Internal and external morphology of mandibular molars: An original micro‐CT study and meta‐analysis with review of implications for endodontic therapy

Abstract

The aim of this radiological micro-CT study and meta-analysis was to determine the morphological features of the root canal anatomy of the mandibular molars. The radiological study included micro-CT scans of 108 mandibular first, 120 mandibular second, and 146 mandibular third molars. For our meta-analysis, an extensive search was conducted through PubMed, Embase, and Web of Science to identify articles eligible for inclusion. Data extracted included investigative method (cadaveric, intraoperative, or imaging), Vertucci type of canal configuration, presence/number of canals, roots, apical foramina, apical deltas, and intercanal communications. In the mesial roots of mandibular molars, the most frequent Vertucci type of canal configuration was type IV, except for the mandibular third molar where type I was most common. Type I was most common in the distal root. There were usually two canals in the mesial root and one in the distal root. Two was the most common number of roots, and a third root was most prevalent in Asia. One apical foramen was most common in the distal root and two apical foramina in the mesial root. Intercanal communications were most frequent in the mesial root. Knowledge of the complex anatomy of the mandibular molars can make root canal therapy more likely to succeed. We recommend the use of cone-beam computed tomography before and after endodontic treatment to enable the root anatomy to be accurately described and properly diagnosed, and treatment outcome to be assessed. Clin. Anat. 31:797-811, 2018. © 2018 Wiley Periodicals, Inc.

Root morphology of mandibular molars: a cone-beam computed tomography study

“…The results obtained in this study agree with those observed in Brazilian, Palestinian, Turkish and Chinese populations, where it was seen that the most frequent morphology for mandibular molars is two canals in the mesial root and one in the distal evaluated by CBCT [5,6,24]. The same results were reported in Egyptian and Brazilian populations using micro-CT [9,23] and in a systematic review that included 64 studies using micro-CT [18]. Evidence shows that ethnicity is more related to the number of roots than to the number or distribution of root canals [7], which would explain the similarity with the results obtained in this study.…”

“…The different anatomical variations represent a technical challenge to achieve success in endodontic treatment [5]. Images obtained by CBCT are a reliable tool for the detection and later instrumentation of complex canal configurations [18] and one of the reasons for which their application in endodontics has increased in recent years [17].…”

Root canal segmentation in cone-beam computed tomography

“…Results showed no statistical differences when the volumes obtained by the "visual micro-CT" and the gold standard were compared. Thus, for micro-CT images, both segmentation methods are reliable to calculate root canal volume, corroborating a previous study 11 . Such findings may be attributed to the high resolution and low noise produced by micro-CT, what makes identification of dentin borders accurate.…”

“…Certain factors however, such as voxel size, acquisition parameters, and number of acquired images, can directly influence the quality of the produced tomographic images 7 . On the other hand, micro-CT has been recently suggested as a possible gold standard for a precise and non-destructive in vitro study of the 3D anatomy of the root canal system 8,9 due to its high resolution, low noise and precise three-dimensional reproduction of the internal and external morphology of the tooth 10,11 .…”

Autotransplantation of the Third Molar: A Therapeutic Alternative to the Rehabilitation of a Missing Tooth: A Scoping Review

“…If the donor tooth is easily accessible, it is possible to treat the root canal before its atraumatic extraction [4,104]. Third molars often present anomalies in the conformation of the roots and root canals, making endodontic treatment difficult [105][106][107]. In these cases, the apical resection of the tooth to be transplanted allows the removal of the more complex part of the root and limits the possible complications of a future orthograde treatment [29].…”