C-shaped canals-prevalence and root canal configuration by cone beam computed tomography evaluation in first and second mandibular molars-a cross-sectional study.

OBJECTIVES: C-shaped root canal configuration is an unusual root canal morphology and one of the most often anatomical variations in root canal systems of second mandibular molars. The purpose of this study was to assess the prevalence, symmetry and configuration of C-shaped canals in first and second mandibular molars in an Israeli population using cone beam computed tomography (CBCT). MATERIALS AND METHODS: One thousand twenty Israel patients' CBCT scans were screened and evaluated. First and second mandibular molars with C-shaped canals were identified. Prevalence configuration along the root and symmetry were analyzed, and new radicular groove classification was proposed. RESULTS: Total of 1465 mandibular second molars and 1229 mandibular first molars were evaluated. The overall prevalence of C-shaped canals in first and second mandibular molars was 0.16 and 4.6%, respectively. No significant difference was found by gender or side of occurrence. The unilateral prevalence of C-shaped canals in mandibular second molars was 55%. C-shaped canal configuration changed along the root in 63% of the cases. CONCLUSIONS: The prevalence of C-shaped canals in first and second mandibular molars in the Israeli population is low in comparison to other subpopulations. Clinicians should be aware of the possible asymmetry, different configuration along the root, and the location of danger zone of this anatomic variation during clinical work. CLINICAL RELEVANCE: CBCT is an efficient three dimensional radiographic examination for evaluation of C-shape root canal configuration. CBCT may help the clinicians during clinical work for considering appropriate cleaning, shaping, and obturation technique according to the characteristic of C-shape root canal configuration.

Successful orthograde treatment of dens invaginatus Type 3 with a main C-shaped canal based on cone-beam computed tomography evaluation.

Dens invaginatus is a rare anatomic variation that is found primarily in maxillary lateral incisors. The management of dens invaginatus is challenging for clinicians; diagnosing the type of malformation, choosing the most appropriate treatment, and carrying out treatment are complicated by the intricate root system of these teeth. The following case report describes the diagnosis and treatment planning of dens invaginatus Type 3 after cone-beam computed tomography evaluation.

Prevalence of 3- and 4-rooted first and second mandibular molars in the Israeli population.

INTRODUCTION: Three-rooted mandibular molars are 1 of the anatomic variations of mandibular molars. The location of the additional root is distolingual (radix entomolaris) or mesiobuccal (radix paramolaris). The purpose of this retrospective study was to assess the prevalence of 3- and 4-rooted mandibular first and second molars in the Israeli population and to classify them according to dimension, curvature, and location of separation from the main root. METHODS: A total of 1020 Israel patients' cone-beam computed tomographic scans were screened and evaluated. The incidence of 3- and 4-rooted first and second mandibular molars were recorded and analyzed. One thousand four hundred sixty-five mandibular second molars and 1,229 mandibular first molars were evaluated. RESULTS: The overall incidence of patients with 3-rooted mandibular first and second molars was 2.6% and 1.78%, respectively. The bilateral incidence of 3-rooted mandibular first and second molars was 26%. The incidence of 4-rooted mandibular second molar was 0.55%. No significant difference was found regarding sex or side of occurrence. CONCLUSIONS: The occurrence of 3-rooted mandibular first molars in the Israeli population was rare, but clinicians should be aware of the special characteristic of this anatomic variation to modify accordingly the form of pulp chamber opening and choose appropriate instrumentation.

Use of Cone-beam Computed Tomography during Retreatment of a 2-rooted Maxillary Central Incisor: Case Report of a Complex Diagnosis and Treatment.

A double-rooted maxillary incisor is an extremely rare anatomic variation. Only a few case reports describe this abnormal anatomy. In recent decades, cone-beam computed tomographic (CBCT) imaging has become more common for endodontic purposes. This case report describes the retreatment of double-rooted maxillary central incisors using CBCT imaging. In 2012, a 20-year-old man was referred to our department because of asymptomatic periapical lesions in teeth #8, #9, and #10. During the evaluation of a periapical radiograph, a rare anatomic variation, in the form of an additional root of tooth #9, was detected, and it was impossible to decide about the source of the lesion between teeth #9 and #10. During retreatment, after gutta-percha removal, CBCT imaging was performed; this allowed proper treatment of the additional root and a final diagnosis of normal periapical tissue of tooth #10 with no treatment needed. The 18-month follow-up revealed a healing lesion in tooth #9 and normal periapical tissue in tooth #10. During the treatment of teeth with an anatomic variation, CBCT imaging can serve as an auxiliary tool for 3-dimensional evaluation that influences treatment steps and techniques. CBCT scanning can be very useful in assessing the actual location of a periapical lesion, which influences diagnosis and treatment planning.