Influence of foraminal enlargement on the healing of periapical lesions in rat molars

  • Paula Maciel Brandão
  • José Antonio Poli de Figueiredo
  • Renata Dornelles MorgentalEmail author
  • Roberta Kochenborger Scarparo
  • Rafael Chies Hartmann
  • Silvana Beltrami Gonçalves Waltrick
  • Ronaldo Araújo Souza
Original Article



The aim of this study was to evaluate the influence of foraminal enlargement on the healing of induced apical periodontitis in a rat model.

Material and methods

Periapical lesions were bilaterally induced in mandibular first molars of 24 Wistar rats, through root canals exposure to the oral environment during 3 weeks. Endodontic treatment was performed in the mesial canal of right molars, which were separated into two experimental groups (n = 12/group). The foraminal enlargement group (FEG) received instrumentation in the entire root canal length, including the cemental canal, while in the non-foraminal enlargement group (NFEG), instrumentation was carried out 1 mm short of the apical foramen. Root canals were filled with gutta-percha and AH Plus sealer, in the same visit, 1 mm short of the apical foramen in both experimental groups. Left molars were not treated and served as a baseline control group. The animals were killed after 4 weeks, and their hemi-mandibles were prepared for radiographic and histological analysis. Data were analyzed by Student’s t test and ANOVA.


Only FEG presented lower areas of periapical radiolucency compared to the control (p < .05). Both FEG and NFEG allowed decreased inflammation intensity (p < .0001 and p < .01) and higher scores of cementum neoformation when compared to non-treated samples (p < .0001). FEG was more effective than NFEG in promoting biological seal, i.e., apical closure with cementum (p < .01). FEG, but not NFEG, showed lower scores of root resorption than the control.


Foraminal enlargement during root canal preparation improved periapical healing in rat molars.

Clinical significance

Foraminal enlargement has been suggested to improve disinfection at the apical portion of root canals. This procedure may favor the healing of chronic periapical lesions.


Endodontics Periapical diseases Root canal preparation Tooth apex 



The work was supported by the Graduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

Informed consent

For this type of study, formal consent is not required.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018
corrected publication 2019

Authors and Affiliations

  • Paula Maciel Brandão
    • 1
  • José Antonio Poli de Figueiredo
    • 2
  • Renata Dornelles Morgental
    • 3
    Email author
  • Roberta Kochenborger Scarparo
    • 4
  • Rafael Chies Hartmann
    • 2
  • Silvana Beltrami Gonçalves Waltrick
    • 2
  • Ronaldo Araújo Souza
    • 1
  1. 1.Department of EndodonticsBahia School of Medicine and Public HealthSalvadorBrazil
  2. 2.Clinical Department, School of DentistryPontifical Catholic University of Rio Grande do SulPorto AlegreBrazil
  3. 3.Department of Stomatology, School of DentistryFederal University of Santa MariaSanta MariaBrazil
  4. 4.Department of Conservative Dentistry, School of DentistryFederal University of Rio Grande do SulPorto AlegreBrazil

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