Morphology and prevalence of middle canals in the mandibular molars: A systematic review

A systematic review and meta-analysis of the prevalence and global distribution of middle mesial canals in mandibular molars identified by CBCT

OBJECTIVES

This systematic review and meta-analysis aimed to evaluate the prevalence of middle mesial canal (MMC) in permanent mandibular molars of different populations and regions based on cone-beam computed tomography (CBCT) studies.

MATERIALS AND METHODS

PubMed, Scopus, Embase, Web of Science, and Open-Grey were searched up to October 2023 according to specific keywords. A hand search was conducted on the references of the included studies and articles from three peer-reviewed journals in endodontics. The main variable of interest was the prevalence of MMC. Additional data such as the total number of included cases, age and country of the population, CBCT device information, voxel size, and field of view details were also extracted. Extracted data were analyzed qualitatively with the JBI quality assessment checklist and quantitatively with STATA software.

RESULTS

Of 32,793 studied teeth, the cumulative prevalence of MMC in both mandibular 1st and 2nd molars was 3.11% (95% CI: 2.00-4.44%). The subgroup analysis reveals a prevalence of 4.15% (95% CI: 2.69-5.89%) for mandibular 1st molars and 1.2% (95% CI: 0.2-2.83%) for mandibular 2nd molars. The highest prevalence of MMC in 1st molar was attributed to South Asia (11.24%) and Africa (6.61%).

CONCLUSIONS

The prevalence of MMC varies among regions. Clinicians should be aware of the potential prevalence of MMC, particularly in mandibular first molars, as a missed MMC could result in endodontic failure.

CLINICAL RELEVANCE

The presence of MMCs varies in different geographic regions (0% to 29.7%). Clinicians should always look for MMC when doing an endodontic treatment on mandibular molars, as the presence of this canal is not uncommon. We suggest searching for this canal as if searching for the second mesiobuccal canal of maxillary 1st molars.

Prevalence and anatomic associations of middle mesial canals and isthmi in mandibular first molars: A CBCT-based study in a Northern Chinese population

This study investigated the prevalence of the middle mesial canal (MMC) and isthmus in a northern Chinese subpopulation using cone-beam computed tomography (CBCT). CBCT images of 1060 mandibular first molars (MFMs) were analysed. Data analysis was performed using the chi-square test, t-test, and multiple logistic regression analysis (p < 0.05). The prevalence of MMC and isthmus was 15.2% and 40.6%, respectively. The average dentinal thickness in the danger zone was 1.61 ± 0.14 mm. Patients younger than 40 years were two times more likely to have MMC (odds ratio [OR] = 2.204). Additionally, for every 1 mm reduction in the MB-ML orifice distance, the likelihood of detection of MMC in MFM nearly doubled (OR = 1.738). Furthermore, MFMs with MB-ML isthmus were five times more likely to exhibit MMC than those without it (OR = 4.756). The findings revealed that the prevalence of MMC and isthmus in MFMs is high and suggested that anatomical and demographic variables can serve as valuable indicators for clinicians in anticipating their presence.

Prevalence of middle mesial root canal in mandibular molars in an Iranian population: A micro-computed tomography study

Background

Knowledge about the anatomic variations of the root canal system and their prevalence is necessary for clinicians to ideally clean the root canal system. The anatomic complexity of the root canal system is one of the reasons for its inadequate debridement, resulting in residual microorganisms and root canal treatment failure. The present study aimed to evaluate the prevalence of middle mesial root canals in mandibular molars in an Iranian population.

Materials and Methods

The samples in the present descriptive/cross-sectional study consisted of mandibular first and second molars (n = 100, with 50 first and 50 s molars). A convenient sampling method was used to collect samples. The teeth were mounted in gypsum and scanned using a micro-computed tomography unit. The images were reconstructed with software, and the relevant checklist was completed by the observers. The data were analyzed with SPSS v26 using the Chi-squared test at a significance level of P < 0.05.

Results

The prevalence of the middle mesial root canal in the present study was 36% for mandibular first molars and 22% for mandibular second molars, with an overall prevalence of 29%. The prevalence of the middle mesial root canal was not significantly different between the first and second mandibular molars (P = 0.12). The mean distance between the mesiobuccal and mesiolingual root canal orifices in the teeth with a middle mesial root canal was significantly higher than in those without the middle mesial root canal (P < 0.001). In addition, there was no significant difference in the prevalence of the middle mesial root canal between the teeth with and without the second distal root canal (P = 0.89).

Conclusion

The prevalence of the middle mesial root canal in the studied population was 29%, which is significant clinically. In addition, the mean distance between the mesiobuccal and mesiolingual root canal orifices in teeth with a middle mesial root canal was higher than that in teeth without this root canal.

Prevalence of middle mesial canal using cone beam computed tomography: A systematic review and meta-analysis

Background

The presence of middle mesial canals in mandibular molars are not commonly encountered in daily practice. However, locating and debriding such anatomical variation during the endodontic therapy is essential to avoid endodontic failure. The aim of this systematic review was to identify the overall prevalence of middle mesial canals (MMC) in mandibular molars using cone-beam computed tomography (CBCT), to assess the influence of different gender on the prevalence of MMCs in mandibular molars and to describe the MMC configurations.

Methods

The review protocol was registered in the PROSPERO database (CRD42021238523). The main electronic databases were searched until February 2022 for prevalence studies on root/canal anatomy in mandibular molars using CBCT imaging, in addition to hand-searched scientific articles in peer-reviewed journals and grey literature. The quality of the included studies was assessed using the Joanna Briggs Institute Critical Appraisal tool. Egger's and Begg's tests and Pearson's chi-square test were used for statistical analysis.

Results

From 523 records, 488 studies were excluded after screening the title and abstract. 35 relevant studies were included for full-text assessment and 28 studies were included in the meta-analysis. The overall prevalence of MMC out of the 19,256 teeth was 5.09% (95% CI: 2.894 to 7.784). The prevalence of MMC was 9.79% (95% CI: 4.296 to 17.224) in males and 13.96% (95% CI: 0.541 to 40.737) in females with a statistically significant difference of 4.16% (95% CI: 2.29 to 6.01). The most MMC configuration found in this review to be confluent with the mesiobuccal canal.

Conclusion

The results showed an overall 5.09% prevalence of MMC in mandibular molars, with a significantly high prevalence in female subjects. Additionally, this canal was found to be confluent with the mesiobuccal canal.

The Prevalence of Middle Mesial Canals in the Second Mandibular Molars of an Iranian Subpopulation: A Cross-Sectional CBCT Study

Background Missed additional canals are a common reason for the failure of root canal treatments. The prevalence of additional canals in molar teeth can vary because of ethnic differences. Hence, this study aimed to determine the prevalence and distribution of middle mesial canals (MMCs) in the second mandibular molars using cone beam computed tomography (CBCT), for an adult population from Kerman in southeast Iran. Methodology De-identified retrospective provided CBCT scans from three private radiology centers in Kerman were reviewed (131 patients; 58 males (44.3%), 73 females (55.7%); age range: 13 to 54 years, mean age: 33). The presence of MMCs in mandibular second molars (222 teeth; 112 left and 110 right) was recorded, along with the morphology of the distal roots in the same teeth. Frequency data were analyzed using the Chi-square test and Fisher's exact test. Results The overall prevalence of MMC in the second mandibular molars was 2.3%. MMCs were found both unilaterally and bilaterally. More MMCs were found in females than males (2.7% vs. 1.7%), and on the left side (2.7% vs. 1.8%), but these differences were not statistically significant (p=1.0). There was no association between the existence of MMC in the mesial root and a second canal in the distal root of the same tooth. Conclusion Based on CBCT scans, the overall prevalence of MMC in mandibular second molars in this population was just below one in 44. Clinicians performing endodontic treatment on second molars should check for the presence of MMC so that this possible additional canal is not missed.

Prevalence of Middle Mesial Canal in Mandibular Molars of a Saudi Subpopulation: A Prospective Cone-Beam Computed Tomography Study

BACKGROUND

Root canal treatment is compromised when one or more root canals are left unmanaged, especially in the case of multirooted teeth. Cone-beam computed tomography (CBCT) has the advantage of clearly recognizing the anatomical structures without any blurring and superimposition. There are few studies that assess the middle mesial canal (MMC) prevalence in the Saudi population using CBCT imaging. Thus, the present study was conducted to assess the MMC prevalence in the first and second mandibular molars in the Saudi population using CBCT imaging.

MATERIALS AND METHODS

Data from 616 patients and 1014 teeth were assessed. The mesial roots of the mandibular first and second molars were examined using CBCT to assess the presence of the MMC in both axial and coronal sections. The potential correlation between the prevalence of MMC was assessed with gender and age. The data collected were subjected to statistical analysis using IBM SPSS version 20.0 software (IBM Corp., Armonk, NY).

RESULTS

The mean age was 34.39 ± 12.12 years, showing male predominance. A total of 2.6% and 0.2% cases of MMC were found in the first and second molars, respectively. A significant difference (p-value < 0.05) was observed among both genders in relation to age groups and the presence of MMC. MMC in the first molar was seen mainly in patients aged <20 years and only one case was reported with MMC in the second molar among patients aged 41-60 years.

CONCLUSION

A higher incidence of MMC was found in the first than the second mandibular molar. For accessing the MMC, the patient's age, high magnification, and troughing are some influential factors. In the future, clinical studies with long-term follow-ups are required to assess the influence of biomechanical preparation of MMC on the result of nonsurgical endodontic management in mandibular first as well as second molars.

Unveiling Hidden Canals: Middle Mesial Canal Prevalence in Mandibular First Molars Using Cone-Beam Computed Tomography Analysis in Central India

Background The most frequent reason involving failure of root canal treatment in molar teeth is the inability to locate additional canals. While much research has been conducted on the morphology of mandibular molars, little is known about isthmuses and middle mesial (MM) canals in the Indian population. The primary aim of the present research was to determine the prevalence of MM canals and isthmuses of mandibular first molars in the Central India population using cone-beam computed tomography (CBCT) images. Methodology CBCT of 140 mandibular first molar teeth was analyzed from the institutional database images in the coronal, sagittal, and axial planes. Data concerning the number of root canals, the presence of middle mesial canals, and the presence of isthmus were noted. Information collected was transferred into an Excel sheet and analyzed using the Statistical Package for Social Sciences (IBM Corp., Armonk, NY, USA). Results Eight images (5.71%) revealed the presence of middle mesial canals with no statistically significant occurrence. The incidence of isthmi in the mandibular first molar was 84.3%, and the presence of isthmi in the coronal third was about 38.6%. This showed a considerable presence. Conclusion There is incidence of the middle mesial canal, which emphasizes the need to locate extra canals in patients undergoing root canal endodontic treatment. The implementation of CBCT will help identify the extra canal before the treatment. This will help ultimately in providing better patient care.

Middle mesial canal in mandibular first molar: A narrative review

Purpose

This review aimed to assess the incidence, anatomical characteristics, identification, and clinical management using conventional techniques and advanced tools to manage MMCs successfully.

Methods

Medline/PubMed and Scopus databases were searched using "Middle mesial canal," "Middle mesial root canal," OR "Accessory mesial canal" keywords from 1 January 1970 and 1 February 2023. The most pertinent articles were chosen for the review from the retrieved articles. In addition, relevant articles were added by manually searching the list of references.

Results

The incidence of MMC is noticeable in younger people, and the confluent canal is the most common type. The majority of MMCs merged with mesiobuccal (MB) canals rather than mesiolingual (ML) canals. Clinical management could be employed using the standard endodontics protocol, and recent radiography technologies, magnification, rotary, and obturation materials can facilitate the procedures.

Conclusion

The possibility of the incidence of MMC is not unusual. Detection and thorough debridement followed by obturation of the canal could increase the success rate of clinical outcomes.

A microcomputed tomographic analysis of the morphological variabilities and incidence of extra canals in mandibular first molar teeth in an Egyptian subpopulation

A well-protected microbial habitat may be present in the root and canal morphology, which is varied and complicated. Before initiating effective root canal treatment, a detailed knowledge of the root and canal anatomical variances in each tooth is a must. This study aimed to investigate the root canal configuration, apical constriction anatomy, location of the apical foramen, dentine thickness, and prevalence of accessory canals in mandibular molar teeth in an Egyptian subpopulation using micro-computed tomography (microCT). A total of 96 mandibular first molars were scanned using microCT, and 3D reconstruction was performed using Mimics software. The root canal configurations of each of the mesial and distal root were classified with two different classification systems. The prevalence and dentin thickness around middle mesial and middle distal canals were investigated. The number, location and anatomy of major apical foramina and the apical constriction anatomy analysed. The number and location of accessory canals were identified. Our findings showed that two separate canals (15%) and one single canal (65%) were the most common configuration in the mesial and distal roots, respectively. More than half of the mesial roots had complex canal configurations and 51% had middle mesial canals. The single apical constriction anatomy was the most common for both canals followed by the parallel anatomy. Disto-lingual and distal locations of the apical foramen are the most common location for both roots. Mandibular molars in Egyptians show a wide range of variations in root canal anatomy with high prevalence of middle mesial canals. Clinicians should be aware of such anatomical variations for successful root canal treatment procedures. A specific access refinement protocol and appropriate shaping parameters should be designated for each case to fulfil the mechanical and biological objectives of root canal treatment without compromising the longevity of treated teeth.

Incidence of missed middle mesial canal in endodontically treated mandibular molar teeth: A cone-beam computed tomography study

Background

In endodontic treatment, the aim is to completely determine, shape, and fill all root canals in a three-dimensional way. Missed canals lead to treatment failure. In mandibular molars, there may be an extra canal called the middle mesial canal between the mesiobuccal and mesiolingual canals.

Aim

The aim of this study was to evaluate the prevalence of missed middle mesial canals in root canal-treated mandibular molar teeth.

Materials and Methods

In this study, cone-beam computed tomography (CBCT) images of 1054 patients were analyzed. We identified 121 endodontically treated mandibular molars and evaluated the prevalence of missed canals.

Results

Although 33.05% of the root canal-treated teeth did not have a middle mesial canal, this canal was detected in the other 66.94%; 97.53% of teeth with a middle mesial canal could not be detected by clinicians.

Conclusion

Clinicians performing endodontic treatment of mandibular molar teeth should not ignore the presence of the middle mesial canal. Thus, it is very important for clinicians to have sufficient information about the localization, morphology, and variations of the middle mesial canal.

The global prevalence of middle mesial canal in mandibular first and second molars assessed by cone beam computed tomography: A systematic review and meta-analysis

BACKGROUND

This meta-analysis sought to identify the in vivo prevalence and influencing factors of middle mesial canal (MMC) in mandibular first and second molars based on cone-beam computed tomography (CBCT) scans.

METHODS

MEDLINE/PubMed, Web of Science, Scopus, SciELO, Google Scholar databases/search engines were searched in period between 15^th and 21^st November 2022, to retrieve the in vivo CBCT-based studies that assessed the prevalence of MMC in mandibular first and/or second molars. The studies were strictly assessed using pre-defined inclusion and exclusion criteria for relevancy and eligibility through screening the title and abstract, and then assessed through reading the full texts using the same criteria. Subsequently, the fulfilled studies were assessed qualitatively using the Newcastle-Ottawa Quality Assessment Scale, and quantitatively using meta-analysis to calculate the pooled prevalence rates of MMC. The publication bias was assessed using funnel plot and Egger's test.

RESULTS

Out of 1,122 studies, 33 studies comprised 13,349 and 7,624 mandibular first and second molars, respectively, were eligible for inclusion. Twenty studies scored high quality, while thirteen scored moderate quality. The global prevalence of MMC in the first molar was 4.4% (95% CI = 0.035-0.053, P<0.001), significantly higher than that of the second molar which was 1.3% (95%, CI = 0.008-0.018, P<0.001). Gender, molar side, and age were not influencing factors of MMC prevalence.

CONCLUSION

The prevalence of MMC is not uncommon, being higher in the mandibular first molar compared to the mandibular second molar. The prevalence of MMC is not influenced by age, molar's side, and gender.

Evaluation of Radix Entomolaris and Middle Mesial Canal in Mandibular Permanent First Molars in an Iraqi Subpopulation Using Cone-Beam Computed Tomography

The aim of this study was to evaluate the radix entomolaris (RE) and middle mesial canal (MMC) in mandibular permanent first molars in an Iraqi subpopulation using cone-beam computed tomography (CBCT). Their prevalence and types were investigated in 201 patients (301 tooth subjects), among which 156 were of the right side, and 145 of the left side mandibular first molars (MFM), using CBCT scans. The effects of gender, age, and unilateral/bilateral on the presence of both RE and MMC were evaluated. Chi-square and Fisher's exact tests were used to determine the level of significance (p ≤ 0.05), and the kappa value was used to check reliability of results of the research. In MFM, the prevalence of right and left RE was 4.5% and 4.1%, respectively, and it was significantly higher in males than females (p = 0.006) based on the Chi-square test. No significant difference was identified in the prevalence of RE in relation to age and tooth position. MMC was found in 14.7% of teeth in the right side and 19.3% in the left side, with no significant differences for age or gender. MMC merged with mesiolingual canal presented with higher prevalence compared to other types of MMC (8.3% right side and 7.6% left side), again with no significant differences for age or gender. Within the limits of this study, no significant association was detected between the prevalence of MMC and RE in MFM.

The mid-mesial canal prevalence in mandibular molars of a Saudi population: A cone-beam computed tomography study

INTRODUCTION

The aim was to assess the prevalence of Mid Mesial Canal (MMC) in the first and second mandibular molars in a Saudi subpopulation sample and assess its relation to side, gender, and age using Cone beam computed tomography (CBCT).

METHODS

The CBCT scans at King Saud University Dental Hospital between 2016 and 2019 were reviewed and filtered. The MMC of the mandibular molars were assessed according to Pomeranz et al. classification which was: (1) independent; (2) fin; (3) confluent with the mesiobuccal canal; and (4) confluent with the mesiolingual canal. Three calibrated observers examined the MMC on all planes at both sides. Age and gender factors were used to analyze that prevalence. A chi-squared test was used and (P ≤ 0.05) was considered to be statistically significant.

RESULTS

395 patients, and 1377 teeth met the inclusion criteria. The total number of mid-mesial canals was 12 (0.9%): nine at the mandibular first molar (1.3%) and three in the mandibular second molar (0.4%). The most common type of mid-mesial canal was confluent (n = 10), of which 6 fused with the mesiobuccal canal and 4 fused with the mesiolingual canal. Two canals were of the fin type, and there was no instance of independent mid-mesial canal. There was no significant difference between all variables: tooth type, tooth side, patient gender, and patient age group (p > 0.05).

CONCLUSION

In this study, the most common MMC configuration was the confluent type followed by the fin type and no independent type were found. The patient side, gender and age did not influence the prevalence of the MMC.

Current strategies for conservative endodontic access cavity preparation techniques-systematic review, meta-analysis, and decision-making protocol

OBJECTIVES

To assess related studies and discuss the clinical implications of endodontic access cavity (AC) designs.

MATERIALS AND METHODS

A systematic review of studies comparing the fracture resistance and/or endodontic outcomes between different AC designs was conducted in two electronic search databases (PubMed and Web of Science) following the PRISMA guidelines. Study selection, data extraction, and quality assessment were performed. Meta-analyses were undertaken for fracture resistance and root canal detection, with the level of significance set at 0.05 (P = 0.05).

RESULTS

A total of 33 articles were included in this systematic review. The global evaluation of the risk of bias in the included studies was assessed as moderate, and the level of evidence was rated as low. Four types of AC designs were categorized: traditional (TradAC), conservative (ConsAC), ultraconservative (UltraAC), and truss (TrussAC). Their impact on fracture resistance, cleaning/disinfection, procedural errors, root canal detection, treatment time, apical debris extrusion, and root canal filling was discussed. Meta-analysis showed that compared to TradAC, (i) there is a significant higher fracture resistance of teeth with ConsAC, TrussAC, or ConsAC/TrussAC when all marginal ridges are preserved (P < 0.05), (ii) there is no significant effect of the type of AC on the fracture resistance of teeth when one or two marginal ridges are lost (P > 0.05), and (iii) there is a significantly higher risk of undetected canals with ConsAC if not assisted by dental operating microscope and ultrasonic troughing (P < 0.05).

CONCLUSIONS

Decreasing the AC extent does not necessarily present mechanical and biological advantages especially when one or more surfaces of the tooth structure are lost. To date, the evidence available does not support the application of TrussAC. UltraAC might be applied in limited occasions.

CLINICAL RELEVANCE

Maintaining the extent of AC design as small as practical without jeopardizing the root canal treatment quality remains a pragmatic recommendation. Different criteria can guide the practitioner for the optimal extent of AC outline form which varies from case to case.

Mandibular First Molar with Six Canals: Case Report of Radix Entomolaris and Middle Mesial Canal

The purpose of this article is to report a successful endodontic treatment of a mandibular first molar with six canals; three root canals in the mesial root, two root canals in the distal root, and one radix entomolaris. The incidence of two anatomical variations presented in this report, middle mesial canal and radix entomolaris, is generally low. Knowledge of the internal anatomy of the root canals and their possible variations, and use of magnification, such as the operating microscope or loupes, can increase the chances of finding additional canals, contributing to the success of endodontic treatment.

Evidence of Second Canal between Permanent Mandibular Central and Lateral Incisors in China; a Systematic Review on CBCT Studies

Introduction

Evidence of second canal in permanent mandibular incisors is frequently questioned in dentistry. The difference in evidence between the two teeth is an interesting argument across different countries and ethnicities. So the aim of the systematic review was to investigate the evidence of second canal between permanent mandibular central and lateral incisors in China.

Materials and Methods

The papers were selected from the electronic databases and hand searching according to inclusion and exclusion criteria. All qualified studies were judged by the reviewers. The selected studies were checked with Joanna Briggs Institute Critical Appraisal tool for prevalence studies. Finally, three studies were selected for the review and meta-analyses. The proportion of the second canal with its confidence interval and forest plot for the meta-analyses were calculated.

Results

The evidences of second canal in permanent mandibular central and lateral incisors in China were 5.6% and 14.1%. Only one study reported bilateral symmetry of the second canal as 58.7% and 76.1% in the two types of teeth. Out of all canal anatomies, Vertucci's type ΙΙΙ was dominant comprising 4.1% and 11.2% together with other second-canal types comprising 1.4% and 3% in permanent mandibular central and lateral incisors. When the proportions were meta-analyzed, mandibular central incisors had been less numerous OR = 0.35 [0.31, 0.40], 0.33[0.28, 0.39], and 0.42 [0.22, 0.79] in the evidence of second canal, of Type ΙΙΙ, and of other types except Type ΙΙΙ than mandibular lateral incisors in China. Out of all second-canal anatomies, Type ΙΙΙ presented 72.5% and 78.9% along with other second-canal types comprising 24.3% and 21.1% in the two teeth in China. Discussion. There was the evidence of second canal which deviated toward the permanent mandibular lateral incisor also in case of bilateral symmetry, the prevalence of Vertucci's Type ΙΙΙ, and other second-canal types out of all canal anatomies.

A mandibular second molar with a middle mesial root canal

The present case report describes the clinical detection and root canal management of a rare middle mesial canal of a Japanese mandibular second molar by troughing preparation using an operating microscope and cone-beam computed tomography.

Cone-beam computed tomography investigation of middle mesial canals and isthmuses in mandibular first molars in a Chinese population

Background

While there is ample research into the anatomy of mandibular molars, little is known regarding isthmuses and middle mesial (MM) canals in Chinese populations. The goal of this study was to determine the prevalence of MM canals and isthmuses in the mesial root of mandibular first molars using Cone-beam Computed Tomography.

Methods

Cone-beam Computed Tomography images of 357 mature mandibular first molars were retrospectively analyzed. Presence of isthmuses and MM canals, and the length of isthmuses in the mesial root were recorded. Meanwhile, we also recorded possible correlated factors such as demographics, side of mandible, presence of separated distal-lingual roots.

Results

Of these 357 teeth, 209 showed evidence of either complete or partial communication in the mesial root. Of these, 11(3.1%) exhibited true MM canals while 198(55.5%) exhibited isthmuses. Sex or side of mandible was not correlated with the prevalence of isthmuses (P > 0.05). However, there was a significant association between the presence of a distal-lingual root and the prevalence of such communication (P < 0.001). The average length of isthmuses was 4.3 ± 3.1 mm.

Conclusions

We detected high rate of isthmuses and low rate of MM canals in mesial roots of mandibular first molars, which is important as such areas should be identified and cleaned during root canal treatment.

Evaluation of Roots and Canal Systems of Mandibular First Molars in a Vietnamese Subpopulation Using Cone-Beam Computed Tomography

Objectives:

The aim of this study is to determine the prevalence of the first lower molars that have two roots or three roots and the number of the root canals of the mandibular first molars in the Vietnamese subpopulation using cone-beam computed tomography (CBCT).

Materials and Methods:

The study was conducted on 166 patients who had CBCT as indicated by dentists in Nguyen Trai Dental CT Center, Ho Chi Minh City using the Picasso Trio (Ewoo Vatech, Korea). The number of root canals of the first lower molars was examined by moving cross-sectional slices from the pulpal floor to the apex. The orifices, middle thirds, and apical thirds of the canals of the first lower molar were observed, and the root canals of each root of the mandibular first molars were observed in three planes.

Results:

The prevalence of two, three, and four root canals of the mandibular first molars was 4.5%, 66.8%, and 28.9%, respectively. For the distal roots of these molars, a classification of Vertucci type I was the most common at a rate of 80.8%–97.6%. Whenever these teeth had three roots, a Vertucci type I was the classification of 100% of distolingual roots.

Conclusion:

Majority of the mandibular first molars has two roots and three canals. CBCT is appropriate equipment useful in investigating the complex root canal morphology of human teeth.