C-shaped Root Canal System Research Articles

C-Shaped Root Canal Systems: Diagnosis and Endodontic Treatment

C-shaped root canal systems are anatomic variations presenting a connection of root canals. Evaluation of preoperative findings are crucial for successful treatment of such cases. In radiological evaluation, comprehension of their morphological features is required for identification of specific findings. Clinically, C-shaped root canals may present different configurations of pulp-chamber and must be considered with 20 caution. It has been reported that a high incidence of C-shaped root canal systems have been shown in mandibular second molars and in Asian populations. In this review, morphological features, radiological diagnostic aspects and management of Cshaped canals are presented.

Analysis of C-shaped Canals by Panoramic Radiography and Cone-beam Computed Tomography: Root-type Specificity by Longitudinal Distribution

IntroductionThe purpose of this study was to document the characteristics of C-shaped canal systems in permanent mandibular second molars using a combination of orthopantomogram (OPT) and cross-sectional cone-beam computed tomographic (CBCT) imaging. MethodsTwo hundred participants (94 men and 106 women, mean age = 35 years) who underwent both routine CBCT and OPT examinations were enrolled. One endodontist and 1 oral radiologist examined the images of 339 mandibular second molars and described the radiographic features of C-shaped canals from OPT images as confirmed by CBCT imaging. Root morphology was classified as nonfused (NFRI–II) or fused (FRI–III) based on OPT images. Cross-sectional root canal configurations (C1–C5) were identified from CBCT imaging at 3 different levels (coronal, middle, and apical). Frequency distributions of root morphology and root canal configurations were compared at each level, and interobserver reliability was tested using the Cohen kappa test. ResultsOf the 339 teeth, 29 (8.6 %) had C-shaped root canal systems. Most of the root canals were NFR type (86%); only 2% had C-shaped root canals (all NFRII). In the FR category, 23 teeth with C-shaped canals were equally distributed between the FRI and FRII subtypes. Interobserver agreement was almost perfect (κ = 0.89 and κ = 0.91; right and left second molars, respectively). Per CBCT imaging, the most common configuration was C3 at all levels; no C5 case was detected. ConclusionsOPT usage can assist in recognizing and diagnosing C-shaped root canal systems. Radicular fusion or proximity is a characteristic feature of C-shaped canal systems. However, nonfused root appearances should also be considered suspicious.

Aetiology, incidence and morphology of the C‐shaped root canal system and its impact on clinical endodontics

The C-shaped root canal constitutes an unusual root morphology that can be found primarily in mandibular second permanent molars. Due to the complexity of their structure, C-shaped root canal systems may complicate endodontic interventions. A thorough understanding of root canal morphology is therefore imperative for proper diagnosis and successful treatment. This review aims to summarize current knowledge regarding C-shaped roots and root canals, from basic morphology to advanced endodontic procedures. To this end, a systematic search was conducted using the MEDLINE, BIOSIS, Cochrane Library, EMBASE, Google Scholar, Web of Science, PLoS and BioMed Central databases, and many rarely cited articles were included. Furthermore, four interactive 3D models of extracted teeth are introduced that will allow for a better understanding of the complex C-shaped root canal morphology. In addition, the present publication includes an embedded best-practice video showing an exemplary root canal procedure on a tooth with a pronounced C-shaped root canal. The survey of this unusual structure concludes with a number of suggestions concerning future research efforts.

Anatomic and diagnostic challenges of C-shaped root canal system.

ABSTRACTSuccessful root canal treatment depends on the thorough management of the canal anatomy. The use of periapical radiographs is essential to identify and monitor the canal's morphological variations. The C-shaped single canaled man-dibular 2nd molar probably requires a different regimen of treatment from the two rooted, three canaled version, as it is rare. Because of the importance of its true diagnosis and treatment, a comprehensive review of published information and investigations about it in addition to approaches for its treatment is necessary. In this article, a detailed review and three case reports with different C-shaped canal configurations have been described which were successfully negotiated, pre­pared and obturated.How to cite this article: Raisingani D, Gupta S, Mital P, Khullar P. Anatomic and Diagnostic Challenges of C-Shaped Root Canal System. Int J Clin Pediatr Dent 2014;7(1):35-39.

Use of cone‐beam computed tomography to evaluate C‐shaped root canal systems in mandibular second molars in a Turkish subpopulation: a retrospective study

To use cone-beam computed tomography (CBCT) to evaluate the prevalence and anatomical features of C-shaped canals in permanent mandibular second molars amongst members of a Turkish population. An endodontist and oral radiologist examined CBCT images of 271 Turkish mandibular second molars to determine the presence of C-shaped canals and their anatomical features. Root canal configurations at five different levels were categorized using the classification of Fan etal. (Journal of Endodontics, 30, 2004a,b, 899-903; 904-8). Bilateral or unilateral occurrence of C-shaped canals and their relationships with gender, age and tooth position were examined and statistically analysed using the chi-squared test. Of the 271 mandibular second molars examined, 24 (8.9%) molars from 17 patients had a C-shaped root canal system. The prevalence of bilateral C-shaped canals was 6.3% amongst 111 patients with bilateral mandibular second molars. There were no significant differences in the distribution of C-shaped canals with respect to gender or age. Only one tooth had the same canal configuration from the orifice to the apex. In the remainder of the teeth, the cross-sectional canal configuration changed at different levels of the root. The configuration of C-shaped canals varied along the length of the root. The prevalence of C-shaped canals in mandibular second molars in this Turkish population was lower than in other Asian populations.

C-shaped canal, an endodontic challenge

Recognition of unusual variations in the canal configuration is critical because it has been established that the root with a single tapering canal and apical foramen is the exception rather than the rule. C-shaped canals are anatomic features that present the clinician with both diagnostic and operational challenges. The early recognition of these configurations facilitates cleaning, shaping, and obturation of the root canal system. .C. configuration, which is an important anatomic variation, presents a thin fin connecting the root canals.The C-shaped root canal system is an anatomical variant of the root canal structure in which a continuous slit or web connects individual root canals. These C-shaped canals present a challenge to the clinician, both at the diagnostic and treatment level. Health Renaissance, January-April 2013; Vol. 11 No.1; 89-91 DOI: http://dx.doi.org/10.3126/hren.v11i1.7610

A Cone-beam Computed Tomography Study of the Root Canal Morphology of Mandibular First Premolars and the Location of Root Canal Orifices and Apical Foramina in a Chinese Subpopulation

IntroductionSuccessful root canal treatment is dependent on detailed knowledge of the morphology of the root canal system. The aim of this study was to investigate the morphology of the root canal systems of mandibular first premolars and the location of root canal orifices and apical foramina in a Chinese subpopulation using cone-beam computed tomography scanning. MethodsA total of 440 cone-beam computed tomographic images of mandibular first premolars were obtained from 238 patients. Tooth position, root canal morphology, the distance between the apical foramen and the anatomic apex, and the distance between the 2 root canal orifices of mandibular first premolars with 2 root canals were investigated. The Fisher exact test was used to analyze the correlation between the number of root canals and tooth position. ResultsOverall, 1.14% (n = 5) of the teeth had a C-shaped root canal system, 77.14% (n = 335) had 1 root canal, and 22.05% (n = 97) had 2 root canals from type II to type V. The remaining 0.68% (n = 3) were classified as type VIII, which had 3 root canals. The most frequent distribution of the distance between the apical foramen and the anatomic apex in 335 mandibular first premolars with 1 root canal was 1–2 mm (n = 192). The distance between the apical foramen and the anatomic apex of mandibular first premolars with 2 root canals was in accord with that of mandibular first premolars with 1 root canal. The distance between the 2 root canal orifices of mandibular first premolars with 2 root canals was approximately 13 mm. ConclusionsMost mandibular first premolars had 1 root canal. More than 1 of 5 mandibular first premolars had complex root canal systems (with 2 or more root canals). This study provides supplemental information about the root canals of mandibular first premolars in a Chinese subpopulation.

Incidence of C-shaped root canal systems in mandibular second molars in the native Chinese population by analysis of clinical methods

The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods. For the recognition of C-shaped root canal system, 1 146 mandibular second molars were selected and examined. Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton's method. C-shaped canals were identified in 397 (34.64%) mandibular second molars by radiography (type I, 31.23% type II, 38.29% type III, 30.48%). Clinical examination showed that 449 (39.18%) cases exhibited C-shaped canal systems (C1, 22.94% C2, 48.11% C3a, 15.59% C3b, 13.36%). As for the result of the radiographic and clinical combined examination, C-shaped root canals were found in 473 (41.27%) mandibular second molars (C1, 21.78% C2, 45.67% C3a, 16.70% C3b, 15.86%). The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination (P<0.05). The study indicated a high incidence of C-shaped canal system in a Chinese population. The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.

C-shaped root canal configuration in mandibular second premolar: Report of an unusual case and its endodontic management

The C-shaped root canal system is an aberration of the root canal system in which a characteristic fin or web connects individual canals, resulting in a C-shaped cross section. This configuration has been rarely reported in the mandibular second premolar. The only other known reported case of a C-shaped canal, with its configuration, in relation to mandibular second premolar is of an extracted tooth. The purpose of this report is to describe the diagnosis, configuration and endodontic management of C-shaped root canal in mandibular second premolar. Clinical techniques to addresses the challenges in endodontic disinfection as well as cleaning and shaping of the C-shaped canal, which is prone to endodontic mishaps, are also discussed in this case report. Reporting of this case emphasizes the need and added advantage of using the dental operating microscope hand in hand with conventional radiography in management of the C-shaped root canal configuration.

C-shaped root canal system in mandibular second molars in a Chinese population evaluated by cone-beam computed tomography

To evaluate the anatomical features of C-shaped canal systems in Chinese mandibular second molars by cone-beam computed tomography (CBCT). A total of 608 patients of Chinese descent with healthy, well-developed mandibular second molars were enrolled. These patients were referred to the West China Hospital of Stomatology and required radiographic examination by CBCT as part of their routine dental treatment. Of the 608 examined CBCT images, 528 showed unilateral intact molars and 80 showed bilateral intact molars. Bilateral molar data were only used to analyse the distribution of unilateral and bilateral occurrences of C-shaped canals. The following in vivo CBCT observations were made: (i) frequency and type of root; (ii) frequency of C-shaped canals by gender, age and tooth position (left versus right); (iii) the classification of cross-sectional canal images of C-shaped canals; and (iv) unilateral and bilateral occurrences of C-shaped canals. Fused roots were present in 39% of molars. A C-shaped canal system was present in 39% of the teeth. This prevalence did not differ with gender, age and tooth position. Most (81%) of the C-shaped canals in individuals with bilateral molars were symmetrical. Most of the canals with uninterrupted 'C'-shapes appeared to divide into two or more canals towards the canal terminus. There was high prevalence of C-shaped canals in the mandibular second molars of Chinese population. The canal systems varied considerably in their anatomical configuration.

Micro-computed Tomographic Comparison of Nickel-Titanium Rotary versus Traditional Instruments in C-Shaped Root Canal System

IntroductionThe purpose of this study was to assess the efficacy of instrumentation of C-shaped canals with ProTaper rotary system and traditional instruments by using micro–computed tomography (micro-CT). MethodsTwenty-four mandibular molars with C-shaped canals were selected in pairs and sorted equally into 2 groups, which were assigned for instrumentation by ProTaper rotary system (ProTaper group) or by K-files and Gates-Glidden burs (Hand Instrument group). Three-dimensional images were constructed by micro-CT. The volume of dentin removed, uninstrumented canal area, time taken for instrumentation, and iatrogenic error of instrumentation were investigated. ResultsHand Instrument group showed greater amount of volumetric dentin removal and left less uninstrumented canal area than ProTaper group (P < .01). The time needed for instrumentation was shorter for ProTaper group than for Hand Instrument group (P < .05). No instrument breakage occurred in both groups, but more conspicuous procedural errors were detected in Hand Instrument group than for ProTaper group. ConclusionsIt was concluded that ProTaper rotary system maintained the canal curvature with speediness and few procedural errors, whereas traditional instrumentation can clean more canal surface.

Anomalous mandibular premolars: a mandibular first premolar with three roots and a mandibular second premolar with a C‐shaped canal system

To describe unusual variations in the root morphology and root canal systems of mandibular first and second premolar teeth extracted for orthodontic reasons. Normally mandibular first and second premolar teeth have single roots with single canals. A 15-year-old patient presented for orthodontic treatment and two mandibular premolar teeth were examined post-extraction. The mandibular first premolar exhibited three distinct, separate roots and the mandibular second premolar exhibited a C-shaped root canal system. The coronal morphology of each of the mandibular premolars revealed dimensions and anatomy within normal limits. The incidence of a three-rooted mandibular first premolar is approximately 0.2%. * Thorough clinical and radiographic interpretation is important in recognizing anomalous root and root canal systems. * The most common forms of root and canal systems and its aberrations must be understood to realize variations from normal do occur. * Successful root canal treatment requires an accurate diagnosis of the root canal system using all available aids. * Value of microcomputed tomography in the study of anatomy ex vivo and cone-beam tomography in clinical endodontics of complex premolar cases is increasing.

Evaluation of a Rotary Instrumentation Method for C-shaped Canals with Micro-computed Tomography

This study aimed to evaluate the safety and efficacy of a method of using nickel-titanium rotary instruments for preparing the C-shaped root canal system. Forty-three human mandibular second molars with a C-shaped canal configuration were prepared with a crown-down approach to an apical dimension of size 30 by using a combination of ProFile and HERO instruments. Micro–computed tomography was used to examine the canal diameter and the remaining thickness of the dentin wall along the root canal. Results showed that only isolated regions in cross section of the C-shaped canal were physically prepared by the rotary instruments. The furcal wall (concave aspect of the “C” in cross section) of all clinically identifiable canals had a similar thickness at a distance 1–7 mm from the apical constriction both before and after instrumentation. More dentin was removed from the outer (convex aspect of the “C”) than the furcal aspect at the apical region, but the converse was true more coronally. All prepared canals showed a taper that matched that of the last instrument used. It was concluded that cleaning of the C-shaped canal system is incomplete with the use of rotary instruments and should be assisted by ultrasonic irrigation. Although rotary instruments seemed to be safe in such canals, further enlargement to an apical dimension greater than size 30 (0.06 taper) is not recommended.

Morphology of C-shaped root canal systems

Morphology of C-shaped root canal systems

Morphometric study of the apical anatomy of C‐shaped root canal systems in mandibular second molars

To investigate the apical anatomy of C-shaped canal systems in mandibular second molars by micro-computerized tomography (microCT) and stereomicroscopy. Forty-four permanent mandibular second molars with a C-shaped root canal systems from a native Chinese population were scanned at 100 microm intervals by microCT at a resolution of 30 x 30 microm. The apical 5 mm of each tooth was reconstructed three-dimensionally for visualization and classification of the canal configuration using Vertucci's criteria. The main and auxiliary (accessory) foramina were examined under a stereomicroscope. Type IV and VIII canal configurations were most often found in the apical 5 mm of these canal systems. The prevalence of accessory canals, lateral canals, inter-canal communications and apical delta were 41%, 25%, 27% and 11%, respectively. Approximately 80% of C-shaped canals had 1-3 apical foramina; the prevalence of accessory foramina was about 48%. The mean distance between the main foramen and the anatomic root apex was 0.84 mm, and that between the accessory foramen and the apex was 1.61 mm. The mean (shortest and longest) diameters of major and accessory foramina were 0.19 - 0.32 mm and 0.07 - 0.10 mm, with a mean form factor of 0.73 and 0.82, respectively. The apical anatomy of C-shaped root canal systems in mandibular second molars is extremely complex with many anatomical variations.

A study on the C-shaped root canal system of mandibular second molar

C형 근관계에 관한 연구 C-shaped canals are known to present a complex canal anatomy with numerous fins connecting individ- ual canals, thus requiring supplementary effort to accomplish a successful root canal treatment. This study examined the frequency of the C-shaped mandibular second molars and interrelation between the clinical records and radiographs to recognize them treated in the Department of Conservative Dentistry of the Chosun University Dental Hospital during a six-year period (1998 - 2004). This study reviewed the clinical records of 227 patients who underwent root canal treatment of the mandibular second molars. After open- ing the chamber, those cases with C-shaped orifices in the pulpal floor were selected, and the C-shaped root canal types were classified according to Melton' s criteria. Three experienced dentists evaluated the radiographs of the C-shaped mandibular second molar on a viewer using a magnifying glass in order to determine if the root apex was fused or separated, the distal root canal was either centered or mesial shift- ed in the distal root, and if there was bilateral symmetry in a panorama. In conclusion, there is a high fre- quency of C-shaped mandibular second molars in Koreans. Simultaneous interpretation of the root shape and distal root canal using the preoperative, working length and post-treatment radiographs is important for diagnosing a C-shaped mandibular second molar. (J Kor Acad Cons Dent 32(4):335-342, 2007)

C-shaped Canal System in Mandibular Second Molars Part IV: 3-D Morphological Analysis and Transverse Measurement

The purpose of this study was to investigate three-dimensional (3-D) morphology of C-shaped root canal system using micro-computed tomography (μCT) and 3-D reconstruction. There were 102 extracted mandibular second molars with fused roots collected from a native Chinese population. The teeth were scanned by μCT and reconstructed by 3-D software. The 98 teeth that possessed a C-shaped canal system were further analyzed. The 3-D reconstructed images of canals were classified into three categories: merging type (type I), symmetrical type (type II), and asymmetrical type (type III). The cross-sectional images of each tooth were submitted to computer analysis, and the minimum canal wall thickness was measured. In these 98 molars, 32 (32.65%) teeth showed a merging type appearance, 38 (38.78%) a symmetrical type and 28 (28.57%) an asymmetrical type. The minimum canal wall thickness in type I was thicker than that in type II or type III in the apical and middle portion (p < 0.05). Being fully aware of the configuration of C-shaped root canal system and the location of minimum wall thickness will ensure more efficient root canal treatment.

C‐shaped root canal in a maxillary first molar: a case report

This case report presents an unusual C-shaped root canal system in a maxillary first molar tooth. Although C-shaped root canals are most frequently seen in the mandibular second molar, they may also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. The present case describes a C-shaped canal in the buccal root of a maxillary first molar. The endodontic access cavity displayed two canal orifices, one leading to the canal system in the buccal root, the other into the palatal root canal system. In the buccal root, what appeared to be the mesial and distal canals joined to form a single C-shaped canal. --Careful examination of radiographs and the internal anatomy of teeth is essential.-- The location and morphology of root canals should be identified at high magnification under the microscope.

C-shaped Canal System in Mandibular Second Molars: Part I—Anatomical Features

The purpose of this study was to investigate the anatomical features of C-shaped root canal system in mandibular second molars using micro-computed tomography (microCT). Fifty-eight extracted mandibular second molars with fused roots were collected from a native Chinese population. The teeth were scanned into layers of 0.5-mm thickness by microCT and measurements were made at eleven levels. The ratio of the depth of the deepest part of the groove to the buccal-lingual thickness of the cross-section of the root was calculated for each tooth. The canal shapes of the scanned cross-sections were assessed and classified according to a modified Melton's method. Results were subject to the Kruskal-Wallis test. Of the 58 molars, 54 had a C-shaped canal system with a mean groove-to-thickness ratio of 47.96%; the four teeth without a C-shaped canal had a mean ratio of 14.82%. Most orifices (98.1%) were found within 3 mm below the cementoenamel junction. Of teeth with a C-shape canal system, a majority demonstrated an orifice with an uninterrupted "C" configuration. Seventeen canals divided in the apical portion, most of which did so within 2 mm from the apex. The cross-sectional shape varied drastically along the length of the canal. Teeth with a high groove-to-thickness ratio had at least one section with C1, C2, or C3 configuration. The canal shape in middle and apical thirds of C-shaped canal systems could not be predicted on the basis of the shape at the orifice level. Section 2 of this paper addressed the correlation between the radiographic appearance and these microCT images.