The Radix Entomolaris and Paramolaris: A Micro–Computed Tomographic Study of 3-rooted Mandibular First Molars

Clinical strategies for successful palato-mesiobuccal canal management-Report of 2 cases

AIM

To describe the management of the palato-mesiobuccal (PMB) canal in maxillary second molars with fused roots using conventional techniques.

SUMMARY

Root canal treatment success hinges upon effectively addressing the intricate and variable anatomy of molar teeth. Failure to do so can lead to persistent infections and treatment failure. Recent advancements in imaging technologies have provided unparalleled insights into dental anatomy, especially in molars. Among these discoveries is the PMB canal, a unique anatomical variant recently reported for the first time in Endodontic literature. This canal, found in maxillary second molars with fused roots and originating from the coronal third of the palatal canal while traversing towards the mesiobuccal root presents challenges in clinical management due to its location. This article is the first to showcase the management of the PMB canal using conventional techniques. In the first case, a 38-year-old male patient presented with asymptomatic irreversible pulpitis in the maxillary second right molar. Following thorough instrumentation and irrigation, the presence of the PMB canal was discovered during root canal preparation. The canal was managed using rotary instruments and obturated successfully, resulting in a symptom-free tooth at an 8-year follow-up. The second case illustrates a similar scenario in a 23-year-old female patient presenting with symptomatic irreversible pulpitis in tooth 17. The PMB canal was identified during treatment and managed using rotary nickel-titanium instruments, leading to a favourable outcome at a 9-year follow-up.

KEY LEARNING POINTS

In fused roots of maxillary second molars, a PMB canal might be expected. Exploration of the buccal wall of the palatal canal under magnification after shaping procedures can reveal the PMB canal orifice in fused roots. Small tapers are suggested for the enlargement of the PMB canal. Continuous bleeding spots in the palatal canal might indicate a possible PMB canal orifice in vital cases. The use of an apex locator is suggested for the differential diagnosis of the PMB canal orifice from a perforation site.

Prevalence of Radix Entomolaris in Mandibular Permanent Molars Analyzed by Cone-Beam CT in the Saudi Population of Ha'il Province

BACKGROUND

The present study aimed to examine the prevalence of radix entomolaris (RE) in the mandibular permanent molar within a specific sub-population in Saudi Arabia.

METHODS

A comprehensive analysis was conducted on 499 cone-beam computed tomography (CBCT) scans of a mandibular molar from a sample of Saudi patients aged between 18 and 65. The primary objective of this study was to investigate the anatomical characteristics of mandibular permanent molars, specifically focusing on the number of roots present. The chi-square test was employed to examine the relationship between various variables.

RESULTS

In the case of mandibular first molars, it was observed that 95.3% of these molars exhibited a bifurcated root structure. In comparison, the remaining 4.7% displayed a triradicular configuration within the sample population under investigation. Although there were some variations, no significant differences in the number of roots were observed between males and females or left and right sides (p > 0.05). In the case of mandibular second molars, it was observed that 96.9% of them exhibited a bifurcated root structure, whereas 2.5% displayed a trifurcated root configuration, and a mere 0.6% possessed a single root. There were no statistically significant variations in the number of roots between males and females or left and right sides (p > 0.05).

CONCLUSIONS

The identification of RE was observed in the mandibular molars. Moreover, the discovered RE roots were predominantly found in the mandibular first molar, displaying a tendency for bilateral occurrence in both male and female individuals.

Mandibular incisors with two canals are associated with the presence of the distolingual root in mandibular first molars: a cone-beam computed tomographic study

Background

This study aimed to evaluate the root canal configurations and the association between mandibular first molars and distolingual root (DLR) and mandibular incisors using cone-beam computed tomography (CBCT).

Methods

Mandibular first molars and incisors were evaluated using CBCT images of 150 patients. Mandibular first molars were classified according to the presence or absence of DLR. The curvature of the DLR was evaluated using Schneider’s method in buccolingual and mesiodistal orientations. The angle of the mesiolingual–distolingual–distobuccal canal orifices (ML–DL–DB) was evaluated at the pulpal floor level. The mandibular central and lateral incisors were classified as either single canal or two canals. The association between the root canal system of the mandibular first molar and mandibular incisors was evaluated. Data were analyzed using the Chi-square test, Student’s t-test, and odds ratios from binary logistic regression. The significance level was set at 5%.

Results

The frequency of mandibular first molars with DLR was 27.0% and that of mandibular incisors with two canals was 25.8%. The curvature of the DLR was 37.1° in the buccolingual orientation and 10.4° in the mesiodistal orientation. The angle of ML–DL–DB was 79.0°. The presence of two canal systems in mandibular incisors was associated with the presence of DLR in the mandibular first molar (left central incisors: p = 0.001, odds ratio = 4.25; left lateral incisors: p < 0.001, odds ratio = 3.8; right central incisors: p = 0.003, odds ratio = 3.86; right lateral incisors: p = 0.001, odds ratio = 3.44) but not with the curvature of the DLR or angle of the ML–DL–DB orifice (p > 0.05).

Conclusions

The mandibular first molar showed a high incidence of separate DLRs. It was confirmed that DLR in the mandibular first molar is highly associated with the presence of two-canal system in the mandibular incisors. This association can aid clinicians in successful endodontic treatments.

Three-Rooted Permanent Mandibular First Molars: A Meta-Analysis of Prevalence

Introduction

Although numerous amounts of high-level evidence were present, they solely emphasized the tooth-level prevalence of three-rooted permanent mandibular first molar. Global patient-level prevalence and bilateral symmetrical distribution of this type of teeth were needed to be tackled across the world. The research question was "What is the global prevalence of three-rooted permanent mandibular first molars?"

Materials and Methods

In vivo epidemiological studies undergone with Cone Beam Computed Tomography (CBCT) were eligible. The proportions of the prevalence of three-rooted permanent mandibular first molars were presented in the forest plots by random effect model. The calculation was performed with MetaXL version 5.3. Subgroup analysis, sensitivity analysis, and publication bias method were also calculated.

Results

Seventy-two studies from 31 countries were selected for both qualitative and quantitative analyses. 26302 patients and 37994 permanent mandibular first molars were included in the analysis. 9% of permanent mandibular first molars all over the world demonstrated 3 roots. These three-rooted teeth were found in 10% of the world population, more than 45% of which revealed bilateral symmetry of that anatomy. Right-side dominance and no sexual dimorphism were seen in the distribution of three-rooted permanent mandibular first molars. Global tooth-level prevalence of Radix Entomolaris and Radix Paramolaris was 12% and 0.1%, respectively.

Conclusion

The prevalence of three-rooted permanent mandibular first molars (PMFMs) was influenced by different geographical locations across the world and also by widespread habitation of the Mongoloid descent. The authors postulate that globalization, together with blending among ethnicities, may have a great impact on the reduction or accentuation of the anatomical significance in some populations.

Geometric Analysis of the Distolingual Root and Canal in Mandibular First Molars: A Micro-computed Tomographic Study

INTRODUCTION

The purpose of this study was to comprehensively assess by micro-computed tomographic imaging the anatomic features of distolingual (DL) roots and canals in mandibular first molars collected from 1 population.

METHODS

One hundred two specimens were examined for the location and initial direction of the DL canal and the relationship between the distance of apical deviation and the angle of root curvature.

RESULTS

All DL roots had only 1 canal. A new 7-category classification system is proposed for the DL roots of mandibular first molars. Most DL roots were type IV (28 teeth), type III (26 teeth), and type V (25 teeth). The average canal curvature in all root types was over 25°. There was a positive correlation between the angles of root and canal curvature for types II, IV, and V (P < .05) but not for types I and III (P > .05). In the buccolingual view, most DL roots were straight, whereas in the mesiodistal view the root curvature was close to the maximum value. The orifice of the DL canal was 4 times further from the line that bisects a line between the mesiobuccal and mesiolingual canal orifices than the distobuccal canal. The angle between the mesiobuccal-mesiolingual line and the horizontal projection of the coronal third of the DL canal on the pulp floor was 8.1° ± 10.0° and 6.1° ± 8.2° for teeth from the left and right side, respectively. The angle between the inserted simulated file and the cementoenamel junction was 57.9° ± 6.3°. Seventy-three percent of the DL canals had no constriction in the apical area. The DL canals were narrow and had a conical frustum-like shape with a 0.04 taper at the apical portion.

CONCLUSIONS

The novel classification of the DL roots helps to better understand the clinically challenging anatomy of the root and canal.

Prevalence of middle mesial canal and radix entomolaris of mandibular first permanent molars in a western Chinese population: an in vivo cone-beam computed tomographic study

Background

The aim of this study was to investigate the prevalence of the middle mesial canal (MMC) and radix entomolaris (RE) in mandibular first permanent molars in a western Chinese population using cone-beam computed tomography (CBCT).

Methods

A total of 1174 CBCT images of the mandibular first molars were collected from West China Hospital of Stomatology, Sichuan University. The following information was recorded and evaluated: the detection rate and location of the MMC and RE, the curvature of the RE, the canal configuration and bilateral symmetry.

Results

The detection rates of the MMC and RE were 3.41 and 25.04%, respectively, as calculated by individuals, and 1.79 and 22.15%, respectively, as calculated by total teeth. The average curvature in the buccolingual (BL) orientation (40.63 ± 14.39°) was significantly larger than that in the mesiodistal (MD) orientation (17.64 ± 7.82°) (p < 0.05). Of 587 patients, 71.72% (421/587) had bilateral symmetry according to the root canal morphology. The prevalence of three-rooted mandibular first molars was higher in males than in females, while the prevalence of two-rooted mandibular first molars was higher in females than in males.

Conclusions

Our results showed that the RE could be detected in almost 1/4 of the western Chinese population; thus, RE detection requires special attention and careful assessment in endodontic treatment.

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Objectives

This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci & Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT).

Methodology

500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci & Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p<0.05).

Results

According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027).

Conclusions

μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems.

Lower First Permanent Molar with an Additional Root Diagnosis and Management

Three rooted lower first permanent molar represents one of the main anatomical variants which is a treatment challenge of clinicians. This study is aimed at presenting a case of a lower first molar with an additional root that was diagnosed and managed successfully using new techniques in endodontics. Tooth #46 was diagnosed as a necrotic pulp with symptomatic apical periodontitis. Different angle radiographs were obtained, and they clearly showed three roots. The procedure was completed under magnification and illumination using an operating microscope. The access cavity was modified to achieve straight line access for all the canals. Careful step-by-step instrumentation was performed using flexible NiTi rotary files. The canals were irrigated using 6% sodium hypochlorite. Afterwards, three-dimensional obturation was completed using warm vertical compaction. Knowledge of the anatomy and an early diagnosis are required to achieve high-quality root canal treatment.

Prevalence of three-rooted mandibular permanent first and second molars in the Saudi population

Introduction

This study aims to explore the frequency and factors affecting the prevalence of an extra root in the lower first and second permanent molars in the Saudi population.

Methods

Images of 379 Saudi patients who underwent CBCT for routine dental treatment were assessed. The CBCT images were evaluated on a 34-inch LED screen in a dark room and assessed by two examiners to count the prevalence of an additional root in the lower molars. Laterality and the gender factors were used to analyze that prevalence. Percentages represent categorical variables; Fisher’s exact test and Chi square test were also used for the categorical variables.

Results

In the lower first molars, the prevalence of extra root in female patients was 5.7%, 3% in male patients and the overall prevalence was 3.05%; in lower second molars, the prevalence was 1.81% in female patients and 3.04% in male patients with an overall prevalence of 1.48%. A statistically significant difference was fond in the existence of an additional root with regard to laterality, to be more common on the right compared to the left side for both mandibular molars. The extra root prevalence was statistically significant in female patients at the first molar compared to male patients (p < 0.05).

Conclusion

The overall of extra roots prevalence in the lower first and second molars in the Saudi population are 3.05% and 1.48%, respectively. Consideration and identification of this variation is essential to ensure successful endodontic treatment.

Prevalence and Distribution of Radix Paramolaris in the Mandibular First and Second Molars of an Iranian Population

Objectives

Inability to find supernumerary roots is one of the most important reasons for root canal therapy failures in molar teeth. This research aimed to determine the incidence and distribution of radix paramolaris in permanent mandibular molars of the population of Kerman. Iran over 2016-2017.

Materials and Methods

This study was performed on a collection of 500 extracted permanent mandibular first and second molars selected by random from different dental centers in Kerman without recording the sex and age of the patients as inclusion criteria. The incidence of additional mesiobuccal root (radix paramolaris), the average root length and morphology of this root was carefully determined following the Calberson and Alexanderson classification pattern.

Results

The incidence of radix paramolaris was 1.2% in mandibular first molars (0.8% Type A and 0.4% Type B) and 0.8% in mandibular second molars (0.4% Type A and 0.4% Type B) of this population. Fischer's Exact test showed that the difference in frequency of the radix paramolaris between first and second mandibular molars of this population was not statistically significant (two-sided P = 0.0001). The average length for radix paramolaris was 13.05 mms in mandibular first and second molars in this study.

Conclusion

Radix paramolaris was found more frequently in mandibular first molars than in mandibular second molars in this sample of 500 mandibular molars. The rate of 1.2% in first molars seems to be higher than reported rates in European or Caucasian populations where the prevalence is typically <0.5%.

Radix Entomolaris in the Mandibular Molar Teeth of an Iranian Population

Purpose. Supernumerary roots in permanent mandibular molar teeth make endodontic treatment more complicated. The aim of this study was to determine the prevalence of Radix Entomolaris (RE) in permanent mandibular first and second molars in the population of Kerman, in the southeast of Iran. Materials and Methods. From a collection of 500 mandibular first and second molar teeth extracted over 2015-2016 at dental clinics in Kerman, teeth were scored for an additional distolingual root, and the average root length and root morphology of this extra root were determined using the De Moor classification scheme. Results. In this population, RE occurred in 6% of mandibular first molars (4% with a straight apex (Type I) and 2% with buccal apical curvature (Type III)). In all cases, RE was the shortest root, with an average root length of 18.37 mm. RE occurred in only 0.8% of mandibular second molars, with an average root length of 18.0 mm. All mandibular second molars with RE were of Type III. Fisher's exact test showed that the difference in frequency between first and second molars was statistically significant (two-sided P = 0.002). Conclusion. Radix Entomolaris occurs more frequently in mandibular first molars than in mandibular second molars in this sample of 500 mandibular molars. The reported rate of 6% in first molars is expected to be higher than reported rates in European or Caucasian populations where the prevalence is typically less than 2%.

Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation

The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present.