Variations Of Mandibular Canal Research Articles

The Investigation of Mandibular Canal Variations in the Turkish Society Comparative with Cone Beam Computerized Tomography and Orthopantomography Methods

Mandibular canal and its neurovascular contents are highly important structures for dental clinicals. Accurate localization of the mandibular canal and determination of its variations are crucial aspects to achieve successful surgical results without complications. Inferior alveolar nerve, artery, and vein could be damaged during surgical interventions and serious complications may occur in post-operative period, such as permanent paraesthesia. Thus, the patients’ health and social life may be seriously affected. The aim of this study was to investigate the prevalence and features of mandibular canal variations in a group Turkish population using cone beam computed tomography (CBCT) and orthopantomography (OPG) techniques. This retrospective study was performed on CBCT and OPG images of 700 patients whose mandibular canal area was clearly observed and aged over 20 years old which were referred to our clinic between 2011-2016. Patients with congenital or acquired deformity affecting the mandible were excluded from the study. In order to make comparative analysis, various measurements were made on both types of imaging. In our study, mandibular canal variation rates were identified as 2.43% (17/700) and 8.57% (60/700) on OPG images and CBCT images, respectively. As a result of our study, it could be said that the mandibular canal variations are not rare cases for the Turkish population. Before risky surgical procedures and when there is a suspicious diagnosis due to inadequacy of OPG imaging method; the CBCT imaging method should be referred in order to prevent complications such as hemorrhage, paresthesia, and traumatic neuroma.

An evaluation of mandibular canal variations: a systematic review and meta-analysis.

The inferior alveolar nerve and vessels are carried via the mandibular canal, which extends bilaterally from the inferior alveolar foramen to the mental foramen. Bifid and trifidmandibular canals result from abnormal fusions of nerve canals. The purpose of this study was to provide an up-to-date and comprehensive analysis of the prevalence ofmandibular canalvariations among healthy adults, and to identify any potential ethnic, sex, or laterality predilections. The prevalence of the bifid mandibular canal was 18.87% and that of the trifid canal 1.3%. Unilateral variants were three times commoner than bilateral. Eachmandibular half had four canals emanating from separate openings on the lingual surface of the mandibular ramus. Retromolar and forward canals were the predominant subtypes, followed by dental; buccolingual were the least frequent. The mean length and diameter ofthe bifid mandibular canalwere 13.62mm and 1.63mm, respectively. The possibility of a bifid mandibular canal is a crucial consideration in dental medicine. Because anatomical variations of themandibular canal are fairly common, awareness of them is essential for anatomy teachers and for surgeons who operate in the oromaxillofacial region.

Systematic review and meta-analysis of mandibular canal variations on cone beam computed tomography.

The purpose of this systematic review was to evaluate the mandibular canal (MC) variations and their anatomical incidences using cone-beam computed tomography (CBCT). Related articles on the anatomical variations of the MC using CBCT were searched through PubMed, Cochrane, and China National Knowledge Infrastructure (CNKI) to identify all relevant articles eligible for inclusion. Data extracted included incidences of the anatomical variations of the MC including the accessory mental foramen (AMF), retromolar foramen (RMF), mandibular lingual foramina (MLF), and the bifid mandibular canal (BMC). In total, 16 descriptive cross-sectional studies (one low quality and fifteen high quality) were included in the meta-analysis analyzing 8862 MC. The meta-analysis performed with a random-effects model showed that the incidence of AMF was 9.54% (95% CI 6.39-12.69%), the incidence of RMF was 23.64% (95% CI 14.44-32.84%). MLF was found in almost all adults studied, and the incidence of BMC was about 38.0%. The foramina and canals branched from the MC presented significant anatomical variations among individuals. CBCT-based study on the anatomical variations of the MC could provide guidance for clinical practice.

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

BackgroundThe 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.ObjectivesThe aim of this study was to determine the prevalence and to classify the morphology of BMCs using digital panoramic radiographs.Material and methodsA 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.ResultsThe 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).ConclusionThis 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.

Do anatomical variations of the mandibular canal pose an increased risk of inferior alveolar nerve injury after third molar removal?

The present study aimed to assess whether anatomical variations of the mandibular canal are associated with neurosensory disturbances of the inferior alveolar nerve (IAN) following mandibular third molar removal. Two observers compared the detection of third molar root-nerve relations and bifurcations of the mandibular canal on panoramic radiographs and CBCT images of 201 patients undergoing removal of 357 mandibular third molars. Potential neurosensory disturbances of the IAN were surveyed ten days after surgery. Fisher's Exact was performed to correlate presence of canal variations to postoperative neurosensory disturbances. Positive and negative predictive values (PPV, NPV) and likelihood ratios (LR + , LR-) were calculated. Thirteen patients reported postoperative altered sensation of the lower lip, with 2 of them having mandibular canal bifurcations on the ipsilateral side of the injury. Fisher's Exact showed that the studied mandibular canal variations were not related to postoperative neurosensory disturbances. CBCT was superior in visualization of anatomical variations of the mandibular canal. Prevalence of bifurcations was 14% on CBCT and 7% on panoramic radiographs. In both imaging modalities and for all parameters, PPVs were low (0.04 - 0.06) and NPVs were high (0.92 - 0.98), with LR ranging around 1. In the present study, the assessed mandibular canal variations had limited predictive value for IAN neurosensory disturbances following third molar removal. While a close relation between the third molar and the mandibular canal remains a high risk factor, mandibular canal variations did not pose an increased risk of postoperative IAN injury after third molar removal.

Anatomical variations of mandibular canal using cone-beam computed tomography - A retrospective study

Background: Precise anatomy and course of mandibular canal is important to obtain the desired outcome of different mandibular surgical procedures and circumvent various surgical complications. This study aimed to document the presence, frequency, and type of mandibular canal variations using cone-beam computed tomography (CBCT). Materials and Methods: CBCT images of 100 patients with a total of 200 sides (right and left) were obtained retrospectively from the database of Government Dental College and Hospital, Mumbai. The presence and type of mandibular canal variation were evaluated and classified according to Naitoh et al. classification (2009) along with Rashsuren et al. modification (2014). Prevalence rates were determined according to gender, side of the mandible, and type. Morphometric analysis of the mandibular canal variations was made. Statistical analysis with Chi-square, analysis of variance (ANOVA), and Scheffe's tests were performed. Results: Mandibular canal variations were found in 13% of patients and 8% of total sides. Type I dental canal (37.50%) was the most common type of accessory canal followed by Type II retromolar canal (31.25%), Type III forward canal type (25%), Type V trifid canal (6.25%), and Type IV buccolingual canal (0%). The retromolar canal had the maximum length and diameter and most of the accessory mandibular canals (60%) had a diameter of more than 50% of that of the main canal. Conclusion: Bifid mandibular canal was the most common anatomical variation of the mandibular canal found in this study with dental canal type being the most frequent type. To avoid iatrogenic injuries, a presurgical detailed evaluation of the mandibular canal using CBCT was suggested.

Assessment of the configuration of the mandibular canal using cone beam computed tomography.

During dental implants placement and bone augmentation procedures, it is important to determine the presence and location of mandibular canal anatomical variation in order to avoid injuries to inferior alveolar bundle. This study aimed to describe the prevalence and configuration of mandibular canal branching in the posterior region of the mandible using cone beam computed tomography (CBCT). The interpretation of the images was conducted according to the presence, classification and location of the mandibular canal. Horizontal and vertical distances from mandibular canal in the ramus region to the molar region was recorded. CBCT images of 751 patients, 486 women (64.7%) and 265 men (35.3%), with a mean age of 54.57 (±13.23; 14-93) years, were interpreted by one calibrated examiner. Out of 1502 hemi-mandibles images, mandibular canal variations were observed in 130 (8.6%). Sixty-four (49.2%) mandibular canal variations were identified on the right side and 66 (50.8%) on the left side. The mean distances between superior cortical of the mandibular canal and the base of mandible, buccal cortical of mandibular canal and buccal cortical bone, and superior cortical of mandibular canal and alveolar ridge were 12.16 mm (±2.68), 4.17 mm (±1.30), and 12.97mm (±4.01), respectively. Type I mandibular canal variation was the most frequent (68; 52.2%), followed by type III (34; 26.1%). Prevalence of mandibular canal variations was 8.6%, type I was the most common and its direction showed proximity with lingual surface in the second molar region.

Prevalence and classification of anatomical variations of mandibular canal in panoramic radiographies

Introduction: Dental surgeries involving structures adjacent to the mandibular canal require greater knowledge of the intraosseous path, anatomical structure, and its variables, reducing the risk of injuries to this region. This research aimed to verify on the panoramic radiographs the anatomical characteristics of the mandibular canal, as well as to analyze and classify its pathways.Methods: The classification of anatomical variations of the mandibular canal was divided into four types: Class A (inferior direction); Class B (mesial direction); Class C (alveolar direction); and Class D (retromolar direction). The sample consisted of 500 exams, 207 (41.4%) males and 293 (58.6%) females, with a mean age of 29.51 years.Results: A prevalence of 30 anatomical variations of the mandibular canal was observed. The most prevalent classifications were Class B (43.6%) followed by Class C (23.1%) and D (33.3%). In no case was the presence of bifid canals classified as Class A. The anatomical variations of the mandibular canal appeared both unilaterally and bilaterally, in which unilaterally the prevalence was on the left side (50%), on the right side (20%), and bilaterally (30%).Conclusions: According to the results obtained in this study, a prevalence of 6% of bifid mandibular canals was found. The most prevalent types of the bifid canal were Class B and Class D, and the highest occurrence of bifid mandibular canals was left unilateral. It is concluded that the appearance of mandibular canal anatomical variations in panoramic radiographs is frequent and that additional care must be taken to approach the region.

Observation of double mandibular canals and types of bifid canals in dry skulls

Background/Aim: The aim of the present study was to assess prevalence and morphologic mandibular canal variations in dry skulls. Material and Methods: Panoramic radiographs were obtained of 57 skulls among the academic collection at the University of Pittsburgh. Orthodontic wire was inserted through the mandibular canal as a reference point at panoramic images for localization of the course of the mandibular canal. Results: Double mandibular canals were present in 2 out of 57 skulls (3,5%); one of them was unilateral the other one was bilateral. Additionally, bifurcation of the mandibular canal and different types of configurations were assessed. In five of the specimens (8,8%) bifid canals were identified. Among them, one case (1,7%) was identified as a forward type. In one case additional canal (1,7%), was detected in the retromolar region, which joined the main canal. Three of the specimens (5,3%) showed accessory canal types. These were the canals that detached from the main canal and proceeded towards the molar teeth roots (dental type). All of these bifid canal types were unilateral. Conclusions: Our results depicted the anatomical variations of the mandibular canal. Dental practitioners should be aware of this underestimated but not a rare occurrence of mandibular canal variations in order to avoid complication during surgical procedures.

Prevalence of bifid mandibular canal according to gender, type and side

Background/purposeAn awareness of mandibular canal variations may help prevent complications due to nerve damage that can occur during surgery. The aim of this study is to evaluate the variations of mandibular canal distribution and frequency via cone beam computed tomography (CBCT), retrospectively, in a Turkish population. Materials and methodsThe study population comprises 500 (250 female, 250 male) randomly selected participants between the ages of 14 and 79 years. The study was conducted in Marmara University, Faculty of Dentistry, in the Department of Dentomaxillofacial Radiology. The distribution and frequency of mandibular canal variations were evaluated using the Naitoh classification, which includes retromolar canal, forward canal, dental canal, and buccolingual canal. The trifid canal was also included in this study. The data were analysed using IBM SPSS statistics 20.0. The data were then compared based on age group and gender. ResultsBifid mandibular canals (BMCs) were found in 200 (40%) of the 500 subjects, and in 248 of the 1000 sides (24.8%). Mandibular canal variations were observed in 71.5% of patients on the right side, 52.5% on left side and 24% bilaterally. The forward canal was the most common type (48.8%), followed by the retromolar canal (26.2%), the dental canal (12.9%), the buccolingual canal (9.7%), and the trifid canal (2.4%). ConclusionBMCs were detected at a high rate in the Turkish subpopulation. Moreover, CBCT appears to be an appropriate method to assess the entity and shape of BMCs.

Bifid canals: identification of three clinical cases using cone-beam computed tomography images

ABSTRACT Anatomical variations of mandibular canal have rarely been reported in the literature. The aim of this paper is to present three clinical cases of bifid mandibular canal diagnosed with cone-beam computed tomography (CBCT) as well as discuss its clinical implications. The first case is very interesting due to its anatomic variation verified in a panoramic radiograph during orthodontic planning, mimicking an odontogenic tumor. The second and the third cases were identified during tomographic evaluation for third molar exodontia. The diagnosis of bifid canals is extremely relevant in order to avoid complications during surgical procedures and implant placement as well as anesthesia failures which cause pain, paresthesia and bleeding. Furthermore, the shape of these anatomical variations can be confused with bone lesions.

Frequency of accessory mental foramen and mandibular canal variations in dental implant patients: a retrospective CBCT study

Frequency of accessory mental foramen and mandibular canal variations in dental implant patients: a retrospective CBCT study

Investigation of bifid mandibular canal frequency with cone beam computed tomography in a Turkish population

Objectives : It is important to know anatomic location and variations of the mandibular canal (MC) for surgical treatment on mandible such as implant operations, impacted molar tooth extraction and sagittal split ramus osteotomy. The purpose of our study is to determine the configuration and incidence of bifid mandibular canal (BMC) using cone beam computed tomography (CBCT). Methods: CBCT scans of 2000 patients were retrospectively analysed. Age and gender of the patients who were included in this study were recorded. BMC was subdivided, frequency was determined. Measurements of mean lengths, superior and inferior angles were performed. The all measurements were performed by one observer in 3 times at intervals of one week to confirm intra-observer reliability. SPSS 21 (Statistical Package for Social Science 21) was used for statistical analysis. It was benefited from Chi-square test to investigate qualitative observation and from T test and one-way analysis of variance for investigation of quantative observation. Differences were considered significant at p<0.05. Results: 1122 of 2000 patients (56.1%) were females and 878 of 2000 patients (43.9%) were males. BMC was observed in 61 of 2000 patients (3.05%). Because location of MC is bilateral, 122 sides in 61 patients were studied. BMC was observed in 65 of 122 sides (53.3%). In 39 of 65 sides (60%), BMC was observed in males, in 26 of 65 (40%) sides, BMC was observed in females. Conclusion: CBCT provides important informations about MC imaging and evaluation of variations. Evaluation of MC variations frequency and informing to surgeon in surgical procedures on mandible provides advantages for successful operations.

Cone-beam computed tomography investigation of crucial mandibular canal variations in Thais

The physiology of the mandibular nerve is an important factor relevant to successful implant planning and surgical procedures in the mandible. Variability among ethnicities may influence the particular safety guidelines for each population. In this study, we retrospectively examined the incidences of canal orientations and variations in Thais using cone-beam computed tomography (CBCT) radiography. CBCT images of 441 mandibular sides of 248 patients aged 20 to 82 years (mean age, 43.7 years) were examined. The incidences of canal courses and variations were assessed by two calibrated observers (Cohen's kappa coefficient >0.8). Descriptive and bivariate statistics were analysed for categorical findings. A p value of <0.05 was considered statistically significant. Two common canal courses were identified: linear curve (Type 1, 39.9%) and elliptic-arc curve (Type 3, 48.1%). In addition, one-fifth of the patients had bifid canals (20.6%). There was a short supplemental canal extending to the second or third molar (Type 2, 53.8%) and a supplemental canal arising in the retromolar pad region (Type 4, 46.2%). An anterior loop was identified in 74.2% of the cases and was frequently bilateral (78.3%). Effective examination of the canal anatomy should be considered prior to surgical procedures because of the shallow curve of the mandibular canal with a high incidence of an anterior loop. In addition, the position of bifid canals was associated with an increased risk of neurovascular alteration in implant placement, sagittal split ramus osteotomy, and retromolar bone harvesting.

Anatomical variations of mandibular canal detected by panoramic radiography and CT: a systematic review and meta-analysis.

To investigate the anatomical variations of the mandibular canal through assessment in situ, panoramic radiography, CT or CBCT and assess their frequency. Articles were selected from databases (Cochrane Library, LILACS, ProQuest, PubMed, Scopus, Web of Science and Google Scholar), articles without limitations of language, in which the main objective was to evaluate the frequency of bifurcation of the mandibular canal through assessment in situ, panoramic radiography, CT or CBCT were selected. A meta-analysis of prevalence using random effects was performed. Using a selection process in two phases, 15 articles were identified, and a meta-analysis was conducted. The results from these meta-analyses showed that the overall prevalence of anatomical variations for in situ studies was 6.46%, and through assessment of panoramic radiography and CT or CBCT the overall prevalence shown was 4.20% and 16.25%, respectively. There are two types of variations of the mandibular canal: the retromolar canal and bifid mandibular canal. The frequency variations through assessing in situ, panoramic radiography and CT or CBCT were 6.46%, 4.20% and 16.25%, respectively.

Mandibular canal, foramina of the mandible and their variations: part II: the clinical relevance of the preoperative radiographic evaluation and report of five cases

AbstractAimsIn part I of the article, a detailed description of the anatomical variations of the mandibular canal and the foramina of the mandible was given. The aim of part II is to discuss the clinical relevance of the anatomical variations.Materials and methodsA literature review was carried out, and five cases of mandibular canal variations are reported.ResultsAnatomical variations of the mandibular canal and foramina of the mandible are reported in bibliography. Bifid and double mandibular canals have been firstly reported in 1973. Since then, the anatomical variations of the mandibular canal have been described by case reports, cadaveric and retrospective radiological studies. It has been proved that the inferior alveolar nerve gives communication fibers to other nerves and extraosseous branches, before entering the mandibular canal, whereas even if it enters the mandible, it branches during its course into the canal. Also, the supplementary innervation of mandibular teeth and periodontal tissues by the long buccal and mylohyoid nerves has been suggested. Several authors also reported the existence of retromolar foramen and supplementary buccal and lingual foramina and their important role either in vascularisation or innervation.ConclusionsThe neurovascular contents of the mandibular canals and foramina gain more importance in oral surgery and implantology because these components are vulnerable to damage during implant placement and sagittal split osteotomy surgery, and complications may occur during the surgery (i.e. unsuspected bleeding, nerve injury). Also, clinicians should be aware of accessory foramina or canals of the mandible in understanding failed inferior alveolar nerve block.

Mandibular canal's anatomy in children with micrognathia: a computed tomography study

Objective To assess the anatomy feature of mandibular canal in children with micrognathia by CT scanning.Methods Three thickness indexes of mandibular canal were measured in 36 cases of children with micrognathia on mandible's coronary CT,including the distance between the mandibular canal and the external surfaces of the mandible (buccal,lingual,and inferior) on each molar regions; the data were analyzed by SPSS13.0 software.Results The mean and standard deviation of three thickness indexes (buccal,lingual,and inferior) were as follows:in the second premolar area:(4.71±1.25),(2.77±1.02),(2.92±0.83) mm; in the first molar area:(2.64±0.99),(4.33±1.12),(2.38±0.72) mm; in the second molar area:(2.44±0.76),(4.20±0.89),(3.38±1.31) mm.There were no significant differences about all the indexes between left and right side.From the second premolar area to second molar area,mandibular canal locating at lingual side accounted for 94.4％ (68 sides),and locating at buccal side acounted for 5.6％ (4 sides).Mental foramen locating between the first and second premolar area acounted for 76.3％ (55 sides),and 23.7％ (17 sides) of mental foramen located in the second premolar area.The mandibular canal with a branch accounted for 3.5％ (3 sides).Conclusions Mandibular canal arises from mandibular foramen,courses the mandible on the inferior and lingual side,and ends in mental foremen.Some anatomical variations of mandibular canal should be noticed by the surgeons,such as a branch line of mandibular canal,coursing on the buccal side,with position of mental foremen moving backward. Key words: Computerized tomography (CT) ; Micrognathia; Mandibular canal

Detection of anatomical variations in mandible by panoramic radiography

Aim: To assess the visibility, frequency and gender variations of mandibular canal, mental foramen, anterior loop of mental nerve, incisive canal and lingual foramen in Indian population. Material and Methods: Retrospective analysis of total 300 panoramic radiographs were selected for the study. Radiographs were analysed for the mandibular canal, mental foramen, anterior loop of mental nerve, incisive canal and lingual foramen by two independent observers and scores were recorded. Intra and inter-examiner reliability was assessed by kappa-statistics percentages of observations were obtained and Chi-square test was used to find out association of age and gender with visibility of anatomical landmarks. Results: The mandibular canal was visible in 100% of the 300 cases. Anterior looping of the mental nerve was not visible in 90% (270) of the cases, with 1.3% having good visibility. The mental foramen was moderately visible in 66% cases. The lingual foramen could not be visualized in 95.3% of the cases, with poor visibility in 0.7%. An incisive canal was observed in 33% of the cases, good visibility with only 1.3%. Contingency tables with Chi-square test showed that gender does not exert any effect on the visibility of the anatomical structures in the mental interforaminal region ( P > 0.05). Chi-square test reveled, significant difference exist between age and visibility of mandibular canal ( P Conclusion: The important conclusion drawn from the present study is that as far as mandibular canal and mental foramen is concerned, panoramic images provide sufficient information. However, it is insufficient for detection of interforamina structures especially for presurgical implant planning in the mental region and may need to be supplemented with three dimensional imaging for better visualization of the area.

Bifid Mandibular Canal in Japanese

The location and configuration of mandibular canal variations are important in surgical procedures involving the mandible, such as extraction of an impacted third molar, dental implant treatment, and sagittal split ramus osteotomy. We report 3 Japanese patients with bifid mandibular canals using panoramic radiograph and multi-slice helical computed tomography (CT) images. In 2 of the 5 sides, the bifid mandibular canal was suggested on panoramic radiograph. The bifid mandibular canal had a short and narrow upper canal toward the distal area of the second molar in 4 sides, and a short and narrow lower canal toward the distal area of second molar in 1 side, as revealed on reconstructed CT images. Since the location and configuration of mandibular canal variations are important in surgical procedures involving the mandible, they should be carefully observed using reconstructed CT images.