Bifid Mandibular Canals Research Articles

Assessment of bifid and trifid mandibular canals using cone-beam computed tomography.

PurposeTo investigate the prevalence of bifid and trifid mandibular canals using cone-beam computed tomography (CBCT) images, and to measure their length, diameter, and angle.Materials and MethodsCBCT images of 500 patients, involving 755 hemi-mandibles, were used for this study. The presence and type of bifid mandibular canal was evaluated according to a modified classification of Naitoh et al. Prevalence rates were determined according to age group, gender, and type. Further, their diameter, length, and angles were measured using PACSPLUS Viewer and ImageJ 1.46r. Statistical analysis with chi-squared and analysis of variance (ANOVA) tests was performed.ResultsBifid and trifid mandibular canals were found in 22.6% of the 500 patients and 16.2% of the 755 sides. There was no significant difference between genders and among age groups. The retromolar canal type accounted for 71.3% of the identified canals; the dental canal type, 18.8%; the forward canal type, 4.1%; and the trifid canal type, 5.8%. Interestingly, seven cases of the trifid canal type, which has been rarely reported, were observed. The mean diameter of the bifid and trifid mandibular canals was 2.2 mm and that of the main mandibular canal was 4.3 mm. Their mean length was 16.9 mm; the mean superior angle was 149.2°, and the mean inferior angle was 37.7°.ConclusionBifid and trifid mandibular canals in the Korean population were observed at a relatively high rate through a CBCT evaluation, and the most common type was the retromolar canal. CBCT is suggested for a detailed evaluation of bifid and trifid mandibular canals before mandibular surgery.

Classification of bifid mandibular canals in the Syrian population using panoramic radiographs

The objective of this study was to classify the different routes of the bifid mandibular canals (BMCs) on 2400 panoramic radiographs in a Syrian population. BMCs were identified, drawn and classified according to the classification of Langlais et al. BMCs were found in 41 cases (0.98%). A total of 15 canals (36.6%) were classified as Class I, 6 canals (14.6%) as Class II, 8 canals as Class III (19.5%) and 12 canals (29.3%) as Class IV. There was no statistically significant association between BMC class and sex or affected jaw side prevalence. The clinical implications of BMC classes are discussed and an algorithm is suggested as a clinical guide for clinicians.

Classification of bifid mandibular canals using cone beam computed tomography

The objective of this study was to classify the morphology of bifid mandibular canals and to evaluate their relationship with the roots of third molars, using cone beam computed tomography (CBCT) scans. The CBCT scans of 75 patients were analyzed and the bifurcations were classified according to Langlais et al. (1985). The relationship of bifurcation and third molars was established according to the following classification: class A--uninvolved, class B--close relationship, class C--intimate relationship and class D--absence of third molars. Data were submitted to descriptive statistics, and the results indicated that the patients' mean age was 48.2 (± 13.2) years. Unilateral bifurcation (Type 1) was the most frequent type (72.6%), followed by unilateral Type 2 (19.3%). Class D was the most frequent (57.33%), followed by class C (21.33%), class B (13.33%) and class A (8%). It could be concluded that most cases presented unilateral bifid mandibular canals extending to the third molar or adjacent regions, and when present, the roots seemed to be a continuation of the bifid mandibular canal.

Comparative analysis of mandibular anatomical variations between panoramic radiography and cone beam computed tomography

The objective of this study is to compare the ability of panoramic radiography and cone beam computed tomography (CBCT) in detecting anatomical variations of the mandibular canal and mental foramen. One hundred twenty-seven preoperative panoramic and CBCT images were evaluated. Two oral and maxillofacial radiologists investigated the presence of bifid mandibular canals and/or additional mental foramina on the right, left, or both sides of the mandible. Intra- and interobserver reliability was determined using Cohen's kappa coefficient. McNemar's test compared the prevalence of mandibular anatomical variations between panoramic radiography and CBCT. The significance level was set at 0.05. Additional mental foramen and bifid mandibular canal were detected in 1.2 and 7.4 % of the panoramic radiographs and 7.4 and 9.8 % of the CBCT images, respectively. The incidence of anatomical variations on the mandibular canal was not significantly different between both imaging modalities (P > 0.05). Although CBCT provides better viewing of anatomical structures, including location, shape, and relationship with the surrounding area, panoramic radiography is a conventional imaging modality that can be used in the study of the bifid mandibular canals.

Observation of the temporal crest canal in the mandibular ramus by cone beam computed tomography and macroscopic study

The mandibular ramus is regarded as a relatively safe zone for a sagittal splitting osteotomy or for harvesting bone during implant treatment. The only important anatomical structure is the mandibular canal. The mandible has some anatomical variants that need to be recognized, such as a bifid mandibular canal, a retromolar canal, and rarely a temporal crest canal (TCC). In this study, cadaver mandibles were used to evaluate the TCC in the mandibular ramus using cone beam computed tomography (CBCT). Altogether, 90 sites on 48 mandibles from Japanese cadavers were examined in this study. The CBCT volumetric images were acquired for areas of 79mm[Formula: see text] 71 mm. Three-dimensional observation of the images was undertaken to estimate the frequency, position of the orifices, and canal continuity. The cadaver mandibles in which the TCCs were observed were dissected from the inner surface to confirm the contents. Five TCCs (5.6%) were observed in 90 observation areas. At least one TCC was confirmed in four (8.3%) of 48 mandibles. Two types of TCC were recognized. Dissection revealed that they contained neurovascular bundles. Three-dimensional diagnosis is essential prior to surgical procedures in the mandibular ramus because unexpected blood vessels may be present that may cause bleeding or complications during the surgery.

Evaluation of Perimandibular Neurovascularization With Accessory Mental Foramina Using Cone-Beam Computed Tomography in Children

The purpose of this study was to clarify the perimandibular neurovascularization with mandibular accessory mental foramina in a children population using cone-beam computed tomography (CBCT) to avoid complications during anesthetic and surgical procedures. This retrospective study evaluated cone-beam CT images for bifid mandibular canals in the mandibles of 63 children (35 girls, 28 boys; age range, 7-16 years; mean age, 12.3 years). Both right and left sides were examined from CT images (n = 126), including axial, sagittal, cross-sectional, and panoramic views as well as reconstructed three-dimensional images, as necessary. The course, length, and superior and inferior angles between canals were classified and measured. Bifid mandibular canals were observed in 34 (27%) of the 126 sides examined. The most frequently encountered type of bifid canal was the retromolar canal (11.1%), followed by the forward (7.14%), buccolingual (6.35%), and dental canal (2.4%). Mean lengths of bifid canals were 10.2 mm on the right side and 10.6 mm on the left side. Mean superior angles were 131 degrees on the right side and 147 degrees on the left side, whereas mean inferior angles were 47 degrees on the right side and 34 degrees on the left side. No statistically significant differences were found in the lengths or angles between the right and left sides or between boys and girls (P < 0.05). The most common position for the mental foramen was between the first and second premolars, and an accessory mental foramen was observed in 4 children (6.34%). This study utilized CBCT images to identify bifid mandibular canals and accessory mental foramina in children. Cone-beam CT was found to be a useful technique for detecting secondary canals. However, despite the fact that CBCT uses less ionizing radiation than other types of three-dimensional imaging, unless the diagnostic information provided through CBCT improves treatment results, CBCT should not be recommended for use in children or adolescents.

Uncommon trajectory variations of the mandibular canal and of the mandibular incisive canal: case report

This paper aims to report and discuss a case in which unusual anatomical variations were observed in the mandibular canal (MC) and the mandibular incisive canal (MIC) in a same patient. A 49-year-old healthy female was referred for mandibular dental implant placement. Panoramic radiography and cone beam computed tomography (CBCT) were performed. Cross-sections, axial, coronal, panoramic reconstructions and volume rendering were obtained. The panoramic radiograph did not show any evidence of abnormality. CBCT showed a bifid MC on the right side. It extended to the buccal cortex, exteriorized for 6mm and returned to its conventional trajectory to reach the mental foramen. On the left side, the MIC initially followed its normal trajectory for 4mm but, in the canine region, it also extended to the buccal cortex and exteriorized. The advent of CBCT in Dentistry allowed a greater accuracy in the diagnosis of anatomical variations in the jaws, preventing injury to the neurovascular bundle and enabling an adequate surgical planning in the region.

Bilateral double mandibular canal - a case report

Objectives: The objective is to draw attention to the anatomical variation of mandibular canal (double mandibular canals). Methods: This case report showing clinical and radiographic findings of a patient who was presented with bilateral double mandibular canals were recorded. Results: Bifid or double mandibular canals can be detected on a panoramic radiograph. More precise information about the course of the canal can be revealed on CBCT scan. Conclusions: The detection of these bifid or double mandibular canals are important because of their clinical implications. Special attention has to be made in the surgical procedures, especially involving the lower jaw.DOI: http://dx.doi.org/10.3329/updcj.v2i1.13958 Update Dent. Coll. j: 2012; 2 (1): 31-34

Trifid mandibular nerve canal

The location and configuration of the mandibular canal are important in surgical procedures involving the mandible. Bifid mandibular canal (BMC) and trifid mandibular canal (TMC) are variations of the normal anatomy. In the literature, occurrence of TMC is much rarer than BMC that only a few cases have been reported. These variations can be detected on a panoramic radiograph however more precise information about the course of the mandibular canal can be revealed on cross-sectional tomographic images. This paper presents a rare case of TMC evaluated by panoramic radiograph and CBCT. The main purpose of this case report is to pay attention to an apparently harmful anomaly, which can induce complications while surgical procedures.

Bifid mandibular canals and the factors associated with their presence: a medical computed tomography evaluation in a Taiwanese population

To examine distribution of bifid mandibular canals in a Taiwanese population and to evaluate factors contributing to the phenomenon. Computed tomographic images from 173 subjects (97 females and 76 males) were obtained using a 64-slice multidetector computerized tomography system, and the presence of bifid mandibular canals, as well as their widths and lengths, was examined. Association of length of bifid canals with possible contributing factors, including gender, age, and side of presentation, as well as size of cross-sectional bony area of mandible along the long axis of mandibular canal, was evaluated. Bifid mandibular canals, with mean values of 10.1 and 0.9 mm in length and width, were found in 53 (30.6%) of 173 patients and 64 (18.5%) of 346 hemi-mandibles. Bifid canals appeared more frequently and tend to penetrate mandible with greater lengths in males if compared with those in females. When males were compared with females and when mandibles with bifid canals were compared with ones without, the former tend to present with larger bony area at corresponding levels of cross-sectional plane than the later, respectively. By regression analysis, significant association was found between length of bifid canals and gender, side of hemi-mandible, and bony area at mid-zone of mandibular canal. Bifid canals were observed in 30.6% of subjects and 18.5% of hemi-mandibles. Significant association between length of bifid canals and gender, side of hemi-mandible, and cross-sectional bony area of mandible was observed.

A false presence of bifid mandibular canals in panoramic radiographs

Free AccessLetter to the editorA false presence of bifid mandibular canals in panoramic radiographsN SermanN SermanSearch for more papers by this authorPublished Online:28 Jan 2014https://doi.org/10.1259/dmfr/16821817SectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail AboutRegarding the research presented on actual bifid mandibular canals in the article published in the October 2011 issue of DMFR,1 the authors must be congratulated on work well presented. However, it is important to bear in mind that a radiograph is a two-dimensional image of a three-dimensional object. Thus, other anatomic structures in the region under discussion must also be considered and included when hypothesizing, even though they may not be in focus.The authors should have included the mylohyoid anatomy in their discussion. The mylohyoid groove commences in the region of the inferior margin of the mandibular foramen, runs downwards and forwards and fades away in the submandibular salivary gland fossa.2 Arensburg and Nathan3 found that in approximately 16% of cases, the mylohyoid groove is partially or totally converted into a bony canal by ossification of the covering membrane; the opening of the canal being seen on a mandible, proximal to the mandibular foramen, while a second opening is present at the distal end of the canal. So in these cases the authors were indeed correct about the presence of the bifid canal, but the second canal could have been the mylohyoid canal. However, the authors did not discuss the anatomy of the mylohyoid structures.It is further noted that fairly deep and/or wide mylohyoid grooves were often not observed on a panoramic radiograph, whereas, at other times, relatively shallow mylohyoid grooves were observed radiologically.2 Thus, the radiological presence of the mylohyoid groove is no indication of its size or depth. The mylohyoid groove may then give the impression, on a panoramic radiograph, that there is a bifid mandibular canal, the subject of the title of the presentation.Further, it was shown that the mylohyoid groove sometimes commences from within the mandibular canal.4 Nevertheless, there are two canals (the mandibular and the mylohyoid) for a short distance.If one is discussing bifid mandibular canals, one may wish to discuss the double foramina exiting the mandible. Kerr et al5 stated that multiple mental foramina do occur.In addition, it should be noted,6,7 particularly when performing surgery in the region of the mental foramen, that the mandibular nerve may have a short extra-osseous course, exiting the mandible at the mental foramen and re-entering via the mandibular incisive foramen. Thus, for a short course there is no intra-osseous course of the mandibular nerve.6What I do find rather confusing is that the title of the article infers panoramic radiology but most of the article discusses cone beam CT.I hope that the authors will include the above facts in their future research.References1 Kim M-S , Park H-W , Kang J-H , Yang S-Y , Moon Y-H , Jung N-R , et al.. A false presence of bifid mandibular canals in panoramic radiographs. Dentomaxillofac Radiol 2011;40:434–438. Link ISI, Google Scholar2 Serman NJ . An osteo-radiographic study of the mandibular canal. MSc thesis. Stellenbosch, South Africa; 1982. pp. 55–56, p. 100. Google Scholar3 Arensburg B , Nathan H . Anatomical observation of the mylohyoid groove and the course of the mylohyoid nerve and vessels. J Oral Surg 1979;37:93–96. Medline, Google Scholar4 Serman NJ , Nortje CJ . Osteo-radiographic observations of the mylohyoid canal. J Dent Assoc S Afr 1983;38:14–16. Medline, Google Scholar5 Kerr DA , Ash MM , Milard HD . Oral diagnosis. 5th edn. St. Louis, MO: CV Mosby Co.; 1978. Google Scholar6 Serman NJ . The mandibular incisive foramen. J Anat 1989;167:195–198. Medline ISI, Google Scholar7 Serman NJ . Differentiation of double mental foramina from extra bony coursing of the incisive branch of the mandibular nerve. An anatomic study. Refuat Hashinayim 1987;5:20–22. Medline, Google Scholar Previous article FiguresReferencesRelatedDetailsCited byThe clinical anatomy of accessory mandibular canal in dentistry7 February 2020 | Clinical Anatomy, Vol. 33, No. 8 Volume 41, Issue 7October 2012Pages: 533-620 © 2012 The British Institute of Radiology History Published onlineJanuary 28,2014 Metrics Download PDF

Bifid mandibular canal: confirmation of limited cone beam CT findings by gross anatomical and histological investigations

The aims of this study were (1) to assess the validity of limited cone beam CT (CBCT) in detecting the distribution of bifid mandibular canals in the retromolar region by comparing its findings with those of panoramic radiography and spiral CT imaging, and (2) to confirm the contents of such canals depicted on limited CBCT images by using gross anatomical and histological methods. Bilateral bifid mandibular canals of a Japanese cadaver were investigated. The canals depicted on panoramic radiography, spiral CT and limited CBCT images were compared. Cross-sectional limited CBCT images of these canals were compared with gross anatomical sections of the mandible and their contents were confirmed histologically. The spiral CT and limited CBCT images showed the bilateral bifid mandibular canals in the retromolar region whereas the panoramic radiographs indicated the presence of only the left bifid mandibular canal. The canal distribution was more distinct in the limited CBCT images than in the spiral CT images and the cross-sectional limited CBCT images were consistent with the gross anatomical sections. Histologically, the canals contained several nerve bundles and arteries among which the largest nerve and artery were of a similar size. Limited CBCT is valuable for assessing the distribution of bifid mandibular canals. It is clinically significant to accurately localize a bifid mandibular canal of the retromolar region because it contains a nerve bundle and artery.

A false presence of bifid mandibular canals in panoramic radiographs

This study was performed in order to verify bifid mandibular canals revealed from panoramic radiographic results. 1000 panoramic radiographs from dental patients and the panorama, cone beam CT (CBCT) and micro-CT from 40 dry mandibles were examined for bifid mandibular canals. The results were confirmed by a stereoscopic and histological examination of the cross-sectioned mandibles. The prevalence of bifid canals detected from the panoramic radiographs was 0.038. The panoramic radiographs from one dry mandible showed two separate radiolucent mandibular canal-like structures delineated by radio-opaque lines. However, a stereoscopic and histological examination of a cross-section of the mandible showed that only one canal was a true canal containing neurovascular bundles: the other was false, reflecting merely a bony trabecular pattern. The presence of bifid mandibular canals determined by panoramic radiography should be judged with great caution in relation to dental surgery.

The clinical relevance of bifid and trifid mandibular canals

BackgroundBifid mandibular canals (BMC) and trifid mandibular canals (TMC) are variations on the normal anatomy with incidences ranging from 0.08% to 65.0%. Such aberrations have an important clinical impact. For example, an extra mandibular canal may explain inadequate anesthesia, especially when two mandibular foramina are involved. Furthermore, during mandibular surgery, a second, or even third, neurovascular bundle may be damaged causing paresthesia, neuroma development, or bleeding.Case reportTwo cases are presented in this article. One patient had a BMC on both sites, and the other patient had a TMC on one site and a BMC on the other site.DiscussionInitial screening for the presence of a BMC or TMC can be executed by conventional panoramic radiography. BMCs or TMCs are diagnosed, before executing mandibular surgery; additional CBCT scanning is indicated.

Assessment of variations of the mandibular canal through cone beam computed tomography

The neurovascular bundle may be vulnerable during surgical procedures involving the mandible, especially when anatomical variations are present. Increased demand of implant surgeries, wider availability of three-dimensional exams, and lack of clear definitions in the literature indicate that features of anatomical variations should be revisited. The objective of the study was to evaluate features of anatomical variations related to mandibular canal (MC), such as bifid canals, anterior loop of mental nerve, and corticalization of MC. Additionally, bone trabeculation at the submandibular gland fossa region (SGF) was assessed and related to visibility of MC. Cone beam computed tomography exams from 100 patients (200 hemimandibles) were analyzed and the following parameters were registered: diameter and corticalization of MC; trabeculation in SGF region; presence of bifid MC, position of bifurcations, diameter, and direction of bifid canals; and measurement of anterior loops by two methods. Corticalization of the MC was observed in 59% of hemimandibles. In 23%, MC could be identified despite absence of corticalization. Diameter of MC was between 2.1 and 4mm for nearly three quarters of the sample. In 80% of the sample trabeculation at the SGF was either decreased or not visible, and such cases showed correlation with absence of MC corticalization. Bifid MC affected 19% of the patients, mostly associated with additional mental foramina. Clinically significant anterior loop (>2mm of anterior extension) was observed in 22-28%, depending on the method. Our findings, together with previously reported limitations of conventional exams, draw attention to the unpredictability related to anatomical variations in neurovascularization, showing the contribution of individual assessment through different views of three-dimensional imaging prior to surgical procedures in the mandible.

Evaluation of bifid mandibular canals with cone-beam computed tomography in a Turkish adult population: a retrospective study

Knowing the anatomic location and also variations of the mandibular canal is especially important for surgical procedures on mandible such as dental implant surgery, impacted molar extraction and sagittal split ramus osteotomy. The purpose of this study was to clarify the incidence and location of bifid mandibular canals in an adult Turkish population to avoid complications during surgical procedures. A retrospective study using cone beam CT images was performed to evaluate bifid mandibular canal in mandible of 242 patients. Both right and left sides were studied (n = 484). Axial, sagittal, cross-sectional and panoramic images were evaluated, and three-dimensional (3D) images were also reconstructed and evaluated, as necessary. The course and length of bifid mandibular canals and the superior and inferior angles between canals were measured. Bifid mandibular canals were observed in 225 (46.5%) of 484 sides examined. The most frequently encountered type of bifid canal was the forward canal (29.80%), followed by the retromolar (28.10%) the buccolingual (14.50%) and the dental canal type (8.30%). Mean lengths of bifid canals were 13.6 mm in the right side and 14.1 mm in the left side. Mean superior angles were 139° on the right and 141° on the left side, whereas mean inferior angles were 38° on the right side and 32° on the left side. No statistically significant differences were found in the lengths or angles between the right and left sides and also for gender (p < 0.05). This study, which utilized CBCT images, uncovered a higher prevalence of bifid mandibular canals than what has been reported in previous studies using conventional radiography techniques.

Canalis mandibulae bifidus en trifidus. Een toevalsbevinding

A 26-year-old man was suffering from pericoronitis of his mandibular third molars. To determine the position of the mandibular canal in relation to the roots of the third molars, a panoramic radiograph was made. The radiograph revealed at the right side a bifid mandibular canal and the upper part of the canal seemed to be related to the third molar. Additionally, a cone beam CT was made, which revealed a bifid mandibular canal at the left side and a trifid mandibular canal at the right side. Anatomical anomalies of the mandibular canal may have clinical implications, such as an increased risk of injury to the inferior alveolar nerve in case of removing a mandibular third molar and inadequate local anesthetics.

Bifid mandibular canals: cone beam computed tomography evaluation

For surgical procedures involving the posterior mandible, it is important to be familiar with the details of the bifid mandibular canal. To our knowledge, there have been no systematic studies evaluating the bifid mandibular canal using sectional imaging. The purpose of this study is to evaluate the incidence and configuration of the bifid mandibular canal using cone beam CT. 252 patients (301 mandible sides) underwent cone beam CT between October 2004 and September 2005 and were included in this study. The cone beam CT images were evaluated for the presence and configuration of the bifid mandibular canal. The patterns of bifurcation were classified into four types according to the classification of Nortjé et al (Variations in the normal anatomy of the inferior dental (mandibular) canal: a retrospective study of panoramic radiographs from 3612 routine dental patients. Br J Oral Surg 1977; 15: 55-63). The diameter of the accessory canal was classified into two categories: 50% or more and less than 50% of the diameter of the main mandibular canal. Of the 301 subjects, 47 (15.6%) demonstrated a bifid mandibular canal. They were Type I in 2, Type II in 40, Type III in 0, and Type IV in 5 cases. The diameter of the accessory canal was greater than or equal to 50% of the main canal in 23, and less than 50% in 24 cases. On the basis of the cone beam CT, a bifid mandibular canal was found in 15.6% of cases, a markedly higher proportion than found in previous reports using panoramic images. Cone beam CT is considered a suitable modality for detailed evaluation of bifid mandibular canals.

Variations of the bony canal in the mandibular ramus using cone-beam computed tomography

The location and configuration of the mandibular canal are important in surgical procedures involving the mandible. Previously, we reported that bifid mandibular canals could be classified into four types: retromolar, dental, forward, and bucco-lingual canals, using cone-beam computed tomography (CBCT). Herein we report three Japanese patients with a bony canal in the mandibular ramus, which was independent of the mandibular canal, using CBCT images. A CBCT unit with a flat panel detector and exposure volume of 102 mm in diameter and 102 mm in height was used. Two-dimensional (2D) and three-dimensional (3D) images in the mandibular ramus region were reconstructed using 3D visualization and measurement software packages. Three bony canals in two patients were considered to correspond to a temporal crest canal, which was raised from the mandibular notch, and reached the antero-inferior region of the coronoid process. One bony canal in one patient, ran bucco-lingually in the mandibular ramus. It is important for variations in the mandibular and bony canals to be carefully observed, by use of CBCT images, in surgical procedures involving the mandible.

Comparison between cone-beam and multislice computed tomography depicting mandibular neurovascular canal structures

The most common diagnostic imaging modalities for cross-sectional imaging in dental implant planning are currently cone-beam computed tomography (CBCT) and multislice CT (MSCT). However, clinical differences between CBCT and MSCT in this task have not been fully clarified. In this investigation, the detection of fine anatomical structures in the mandible was assessed and compared between CBCT and MSCT images. The sample consisted of 28 patients who had undergone CBCT and MSCT. The bifid mandibular canal in the mandibular ramus, accessory mental and buccal foramina, and median and lateral lingual bony canals were observed in 2-D images, and the findings were compared between CBCT and MSCT. Four of 19 canals observed in CBCT were not observed in MSCT images. Three accessory mental foramina in 2 patients and 28 lateral lingual bony canals in 18 patients were observed consistently using the two methods. Depiction of fine anatomic features in the mandible associated with neurovascular structures is consistent between CBCT and MSCT images.