A micro-computed tomographic evaluation of maxillary first molar root canal morphology in Black South Africans.

PURPOSE: This study was conducted to investigate the root canal anatomy of maxillary first molars in Black South Africans. METHODS: Micro-computed tomography was used to investigate 101 maxillary first molars (53 teeth from the right, 48 from the left; 50 male and 51 female teeth). The number of root canals in each tooth was determined, and the relationship between side, sex and age was analyzed using chi-squared test. To determine intra- and inter-observer reliability, Cohen's kappa coefficients were calculated. RESULTS: Intra- and inter-rater agreements of 96.92% and 98.08% were achieved, respectively. Most teeth contained either three or four canals, but a second, third and fourth mesio-buccal canal was found in 60.39%, 5.94% and 0.99% of teeth, respectively. The disto-buccal and palatal roots contained predominantly single canals, but additional canals were noted in 2.97% and 1.98% of teeth. Four canals were common in females and teeth on the right side often contained a second mesio-buccal canal. However, the prevalence of a third mesio-buccal canal was higher in males than in females. CONCLUSION: The teeth studied showed diversity and variations between sexes and arch sides. These findings will aid clinicians in endodontic treatment and will be applicable for educational purposes.

Prevalence and morphology of different root canal systems in mandibular premolars: a cross-sectional observational study.

BACKGROUND: This study investigated the prevalence and morphology of C-shaped and non-C-shaped root canal systems in permanent mandibular first (PM1) and second (PM2) premolars using retrospective analysis of cone-beam computed tomography (CBCT) scans, and panoramic radiographs. METHODS: CBCT scans from 2000 patients were screened for the presence of premolars with C-shaped canals and then assessed at three axial levels to determine the canal classification. The teeth were also assessed for Vertucci configuration, number of roots, and radicular grooves. Pre-existing panoramic radiographs were evaluated to identify features specific to PM1/2 with multiple canals or C-shaped anatomy. RESULTS: A total of 1576 PM1 and 1424 PM2 from 880 patients were evaluated. The overall prevalence of C-shaped canals was 2.2% (3.3% PM1, 1.0% PM2), with 49 (5.6%) patients presenting with at least one C-shaped mandibular premolar. There were 2.3 ± 0.6 and 2.4 ± 0.5 different classifiable cross-sections per tooth for PM1 and PM2, respectively. The sudden disappearance or bifurcation of a canal on panoramic radiographs was associated with the presence of multiple canals (P < 0.001) or C-shaped anatomy (P = 0.03). CONCLUSIONS: There was substantial variation in cross-sectional anatomy within and between C-shaped premolars, which will affect endodontic treatment planning. © 2023 Australian Dental Association.

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

OBJECTIVES: 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). MATERIALS AND METHODS: 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). RESULTS: 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. CONCLUSION: 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.

Prevalence and C-shaped root canal configuration in lower molars in the metropolitan region, Chile / Prevalencia y configuración de conductos en C en molares inferiores de la región metropolitana, Chile

Objetive: The aim of this study was to determine the prevalence, demographics, and root configuration of C-shaped canals of mandibular molars by means of cone beam computed tomography in the population of the Metropolitan Region, Chile. Material and Methods: 912 molars (456 first and 456 second molars) resulting from the analysis of 228 mandibular CT scans were evaluated. The root configuration was established by means of a panoramic reconstruction and axial tomographic sections, classifying the presence and type of canals through the analysis of five sections or cuts along the root. Data were statistically analyzed using a 5% confidence interval. Results: Of the 912 molars analyzed, 70 were classified as C-shaped canals (7.68%), corresponding to 58.33% of those molars that presented fused roots. 95.7% of this root canal configuration was observed in lower second molars, occurring more frequently in females (n=45, 64.29%). 45.65% of the cases that presented C-shaped canals were bilateral and the most frequent configuration was C3 (n=401, 66.63%) according to the Melton classification.Conclusion: The C-shaped canals of the mandibular molars in the studied population were observed mainly in second molars, showing a clear prevalence among females and a high percentage of bilaterality. The presence of fused roots significantly increases the possibility of finding this type of root configuration.

Objetivo: El objetivo del presente estudio fue determinar, por medio de tomografía computarizada de haz cónico, la prevalencia, demografía y configuración radicular de los conductos en forma de C de molares inferiores en la población de la Región Metropolitana, Chile. Material y Métodos: 912 molares (456 primeros y 456 segundos molares) resultantes del análisis de 228 tomografías mandibulares fueron evaluados. Mediante una reconstrucción panorámica y cortes tomográficos axiales se estableció la configuración radicular, clasificando la presencia y tipo de conducto por medio del análisis de 5 cortes a lo largo de la raíz. Los datos fueron analizados estadísticamente con un intervalo de confianza del 5%. Resultados: De los 912 molares analizados, 70 fueron clasificados como conductos en forma de C (7.68%), correspondiendo al 58.33% de aquellos molares que presentaron raíces fusionadas. El 95.7% de esta configuración de conductos fue observada en segundos molares inferiores, presentándose con mayor frecuencia en mujeres (n=45, 64.29%). El 45.65% de los casos que presentaron conductos en C se manifestaron bilateralmente y la configuración más frecuente observada fue la C3 (n=401, 66.63%) según la clasificación de Melton. Conclusión: Los conductos en forma de C de los molares mandibulares en la población estudiada fueron observados principalmente en segundos molares, marcando una clara predilección por el sexo femenino y un alto porcentaje de bilateralidad. La presencia de raíces fusionadas aumenta significativamente la posibilidad de encontrar este tipo de configuración radicular.

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

BACKGROUND: The 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). METHODS: 190 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. RESULTS: Overall, 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. CONCLUSIONS: The 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.

AIM: The 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. METHODS: Sixty 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. RESULTS: Specimens 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. CONCLUSION: The specimens treated with PDT showed the highest push out bond strength with least number of failures.in c-shaped root canals.

Comparison of the Self-Adjusting File and Hedström File Used as Supplementary Instruments for the Remaining Filling Material Removal During Retreatment of C-Shaped Canals: A Micro-CT Study.

Objective: The aim of this study was to evaluate the use of Self-adjusting file (SAF) system and Hedström (H) file for removing remaining filling material (RFM) from C-shaped canals. Methods: 20 C-shaped mandibular second molars with C1 configurations were instrumented, filled with tagger´s hybrid technique. Samples were divided into 2 groups (n=10). Reciproc R25 and a Mtwo 35/04 file were used for retreatment in both groups. Then, a 2.0 SAF file (group I) and a #35 H file (group II) were used as supplementary steps for RFM removal. Micro-CT scanning was performed after every procedure. Total volumes were calculated and converted into percentages. Also, the minimum wall thickness at 3, 5, 7 mm from apex was calculated. The Prism 7.0 software was used as the analytical tool with a significance of 5%. Results: Initial obturation removal was approximately 64% in group I and 67% in Group II. The apical third had the highest values of RFM. The use of a H file significantly reduced the RFM compared to SAF in the total canal length respectively (30% vs 18%) and at 1-3 mm and 3-6 mm when compared to the use of SAF. A statistically significant decrease of RFM and minimum wall thickness were observed in both groups (P<0.05). Conclusion: None of the retreatment techniques completely removed RFM. The apical region was the more unaffected area. Also, the SAF file was less effective than the H file in removing the RFM. Although C-shaped canals possesses thinner dentinal wall thickness, no excessive dentine removal was observed after each instrument use.

Investigation using cone beam computed tomography analysis, of radicular grooves and canal configurations of mandibular premolars in a Turkish subpopulation.

OBJECTIVE: To conduct an in vivo evaluation of prevalence of root canal configurations, lengths of C-shaped canals, prevalence and depths of radicular grooves (RGs), in mandibular first and second premolars in a Turkish subpopulation using cone beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images of 327 first and 264 second premolars were included. Canal configurations, locations, lengths, and types of C-shaped canals, and RGs were evaluated on CBCT images. Data were statistically analyzed (P < 0.05). RESULTS: First and second premolars were classified as follows: type I, (83.8%, 97.72%); type V, (12.22%, 0.76%); type III, (3.06%, 0.76%); and other types. RGs were exhibited by 14.68% of first and 2.27% of second premolars (P < 0.05). Incidence of complex canals (types III, V and other types, 89.8%) in first premolars with RGs was significantly higher versuswithout RGs (P < 0.05). C-shaped configuration was exhibited by 4.58% of first (80% semilunar-type), and 1.13% of second premolars (P < 0.05). All first premolars with C-shaped canals showed RGs and complex canals. CONCLUSIONS: Complex canals and RGs frequently co-exist in mandibular premolars. C-shaped canals are not common in mandibular premolars, and mostly located in middle thirds. Type V is the most prevalent complex canal configuration in first premolars, and frequently associated with a C-shaped semilunar-type anatomy.

A new system for classifying tooth, root and canal anomalies.

Understanding the normal anatomical features as well as the more unusual developmental anomalies of teeth, roots and root canals is essential for successful root canal treatment. In addition to various types of root canal configuration and accessory canal morphology, a wide range of developmental tooth, root and canal anomalies exists, including C-shaped canals, dens invaginatus, taurodontism, root fusion, dilacerations and palato-gingival grooves. There is a direct association between developmental anomalies and pulp and periradicular diseases that usually require a multidisciplinary treatment approach to achieve a successful outcome. A number of classifications have categorized tooth, root and canal anomalies; however, several important details are often missed making the classifications less than ideal and potentially confusing. Recently, a new coding system for classifying root, root canal and accessory canal morphology has been introduced. The purpose of this article is to introduce a new system for classifying tooth, root and canal anomalies for use in research, clinical practice and training, which can serve as complementary codes to the recently described system for classifying root, as well as main and accessory canal morphology.

Retrospective Study of Root Canal Configurations of Mandibular Third Molars Using CBCT- Part-II.

INTRODUCTION: Abnormal root canal morphologies of third molars can be diagnostically and technically challenging during root canal treatment. AIM: The aim of this retrospective study was to investigate the root and canal morphology of mandibular third molars in Central India population by using Cone Beam Computed Tomography (CBCT) analysis. MATERIALS AND METHODS: CBCT images of 171 mandibular third molars were observed and data regarding number of roots, number of canals, Vertucci's classification in each root, prevalence of C shaped canal, gender and topographical relation of morphology in mandibular third molar was statistically evaluated. RESULTS: Majority of mandibular third molars had two roots (84.2%) and three canals (64.3%). Most mesial root had Vertucci Type II (55.6%) and Vertucci Type IV (22.2%), distal root had Type I canals (87.5%). Over all prevalence of C shaped canals in mandibular third molars was 9.4%. CONCLUSION: There was a high prevalence of two rooted mandibular third molars with three canals.

Evaluation of Conventional Radiography and an Electronic Apex Locator in Determining the Working Length in C-shaped Canals.

INTRODUCTION: The purpose of this in vitro study was to compare the accuracy of working length determination using the apex locator versus conventional radiography in C-shaped canals. METHODS AND MATERIALS: After confirming the actual C-shaped anatomy using cone-beam computed tomography (CBCT), 22 extracted C-shaped mandibular second molars were selected and decoronated at the cemento-enamel junction. The actual working length of these canals were determined by inserting a #15 K-file until the tip could be seen through the apical foramen and the working length was established by subtracting 0.5 mm from this length. The working length was also determined using conventional analog radiography and electronic apex locator (EAL) that were both compared with the actual working length. The data was statistically analyzed using paired t-test and marginal homogeneity test. RESULTS: There was no significant differences between the working length obtained with apex locator and that achieved through conventional radiography in terms of measuring the mesiolingual and distal canals (P>0.05); while, significant differences were observed in measurements of the mesiobuccal canals (P=0.036). Within ±0.5 mm of tolerance margin there was no significant difference between EAL and conventional radiography. CONCLUSION: The apex locator was more accurate in determination of the working length of C-shaped canals compared with the conventional radiography.

Micro-computed Tomographic Analysis of Mandibular Second Molars with C-shaped Root Canals.

INTRODUCTION: The goal of the present study was to evaluate the morphometric aspects of the internal anatomy of the root canal system of mandibular second molars with C-shaped canals. METHODS: Fifty-two extracted second mandibular molars with C-shaped canals, fused roots, and radicular grooves were selected from a Brazilian population. The samples were scanned with a micro-computed tomographic scanner at a voxel size of 19.6 µm. The root canal cross sections were recorded as C1, C2, C3, and C4 root canal configurations according to the modified Melton classification. Morphometric parameters, including the major and minor diameters of the root canals, the aspect ratio, the roundness, and the tridimensional configuration (merging, symmetric, and asymmetric), were evaluated. RESULTS: The 3-dimensional reconstruction images of the teeth indicated an even distribution within the sample. The analysis of the prevalence of the different cross-sectional configurations of the C-shaped molars revealed that these were predominantly of the C4 and C3 configurations (1 mm from the apex) and the C1 and C2 configurations in the cervical third. According to the morphometric parameters, the C1 and the distal aspect of the C2 configurations exhibited the lowest roundness values and higher values for the area, major diameter, and aspect ratio in the apical third. CONCLUSIONS: Mandibular molars with C-shaped root canals exhibited similar distributions of symmetric, asymmetric, and merging type canals. The C1 configuration and the distal aspect of the C2 configuration exhibited the highest area values, low roundness values, and large apical diameters.

A comparison of four gutta-percha filling techniques in simulated C-shaped canals.

AIM: To compare four gutta-percha filling techniques in simulated C-shaped canals based on filling quality at three cross-sectional levels, filling time and the apical extrusion of gutta-percha. METHODOLOGY: Forty resin simulated C-shaped canals were constructed and filled using one of four techniques: cold lateral compaction (LC), ultrasonic compaction (UC), single cone with injectable gutta-percha (Obtura II(™) ) (IT) and core-carrier (Thermafil(®) ) (CC). Cross sections were made at 1 (L1), 3 (L3) and 6 (L6) mm from the canal terminus. Areas of gutta-percha, sealer and voids in each cross section were measured using an image analysis system. Data were analysed using a univariate general linear model and post hoc test (Dunnett's T3). Data on time taken to fill canals was evaluated using the Bonferroni post hoc test. RESULTS: CC had more gutta-percha and less sealer compared with IT at L1 (P < 0.05). LC had marginally significantly less gutta-percha than CC at this level (P = 0.049). At level 3 mm, significantly more gutta-percha and less sealer were present in IT compared with LC (P < 0.05). The techniques showed no difference in quality at L6. The time for LC (20.72 min) was three times longer than for both IT (6.11 min) and CC (6.67 min), whereas for UC (26.92 min), it was four times longer (P < 0.001). Finally, the four techniques were not different in the occurrence of apical extrusion of gutta-percha. CONCLUSIONS: The core-carrier technique was the most effective technique when assessed by gutta-percha area in this simulated C-shaped canal.

C-shaped root canal configuration: A review of literature.

The aim is to review and discuss the etiology, incidence, anatomic features, classification, diagnosis and management of the C-shaped canal configuration. C-shaped canal configuration is a variation that has a racial predilection and is commonly seen in mandibular second molars. The intricacies present in this variation of canal morphology can pose a challenge to the clinician during negotiation, debridement and obturation. Manual and electronic searches of literature were performed from 1979 to 2012, in Pub Med by crossing the keywords: C-shaped canals, mandibular second molar, mandibular first premolar, root canal morphology. Knowledge of the C-shaped canal configuration is essential to achieve success in endodontic therapy. Radiographic and clinical diagnoses can aid in identification and negotiation of the fan-shaped areas and intricacies of the C-shaped anatomy. Effective management of this anomalous canal configuration can be achieved with rotary and hand instrumentation assisted with sonics and ultrasonics. Modifications in the obturation techniques will ensure a 3-dimensional fill of the canal system and chamber retained restorations like amalgam or composites, serve as satisfactory post endodontic restorations.