C-shaped Root Canal Research Articles

Root canal morphology and variations in mandibular second molars: an in vivo cone-beam computed tomography analysis

BackgroundThe purpose of this study was to determine the anatomical variations of the root canal system of mandibular second molars using cone-beam computed tomography (CBCT).Methods190 mandibular second molars cone-beam computed tomography images were reviewed. The evaluation was performed by a radiologist with endodontic experience and two endodontists trained with CBCT technology. Tooth position, number of root and root canals, C-shaped root canal system configuration, presence of extra root (radix), and radicular grooves were assessed. Data was statistically analyzed using The Chi-square test (α = 0,05) to determine any significant difference between gender and the total number of root and root canals, and any significant difference between gender and root canal anatomical variation.ResultsOverall, 85.5% showed two separated roots, 12.1% a single root, 2.6% three roots or radix. 87.7% showed three root canals, 12.1% two root canals, 2.6% four root canals, and 1.6% a single root canal. 10% showed a single foramen, 75.3% two foramina, 13.6% three foramina and 1% showed four foramina.19.5% showed C-shaped anatomical variation, 51.4% in male patients, 48.6% in female patients. According to Fan classification: C1 13.6% in cervical third, C2 10% in the middle third, C3 17.3% in middle third, 15.5% in apical third, and C4 12.7% in the apical third. Root canals number in these samples were 5.4% a single canal, 21.6% two canals, 70.3% three canals, and 2.7% four canals. The root showed 46% with one foramen, 46% two foramina, and 8% three foramina. Radicular grooves 83.3% were found in the lingual area and 16.2% towards the buccal area.ConclusionsThe most prevalent anatomic presentation of the evaluated sample was a mandibular second molars with two roots, three root canals, and two apical foramina. Their variation was C-shaped root canals and Radix Paramolaris.

Effectiveness of photodynamic therapy on bonding strength and failure modes of fiber-posts in c-shaped treated root canals

AimThe present study aimed to assess the push-out bond strength (PBS) and failure modes of fiber-posts after photodynamic therapy (PDT) and Erbium yttrium scandium gallium garnet (Er,Cr:YSGG) in c-shaped canals. MethodsSixty molars with c-shaped root configuration were studied. The endodontic prepared teeth specimen were equally randomized into four groups: i) photodynamic therapy (PDT); ii) Er,Cr:YSGG; iii) chlorhexidine and; iv) control group. Post root filling, 10 mm space was prepared for insertion of post in the root canals. The push-out bond strength was evaluated using Universal testing machine. Modes of failure were evaluated as adhesive, cohesive and admixed. Mean values were computed between groups using Kruskal-Wallis test followed by Bonferroni post hoc test. Comparison between two thirds of root sections were analyzed using Friedman test. P-value was set at 0.05 or less. ResultsSpecimens treated with PDT reported the highest mean PBS (8.56 ± 2.12 MPa), while the lowest PBS was observed in NaOCl group (6.92 ± 2.21 MPa). Thirteen failures were observed at the adhesive post interface, whereas 22 failures were found at the interface forming between the dentin surface and adhesive. Similarly, 9 failures were categorized as mixed. For PDT group, a sum of 3 failures and 4 failures were noted at the apical and cervical points. ConclusionThe specimens treated with PDT showed the highest push out bond strength with least number of failures.in c-shaped root canals.

Comparison of Two Post Preparation Methods in Mandibular Second Molars with a C-shaped Root Canal Configuration.

To compare the reduction of residual dentine thickness of two different post preparation methods on the mandibular second molars with a C-shaped root canal configuration. A total of 26 extracted right mandibular second molars with a C-shaped root canal configuration were selected and paired based on similar canal morphology. Each of the paired teeth was randomly allocated to the heat and ultrasonic instruments group (HU group) or Peeso Reamer (Mani, Utsonomiya, Japan) group (PR group) (n = 13) and received post preparation with different instruments after the same endodontic treatment. The reduction of residual dentine thickness and the minimal remaining dentine thickness at the apical sections at 4 or 7 mm below the cementoenamel junction (CEJ) were recorded. The data were analysed using an independent samples t test (α = 0.05). The reduction of residual dentine thickness for the HU group was less than that for the PR group in the two sections. Moreover, at the section 7 mm below the CEJ, the teeth reduction of the distolingual wall in the HU group (0.022 ± 0.007 mm) was significantly lower than that in the PR group (0.101 ± 0.013 mm) (P < 0.01). Using heat and ultrasonic instruments to perform post preparation could follow the original canal configuration to save more tooth structure in the remaining root canal wall, minimise the reduction of residual dentine thickness and decrease the incidence of root canal perforation.

Endodontic management of Type-2 and Type-3 C-shaped root canal system in mandibular second molars: A case series

The most common anatomical variation of the root canal system is a C-shaped root canal configuration and exists mostly in mandibular second molars, but may be found also in other teeth. Because of the broad spectrum of canal configurations, management of C-shaped canals is challenging for clinicians in diagnosis, shaping, cleaning and obturation. First case of c-shaped canal was documented in literature by Cooke and Cox in 1979. In this case series, we present the management of C-shaped canal configuration in mandibular second molars.

Evaluation of C-shaped canals in mandibular second molars of a selected patient group using cone beam computed tomography: prevalence, configuration and radicular groove types.

The aim of the present study was to examine the prevalence, symmetry and configurations of C-shaped canals and radicular groove types in mandibular second molars according to age and sex in a Turkish sub-population using cone beam computed tomography (CBCT). In total, 674 CBCT images (368 females and 306 males, aged 18-76 years) of 1348 mandibular second molars were evaluated. The symmetry, configuration of C-shaped root canals, radicular groove types with age and sex were noted. One sample chi-square test and chi-square test were used to determine statistically significant differences. The statistical significance level was set at p < 0.05. Of the 1348 mandibular second molars evaluated, 10.7% had C-shaped root canals. C-shaped root canals appeared to be significantly more common in females than in males (p < 0.05). C1 (44.4%) was the most frequent configuration in the coronal third, and C2 (44.4%), and C4 (31.9%) were the most frequent configurations in middle and apical thirds, respectively. Type 2 (45.1%) was the most common radicular groove type (p < 0.05). The frequency of C-shaped root canals in mandibular second molars in a Turkish sub-population was considerably high (10.7%). CBCT can aid the detection of C-shaped canals and their configurations. Dentists should consider the possibility of C-shaped canals in root canal treatment of mandibular second molars, as these configurations have implications for biomechanical preparation and filling methods.

Prevalence and Morphology of C-Shaped Canals: A CBCT Analysis in a Korean Population.

This retrospective study of roots with C-shaped canals investigated their prevalence, configuration type, and lingual wall thickness, as well as the panoramic radiographic features of roots in permanent mandibular second molars confirmed to have C-shaped canals on cone-beam computed tomography (CBCT) in a Korean population. In total, 1884 CBCT images of mandibular second molars were examined by two endodontists to analyze the presence of C-shaped canals according to age and sex. The bilateral occurrence of C-shaped roots and their morphology on panoramic radiography were assessed and statistically analyzed using the chi-square test. The classification of Fan et al. was applied to categorize the configurations of C-shaped canals. The lingual wall thickness was calculated in the mesial, middle, and distal areas at the orifice and at 5 mm from the apex. The Mann–Whitney U test was used to analyze the mean difference of lingual wall thickness between the apex and orifice level. A P value of 0.05 was considered to indicate statistical significance in the statistical analyses. Of 2508 mandibular second molars, 924 (36.8%) had C-shaped root canals. The prevalence was significantly lower in the over 61 age group (24.08%) than in the 21–30-year age group (40.02%) and was higher in women (42.32%). Most cases were bilateral (85.9%). The C1 type was the most common (35.3%). The prevalence of C1 type canals decreased, while that of C3b type canals increased with age. In 75.2% of teeth having C-shaped root canals on CBCT, fused roots were observed on panoramic views. The difference in the lingual wall thickness at the orifice and 5 mm from the apex was significant in the middle area in all configurations of C-shaped root canals. When performing nonsurgical or surgical endodontic procedures of the mandibular second molars, clinicians should consider age, sex, ethnicity, and anatomical variations.

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.

In Mandibular Second Molars, Prevalence of C-Shaped Root Canals

Objective: The purpose of this study was to perform cone beam computed tomography (CBCT) to assess the frequency of mandibular second molars with C-shaped root canals in a population living in Pakistan. Study Design: Retrospective study Place and Duration: This retrospective study was conducted at Bakhtawar Amin Medical and Dental College during in the period from June, 2022 to November, 2022. Methods: Total 118 patients were presented with mandibular second molars scheduled for root canal treatment. CBCT scans of patients from diagnostic imaging center were selected. C-shaped root canals were determined by radiographic method using Fan’s criteria. The frequency and distribution of canals and their configuration along with the position of lingual/buccal grooves in the images were evaluated. SPSS 22.0 was used to analyze all data. Results: There were majority 72 (61.02%) females and 46 (38.98%) were males in this study. In our study mean age of the patients was 26.16±13.74 years. Frequency of C-shaped mandibular second molars was found in 12 (10.2%) cases. Among 12 cases, majority of the C-shaped root canals found in right side 7 (5.9%) and 5 (4.2%) C-shaped root canals found in left side. Majority of the C-shaped root canals found in females. Frequency of buccal groove among C-shaped root canals was 6 followed by both buccal and lingual groove in 4 and only lingual groove in 2 cases. Conclusion: According to CBCT analysis, 10.2% of second molars exhibited C-shaped canals. These teeth stood out due to the presence of a deep buccal groove. Right-sided mandibular second molar presence was statistically significant (P = 0.016), according to the data. Keywords: CBCT, Mandibular Second Molars, C-shaped canals, Buccal Groove

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.

Efficacy of root canal treatment in c-shaped canals with adjunctive photodynamic therapy using micro-CT.

To investigate the efficacy of conventional root canal treatment (cRCT) with adjunctive photodynamic therapy (aPDT) against microbial biofilms within infected c-shaped root canals. In this in vitro report, the inoculation of 20 freshly extracted human mandibular molar teeth having c-shaped root canal configuration was performed with E. faecalis and P. aeruginosa to produce three-day biofilms in prepared canal system. PDT used a combination of chlorin (ce6) and polyethylenimine (PEI) as the photosensitizer (PS). A 200 μ-fiber was employed to deliver a 660 nm diode laser light into the root canal, and this was compared and conjugated with conventional endodontic treatment utilizing antiseptic irrigation and mechanical debridement. The utilization of aPDT (group-2) resulted in a considerable decrease in the count of E. faecalis and P. aeruginosa from 12.84 ± 2.18 CFU/mL to 5.13 ± 0.67 CFU/mL, and from 14.06 ± 3.98 CFU/mL to 4.82 ± 1.05 CFU/mL pre-and post-treatment, respectively. A statistically significant reduction in the bacterial counts of both microbes was observed after treatment among the samples of the both study groups (p < 0.05). Specimens in group-2 (8.42 ± 1.14 MPa) demonstrated the highest mean push-out bond strength, whereas the lowest was shown by samples in group-1 (7.08 ± 1.09 MPa). ANOVA showed no statistical difference between the research groups (p = 0.676). The independent t-test revealed that the mean push-out bond strength scores of the cervical segments were higher than the apical and middle segments of roots in research groups (p < 0.05). In c-shaped root canals, the application of photodynamic therapy as an adjuvant to conventional root canal treatment contributes to a statistically significant decrease in the microbial count of E. faecalis and P. aeruginosa along with an improved push-out bond strength of the root canal filling material with root.

Mandibular second molars' C-shaped canal frequency in the Pakistani subpopulation: A retrospective cone-beam computed tomography clinical study

Introduction: The adequate knowledge of the canal configuration can improve the quality and prognosis of endodontic treatment. The aim of the study was to determine the frequency of C-shaped root canal in the mandibular permanent second molars among a Pakistani subpopulation sample by utilizing cone-beam computed tomography images. Materials and Methods: Cone-beam computed tomographic images of 360 patients with 720 mandibular second molars were analyzed for the presence of C-shaped canal configuration. The root canal system was classified according to Fan's classification at three distinct levels. Unilateral or bilateral presence of C-shaped root canals and the location of the longitudinal groove were assessed. Moreover, the correlation of frequency of C-shaped canal with the gender was measured using the Chi-square test. The data were analyzed using SPSS version 23. Results: Of 720 mandibular second molars of 360 patients, 10% of teeth were found to have C-shaped canals in 48 patients. The most commonly noted C-shaped canal configurations in the coronal and middle third were C1 (41.7%) and C3 (37.5%), respectively, whereas C2 (33.3%) and C4 (33.3%) configurations were commonly found in the apical third. Twenty-four of 48 patients had bilateral C-shaped root canals. Overall, 37.5% of the teeth were right-sided teeth and 62.5% were left-sided teeth. The frequency of C-shaped canals was significantly higher in females as compared to males, 15.6% and 4.2%, respectively (P = 0.03). The longitudinal groove was most commonly located on the lingual surface (66.7%). Conclusions: The frequency of C-shaped canal configuration in the Pakistani subpopulation was 10% in the mandibular second molar teeth.

Disinfecting and Shaping Type I C-shaped Root Canals: A Correlative Micro–computed Tomographic and Molecular Microbiology Study

IntroductionThis ex vivo study compared the disinfection and shaping abilities of 2 preparation protocols in C-shaped canals. MethodsMandibular second molars with type I C-shaped canals were pair matched based on micro–computed tomographic (micro-CT) analysis and distributed into 2 groups. The canals were contaminated with a mixed bacterial culture and prepared using 2 protocols, both with 2.5% sodium hypochlorite irrigation: XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) supplemented with XP-endo Finisher (FKG Dentaire) (XP-E) and BioRaCe (FKG Dentaire) supplemented with a Hedström file (Dentsply/Sirona, Tulsa, OK) (BR-Hed). Micro-CT scans and intracanal bacteriologic samples were taken before (scan #1 and sample 1) and after preparation (scan #2 and sample 2) and after the supplementary step (scan #3 and sample 3). Canal shaping was evaluated by micro-CT imaging, and disinfection was assessed by quantitative polymerase chain reaction. ResultsMicro-CT data from the XP-E (n = 21) and BR-Hed (n = 23) protocols revealed no significant differences between groups regarding shaping parameters (canal volume, surface area, structure model index, and prepared walls) after preparation and after the supplementary step (P > .05). All these parameters significantly increased after each preparation step (P < .05), except for structure model index changes after the XP-endo Finisher (P > .05). Bacteriologic data from the XP-E (n = 21) and BR-Hed (n = 22) groups showed that 14 (66.7%) and 10 (45.5%) S2 samples still had detectable bacteria, respectively. The corresponding figures for supplementary steps with the XP-endo Finisher and Hedström file were 11 (52.4%) and 10 (45.5%), respectively. Bacterial counts in sample 1 significantly decreased in samples 2 and 3 in both groups (P < .01). Intragroup comparison between sample 2 and sample 3 showed a 66% reduction in counts after using the Hedström file and 18% after using the XP-endo Finisher (P > .05 for both groups). The quantitative bacterial reduction was not different between groups (P > .05). ConclusionsThe XP-endo Shaper and BioRaCe systems have similar disinfecting and shaping abilities in C-shaped canals. Supplementary steps with the Hedström file and the XP-endo Finisher were similarly effective in improving shaping, but this was not sufficient to enhance disinfection. About half of the cases, in both groups, still harbored detectable amounts of bacteria.

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.

Association between the presence of distolingual root in mandibular first molars and the presence of C-shaped mandibular second molars: a CBCT study in a Taiwanese population.

The purpose of this study was to assess the prevalence of C-shaped canals in permanent mandibular second molars (SMs) and to determine whether its appearance was associated with the presence of distolingual root (DLR) in permanent mandibular first molars (FMs). Three hundred and eighty patients were qualified for evaluation of their FMs and SMs using cone beam computed tomography. The prevalence, distribution pattern, external root morphology, and the internal root canal anatomy of the examined molars were recorded and analyzed. Furthermore, the association between the root canal configurations of SMs and the appearance of DLR in FMs was also assessed. The prevalence of SMs with C-shaped root canals was 44.7%. The most common root canal configuration type of the one-rooted SMs with C-shaped anatomy was C3 (45.6%), followed by C2 and C1. The frequency of C-shaped canals in SMs was 45.4% in Non-DLR group, 52.8% in unilateral DLR group, and 33.9% in bilateral DLR group, respectively. Moreover, the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was significantly lowered. The association between the presence of DLR in FMs and C-shaped canal configurations in neighboring SMs was surveyed, and the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was found to be significantly lowered.

Cone Beam Computed Tomography (Cbct) and Endodontic Microscopic Assessment of C-Shaped Canal Systems in Mandibular Second Molars

By knowing the anatomy of the tooth including root canal, dentists also have gathered physiologically anomalous requirements for effective root canal treatment. An exceptional morphology is present in the root canal system known as the C-shaped root network. A substantial volume of evidence already has come out on C-shaped root canal systems. The analysis provides an extensive description of root through root canals in the form of C. Characteristics of this exceptional morphology were studied mainly focused on macroscopic, microscopic and functional measurements including odontogenetic tooth shape analyses. To trying to clarify the clinical nature of C-shaped root canals, we sought to isolate them both. In addition to summarizing existing experiences, another of the objectives of this investigation was to find evidence that supports our interpretation of the C shaped root canal network. In fact, new advances in 3D mapping techniques help clarify the reliable etiology of the physiology of the Cshaped root canal network. Studies of extreme scenarios such as C-shaped root anatomy or morphology with rectangle and squared channels will also help us gain the wide range with root morphologies found in man’s teeth which eventually result in better care outcomes for patients and dentists and their satisfaction.

Prevalence of C-Shaped Canals in Anterior and Posterior Teeth of Iranian Population Using Cone Beam Computed Tomography

Background: Lack of knowledge of root anatomy is the second most common reason for failed endodontic therapy. Therefore, acquiring knowledge about it leads to a more effective treatment. C-shaped canal is an anatomical variation that causes clinical challenges. The objective of this study is to determine the occurrence of the C-shaped roots in permanent anterior and posterior teeth of the Iranian population using CBCT (cone beam computed tomography) scans. Methods: This was a descriptive cross-sectional study. In this study, 1408 teeth were assessed. Cranex 3D Mid was used to prepare CBCT images. Each tooth was examined in axial sections, and five different levels were identified as coronal, medium, apical, 1/3, and 2/3. The canal shapes were classified into 5 categories based on modified Melton’s method. Data were analysed using the chi-square test at a significance level of 5%in SPSS version 24.0. Results: In total, of 1408 teeth which were evaluated, 7.81% (110) were confirmed to have C-shaped canals. The occurrence of the C-shaped canal was significantly higher in molars (P &lt; 0.001). The occurrence of the C-shaped canal was significantly higher in mandibular teeth (10.04%) compared to maxillary teeth (5.81%) (P &lt; 0.001). The most common C-shaped canal category was C1 (57.27%). The relationship of gender and age with the C-shaped canal occurrence was not statistically significant (P = 0.585, P = 0.562, respectively). Conclusions: CBCT is a useful tool to evaluate C-shaped root canal morphology. The high occurrence of the C-shaped canal in the Iranian population requires clinical awareness.

Mandibular molar C-shaped root canals in 5th millennium BC China

ObjectiveThe aim of this study was to analyze the occurrence and variations in C-shaped canals in ancient Chinese teeth and compare the differences of these features between ancient and age-matched modern populations. DesignApproximately 5000-year-old craniofacial bone remains were collected from the fossils of 38 individuals (total: 68 mandibular second molars) excavated from the Jiaojia site. The control group comprised of an equal number of randomly selected modern samples. We used cone-beam computed tomography to scan the mandible along the apex-crown axis and analyzed the canal morphology, based on Fan’s categorization criterion, at 2 mm, 5 mm, and 8 mm to the apical level. Grooves on the lingual and buccal sides were also recorded. ResultsThe proportion of C-shaped roots among ancient samples on the left and right sides were 48.57 % (17/35 teeth) and 54.55 % (18/33 teeth), respectively, and 51.47 % (35/68 teeth) in the total sample. Conversely, in the control group, 44.12 % (15/34) and 38.24 % (13/34) occurred on the left and right sides, respectively, and 41.18 % (28/68) in the total sample. Among the C-shaped canals from the Jiaojia site samples, the classification type changed between two adjacent levels in 84.31 % of samples. Approximately 35 (51.5 %) teeth had a fused root, 20 (29.41 %) had one shallow buccal and one deep lingual groove. The occurrence of C-shape variation was not significantly correlated with time (p＞0.05). ConclusionsThis study identified a high rate of C-shaped root canals among individuals of Jiaojia who lived approximately 5000 years ago.

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.

Unusual Maxillary First Molars with C-Shaped Morphology on the Same Patient: Variation in Root Canal Anatomy

A maxillary first molar should be considered a four-canal tooth until proved otherwise; however, a clinician should also be aware of the possibility of the presence of C-shaped root canal configuration with or without possibility of splitting into two or three canals. The two clinical cases reported in this paper describe the endodontic treatment of two maxillary first molars, on the same patient, with uncommon anatomy: the first case is about a maxillary first molar with only one C-shaped root and one oval canal with a large buccolingual diameter, a C1 type according to Fan's classification; the second case, about the contralateral maxillary first molar, is probably the first case documented of a maxillary first molar with a C-shaped root canal and C-shaped root with complete fusion of the three roots, having a C3 configuration.

A micro-computed tomographic study of remaining filling materials of two bioceramic sealers and epoxy resin sealer after retreatment.

ObjectiveThis study evaluated the presence of residual root canal filling material after retreatment using micro-computed tomography (micro-CT).Materials and MethodsExtracted human teeth (single- and double-rooted, n = 21/each; C-shaped, n = 15) were prepared with ProFile and randomly assigned to three subgroups for obturation with gutta-percha and three different sealers (EndoSeal MTA, EndoSequence BC sealer, and AH Plus). After 10 days, the filling material was removed and the root canals were instrumented one size up from the previous master apical file size. The teeth were scanned using micro-CT before and after retreatment. The percentage of remaining filling material after retreatment was calculated at the coronal, middle, and apical thirds. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni post hoc correction.ResultsThe tested sealers showed no significant differences in the percentage of remaining filling material in single- and double-rooted teeth, although EndoSeal MTA showed the highest value in C-shaped roots (p < 0.05). The percentage of remaining filling material of AH Plus and EndoSeal MTA was significantly higher in C-shaped roots than in single- or double-roots (p < 0.05), while that of BC sealer was similar across all root types. EndoSeal MTA showed the highest values at the apical thirds of single- and double-roots (p < 0.05); otherwise, no significant differences were observed among the coronal, middle, and apical thirds.ConclusionsWithin the limitations of this study, a large amount of EndoSeal MTA remained after retreatment, especially in C-shaped root canals.