The C-shaped root canal systems in mandibular second molars in an Emirati population

Evaluation of Mental Foramen and Mandibular Canal Course and Location in an Emirati Subpopulation

INTRODUCTION AND AIMS

Violations of the mandibular canal (MC) and mental foramen (MF) and subsequent injuries to their neurovascular bundle have been reported after surgical and nonsurgical dental procedures. Besides using advanced technologies such as cone-beam computed tomography (CBCT), clinicians should be aware of the anatomy and location of MC and MF in different populations. This study aims to describe the morphologic characteristics of the MF, MC, and its intrabony location in relation to the apices of mandibular posterior teeth in an Emirati subpopulation using CBCT.

METHODS

A total of 3700 CBCT scans were screened, and 154 scans that met the inclusion and exclusion criteria were randomly selected. The scans were assessed using 3-dimensional multiplanar imaging for the following structures: the location of MF and the MC course, its intrabony location, and its relationship to the apices of the mandibular posterior teeth. The data were analysed statistically using SPSS software.

RESULTS

The MC ran lingually and inferiorly at the posterior region and became more buccal and superior towards the MF. The distal root of the mandibular second molar was found to be the closest root to the MC (2.06 ± 1.83 mm). Moreover, the most common location of the MF was distal to the contact area between the 2 premolars (0.83 ± 1.84 mm) with a significant negative correlation to age (with and increase in age, the MF moves distally). The distance between the root apices and the MC was statistically significantly affected by age (positive correlation) and gender (male patients had a greater distance).

CONCLUSIONS

The common course of the MC is lingual and inferior posteriorly and becomes more buccal and superior towards the MF, which is located mostly between the mandibular first and second premolars. Furthermore, the distal root of the mandibular second molar is the closest to the MC and has a positive relationship with age.

Prevalence of radix accesoria dentis in a northern Peruvian population evaluated by cone-beam tomography

Radix accessoria dentis are anatomical variations of the mandibular molars and identifying them radiographically can be challenging for the clinician, especially in specific areas such as endodontics. The objective this study was to determine the prevalence of radix accessoria dentis evaluated in cone-beam computed tomography in a northern Peruvian population. The study design was descriptive and cross-sectional. The sample consisted of 2640 permanent mandibular first and second molar teeth evaluated by cone beam tomography. Non-probabilistic convenience sampling was used. For the analysis of radix accesoria dentis, the axial and coronal views of the tomography were evaluated. Prevalence was evaluated according to sex and according to type of tooth and average length. The statistical analyses used were the chi-square test and Kruskal-Wallis H test to find the correlation of the variables. A prevalence of 2.5 % of radix accesoria dentis was determined. According to sex, radix accesoria dentis was present in 1.36 % in females and 1.14 % in males (p > 0.05). The tooth 4.6 obtained the highest prevalence with 1.33 % (p > 0.05) and the average length of radix accesoria dentis found was 9.27 mm (p > 0.05). The prevalence of the radix accesoria dentis evaluated in cone beam tomography in a northern Peruvian population is low. Sex does not influence its presentation. Mandibular first molars are the ones that present the greatest amount of this anatomical variation and the average length of the radix accesoria dentis is less than 10 mm.

Association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography

BACKGROUND

Knowledge about the anatomy and morphology of the root canal system is essential for successful surgical and non-surgical root canal treatments. However, precise assessment of the root morphology and anatomy is not often possible on two-dimensional radiographs. This study aimed to investigate the association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography (CBCT).

METHODS

This cross-sectional study evaluated 1,231 CBCT scans of mandibular second molars obtained between October 2018 and February 2022 that were retrieved from the archives of a private radiology clinic. Panoramic-like images were reconstructed from the CBCT scans. The root morphology of mandibular second molars was classified on panoramic-like images as type 1, 2, 3, 4, or 5. The root pattern on axial CBCT images was classified into three types of single, double and C-shaped. The association of root morphology on panoramic-like and axial CBCT views was analyzed by the Chi-square test and Fisher's exact test at 0.05 level of significance.

RESULTS

Of all, 62.7% of mandibular second molars were type 1; out of which, 97.3% had a double-root pattern on axial CBCT images. Also, 28.6% of them were type 2; of which, 92.6% had a double-root pattern. Moreover, 3.9% were type 3; of which, 47.9% had a C-shaped pattern; 0.9% were type 4, and 45.5% of them showed a single-root pattern; 3.8% were type 5 with 76.6% of them showing a single-root pattern. The prevalence of C-shaped canals was higher in females, and most C-shaped canals had a C3 pattern.

CONCLUSION

Root morphology on panoramic-like CBCT views had a strong association with the root canal pattern on axial CBCT views. According to the results, mandibular second molars with a type 3 morphology on panoramic-like CBCT images are highly probable to have a C-shaped canal.

The global prevalence of middle mesial canal in mandibular first and second molars assessed by cone beam computed tomography: A systematic review and meta-analysis

BACKGROUND

This meta-analysis sought to identify the in vivo prevalence and influencing factors of middle mesial canal (MMC) in mandibular first and second molars based on cone-beam computed tomography (CBCT) scans.

METHODS

MEDLINE/PubMed, Web of Science, Scopus, SciELO, Google Scholar databases/search engines were searched in period between 15^th and 21^st November 2022, to retrieve the in vivo CBCT-based studies that assessed the prevalence of MMC in mandibular first and/or second molars. The studies were strictly assessed using pre-defined inclusion and exclusion criteria for relevancy and eligibility through screening the title and abstract, and then assessed through reading the full texts using the same criteria. Subsequently, the fulfilled studies were assessed qualitatively using the Newcastle-Ottawa Quality Assessment Scale, and quantitatively using meta-analysis to calculate the pooled prevalence rates of MMC. The publication bias was assessed using funnel plot and Egger's test.

RESULTS

Out of 1,122 studies, 33 studies comprised 13,349 and 7,624 mandibular first and second molars, respectively, were eligible for inclusion. Twenty studies scored high quality, while thirteen scored moderate quality. The global prevalence of MMC in the first molar was 4.4% (95% CI = 0.035-0.053, P<0.001), significantly higher than that of the second molar which was 1.3% (95%, CI = 0.008-0.018, P<0.001). Gender, molar side, and age were not influencing factors of MMC prevalence.

CONCLUSION

The prevalence of MMC is not uncommon, being higher in the mandibular first molar compared to the mandibular second molar. The prevalence of MMC is not influenced by age, molar's side, and gender.

Prevalence and correlation of C-shaped root canals of mandibular premolars and molars in Eastern Chinese individuals

The aim of this study was to investigate the prevalence, correlation, and differences of C-shaped root canals (CSRCs) morphology in permanent mandibular premolars and molars in Eastern Chinese individuals using cone-beam computed tomography (CBCT). A total of 8000 mandibular first premolars (MFPs), mandibular second premolars (MSPs), mandibular first molars (MFMs), and mandibular second molars (MSMs) CBCT images from 1000 patients (692 females and 308 males) were collected. The prevalence, correlation, bilateral/unilateral presence, the morphology of CSRCs, level of canal bifurcation, gender differences, and location of radicular grooves (RGs) were evaluated. The prevalence of CSRCs in MFPs, MSPs, MFMs and MSMs were 10.25%, 0.25%, 0.55% and 47.05%, respectively. The prevalence of CSRCs in MFPs of males was higher than that in females, while the prevalence of CSRCs in MSMs of females was higher than that in males (P < 0.05). The bilateral symmetry presence of CSRCs in MSMs was significant but not in MFPs, MSPs, and MFMs. RGs were predominantly found on the mesiolingual (ML) surface of premolars and the lingual surface of molars. There was a high prevalence of CSRCs in MFPs and MSMs in the Eastern Chinese population, but there was no correlation. The prevalence of CSRCs in MFPs and MSMs differ significantly by gender (P < 0.05).

A CBCT based cross sectional study on the prevalence and anatomical feature of C shaped molar among Jordanian

The prevalence and anatomical features of C-Shaped Mandibular Second Molars (MSMs) are rarely studied in Jordanian sub-population. This study then took a part to evaluate the prevalence of C-shaped in MSMs using cone-beam computed tomography (CBCT) in the Jordanian sub-population. It used a cross-sectional design and three thousand scans collected over eight years between 2011 and 2019. The data were then reviewed for whether they were fully formed of MSMs. A total of 2037 cases that had 2845 MSMs were evaluated to identify C-shaped canals at coronal, middle, and apical sites. An oblique slicing module perpendicular to the long axis of MSMs was used to evaluate the teeth. The type and frequency of C-shaped canals, as well as the correlations between sex and side (right/left) and between sex and groove direction (buccal/lingual) were measured using the chi-square test on SPSS software at the significance level of 95%. A total of 342 teeth of 243 patients were C-shaped molars, which comprised 12% of the patient's teeth and 99 of them as a bilateral C-shaped canal with mean age of 40 years and sex ratio of 2:1 between female and male. With the limitations of this study, the lingual groove and type 3 were the most common properties of MSM. Besides, the Jordanian population mostly had C-shaped canals.

Anatomical Evaluation of Root and Root Canal Morphology of Permanent Mandibular Dentition among the Saudi Arabian Population: A Systematic Review

This study aimed to conduct a compendious review of root canal morphology of “permanent mandibular teeth in different regions of Saudi Arabia” to obtain a large sample representing the total population. A detailed search through the databases Web of Science, Scopus, and PubMed was conducted following the PRISMA guidelines. The data were analyzed based on the following inclusion criteria: original full-length original articles that reported the variables of interest “(number of roots, number of canals, Vertucci's classification system and C-shaped canals or mid-mesial canals)” of the mandibular teeth and conducted on Saudi subjects. The retrieved data were presented as frequencies and percentages. The results revealed that 56.6% of mandibular central incisors had one canal and Vertucci type I (56.6%), while 57.4% of the mandibular lateral incisors had one canal, with Vertucci types I and III most frequent. In mandibular canines, 91.8% had one canal and 8.2% had two canals. Most of the mandibular first premolars had one root (86.6%), while almost all mandibular second premolars (91.5%) had one canal, and 96.9% had Vertucci type I configuration. Among the mandibular first molars, three and four canals were prevalent in 58.7% and 40.6%, respectively. The majority of mesial roots had Vertucci type IV (60.6%), and most of distal roots had Vertucci type I (72.2%). Most of the mandibular second molars had three canals (87.3%) and showed Vertucci type IV (39.4%) canals for mesial roots and Vertucci type I (95.6%) for distal roots. The C-shaped canals were seen in 8% of first premolars and 9.8% of second molars. The middle mesial canal was found in 4.2% and 0.4% of first and second molars, respectively. This review could represent “the population of Saudi Arabia as the included samples were combined from different regions of the country.” Some variations were noticed within the same group of teeth from different regions. However, the overall results of combined samples were comparable to the other international studies.