C-shaped Configuration Research Articles

Endodontic retreatment of a mesotaurodontic mandibular first molar with C-shaped configuration in a patient with multiple taurodonts: A case report and review of literature

Abstract Taurodontism is a dental anomaly characterized by an apical displacement of the pulp chamber floor, resulting in a large pulp chamber with short roots. It can be associated with certain syndromes and abnormalities, although it is common to occur as an isolated characteristic. This anomaly can occur along with other root canal system anomalies such as C-type configuration. The aim of this report is to present the successful endodontic management of a C-shaped mesotaurodontic mandibular molar and review the literature available on this matter. A 23-year-old Persian female was referred by her dental surgeon to complete the root canal treatment of her right mandibular first molar (#46). Clinical examination showed a temporized cavity with no response to pulpoperiapical tests or visible pocket depth while an elongated root trunk with slight periodontal ligament widening, incomplete obturation of the root canal system, and periapical radiolucency was evident on the intraoral radiograph. Cone-beam computed tomography (CBCT) revealed a taurodontic and type III C-shaped root canal configuration. With a diagnosis of previous treatment and asymptomatic apical periodontitis, the patient was scheduled for root canal retreatment. The same anomaly was discovered in other molar teeth on the panoramic radiograph taken before the primary treatment of tooth #46. At a 2-month follow-up session, the tooth was found asymptomatic clinically and radiographically. The past publications about the management of nonsyndromic taurodontic molars were also reviewed. The review of 29 similar articles showed that preoperative CBCT, magnification with illumination, along with active irrigation are helpful items in managing such cases.

Nonlinear dynamic modelling and analysis of a rotating composite thin-walled beam considering ice coating

For rotating structures operating in severe weather conditions, ice coating phenomenon is an established issue that impairs the reliability and effectiveness of the structures by changing the dynamic behaviors. To explore the influence mechanisms of ice coating on the dynamic behaviors of rotating structures, this work presents an analytical dynamic model for nonlinear forced vibration of a composite thin-walled beam under both rotating and ice coating conditions. The ice coating is considered as C-shaped configuration which can affect the system parameters of the beam, especially aerodynamic performance. With effect of out-of-plane warping taken into account, the nonlinear dynamic equation of the beam is established using Hamilton's principle. The Galerkin discrete method together with the incremental harmonic balance method (IHB) as well as pseudo arclength continuation technique are adopted to obtain the periodic response of the nonlinear system. Then, a detailed parametric study on natural frequency, frequency-response and bifurcation behaviors is numerically conducted. Special attention is paid to the effects of ice coating, rotating angular velocity, inflow velocity and design parameters on the linear and nonlinear dynamic behaviors of the beam. Results reveal a prominent change in natural frequency, vibration amplitude and cusp bifurcation of multivalued region under the combined effects of ice coating and rotating motion. Such ice-induced changes exhibit the requirement of vibration control and optimization design consideration for rotating structures operating in icing coating conditions.

How to Manage FAN’S C Shape Canals along with S Shape Morphology in Indian Population: A Case Series and Narrative Review

The C-shaped root canals offer greater negotiation, debridement, and obturation difficulty as they present with intercommunications, lateral canals, and reduced dentin thickness. Objective: This case series elaborates on the recognition that these varying configurations is important to enhance adequate cleaning, shaping, and sealing of the root canal. Case Reports: On clinical examination, all the teeth showed caries were nonresponsive to sensibility tests and toother diagnostic tests, suggestive of pulp necrosis with apical periodontitis. Conventional root canal treatment with different techniques and obturation systems have been used. This case series presents the successful management of various C-shaped configurations classified by Fan et al. and emphasizes the different treatment approaches for effective therapy. The cleaning and shaping process should always follow the canal anatomy to maintain the canal shape at the same point the primary and secondary curvatures and thin interconnections are negotiated, prepared, and sealed. Conclusion: The morphological variation existence and their different types and management should be known for improved healing and enhanced success of root canal treatment.

Suppressing trap density and energy loss via skeleton asymmetry strategy enables highly efficient all-small-molecule organic solar cells

Reducing energy loss while ensuring the required charge collection is of vital importance to high-performance all-small-molecule organic solar cells (SM-OSCs) limited by high trap density (1016 ∼ 1018 cm−3) in bulk heterojunction films. Herein, we show that the trap density in SM-OSCs can be dramatically reduced by designing a small-molecule donor (SMD) using a skeleton asymmetry strategy. Compared with its symmetric counterpart, TBD-BCl with an asymmetric thienobenzodithiophene (TBD) central core has different rotational energy barriers and a transformed C-shaped configuration, endowing blend films with strong intermolecular interactions and higher crystallinity. Thus, blending TBD-BCl with the L8-BO acceptor leads to a low trap density of 3.21 × 1015 cm−3 and density of state of 46 meV relative to BDT-BCl:L8-BO films. In addition, joint experimental and theoretical studies revealed that the TBD-BCl:L8-BO complex with a much lower driving force can still facilitate exciton dissociation, suppress charge-carrier recombination, and significantly reduce energy loss in devices. As a result, SM-OSCs based on TBD-BCl:L8-BO deliver a higher efficiency of 16.2% and an improved Voc of 0.91 V. Overall, the experiments and theory calculations in this study provide a new perspective for designing SMDs that suppress trap states and reduce the energy loss in SM-OSCs.

A two-phase simulation for analyzing the hydraulic-thermal performance of Cu–Water nanofluid within a tube enhanced with W- and C-shaped ribs

The present study numerically investigated the simulation of two-phase nanofluid (NF) flow to examine the thermal performance of Cu–water NF within an enhanced tube with W- and C-shaped ribs in the heat exchangers (HEX). In this research, the effect of volume fraction (φ = 0.2, 0.4, 0.6, and 0.8%), and diameter (15, 20, 25 and 30 nm) of copper nanoparticles and the type and size of the turbulators (TRB) (W- and C-shaped ribs together), which were designed for the first time on Heat transfer (HT), were discussed. Heat transfer flow (HTF) entered the test section at Tin = 290 K in various velocities related to different Reynolds numbers (Re) 5000, 10000, 15000 and 20000. Based on the Eulerian-Eulerian two-phase method, the governing equations were solved. Different rib geometrical parameters were determined, and the optimization was performed to achieve the maximum performance evaluation criteria (PEC). According to obtained results, the PECs were more than 1, which indicated that these TRB were impressive from a hydraulic-thermal performance. Furthermore, the PEC variations of C- and W-shaped models were not similar. For the C-shaped configuration, the PEC values always enhanced with Re enhancement, while for the W-shaped model, the PEC values enhanced till Re = 10000, and then decreased till Re = 20000. The PEC values of the optimum model (W-shaped, NB = 6 and R = 15 mm) filled by NF at φ = 0.8% and dnp = 30 nm in Re = 5000, 10000, 15000 and 20000 are 1.491, 1.498, 1.482 and 1.469, respectively.

Assessment of root and root canal morphology of mandibular premolars using cone beam computed tomography in a tertiary center of Nepal

Introduction: Mandibular premolars are considered an enigma in dentistry because of their variability in anatomical and morphological features making it difficult to treat endodontically. This study was conducted to determine the root and canal morphology of mandibular premolars in the Nepalese population by using cone beam computed tomography imaging. Methods: One hundred and thirty-four cone beam computed tomography images of the Nepalese population were collected by convenience sampling method from April 1 to August 31, 2022 in Bir Hospital, Kathmandu, Nepal. A total of 536 premolars (268 mandibular first premolars and 268 mandibular second premolars) were evaluated by two examiners (one endodontist and one oral radiologist). Canal configuration was classified according to Vertucci’s classification. Results: In mandibular premolar teeth, the majority had one root followed by two roots and fused roots. The most common configuration in mandibular premolars was Vertucci’s type I (83.88% and 96.65% in the first and second premolar respectively) followed by type V (9.89%) in the first premolar and type III (1.86%) in the second premolar. Vertucci’s type VII (0.37%), C-shaped configuration (1.46%), and an unusual configuration (0.37%) were observed in the first premolar. In mandibular first premolars, males showed more variation than females; while in second premolars, females showed more variation than males. Conclusions: Mandibular premolar teeth showed variation in root and canal morphology with one root and Vertucci’s type I in the majority of the cases.

Scanning structural mapping at the Life Science X-ray Scattering Beamline.

This work describes the instrumentation and software for microbeam scattering and structural mapping at the Life Science X-ray Scattering (LiX) beamline at NSLS-II. Using a two-stage focusing scheme, an adjustable beam size between a few micrometres and a fraction of a millimetre is produced at the sample position. Scattering data at small and wide angles are collected simultaneously on multiple Pilatus detectors. A recent addition of an in-vacuum Pilatus 900k detector, with the detector modules arranged in a C-shaped configuration, has improved the azimuthal angle coverage in the wide-angle data. As an option, fluorescence data can be collected simultaneously. Fly scans have been implemented to minimize the time interval between scattering patterns and to avoid unnecessary radiation damage to the sample. For weakly scattering samples, an in-vacuum sample environment has been developed here to minimize background scattering. Data processing for these measurements is highly sample-specific. To establish a generalized data process workflow, first the data are reduced to reciprocal coordinates at the time of data collection. The users can then quantify features of their choosing from these intermediate data and construct structural maps. As examples, results from in-vacuum mapping of onion epidermal cell walls and 2D tomographic sectioning of an intact poplar stem are presented.

A Systematic Review: Prevalence of C Shaped Configuration in Upper-maxilaryand Lower-mandibular First Premolar

In most cases, the C-shaped pattern is found in mandibular second molars. Additionally, C-shaped canals can also occur in mandibular premolars, maxillary molars, and mandibular third molars. It poses challenges like debridement, obturation, and possibly the outcome of root canal treatment. The purpose of this study is to make a systematic review of studies related to the prevalence and morphology of C shaped canals in premolar teeth. Using pre-designed forms, data were extracted from online databases such as Medline and PubMed Central. We extracted citations and characteristics of studies, such as names of authors, date of publication, country, title, definition of C shaped canal configuration, and classification of C shaped canal configuration in upper and lower first premolars. Even though they are rare, mandibular premolars are also known to have C-shaped canal systems. Approximately 10-18% of mandibular first premolars have C-shaped canals, according to studies. Treatment is more challenging for patients with C-shaped canals. The frequency of C-shaped configurations in premolar teeth is likely to be affected by regional characteristics and gender of the population. Having these factors in mind before surgery allows dentists to better plan, coordinate, and perform complex morphologies.

The C-shaped root canal systems in mandibular second molars in an Emirati population

Our study aimed to describe the root and canal morphology of mandibular second molars in Emirati population and to study the prevalence and types of morphological change in C-shaped canal configuration along the root length in an effort to describe C-shaped molars as a unit. Cone beam computed tomography (CBCT) scans of Emirati patients were analyzed in multiple plans and root and canal configuration of mandibular second molars were evaluated. Moreover, specific types of morphological change in C-shaped canal configuration along root length were studied and reconstructed using 3D reconstruction software. A total of 508 mandibular second molars were evaluated. Among the non-C-shaped mandibular second molars, two separate roots were the most prevalent root morphology (78.3%). The mesial root's most common root canal configuration was Vertucci Type II (46.5%), and in the distal root, Vertucci Type I (90.5%). The prevalence of C-shaped mandibular second molars was 17.9% and was significantly prevalent (P < 0.001) in females. Specific types of morphological change in C-shaped molars along the root length were observed and described for the first time, in which the most common types of morphological change were C1-C2-C3d (18%), C1-C3c-C3d (15.4%), C4-C3c-C3d (7.7%), and C3c-C3c-C3d (7.7%). This study showed wide variations in the root and canal morphology in mandibular second molars in Emirati population with a relatively high prevalence of C-shaped canal configuration (17.9%). Moreover, specific types of morphological change in C-shaped configuration were detected and described for the first time in this population.

Prevalence and Configuration of C-shaped Canals in Lower Molars from a Chilean Subpopulation

Objective: To determine the prevalence of C-shaped canals in lower molars (first and second molars) in a Chilean subpopulation, and to identify root configuration and demographic characteristics using cone beam tomography. Materials and method: 912 molars (456 first and 456 second molars) resulting from the analysis of 228 mandibular CBCT scans (89 men and 139 women between 15 and 80 years old) were evaluated. Through panoramic reconstruction and axial tomographic sections, the root configuration was established, and the presence and type of C-shaped canal were classified, analyzing 5 levels along the root canal. Data were statistically analyzed with a 5% significance level. Results: Of the 912 molars analyzed, 69 were classified as C-shaped (7.57%), constituting 65.72% of those molars that presented fused roots. 100% of this configuration of canals was observed in lower second molars, presenting a higher prevalence in women (n = 49, 71.01%). 40.82% of the cases that presented a C-shaped configuration manifested bilaterally. The most frequent C-shaped canal configuration was C3 (n = 347, 66.10%), according to Melton's classification. Conclusion: The C-shaped canals in the studied population were observed entirely in lower second molars, showing a clear predilection for the female sex and a high rate of bilaterality. Keywords Anatomy; Cone beam computed tomography; Dental pulp cavity; Endodontics.

Evaluation of C-shaped canal configuration in maxillary molars: A retrospective cone-beam computed tomography study

Objective: The aim of this retrospective study was to evaluate the prevalence of C-shaped canal configuration in maxillary first and second molars according to sex and gender by using CBCT in a Turkish population.&#x0D; Methods: In this retrospective study, 709 first and 739 second maxillary molars were examined. CBCT images of teeth were examined in different axial sections to determine the presence of C-shaped canal configuration. C-shaped canal configuration was classified into five groups according to the fusion of root canals. Prevalence of C-shaped canal configuration between first and second molars, age groups and genders were compared. &#x0D; Results: Total of 1448 teeth were evaluated and 3% (43) of them had C-shaped canal configuration. The presence of C-shaped canal configuration was significantly more common in the second molars than the first molars (p = 0.000) No significant difference in the prevalence of C-shaped configuration was observed comparing genders and age groups (p&gt;0.05). Type A and E canal configuration were not detected in first molars. &#x0D; Conclusion: C-shaped canal configuration is a rare anatomical variation of maxillary molars. &#x0D; This variation includes fins or isthmuses connecting root canals which create challenges during endodontic treatment. Perceiving the variations with CBCT imaging helps clinicians to understand and treat complex cases without complication. Clinicians should be knowledgeable about the rare variations for better outcomes.

C-Shaped Canal in Second Molar of Mandible among Cases of Cone Beam Computed Tomography in Tertiary Care Centres: A Descriptive Cross-sectional Study.

C-shaped canal configuration is mostly found in the mandibular second molar. The morphological characteristic of a C-shaped canal is the presence of a fin or web connecting the individual canal, making it difficult for cleaning, shaping, and obturation. The objective of this study was to find out the prevalence of C-shaped canal in mandibular second molar among cases of Cone Beam Computed Tomography in tertiary care centres. The descriptive cross-sectional study was conducted in the department of conservative dentistry and endodontics of tertiary care centres from 20th June 2020 to 20th December 2020 after receiving ethical approval from the Nepal Health Research Council on 19 June 2020. Cone-beam computed tomography images of 199 mandibular second molars with completely formed roots were used. Teeth with orthodontic braces, root resorption, root canal filling, and post were excluded from the study. The research was conducted taking a tooth as a unit. Convenience sampling was done. Statistical analysis was done by using Statistical Package for Social Sciences version 16. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. The prevalence of C-shaped canal according to this study is 25 (12.6%) (7.99-17.21 at 95% Confidence Interval). The findings of the study conclude that C-shaped configuration is quite frequent in mandibular second molar among cases of Cone Beam Computed Tomography. A careful pre-operative radiographic evaluation may be helpful for diagnosing C-shaped configuration prior to root canal treatment.

C-Shaped configuration of the canal in mandibular molars: A case report

The primary concern of this case report is to discuss and review the different etiological features of c shaped canals, with its incidence, along with anatomical features, diagnosis and management of the c shaped configuration of the canal in the molars of the mandibular arch. Literature revealed that c shaped canal configuration is slightly a different variation that has a predilection towards the racial and most of the times or most commonly is seen in mandibular molars that too most commonly in second molar of the mandibular arch. This morphology when present in the canal may posses difficulty in shaping of the canal, cleaning of the canal as well as debridement of the canal along with obturation of the canal. The one of the most common way in the management of this c shaped canal morphology is done by with the help of usage of rotary instruments and can also with the use of hand instruments that too assisted with sonics as well as ultrasonics.

Cone\u2010beam computed tomography evaluation of C-shaped root and canal morphology of mandibular premolars

BackgroundMandibular premolars are complicated teeth to endodontically treat due to the anatomical variations that can present. The purpose of this study was to determine the presence of C-shaped configurations in mandibular premolars by cone-beam computed tomography (CBCT).Methods380 mandibular first premolars and 308 mandibular second premolars cone-beam computed tomographic images were obtained from 292 patients (175 female and 117 male). Tooth position, number of roots, root canals, C-shaped root canal system configuration, level of canal bifurcation and radicular grooves were evaluated by two endodontists trained in CBCT evaluation; previously calibrated between them, and a radiologist with endodontic experience. Data were statistically compared by The Chi-square test (α = 0.05) to examine any significant difference between gender and C-shaped root canal system and any significant difference between C-shaped configuration according to Fan criteria and gender.ResultsOverall 100% (n = 688) teeth examined, 19.2% (n = 132) had a C-shaped root canals system. 9.16% (n = 63) in male patients and 10.03% (n = 69) in female patients. The prevalence of C-shaped root canal system in mandibular first premolar was 83.33 and 16.66% in mandibular second premolars. According to Fan classification, the mandibular first premolars showed 3.63% as C1, 9.09% C2, 59.09% C3, 21.81% C4a, 1.8% C4b. Mandibular second premolars showed 13.63% as C1, 18.18% C2, 13.63% C3, 27.27% C4a, 9.09% C4b. Male patients showed 4.54% as C1, 3.78% C2, 22.72% C3, 11.36% C4a, 0.75% C4b, and 4.54% out of classification. Female patients showed 0.75% as C1, 6.81% C2, 30.03% C3, 9.84 C4a, 2.27% C4b, and 2.27% out of classification. The 53.36% canal bifurcation in mandibular first premolars and 50.09% in mandibular second premolars were in the middle third. No statistical differences were found between C-shaped root canal system and gender or C-shaped configuration according to Fan criteria and gender. P was < 0.05.ConclusionsWithin the limitation of this study, the presence of C-shaped anatomical system is relatively low in mandibular second premolars than in mandibular first premolars.

Effectiveness of various endodontic systems in treating teeth with C-shaped root canals

Introduction — C-shaped configuration is amongst the most complicated root canal varieties requiring additional effort for successful endodontic treatment. The goal of this study was the laboratory comparison of the endodontic treatment efficiencies via XP-endo vs. Gentlefile systems for the teeth with C-shaped root canals. Material and Methods — In laboratory settings, 36 teeth with established C-shaped configuration, extracted for medical reasons (24 mandibular premolars and 12 mandibular second molars), underwent the root canal treatment by XP-endo (XP) and Gentlefile (GF) systems. Treatment quality was evaluated on the basis of dye penetration tests and examination of root dentinal surface with a scanning electron microscope. The significance of differences between the groups was assessed via Mann-Whitney U test. Results — For GF instruments, the average size of stained area in the apical third of teeth was 3.33±2.73%, while in the coronal third it amounted to 13.49±13.58%. The results of using the XP instruments demonstrated the average size of stained area in the apical third equal to 15.45±12.48%, while in the coronal third it was 37.30±14.06%. The scanning electron microscopy revealed a rougher surface of dentin and the remnants of stained layer in root canals treated with GF system. Conclusion — Thus, XP instruments exhibited a better treatment quality compared with GF system. The obtained data may justify the choice of instruments for endodontic teeth treatment in case of an intricate root canal system.

Endodontic management of maxillary permanent molar C-shaped morphology

Aim: Report on the successful endodontic management of 4 permanent maxillary molars with a C-shape configuration of the root canal system. Summary: Even though C-shaped anatomies are more commonly described in the mandibular molars, its occurrence in permanent maxillary molars has also been reported. Complexity of the root canal system may pose a difficulty in achieving proper chemo-mechanical debridement, and consequently jeopardize the success of endodontic therapy. Additional dedicated armamentarium can help the clinician recognize, assess, plan and better manage such complex configurations. Key learning points Although of rare prevalence, clinicians must be aware and recognize the possible existence of a C-shaped root canal configuration in both first and second permanent maxillary molars. This anatomy can be attributed to an embryologic alteration that leads to the non-division of roots during the root formation stage of tooth formation. Further studies on the prevalence of the C-shaped configuration in permanent maxillary molars may contribute to a better understanding and, consequently, proper management of this morphology. Specific tools, such as the dental operating microscope and specific ultrasonic tips, as well as additional means of enhancing chemical debridement, are essential for the correct management of these intricate anatomies and appear to positively impact outcome of root canal treatment.

C-Shaped canal system - A Case report

ABSTRACT&#x0D; C-shaped canals are anatomic variants in root canal morphology. This c-shaped configuration should be diagnosed earliest as it influences the management of such cases more efficiently. They pose challenges in shaping, cleaning and obturating protocols. We require a file system which can contact and shape all possible surfaces of the c-shaped canal. Some of these file systems are XP-endo shaper files (FKG), SAF (ReDent NOVA). For cleaning, advocated systems are XP- endo finisher files (FKG), SAF, ultrasonic files like irrisafe, sonic files (endo-activator), endo-vac system. 3-D obturation should be done wih downpack and backfill technique (warm vertical or continuous wave of compaction)

Taurodontism and C-shaped anatomy: is there an association?

To evaluate the relation between taurodontism and C-shaped configuration, as well as the prevalence and classification according to sex, left/right position, and arc length in the mandibular premolar and molar teeth using cone beam computed tomography (CBCT). The presence of taurodontism and C-shaped configuration were evaluated using CBCT scans and classified by two independent radiologists. The sex, location in the jaw (left-right), and mandibular arc length measurements were recorded. The Chi-square test was used to determine the presence of taurodontism and C-shape configuration according to sex, left/right location, and independent-sample t tests were used to assess the relation between the arc length. The prevalence of taurodontism was significantly higher in the female population, whereas the C-shaped configuration was more frequent in males (p < 0.05). In both sexes, the most common type was hypotaurodont (7.5%). In the molars, the prevalence was significantly higher in second molars, and the most common C-shaped configuration type was C3 (39.3%). The prevalence was significantly higher in the first premolar, with C2 (22.4%) being the most frequent type in the premolars (p < 0.05). The arc length and location in the jaw were not significantly affected (p > 0.05). A high correlation was revealed between taurodontism and complicated C-shape canal configurations. Practitioners should be very careful about the presence of C-shape morphology in taurodontism treatment, and various types of C-shaped morphology ranging from coronal to the apical direction.

C-shaped canals in mandibular molars of a Brazilian subpopulation: prevalence and root canal configuration using cone-beam computed tomography.

To assess C-shaped root canal configuration by identifying its prevalence and each configuration type proportion, according to tooth (mandibular first or second molar) and demographic characteristics in a Brazilian population, using cone-beam computed tomography (CBCT). Moreover, it was verified if there is a relationship between root canal configuration observed in two-dimensional reconstructions of CBCT and presence of C-shape. Mandibular jaw CBCT scans (184 males and 220 females, aged 15 to 80years), which presented 1464 mandibular molars (710 first molars and 754 second molars), were assessed. Teeth were evaluated for the presence and type of C-shaped root canals by observing the roots at five levels in CBCT axial reconstructions. Root canal configuration was assessed in panoramic reconstructions. Data were statistically analyzed at a significance level of 5%. Of the 1464 mandibular molars, 125 (8.5%) were classified as C-shaped. This variation was more prevalent in females (n = 107, 85.6%) and in second molars (n = 108, 86.4%). C1 (uninterrupted C-shaped canal) was the most prevalent type of C-shaped configuration (41.76%), while C5 (no canal lumen) was the least prevalent type (0.96%). Single root with single canal in panoramic reconstructions was the most predominant configuration for C-shaped teeth (n = 54, 43.2%). Fused roots presented 17.2 higher odds of being associated with C-shaped root canals than non-fused roots. C-shaped root canals were more prevalent in mandibular second molars and in females. Additionally, clinicians should bear in mind the greater possibility of C-shaped configuration in mandibular molars with fused roots. Mandibular molars with C-shaped canals present a clinical challenge. A higher C-shaped proportion was noted in radiographic fused root types, which had 17.2 higher odds of presenting such anatomy when compared to radiographic non-fused roots. Root radiographic features may help in diagnosis of complex C-shaped morphologies.

Frequency of non-single canals in mandibular premolars and correlations with other anatomical variants: an in vivo cone beam computed tomography study

BackgroundA knowledge regarding anatomical variants is important to achieve success in endodontic treatment. Root canal treatment of mandibular first premolars (PM1 s) is challenging due to the existence of numerous variations in canal configurations, including a C-shaped variant. We aim to determine the frequency and morphologic characteristics of non-single canals of mandibular first (PM1 s) and second (PM2 s) premolars in a Korean population using cone beam computed tomography (CBCT) and to evaluate correlations between non-single canals of PM1 s and other anatomical variants, such as distolingual roots (DLRs) in mandibular first molars (M1 s) and C-shaped canals in mandibular second molars (M2 s).MethodsA total of 971 PM1 s and 997 PM2 s from 500 patients were examined in vivo by CBCT. Root canal configurations and C-shaped canals were determined in accordance with the Vertucci classification and Fan classification, respectively. The correlation between non-single canals in PM1 s and DLRs in M1 s was evaluated using logistic regression analysis.ResultsPM2 s typically had one root (99.89%) with one canal (98.4%). Among PM1 s with non-single canals (21.2%), Vertucci type V (10.9%) and C-shaped (3.7%) canals were prevalent. Among C-shaped PM1 canals, the majority were Vertucci type V (77.8%); a C-shaped configuration (C2) was predominant mostly at the middle and/or apical third of the root. After adjusting for other variables (i.e., sex, age, and side), C-shaped canals in PM1 s was significantly correlated with the presence of DLRs in M1 s (odds ratio = 2.616; 95% confidence interval, 1.257–5.443; p = 0.010).ConclusionsThe presence of C-shaped PM1 canals was positively related to the presence of DLRs in M1 s. Although C-shaped canals in PM1 s are difficult to distinguish, this finding could aid clinicians in predicting C-shaped canal configurations in PM1 s of patients who exhibit DLRs in M1 s.