Root Anatomy and Canal Configuration of Maxillary Molars in a Brazilian Subpopulation: A 125-μm Cone-Beam Computed Tomographic Study

Evaluation of Root Anatomy and Canal Configuration of Human Permanent Maxillary First Molar Using Cone-Beam Computed Tomography: A Systematic Review

The aim of this paper is to review the literature on root canal configuration (RCC) and the frequency of occurrence of a second mesiobuccal canal (MB) in human permanent maxillary first molars where cone-beam computed tomography (CBCT) is used. Online electronic databases such as PubMed-Medline, Embase, Scopus and Cochrane Library were searched using appropriate keywords from the earliest available date until 12th June 2022, without restriction on language. In the mesiobuccal root, type I was the most frequent (33.29%), followed by types II and IV (27.18% and 26.36%, respectively). Moreover, 68.2% of maxillary first molars had a second MB canal. For both the distobuccal and palatal roots, type I was the most prevalent, with 99.08% and 97.83% occurrence, respectively. All other types were infrequent. Type I RCC is most frequent in all the roots of the maxillary first molars. Hence, care must be taken during biomechanical preparation of the MB roots.

Root and Root Canal Configuration Characterization Using Microcomputed Tomography: A Systematic Review

This systematic review’s objective was to conduct a complete analysis of the literature on the root canal morphology using advanced micro-computed tomography. The electronic web databases PubMed, Scopus, and Cochrane were examined for research papers concerning the chosen keywords, evaluating the root canal morphology using Micro-CT, published up to 2021. The articles were searched using MeSH keywords and searched digitally on four specialty journal websites. DARE2 extended (Database of Attributes of Reviews of Effects) was used to assess bias risk. The information was gathered from 18 published studies that strictly met the criteria for inclusion. In the included studies, a total of 6696 samples were studied. The studies were conducted on either maxillary (n-2222) or mandibular teeth (n-3760), permanent anteriors (n-625), and Third molars (n-89). To scan samples, a Scanco Medical machine in was used in 10 studies, Bruker Micro-CT in 34, and seven other machines were utilized in the rest. Bruker Micro-CT software from Kontich, Belgium, VG-Studio Max 2.2 software from Volume Graphics, Heidelberg, Germany, was the most commonly used software. The minimum Voxel size (resolution) adopted in the included studies was 11.6 µm. However, 60 µm was the maximum. Most studies classified the root canal morphology using Vertucci’s classification system (n-16) and the four-digit system (n-6).

Prevalence of Missed Canals and Their Association with Apical Periodontitis in Posterior Endodontically Treated Teeth: A CBCT Study

Background

This study aimed to assess the prevalence of missed canals in endodontically treated teeth and their association with apical periodontitis in a Saudi Arabian population using CBCT.

Materials and Methods

A total of 208 CBCT radiographs were investigated. For each tooth, radiographs of axial, coronal, and sagittal segments were acquired to appraise the external as well as the internal structure of the root canal system and apical area. In root canal-treated teeth, unfilled canals appearing from the cementoenamel junction to the apex were defined as missed untreated canals; and a periapical lesion was considered when disruption of the lamina dura was detected, and the low-density area associated with the radiographic apex was at least twice the width of the periodontal ligament space. The data were presented as frequencies and percentages. The Z-test was used to analyze the differences in proportions with the significance level set at P value <0.05.

Results

The overall prevalence of missed canals among endodontically treated teeth was 18%. The prevalence of missed canals was higher in maxillary first molars with 40.6%. The overall prevalence of apical periodontitis among teeth with missed canals was 90%. It was 84.2% in the maxilla and 100% in the mandible. The second mesiobuccal canal in the maxillary first molars and mesiobuccal and distobuccal canals in mandibular teeth were the most missed canals.

Conclusion

Apical periodontitis in root canal-treated teeth with missed canals was high (90%), with most identified missed canals in maxillary and mandibular first molars.

Maxillary First Molars with Two Palatal Root Canals

Understanding the anatomical variations in the roots and root canal systems of a tooth is important for the success of root canal treatment. The palatal roots of the maxillary molars have fewer anatomical variations than the other roots, and fewer variations occur in the first molars than in the second molars. This case report describes two distinct cases of maxillary first molars with two palatal canals. For the root canal treatment of teeth with anatomical variations, it is essential to plan specific treatment strategies using cone-beam computed tomography and to execute them using a dental operating microscope. Knowledge of the anatomical variations in the palatal roots of maxillary first molars will help to increase the success rate of root canal treatments.

Four-Rooted Maxillary First Molars: A Systematic Review and Meta-Analysis

Objectives

The majority of human maxillary first molars is usually described as having three roots, but different morphologies were documented in several studies and case reports. One very rare and less investigated anatomical anomaly is the occurrence of four radicular structures in the upper first molars. This communication aimed to define the prevalence of four-rooted maxillary first molars on a meta-analytical basis. The external and internal morphology of these teeth was described by the collection of published case reports.

Materials and Methods

Six electronic databases were accessed to collect case reports dealing with four-rooted maxillary first molars, as well as population-based cone-beam computed tomography (CBCT) studies. Afterward, the publications were selected according to predefined inclusion/exclusion criteria and evaluated using the Joanna Briggs Institute Critical Appraisal tool. The teeth of the chosen case reports were then independently analyzed by two dental professionals according to different dental classifications. Furthermore, the population studies were meta-analyzed to calculate the global and regional prevalence of four-rooted maxillary molars.

Results

Included were forty-nine population-based CBCT studies containing 26663 maxillary first molars. Upon these data, the global incidence of four-rooted maxillary molars was meta-analytically determined as 0.047% (95%-CI:0.011-0.103%). In combination with the case reports, it was pointed out that this anomaly is distributed worldwide. Furthermore, forty-eight case reports were included containing fifty-three maxillary molars with four roots. The analyzed teeth exhibited Versiani´s pulpal chamber floor Types A and B. The majority of four-rooted maxillary first molars were classified as Type I regarding Christie's configuration. But, also 7.54% of the altered teeth could not be described by this classification. 62.34% exhibited four root canals, but also variations with five, six, or seven canals were identified. Furthermore, a significant difference was found in the occurrence rate between male and female patients.

Conclusion

Due to the worldwide occurrence, dental professionals should be aware of this rare anomaly to avoid treatment errors, especially during endodontic or surgical therapies.

Analysis of Root Canal Curvature and Root Canal Morphology of Maxillary Posterior Teeth in Guizhou, China

Background

We investigated the root canal curvature and morphology of maxillary posterior teeth in Guizhou, China, to provide references for clinical practice.

Material/Methods

We collected 274 maxillary posterior teeth in Guizhou Province, China. The root canal curvature was observed by X-ray film measurement. Two hundred teeth were selected to make transparent tooth models, and root canal configuration was recorded according to Vertucci classification criteria. The position of the MB2 root canal orifice and the mesiobuccal root canal configuration were observed by micro-computed tomographic (micro-CT) scanning. The t test and the chi-square test were used for statistical analysis.

Results

The root canals of the maxillary posterior teeth showed more significant curvature in the mesiodistal direction than in the buccolingual direction (P<0.05). The MB2 root canal of maxillary molars showed severe bending in the mesiodistal direction: 25.16±6.6 degrees and 28.05±8.65 degrees in first and second molars, respectively. The detection rate of MB2 was 48% in maxillary first molars and 32% in maxillary second molars. The results of micro-CT showed that the vertical distances between the MB2 and MB-P line were 0.64±0.34 mm and 0.57±0.28 mm in first and second molars, respectively.

Conclusions

The root canal morphology and curvature of maxillary posterior teeth varied greatly in the Guizhou population, which increases the difficulty of treatment. It is necessary for clinicians to gain understanding of the root canal and to improve the success rate of root canal therapy.

The frequency of the second mesiobuccal canal in maxillary first molars among a sample of the Kurdistan Region-Iraq population - A retrospective cone-beam computed tomography evaluation

Background/purpose

One of the most complexes in root and canal anatomy is the maxillary first permanent molar. This study aimed to analyze the frequency of mesiobuccal (MB2) canal and its apical portals of exit, in patients belonging to different gender-age groups and determine the possible relation with sex and age.

Materials and methods

A CBCT scan images were accessed from a documented database of 343 patients (178 male, 165 female), who had an oral and maxillofacial examination. The age of the patients ranging from 12 to 63 years. The frequency of the MB2 canal and its portals of exit apically were observed. Age and gender correlation were calculated using the χ2 test. P < 0.05 was considered significant.

Results

A total of 634 maxillary first molars (335 male, 299 female) were included. The MB2 canal was found in 53.78% of the cases. A significantly higher incidence of the MB2 canal was detected in males than in females. No correlation in the presence and/or absence of the MB2 canal in terms of age. When MB2 canal present, a single apical foramen was observed in 66.28% of the cases, two apical foramina were present in 33.72% of the cases.

Conclusion

MB2 canals may be present in approximately half of the cases, from which one third of the cases have their own apical portal of exit.