Clinical Oral Investigations

, Volume 22, Issue 3, pp 1385–1393 | Cite as

Influence of the internal anatomy on the leakage of root canals filled with thermoplastic technique

  • Anas Al-Jadaa
  • T. Attin
  • T. Peltomäki
  • C. Heumann
  • P. R. Schmidlin
  • F. Paquè
Original Article



The aim of this paper is to evaluate the influence of the internal anatomy on the leakage of root canals filled with the thermoplastic technique.

Materials and methods

The upper central incisors (UCI) and mesial roots of the lower molars (MRLM) (n = 12 each) were tested regarding leakage using the gas-enhanced permeation test (GEPT) after root filling. The quality of the root fillings was assessed using micro-computed tomography (μCT) by superimposing scans before and after treatment to calculate unfilled volume. The calculated void volume was compared between the groups and correlated to the measured leakage values. Data were analyzed using t test and Pearson’s correlation tests (p < 0.05).


The mean void volume did not differ between UCI and MRLM (13.7 ± 6.2% vs. 14.2 ± 6.8%, respectively). However, significantly more leakage was evident in the MRLM (p < 0.001). While the leakage correlated highly to the void volume in the MRLM group (R 2 = 0.981, p < 0.001), no correlation was found in UCI (R 2 = 0.467, p = 0.126).


MRLM showed higher leakage values, which correlated to the void volume in the root canal fillings.

Clinical relevance

Care should always be taken while doing root canal treatments, but attention to teeth with known/expected complex root canal anatomy should be considered.


Endodontics Leakage μCT Root canal anatomy 



The work was supported by the Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zürich, Switzerland.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in studies involving human teeth were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The current research protocol was according to the guidelines of Good Clinical Practice (ICH, Geneva, Switzerland) and did not alter the treatment plan of any of the involved patients. The institutional ethics committee approved the procedures.

Informed consent

The patients gave an informed consent that their extracted teeth could be used for study purposes anonymously.


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Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental MedicineUniversity of ZurichZürichSwitzerland
  2. 2.Oral and Maxillofacial UnitTampere University HospitalTampereFinland
  3. 3.Department of StatisticsUniversity of MunichMunichGermany

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