Root and Root Canal Morphology: Study Methods and Classifications

Background: Morphology of the root canal system is divergent and unpredictable, and rather linked to clinical complications, which directly affect the treatment outcome. This objective necessitates continuous informative update of the effective clinical and laboratory methods for identifying this anatomy, and classification systems suitable for communication and interpretation in different situations. Data: Only electronic published papers were searched within this review. Sources: “PubMed” website was the only source used to search for data by using the following keywords "root", "canal", "morphology", "classification". Study selection: 153 most relevant papers to the topic were selected, especially the original articles and review papers, from 1970 till the 28th of July 2021. Conclusions: This review divided the root canal analysis methods into two approaches; clinical and in vitro techniques. The latter has shown more precise non-subjective readings, on the other hand; the clinical methods provide direct chair side diagnosis for the clinical cases. The classification systems reviewed in the present study, started with the oldest trials that simply presented the root canal systems, according to the degree of angulation, or by coded Latin numbers or English letters. Then, the most recent systems were also presented that were persisted with continuous editions up to date. These new systems could briefly describe the root and root canal’s internal and external details in a small formulation, without confusion and in an easily communicated manner, highly recommended specially for students, teachers, and researchers

Vertucci's Root Canal Configuration of 11376 Mandibular Anteriors and its Relationship with Distolingual Roots in Mandibular First Molars in A Cantonese Population: A Cone-Beam Computed Tomography Study

Background: Cone-beam computed tomography (CBCT) was used to study the root canal system of mandibular anteriors (MAs) in a Cantonese population and to evaluate the correlation between the complicated root canal configurations of mandibular lateral incisors (MLIs) and the presence of distolingual roots (DLRs) in mandibular first molars (MFMs).Methods: A total of 11376 mandibular anterior teeth were scanned by CBCT. Those whose images met the inclusion criteria were first analysed according to Vertucci's root canal configuration and then grouped based on gender, age, and side, and their effects on root canal morphology were analysed. Finally, statistical analysis was used to evaluate the correlation between the complicated root canal configurations of MLIs and the existence of DLRs in MFMs. All statistical analyses were performed by using SPSS 21.0 software. Quantitative data are presented as the mean ± standard deviation. Student’s t tests were used to calculate statistical significance. P < 0.05 was considered statistically significant.Results: In MAs in the Cantonese population, all mandibular central incisors (MCIs) and MLIs had one root, and 0.37% of mandibular canines (MCs) had two roots. The most common Vertucci's root canal configuration was Vertucci I followed by Vertucci III. A total of 30.91% of MLIs and approximately 8% of MCIs and MCs have complicated root canal configurations. There were no significant differences in the prevalence of DLRs in MFMs and the incidence of complicated root canal configurations of MLIs between males and females or between the right and left teeth. However, a significant difference was found in different age groups of root canal configurations in MLIs. Moreover, significant ipsilateral and contralateral correlations between MFMs with DLRs and MLIs with complicated root canal configurations were observed on both sides.Conclusion: There is a correlation between the presence of DLRs in MFMs and complicated root canal morphology in MCIs in the Cantonese population.

Retrospective Evaluation of Variations in Root Canal Morphology of Permanent Maxillary Premolars Among the Emirate Population

Background: This research aims to identify the most common morphology of the upper premolars in a group of local and nonlocal people in the UAE using cone-beam computed tomography (CBCT).Methods: CBCT images of a total of 214 intact maxillary premolars were analysed with 3D reconstruction GALAXIS viewer software. The Pearson Chi squared test and the two samples t test were applied.Results: In all, 90% of the maxillary first premolars had two roots (92% females, 88% males, 83% locals, 96% nonlocals). A total of 52% of maxillary second premolars had two roots (47% females, 56% males, 38% locals, 67% nonlocals). Two cases had three roots among local males. A significant difference of one root in the maxillary second premolar was observed between locals (63%) and nonlocals (33%), while two roots were higher among nonlocals (67%) than locals (37%, p = 0.002). Three roots were discovered in two teeth of the local UAE first premolar. The most common canal morphology in the maxillary first premolar group among local UAE subjects was type V (52%), and among nonlocal UAE subjects was type V (59%). Additional types included 7 (13.2%) identified and unrelated to the Vertucci classification. The dominant canal morphology in the maxillary second premolar among local UAE subjects was type II (32%), and among nonlocal UAE subjects was type V (25%); among the additional types, 12 (23.1%) were identified and not related to the Vertucci classification. There was a significant difference in the distance from the pulp chamber roof to the cementoenamel junction (CEJ) and the measurement between the single-rooted maxillary premolar CBCT for local UAE subjects was 1.36 mm (SD ±0.75) and for nonlocal subjects was 1 mm (SD ±0.27, p = 0.049). There were statistically significant differences in all measurements between multiple rooted maxillary premolar CBCTs for local UAE and South Asian subjects (p < 0.05)Conclusions: The results suggest a more quantitative approach to maxillary first and second premolar access cavity preparation in the UAE population to prevent errors and iatrogenic damage when identifying the canals; using CBCT measurements for more precise access preparations may be advantageous.

ANATOMICAL VARIATIONS AND VARIOUS TECHNIQUES OF IDENTIFICATION OF MULTIPLE ROOT CANALS: A REVIEW

Variations in root canal morphology presents a constant challenge for clinicians in their detection and management. Locating and treating these extra canals is important in order to achieve favorable prognosis in endodontic therapy. This review article presents the anatomical variations, frequency of occurrence of aberrant root canal configuration and methods of identification using advanced imaging techniques like CBCT, DOM and loupes.

Treatment of anatomic canal variations in premolar teeth: Five case reports

Aim: The aim of this case report is to present a series of anatomical variations and endodontic treatments in four two-canal mandibular premolar teeth and three rooted three-canal maxillary second premolar teeth with root canal treatment indications identified via clinical and radiographic examinations. The success of root canal treatment is achieved with a thoroughly examined root canal morphology that has been accurately determined radiographically and clinically before adequate shaping, irrigation, and hermetic filling procedures. Root canals that are not found or not adequately disinfected can cause root canal treatment failure and complications, such as pain, swelling, or persistent fistula, also known as flare-up, after treatment. Canal variations in the teeth were detected via periapical radiographs during the root canal instrumentation stage. Methodology: The endodontic treatments of four two-canal mandibular premolar teeth and one triple-rooted three-canal maxillary second premolar with root canal treatment indications were described. Conclusion: To achieve full success in root canal treatment, anatomical variations should be examined in detail before and during treatment, and treatment should be completed with appropriate techniques. How to cite this article: Dinger E, Bodrumlu E. Treatment of anatomic canal variations in premolar teeth: Five case reports. Int Dent Res 2021;11(Suppl.1):279-84. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.41 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Root Canal Morphology and Configuration of the Mandibular Canine: A Systematic Review

The aim of this study was to systematically review the root canal morphology and configuration (RCC) of mandibular canines (MaCa). The review was registered in the PROSPERO database (ID-272297) and it was carried out following the PRISMA guidelines. Three electronic databases (MEDLINE via PubMed, Embase, Scopus) were searched. Randomized controlled trials, cross-sectional, cohort, comparative, evaluation and validation studies have been included. The anatomical quality assessment (AQUA) tool was used for a quality assessment of the anatomical studies. Of 910 studies retrieved from the systematic search, 28 studies investigating RCCs were included. Most MaCa were single-rooted (87.9–100%), while two-rooted MaCa were present up to 12.1%. The 1-1-1/1 (35.8–96.4%) was the most commonly reported RCC, followed by 2-2-1/1 (0.2–22.0%) and 1-2-1/1 (0.9–20.0%). A high frequency of 1-1-1/1 RCC in MaCa has been described. Most systematic review reports confirm that two-rooted MaCa are found considerably less frequently than single-rooted ones.

Prevalence of complex root canal morphology in the mandibular first and second premolars in Thai population: CBCT analysis

Background Mandibular premolars demonstrate high variability in root canal morphology, especially mandibular first premolars. The purposes of this study were to determine the prevalence of root canal configurations of mandibular premolars according to Vertucci classification in a Thai population. Methods Total of 1159 CBCT images of Thai patients who received radiographic imaging at the Department of Radiology, Faculty of Dentistry, Chulalongkorn University in 2017–2018 was evaluated. The data were reported using descriptive statistics and the relationship between the prevalence of the root canal complexities and sex was analyzed using the chi-squared test. Results The most common root canal configuration was Vertucci type I, with a 63.1% and 98% prevalence in the mandibular first and second premolars, respectively. More than 98% of mandibular premolars had a single root. The prevalence of a bifurcation was 28.5% and 1.5% in the mandibular first and second premolars, respectively. The prevalence of a trifurcation was 3.2% in the mandibular first premolar. A C-shaped root canal was observed at 23.7% and 0.7% in the mandibular first and second premolars, respectively. The level of branching was mostly found at the middle 1/3 of the root. Bilateral appearance of the same root canal configuration was identified in 80.3% and 95.9% in the mandibular first and second premolars, respectively. There was no relationship between sex and the prevalence of a bifurcation, trifurcation, or C-shaped root canal. Conclusion Mandibular first premolars have more root canal complexities than mandibular second premolars. Horizontal tube shift x-ray technique, CBCT, dental operating microscope, and knowledge of root canal configurations have an important role in root canal identification in mandibular premolar with suspected complex root canal morphology.