Clinical Oral Investigations

, Volume 22, Issue 3, pp 1363–1373 | Cite as

Outcome of secondary root canal treatment filled with Thermafil: a 5-year follow-up of retrospective cohort study

  • Chiara Pirani
  • Francesco Iacono
  • Maria Rosaria Gatto
  • Raquel Michelle Fitzgibbon
  • Stefano Chersoni
  • Hagay Shemesh
  • Carlo Prati
Original Article



The aim of the present retrospective cohort study was to assess the 5-year outcome and survival of secondary root canal treatments (2°RCT), exploring the influence of pre-, intra-, and post-operative variables.

Materials and methods

One hundred thirty-two endodontically retreated teeth were radiographically and clinically re-examined after 5 years. 2°RCT had been performed during a Masters program following standardized protocols and filled with AH Plus/Thermafil (TF). Pre-, intra-, and post-operative data were collected. The 5-year outcome was blindly evaluated and categorized as healed/diseased on the basis of the periapical index. Bivariate analysis and chi-square test evaluated the association between outcome and 31 demographic/clinical parameters. Multilevel analysis was performed at both patient and tooth level. Statistical significance was calculated at 5% level.


At 5-year evaluation, survival rate was 80% with 7.5% lost for endodontic reasons. Eighty-three percent of the teeth were classified as healed. Multilevel analysis identified significant predictors of increased survival: female gender (p = 0.012), absence of a pre-operative metal post (p = 0.017), conservative apical preparation (diameter size < #35) (p = 0.039), teeth restored with a crown (p = 0.009), and final PAI (after 5 years) ≤ 2 (p = 0.001). Multilevel analysis identified as predictor healing: not being a smoker (p = 0.048) and conservative apical preparation < size #35 (p = 0.037).


Outcome of 2°RCT filled with Thermafil was successful at 5 years, showing a high rate of survived and healed teeth comparable to that reported previously for other obturation techniques.

Clinical relevance

Present findings confirm 2°RCT as a valid therapeutic option to retain natural teeth.


Carrier-based system Clinical study Outcome predictors Secondary endodontic treatment 



The work was supported by the Master in Clinical Endodontology, Department of Biomedical and Neuromotor Sciences (DIBINEM), Alma Mater Studiorum—University of Bologna, Bologna, Italy.

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 participants 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.

Informed consent

Informed consent was obtained from all individual participants included in the study.


Although a variety of Dentsply products have been provided to the University of Bologna as part of Dentsply’s global “School Grant Program”, Dentsply was neither aware of this study nor informed of the results prior to publication.


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Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  • Chiara Pirani
    • 1
  • Francesco Iacono
    • 1
  • Maria Rosaria Gatto
    • 1
  • Raquel Michelle Fitzgibbon
    • 1
  • Stefano Chersoni
    • 1
  • Hagay Shemesh
    • 2
  • Carlo Prati
    • 1
  1. 1.Department of Biomedical and Neuromotor Sciences (DIBINEM), School of Dentistry, Endodontic Clinical Section, Master in Clinical EndodontologyAlma Mater Studiorum University of BolognaBolognaItaly
  2. 2.Endodontology, Academic Center for Dentistry AmsterdamUniversity of Amsterdam and VU UniversityAmsterdamNetherlands

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