Mandibular Canal Branching Assessed With Cone-Beam Computed Tomography

This study aimed to evaluate the prevalence and type of mandibular canal branching in a sample of the Iranian population through cone-beam computed tomography (CBCT) images. This cross-sectional study was performed on CBCT records of 300 patients (112 males and 188 females; mean age 30.14 ± 10.96 y). The presence of mandibular canal branch (MCB) was evaluated by reconstructing multiple panoramic views and buccolingual cross-sections, according to Naitoh's classification. The prevalence of MCB, the type of MCB, and the demographic information of all patients were recorded. The maximum number of branching and the maximum type of branching were also registered for each patient. Mandibular canal branching was observed in 131(43.7%) of 300 CBCT images without side or sex differences ( P > 0.05). The most frequent type was dental, followed by the retromolar, forward, and buccolingual types, respectively. There was a statistically higher frequency of retromolar canal in females than in males (odds ratio: 1.14 ± 4.25; P = 0.013). About 46% of patients with MCB had more than one accessory canal and 29% displayed more than one type of MCB. The coincidence of dental and retromolar canals in a patient was the most prevalent combination. Considering the relatively high prevalence of MCB (43.7%), it is recommended to keep in mind the possibility of anatomical variations of the inferior alveolar nerve during dental procedures to avoid postsurgical complications. The high possibility of observing multiple numbers and types of branching in the patients should also be considered during preoperative assessments.

Prevalence and characteristics of accessory mandibular canals in an eastern Chinese population by cone beam computed tomography

PURPOSE

This retrospective study aimed to determine the prevalence and morphological characteristics of accessory mandibular canals (AMCs) in an eastern Chinese population to provide clinical guidance for reducing intraoperative and postoperative complications.

METHODS

Cone beam computed tomography (CBCT) scans of 300 Chinese patients were used to identify AMCs according to a modification of Naitoh's classification. The length of the branch (L0) and the upper and lower angles between the branch and mandibular canal were measured on sagittal images. Additionally, the branches were divided into narrow or wide types by calculating the ratio of the branch diameter to the main canal diameter. The location of the bifurcation point was characterized by measuring its distance to the buccal wall of the mandible (L1), lingual wall of the mandible (L2) and alveolar ridge (L3).

RESULTS

The prevalence rate of AMCs was 40.7% (95% CI: 35.1-46.3), and the most common type was the retromolar canal, followed by the forward canal, dental canal, trifid mandibular canals (TMCs) or others, inferior canal and buccolingual canal. Twenty-one cases of multiple branches with unusual patterns were observed in the study. The average values of L0, L1, L2 and L3 were 15.05 ± 0.63 mm, 5.79 ± 0.14 mm, 4.40 ± 0.18 mm and 14.61 ± 0.31 mm, respectively. The mean upper angle and lower angle were 141.59° ± 2.44° and 50.64° ± 2.57°, respectively. Approximately 20.8% of the branches were defined as wide type, and no statistical significance was found between different types.

CONCLUSION

AMCs are not rare anatomic variations of the mandibular canal in the eastern Chinese population; thus, CBCT examination is highly recommended for precise evaluation before surgeries involving the mandibles.

Orthodontic Approaches in the Management of Mandibular Fractures: A Scoping Review

Non-surgical approaches have been proposed in the management of mandibular fractures, especially in children, but there is a lack of clear guidelines on the clinical indications of conservative approaches. The aim of this scoping review is to provide the available evidence of the role of the orthodontist in the management of mandibular fractures. The PRISMA-ScR guidelines were followed to select eligible articles from the PubMed, Scopus, and Web of Science databases according to precise inclusion criteria. The research questions were formulated as follows: "what is the scientific evidence concerning the rule of orthodontists in the management of mandibular fractures" and "the preferential use of the direct bonding technique with orthodontic brackets rather than rigid arch bars"? Seventeen articles were included. Five articles presented the use of removable acrylic splints or functional appliances, six articles concerned the employment of cemented acrylic or rigid splints, and six articles described the management of mandibular fractures in adults and children using orthodontic brackets or mini-screws. Most of these techniques have been employed in children and growing subjects, while fewer data were available regarding conservative treatments in adults. Preliminary evidence suggests that condylar and some minor parasymphyseal fractures in children may be managed with conservative approaches. In adults, minor condylar and stable body mandibular fractures with minimal displacement have been reduced similarly. However, there are no sufficient elements that could suggest the preferential use of orthodontic brackets over rigid arch bars in adults. Further randomized and non-randomized clinical trials with long follow-ups will be needed to better define the clinical indications of the orthodontic approaches in the management of mandibular fractures based on severity, location, and age.

Orthognathic Surgery in Goldenhar Syndrome With a Rare Course of the IAN

Although there are multiple variations of accessory foramina described in the literature, to our knowledge there is only 1 report of an isolated mandibular foramen and inferior alveolar neurovascular bundle that courses through the lateral ramus, particularly in those with branchial arch syndromes. Goldenhar syndrome, of the oculo-auriculo-vertebral spectrum, is a rare congenital condition, which most characteristically presents with hemifacial microsomia. Depending on the severity of hemifacial microsomia, there are predictable treatment modalities to correct the consequent facial asymmetry. We report on a patient with Goldenhar syndrome who was found to have a unique course of the inferior alveolar nerve during orthognathic surgery work-up and treatment.

Bifid Mandibular Canal: A Proportional Meta-Analysis of Computed Tomography Studies

Introduction

Growing body of evidences showed different grades in prevalence of bifid mandibular canals. Because the previous reviews focused solely on patient-level occurrence, hemi-mandible-level prevalence, bilateral symmetry, length, and diameter of bifid mandibular canals were required to be estimated collectively. The research question of this meta-analysis was "What is the prevalence of bifid mandibular canal among patients seeking computed tomography examinations"?

Materials and Methods

In vivo, computed tomography, and cross-sectional studies were eligible. Studies, with less than 100 subjects or anatomic site restriction or controlled class of bifid mandibular canal, were excluded. Joanna Briggs Institute (JBI) critical appraisal tool for prevalence studies was used to assess methodological quality of all included studies. Random effect meta-analyses for proportion of bifid mandibular canal were done.

Results

40 studies met the inclusion criteria. All studies were selected for both systematic review and meta-analyses. Totally, 17714 patients and 31973 hemi-mandibles were included. All eligible studies showed moderate risk of bias on average. Resulting from the random effect model, more than 20% of patients seeking computed tomographic examinations had bifid mandibular canals (BMCs) which penetrated into slightly more than 14% of hemi-mandibles. Of the patients having bifid mandibular canals (BMCs), nearly 23% exhibited such anatomy on both sides of their mandibles. Estimated mean length and diameter of the accessory canals of bifid mandibular canals were 12.17 mm and 1.54 mm, respectively.

Conclusion

The geographical locations, classifications, reliability test, and voxel size of computed tomography were all implicated in the prevalence of bifid mandibular canals along with gender and laterality, although considerable heterogeneity and bias were detected.

Prevalence and Characteristics of Accessory Mandibular Canals: A Cone-Beam Computed Tomography Study in a European Adult Population

The purpose of this observational study is to evaluate the prevalence and main characteristics of bifid canals within a European adult population, analyzing cone-beam-computed tomography (CBCT). The population study examined 300 subjects. The CBCTs were performed between 2012 and 2019, using PaX-Zenith3D with a standard protocol of acquisition. The parameters analyzed were the presence and lengths of the bifid mandibular canals. The sample included 49% male and 51% female participants. The mean age of the patients was 47.07 ± 17.7 years. Anatomical variants of the mandibular canal were identified in 28.8% of the sides and 50.3% of the patients. In 7.3% of the subjects, the anatomical variants were present bilaterally. The most frequently encountered bifid canal was Type 3 (40.5%), followed by the Type 1 canal (39.3%), the Type 2 canal (14.5%), and the Type 4 canal (5.9%), 40% on the right side and 60% on the left side. The average length of the bifid canals located on the right side of the mandible was 11.96 ± 5.57 mm, compared to 11.38 ± 4.89 mm for those measured on the left side. The bifid mandibular canal is a common anatomical variation of the mandibular canal. It is fundamental to performing an accurate preoperative evaluation using CBCT analysis to avoid and/or reduce intraoperative and postoperative complications.

Assessment of Accessory Canals and Foramina in the Mandibular Arch Using Cone-Beam Computed Tomography and a New Classification for Mandibular Accessory Canals

Objectives

The objectives of the study include the following: (i) to assess the presence of accessory canals and foramina in the body of the mandible using cone-beam computed tomography (CBCT), (ii) to evaluate the location, number, diameter, and length of accessory canals in the body of the mandible, and (iii) to propose a new classification for mandibular accessory canals based on the location.

Methods

A total of 50 (25 males and 25 females) CBCT scans were analyzed in three anatomical planes and three-dimensional (3D) reconstructions for the exact number, location, diameter, and accessory length canals and accessory foramina in the body of the mandible. The statistical analysis used was an independent t-test.

Results

Out of 50 CBCT scans, a total of 243 accessory canals and 245 accessory foramina were found. About 53% of accessory canals and foramina were found in males, while 47% were observed in females; 89% were evident in the anterior region, and only 11% were in the posterior region. The majority (64%) of the medial lingual canals had a diameter greater than or equal to 1 mm, while only 32% of accessory canals had a diameter of less than 1 mm (p < 0.05). The mean length of median lingual canals in females was 1.2910 ± 0.2582 mm and 2.6438 ± 0.5288 mm in male subjects. Mandibular accessory canals are classified broadly into anterior and posterior accessory canals, which have further subdivisions.

Conclusion

CBCT plays a dynamic role in determining the mandible location of various neurovascular structures, including accessory canals and foramina. Female subjects were observed with more accessory canals and foramina and more common in the anterior region than in the posterior region.

What are the retromolar and bifid/trifid mandibular canals as seen on cone-beam computed tomography? Revisiting classic gross anatomy of the inferior alveolar nerve and correcting terminology

PURPOSE

Since cone-beam computed tomography was developed, a number of radiological studies on the bifid mandibular canals (BMCs) and trifid mandibular canals (TMCs) have been reported. However, many of the suggested subtypes of the BMC described in the literature seem to be normal branches of the inferior alveolar nerve. This might be due to a lack of revisiting classic anatomical studies in the field of radiology. Therefore, such studies are revisited here.

METHODS

A database search using PubMed and Google Scholar was conducted on BMC and TMC. Eighty-nine articles underwent full-text assessment. The reported three classifications of BMC and the six modified classifications were reviewed and compared to the intramandibular inferior alveolar nerve branches.

RESULTS

Some subtypes of BMC and TMC simply represent normal inferior alveolar nerve branches, i.e., retromolar branch, molar branch (alveolar branch/dental branch), large mental branch, or communicating branch. Others such as Naitoh's type III BMC and forward canal might be a true BMC.

CONCLUSION

We found that the bifid mandibular canal is an additional intramandibular canal running parallel to the mandibular canal with/without confluence with the main canal through comparison of classifications of BMC/TMC between the radiology and anatomy fields.

Mandibular Canal Location and Cortical Bone Thickness in Males and Females of Different Age Groups: A Cone-beam Computed Tomography Study

AIM: The purpose of the study was to measure and compare the prevalence of mandibular canal (MC) location variations in regard to mandibular first molars in both genders at different age groups. METHODS: A retrospective study was performed on 80 cone-beam computed tomography scans. Distance between MC and apical apices of first molars, buccal and lingual cortical plates was measured in both sides. RESULTS: 80 scans with 160 sides were analyzed. Distances was measured bilaterally for all scans with mean (5.22 ± 0.77) in men versus (4.1 ± 0.7) in women at group age 31–40 apical to apices of first molars. The mean was (3.77 ± 0.62) in men versus (2.81 ± 0.47) in women at same age group at buccal side, lingually the mean was (4.02 ± 0.67) in men versus (3.67 ± 0.26) in women in the same age group. CONCLUSION: Our study showed that there were decrease in measurements in older age group in both genders and in female groups more than male groups but with no statistical significant difference.

Anatomical Variations of the Bifid Mandibular Canal on Panoramic Radiographs in Citizens from Zagreb, Croatia

Background

The bifid mandibular canal (BMC) is an anatomical variation with reported prevalence ranging from 0.08 to 65%. Identifying anatomical variations of mandibular canal is very important in order to prevent possible complications during oral surgical and other dental procedures.

Objectives

The aim of this study was to determine the prevalence and to classify the morphology of BMCs using digital panoramic radiographs.

Material and methods

A retrospective study was conducted that included 1008 digital panoramic radiographs (412 female and 596 male) used to identify the type of BMC. Panoramic radiographs were analyzed by three oral surgeons and one dentist, and BMCs were classified into six different types, 4 types according to Langlais et al. (types 1-4), and two new types (types 5 and 6) described by authors.

Results

The prevalence of BMC was 4.66% (n=47), with no significant differences in gender between BMC types (P=0.947; χ²=0.74). The prevalence of type 1 BMC was 0.79% (n=8), type 2 2.08% (n=21), type 3 0.30% (n=3), type 4 0% (n=0), type 5 0.89% (n=9) and type 6 0.60% (n=6).

Conclusion

This study revealed a relatively high prevalence of BMCs among Zagreb citizens. Furthermore, two new types of BMCs were described. These results stress the importance of a careful and thorough radiographic analysis prior to each invasive procedure in the mandible.

Prevalence of bifid and trifid mandibular canals with unusual patterns of nerve branching using cone beam computed tomography

Lack of knowledge concerning the inferior alveolar canal anatomical variations had proven to increase the incidence of surgical complications, so the study aimed to assess the configuration and prevalence of bifid and trifid mandibular canals using cone beam CT in Egyptian subpopulation. Cone beam CT scans of 278 patients (530 hemi-mandibles) were included in the study, in which bifid and trifid mandibular canals or any other branching patterns were recorded and evaluated. Bifid canals were categorized following Naitoh classification, and the diameter of the main mandibular and accessory canals was measured. Bifid canals were detected in 181 canals (34%) while trifid canals in 46 canals (8.7%). Upon classifying the bifid canals, 78 canals showed forward type, 40 retromolar type, 33 dental type, and 7 canals showed buccolingual type. Two special bifid canals subtypes were reported in 23 canals and nine distinct patterns of trifid canals were reported in our study. In addition, unusual patterns of canal branching were reported in 5 cases. The mean diameter of the accessory canals was 1.18 ± .54 mm and the main canal was 3.98 ± 1.31 mm. This study reported a high prevalence (54%) of canal branching, which reinforces the importance of cone beam CT in pre-surgical planning.

Anatomical variations of the mandibular canal and their clinical implications in dental practice: a literature review

INTRODUCTION

The anatomical variations of the mandibular canal have been described according to the number of additional branches it presents, bifid and trifid. Within the bifids we can also find subtypes of variations such as the retromolar mandibular canal. These anatomical variations can have important clinical implications for the work of dental professionals.

METHODS

A systematic search of the literature was carried out in different databases that met the following criteria: articles published between 2000 and 2020, and articles that established a clinical correlation with variations in the mandibular canal.

RESULTS

After applying inclusion and exclusion criteria, 32 articles were obtained, in which the variations of the mandibular canal were identified, their prevalence and incidence, which was very varied between the different articles, it was also found that the CBCT was the main technique to identify the anatomical variations of the mandibular canal. Lastly, the anatomical variations of the mandibular canal have a direct clinical correlation with pre-surgical, intra-surgical and postsurgical complications in pathologies that require surgical intervention.

CONCLUSIONS

The anatomical variations of the mandibular canal have a high incidence, so knowing them is of vital importance both for clinicians and anatomy professors who provide morphological training. We believe that research should focus on describing and diagnosing the causes of these anatomical variations. That said, there is also a continuous challenge for all health professionals to learn about the different anatomical variations that the human body presents and how these can affect clinical practice.

[Importance of cone beam computed tomography in the recognition of the trajectory and anatomical variants of the mandibular canal. A review of the literature]

The objective of this study was to provide an updated review of the literature on the importance of the use of cone beam computed tomography (CBCT) in the recognition of the trajectory and variants of the mandibular canal (MCV).CBCT allows obtaining high quality images and visualization with an accuracy of approximately 94%, compared to 53% with periapical intraoral radiography (RIP) and 17% with panoramic extraoral radiography (REP), making CBCT an important diagnostic tool.The incidences of MCV in CBCT studies were between 1.3% and 69%, with differences between patients of different ethnic origins and within the same ethnic population, and in the types and configurations of MCV within each ethnic group. The studies available in the literature provide a histological description of the content of MCV. The presence of nerve and artery bundles of different calibers suggests that patients present clinical symptoms only if the neurovascular bundle reaches a certain size and number of fascicles. This review provides a description of the different classifications available and updated with CBCT.