An in vitro assessment of type, position and incidence of isthmus in human permanent molars

Authors

  • Fernando José Camello de LIMA State University of Campinas; Piracicaba Dental School; Department of Restorative Dentistry; Endodontics Division
  • Francisco MONTAGNER State University of Campinas; Piracicaba Dental School; Department of Restorative Dentistry; Endodontics Division
  • Rogério Castilho JACINTO State University of Campinas; Piracicaba Dental School; Department of Restorative Dentistry; Endodontics Division
  • Glaucia Maria Bovi AMBROSANO State University of Campinas; Piracicaba Dental School; Biostatistics Division; Department of Social Dentistry
  • Brenda Paula Figueiredo de Almeida GOMES State University of Campinas; Piracicaba Dental School; Endodontics Division; Department of Restorative Dentistry

DOI:

https://doi.org/10.1590/1678-775720130585

Abstract

Root canal anatomical complexities, such as isthmus, may limit the action of the endodontic instruments, irrigant solutions and intracanal medications, leading to endodontic treatment failure. Objectives: This in vitro study assessed the type, position and incidence of isthmus in human permanent molars. Material and Methods: One hundred and twenty eight upper and lower first and second permanent molars were analyzed. The roots were embedded in transparent resin, and then split at different distances from the apex (1.0-2.5-4.0-5.5-7.0 mm). Following the sample examination in stereomicroscope, the data were submitted to chi-square statistical test at a 5% significance level. Results: The highest isthmus incidence was at 7.0 mm from the root apex in all samples, except the distal root of lower molars (at 5.5 mm). In upper and lower molars, type V (complete isthmus with a continuous opening between the two main root canals) was the most common classification of isthmus (28.8%). In the mesial root of first and second mandibular molars, type IV had the highest incidence (36% and 23.9%, respectively). Conclusion: It was concluded that isthmus was widely found in flat roots, with a low percentage in areas close to the apex. In upper and lower molars, these structures were most frequently found at 7 mm from the apex.

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Published

2014-07-01

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Section

Original Articles