
StatePublished - Dec 2017
Externally publishedYes

Bibliographical note

Funding Information:
This study was supported by the Brazilian Funding Agency FAPESP (grant 2013/03695-0). The authors deny any conflict of interest.

Publisher Copyright:
© 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd

Copyright 2017 Elsevier B.V., All rights reserved.


  • dental anatomy
  • fused roots
  • maxillary molars
  • micro-computed tomography


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