Three-rooted Mandibular Molars Research Articles

Investigation of the furcation morphology of permanent mandibular first molars by using micro-computed tomography

BackgroundTo investigate the anatomic features of the root furcation of permanent mandibular first molars.MethodsA total of 50 extracted mandibular first molars (25 two-rooted and 25 three-rooted) were collected and scanned using micro-computed tomography. The digital models of teeth and root canal systems were reconstructed three-dimensionally. The tooth models were displayed in parallel projection mode from buccal and distal views. Screenshots were captured and subsequently analyzed using Image-Pro Plus 6.0 software after calibration. The furcation angle, root trunk length, maximum depth and level of distal root concaves of mesial roots, and length of enamel projections were measured, and the furcation types (classified into type V, type U and type W) were detected. Statistical analysis was performed using the Shapiro-Wilk’s test, one-way analysis of variance, Student’s t-test and Chi-square test.ResultsThe mean furcation angle between the distobuccal (DB) and distolingual (DL) roots (in distal view) was the greatest (59.2°), whereas the furcation angle between the mesial and DL roots (in buccal view) was the smallest (25.4°) among the four furcation angles (all p < 0.05). Regarding the furcation types, bucco-lingual root trunk length, maximum depth and site of the distal root concavities, and enamel projection length, no significant differences were detected between the three- and two-rooted molar groups (all p > 0.05). The frequency of type V was the highest (54.0%), followed by type U (26.0%), and type W had the lowest occurrence rate (20.0%). The mean length of distal root trunk in the three-rooted mandibular molars was significantly greater than that of the buccal/lingual one (3.7 mm vs. 3.0 mm, p < 0.01). The maximum depth of the distal concavities of the mesial roots was on average 0.66 ± 0.19 mm, and the site was located at an average of 2.8 ± 1.3 mm below furcation. The mean length of buccal enamel projections was significantly longer than that of lingual ones (3.1 mm vs. 0.7 mm, p < 0.01).ConclusionsThe furcation anatomy of the mandibular first molar is complex, and the presence of the DL root may further complicate its topography. A thorough understanding of these anatomic features is essential for successful periodontal treatment.

Prevalence of C-shaped canals and three-rooted mandibular molars in the Iranian population by using cone-beam computed tomography.

This study aimed to evaluate the prevalence of C-shaped canals and three-rooted mandibular molars in the Iranian population using cone-beam computed tomography (CBCT). This study evaluated mandibular teeth on 292 CBCT scans of patients referred to the Department of Radiology, Faculty of Dentistry, Islamic Azad University, Isfahan, Iran. All CBCT scans were obtained with the same three-dimensional CBCT scanner, and sections were reconstructed in all three planes (sagittal, axial, and coronal) with 1 mm slice thickness. A total of 291,402, and 200 first, second, and third molars, respectively, were evaluated. Data were analyzed using SPSS software (version 26.0). Of 291 mandibular first molars, 0.7% were single-rooted, 96.6% were two-rooted, and 2.7% were three-rooted. The prevalence of C-shaped canals was 1.7% in mandibular first molars. Of 402 mandibular second molars, 8.5% were single-rooted, 90.5% were two-rooted, and 1% were three-rooted. The prevalence of C-shaped canals was 2% in mandibular second molars. Of 200 mandibular third molars, 21.5% were single-rooted, 77.5% were two-rooted, and 1% were three-rooted. The prevalence of C-shaped canals was 2% in mandibular third molars. In the present study, the majority of mandibular molars were two-rooted, and three-rooted mandibular molars were less common. The third and second mandibular molars both had an increased prevalence of C-shaped canals. Mandibular first molars had the highest prevalence of three-rooted molars.

Radiographic Investigation of Root Canal Morphology of Permanent Mandibular Molars in Makkah Population (Saudi Arabia) Using Cone-Beam Computed Tomography.

Objectives This study aimed to analyze the root canal morphology of first and second permanent mandibular molars among Makkah population by using cone-beam computed tomography (CBCT). Materials and Methods CBCT images of two hundred eight patients were obtained from the Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia. In all images, mandibular first and second molars were evaluated for the number of roots and their morphology, number of root canals, canal configuration in each root according to Vertucci's classification, and the presence of a C-shaped canal. Results Most of the mandibular first molars had two roots (96.5%) and three root canals (77.7%). Type IV canal configuration prevailed (75.6%) in the mesial roots, and type I canal configuration prevailed (71.7%) in the distal roots. For the mandibular second molars, the majority had two roots (96.3%) and three root canals (82.7%). Type IV canal configuration prevailed (48%) in the mesial roots and type I (99.1%) in the distal roots. C-shaped canals were detected in 5.7% of the mandibular first molars and 4% of the mandibular second molars. There was no statistical difference between the mandibular first and second molars (P > 0.05) in the shape of the roots and the presence of the C-shaped canals. Conclusion Most of the mandibular molars in Makkah population presented with two roots and three root canals. The incidence of three-rooted mandibular molars was low, and it was higher in the first molars than second molars. The type IV root canal system prevailed in mesial roots and type I in distal roots.

Prevalence of C-shaped Canals and Three-rooted Mandibular Molars Using CBCT in a Selected Thai Population.

C-shaped canals and three rooted mandibular molars are challenging to treat. These anatomies are commonly found in mandibular molars, especially in the Mongoloid population. However, there is no report on these anatomies using cone-beam computed tomography on all three mandibular molars in Thais. The objectives of this study were to determine the prevalence of C-shaped canals and three-rooted mandibular molars in Thais and investigate whether there is a relationship between these morphology and gender. Three pre-calibrated observers independently determined the presence of each anatomy using a specific protocol in 753 molars from cone-beam computed tomographic images. The three observers randomly re-evaluated 20% of the samples to determine inter- and intra-observer agreement using Cohen's Kappa statistic. The relationship of these root canal anatomy with sex was analysed by the Chi-square test. The prevalence of C-shaped canals and three-rooted molars was 0.39% and 12.1%, 42.4% and 3.9%, and 16.6% and 9.1% in first, second, and third mandibular molars respectively. The inter-/intra-observer reliability of the results was extremely high. This cross-sectional study showed the prevalence of C-shaped canals in mandibular second molars was relatively high and should be considered normal root canal anatomy in Thais. The prevalence of three-rooted molars was highest in first molars and frequently found in third molars. Cone-beam computed tomography was a reliable technique to determine root canal anatomy.

The relationship of the occurrence between three-rooted deciduous mandibular second molars and three-rooted permanent mandibular first molars in children

Background/purposeThis study aimed to determine the correlation between the occurrence of three-rooted deciduous mandibular second molars and three-rooted permanent mandibular first molars in children. Materials and methodsOrthopantograms (n = 977) obtained from August 2008 to December 2010 were retrospectively screened and examined. Among the 977 orthopantograms, those of 591 participants (314 boys and 277 girls; mean age, 8.7 years) with bilateral deciduous mandibular second molars and permanent mandibular first molars were studied. The gender predilection and prevalence of three-rooted mandibular molars were assessed, and the pattern of concurrence was investigated. ResultsThe prevalence of three roots were 28.4% and 27.6% in the deciduous mandibular second molars and permanent mandibular first molars, respectively. Bilateral occurrence of three-rooted mandibular molars was almost 60% for both deciduous and permanent molars. There was a significantly greater prevalence of three-rooted mandibular molars on the right side of the mandible than that on the left side. ConclusionDeciduous and permanent molars show a similar prevalence of three roots. The presence of three-rooted deciduous mandibular second molar can strongly predict the possibility of three roots in permanent mandibular first molar.

Three-rooted Mandibular Molars&amp;mdash;An Endodontic Enigma: A Case Series

Three-rooted Mandibular Molars&amp;mdash;An Endodontic Enigma: A Case Series

Prevalence and Characteristics of Three-rooted Mandibular Molars in Saudi Population: A Retrospective Radiographic Analysis

To study the prevalence of three-rooted mandibular permanent first molars (PFM) among Saudi population in Al Zulfi. Subjects were selected from the patients' records, College of Dentistry, Majmaah University, Al Zulfi, Kingdom of Saudi Arabia. Healthy patients with the presence of both mandibular PFM, orthopantomogram (OPG) and/or intraoral periapical (IOPA) radiographs were included in the study. All patients included were evaluated by a single examiner using OPG and IOPA radiographs. The occurrence of three roots, status of the tooth and associated anomalies were considered for analysis. Descriptive statistics performed using IBM SPSS (Version 21.0) at a 95% confidence interval (p < 0.05) while the Chi-square test and Fisher test were used for the incidence, and comparison of occurrence of the third root in PFM in the mandibular arch. A sample of 433 subjects was selected randomly based on our inclusion criteria. Only 24 (5.5%) subjects had evidence of three-rooted mandibular PFM with the mean age of 27.67 years. The frequency of bilateral and unilateral three-rooted mandibular PFM was 2.3% (10) and 3.2% (14), respectively. Overall 41.6% of subjects were witnessed with the bilateral occurrence and unilateral occurrence was 58.4% [(57% (8) were on the right and 42% (6) were left side] (p < 0.05). However, no significant relationship was observed between the left and right occurrence of three-rooted mandibular PFM (p < 0.05). Thirty-four (7.8%) PFM were presented with three roots and among them, 70% (24) received treatment. Dilacerations (12.5%), taurodontism (37%) and hypodontia (4%) were associated with three-rooted PFM in the mandibular arch. Kappa statistics showed excellent intra-examiner reliability (κ = 0.9). The prevalence of three-rooted PFM was 5.5% in the present study and unilateral occurrence is very common. Over 70% of these PFM received dental treatment in Saudi Arabia population. Always, IOPA radiographs are required to confirm the evidence of three-rooted mandibular PFM where three-dimensional imaging is not available. An Eagle's eye of an endodontist on three-rooted PFM is of utmost importance in the treatment protocol when the tooth is planned for root canal therapy.

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

ABSTRACTThe 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.Objectives:To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT.Material and Methods:CBCT images of 116 patients were reviewed to determine the prevalence of three-rooted first mandibular molars in a Brazilian subpopulation. Furthermore, with the use of micro-CT, 55 extracted three-rooted mandibular first molars were scanned and reconstructed to assess root length, distance between canal orifices, apical diameter, Vertucci's classification, presence of apical delta, number of foramina and furcations, lateral and accessory canals. The distance between the orifice on the pulp chamber floor and the beginning of the curvature and the angle of canal curvature were analyzed in the distolingual root. Data were compared using the Kruskal-Wallis test (α=0.05).Results:The prevalence of three-rooted mandibular first molars was of 2.58%. Mesial roots showed complex distribution of the root canal system in comparison to the distal roots. The median of major diameters of mesiobuccal, mesiolingual and single mesial canals were: 0.34, 0.41 and 0.60 mm, respectively. The higher values of major diameters were found in the distobuccal canals (0.56 mm) and the lower diameters in the distolingual canals (0.29 mm). The lowest orifice distance was found between the mesial canals (MB-ML) and the highest distance between the distal root canals (DB-DL). Almost all distal roots had one root canal and one apical foramen with few accessory canals.Conclusions:Distolingual root generally has short length, severe curvature and a single root canal with low apical diameter.

Cone beam CT evaluation of mandibular molar root canal morphology in a Turkish Cypriot population.

Microorganisms in untreated or overlooked root canals can cause endodontic failure or infection and inflammation. Therefore, clinicians should familiarize themselves with patient's root canal anatomy and morphology. The objective of this retrospective study was to analyze and characterize mandibular root canal morphology using cone beam computed tomography (CBCT) in a Turkish Cypriot population. This cross-sectional study consisted of retrospective evaluation of CBCT scans from 272 adult patients (aged 16-80years). The number of roots and canals and the canal configuration in each root were evaluated using Vertucci's classification. The incidence of additional roots and of C-shaped canals in the mandibular first and second molars was also noted. Pearson chi-square tests were performed to analyze canal configurations, laterality, and gender (p≤0.05). For the female and male patients, 94.5 and 94.4% of the mandibular first and 96.7 and 97.2% of the mandibular second molars had two roots, respectively. In females, 4.4% of mandibular first molars had three roots versus 2.7% of mandibular first molars in male patients. Type IV was the most prevalent canal configuration regardless of the gender (female 61.3% and male 64.2%) in the mesial roots. No statistically significant differences according to gender or laterality were found in the incidence of additional canals for either maxillary first or second molars. Type IV was the most prevalent canal configuration of both the mandibular first and second molar teeth. There was a low prevalence of three-rooted mandibular molars in this particular population. The current study is the first of its kind to include a Turkish Cypriot population and, thus, provides baseline data for these patients regarding appropriate root canal treatments.

A micro-computed tomographic analysis of the apical anatomy of permanent three-rooted mandibular first molars

To investigate the anatomic features of the root apexes of permanent three-rooted mandibular first molars. A total of 122 permanent mandibular first molars of Han Chinese patients were collected. Twenty three-rooted and 25 two-rooted molars were scanned by micro-CT and then reconstructed three-dimensionally. The apical anatomy of the tooth models were analyzed in software Mimics 10.01. The long and short diameters of the apical constriction (AC), the distances between AC, apical foramen (AF) and apex were measured. One-way ANOVA and LSD-t tests were used to compare the groups in relation to AC diameter and the distances between the AC, AF and apex. The AF of the mesiobuccal (MB) canals most frequently presented at the distal side of the apex (10 cases in three-rooted and 6 cases in two-rooted group), and of the mesiolingual (ML) canals, most often at the lingual side (8 cases in each group). The AF of the distobuccal (DB) roots were frequently located at the distolingual (DL) side (10 cases), and those of the DL roots and distal canals of two-rooted molars were most often at the buccal (7 cases) and distal (11 cases) sides, respectively. The percentage of the "classical" singular AC was 53% (80/151). The average long(D) and short(d) diameters of the AC of the DB canals were (0.32 ± 0.09) mm and (0.25 ± 0.05) mm, respectively, significantly larger than the DL canals [D = (0.27 ± 0.08) mm, d = (0.22 ± 0.06) mm, P < 0.05] and the ML canals [D = (0.24 ± 0.06) mm, d = (0.19 ± 0.06) mm, P < 0.01). In three-rooted group, the mean distances between AC and AF, AF and apex, and AC and apex were (0.67 ± 0.32), (0.49 ± 0.28) and (1.01 ± 0.34) mm, respectively. The AF of three-rooted mandibular molars frequently deviate from the root apex, and the AC of the DB canal is wider than those of the other canals. The mean distances between AC, AF and the apex suggest that root canal therapy should terminate at 1 to 1.5 mm short of the radiographic apex.

3-D diagnosis-assisted management of anomalous mandibular molar

This case report describes the successful non-surgical endodontic management of carious exposed three-rooted mandibular molar with four root canals detected on the pre-operative radiograph taken with 20 degrees mesial angulation and confirmed with a 64-slice helical computed tomography scan-assisted 3-D-reconstructed images. Access cavity shape was modified to locate the extra canal with respect to the distolingual root in the left mandibular first molar. Copious irrigation was accomplished with 5.25% sodium hypochlorite and 17% EDTA. Biomechanical preparation was done using protapers. Calcium hydroxide dressing was done for 1 week. The tooth was obturated using gutta percha and AH 26 root canal sealer, and it was permanently restored with composite. Clinical examination on follow-up visits revealed no sensitivity to percussion and palpation in the left mandibular first molar. Thorough knowledge of root canal variations and use of advanced diagnostic modalities lead to successful non-surgical management of the complex cases.

Root Canal Morphology of Permanent Three-rooted Mandibular First Molars: Part II—Measurement of Root Canal Curvatures

Introduction The distolingual (DL) roots of three-rooted mandibular molars often challenge clinicians during root canal therapy. This study investigated canal curvatures in permanent three-rooted mandibular first molars by using micro–computed tomography (micro-CT) scans. Methods Twenty three-rooted (group 1) and twenty-five two-rooted mandibular first molars (group 2) were scanned by micro-CT. The specimens were reconstructed 3-dimensionally by the software Mimics 10.01 and shown in a parallel projection mode. The images of the root canals in clinical view (CV) and proximal view (PV) were analyzed by the software Image-Pro Plus. Schneider method and a modified Pruett method were used to measure the angles and radius of canal curvatures. Results In the three-rooted molar group in a CV, the average angles of primary curvatures were 24.34 degrees for the mesiobuccal, 22.39 degrees for the mesiolingual, 13.71 degrees for the distobuccal (DB), and 13.81 degrees for the DL canal. In a PV, the average angles were 16.60 degrees for the DB and 36.06 degrees for the DL canal, respectively. Secondary curvatures were frequently seen in a CV (60%) for the DB canals, with an average angle of 26.94 degrees. In a PV, the average central angle of curvature was 59.04 degrees for the DL canal, and the average radius and curve length were 6.17 and 5.73 mm, respectively. In general, no statistically significant difference was found for canal curvatures in the mesial roots between the three-rooted and two-rooted molar groups (P > .05). Conclusions A better understanding of the canal curvatures is essential for successful endodontic treatment of three-rooted mandibular first molars.

Detection of Permanent Three-rooted Mandibular First Molars by Cone-Beam Computed Tomography Imaging in Taiwanese Individuals

This study determined the prevalence of permanent three-rooted mandibular first molars and their morphology among a Taiwanese population by using cone-beam computed tomography (CBCT). Images from 744 patients were screened to obtain 123 samples for this study. All permanent mandibular first molars were evaluated in axial sections from the pulpal floor to the apices of the roots to determine the number of roots. The interorifice distances from the distolingual (DL) canal to the mesiobuccal (MB) and distobuccal (DB) canals were also estimated. The prevalence of permanent three-rooted mandibular first molars was 33.33%, with a bilateral incidence of a symmetrical distribution of 53.65%. There was a significantly greater incidence of three-rooted teeth on the right side of the mandible than on the left, but gender did not show a significant relationship with this variant prevalence.The mean interorifice distances from the DL canal to the DB, MB, and ML canals of the permanent three-rooted mandibular molars were 2.7, 4.4, and 3.5 mm, respectively. The high prevalence of the DL root in permanent mandibular first molars among the Taiwanese (Chinese) population and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments.

Resolution of Furcation Bone Loss Associated with Vital Pulp Tissue After Nonsurgical Root Canal Treatment of Three-Rooted Mandibular Molars: A Case Report of Identical Twins

This case report demonstrates the simultaneous development of furcation bone loss in three-rooted tooth #30 with vital pulp tissue in identical twins. In the first report, resolution of furcal bone loss was seen after nonsurgical root canal treatment. In the second report, furcal bone loss resolved after non-surgical root canal treatment, and periodontal therapy reduced probing depths to maintainable levels.

Entrapment of the Inferior Dental Nerve by a 3-Rooted Mandibular Third Molar — Case Report

Three-rooted mandibular molars occur in certain races and their presence may imply clinical complications. A case is reported of an unusual anatomical relation of the inferior dental nerve with the extra root of a mandibular third molar, which was displaced by an associated dentigerous cyst. Intraoperatively, it was discovered that the nerve was situated close to the curved, extra distolingual root, which had to be surgically divided to release the nerve. Racial, clinical, and radiographic features of this morphological form, together with its clinical relevance, are discussed.