Position of the Mental Foramen in a Korean Population: A Clinical and Radiographic Study

A rare case of an anatomical variant of nonexistent mental foramen

The mental foramen (MF) is an important anatomical landmark in the jaw, where the sensory nerve (mental nerve) and blood vessels emerge. To avoid sensory impairment or paresthesia caused by mental nerve damage, the MF must be accurately identified and localized. The literature describes a variety of anatomical variants of the MF, such as changes in its position, emergence profile or the presence of extra foramina. This case report documents a rare case of nonexistent mental foramina on the left side of the jaw, which was detected incidentally using cone-beam computed tomography (CBCT) prior to implant surgery planning.

Assessment of the mandibular incisive and mental canal in dentate and edentulous mandibles using cone-beam computed tomography

Objectives

This study evaluated the prevalence, diameter and location of the mandibular incisive canal (MIC) and the transition pattern and anterior loop length (ALL) of the mental canal and compared these values between dentate and edentulous mandibles.

Methods

A total of 187 cone-beam computed tomography (CBCT) images of mandibles, namely, 100 images of dentate mandibles and 87 images of edentulous mandibles, were obtained. CBCT data related to the incisive canal and mental canal were analyzed by one examiner.

Results

The prevalence of the MIC was 75∼78 %, showing no difference based on laterality or the presence of teeth. The ALL significantly differed depending on the presence of teeth as well as sex. The presence of teeth affected the size of the MIC in the female group, and the diameter of the MIC in the edentulous group was significantly narrower than that in the dentate group. The diameter of the MIC was significantly greater in males than in females in the edentulous group. Meanwhile, the location of the MIC in the male group depended on the presence of teeth at each measuring point, and the MIC was significantly closer to the lower border of the mandible in the female group than in the male group at all measuring points except at 0 mm.

Conclusions

This study indicated that the presence of teeth significantly affects the type of transition of the mental canal, the ALL, and the diameter and location of the MIC. Additionally, sex could be a factor affecting MIC location, MIC diameter and anterior loop length.

Mental foramen and apical foramen: A dangerous anatomical proximity

The study evaluated the spatial position of the mental foramen (MF) using 300 cone-beam computed tomography. The spatial position was analyzed with the horizontal location and relative location (distance between apical foramen and MF). The horizontal location was assessed through three positions (positions 1, 2, and 3). The relative location was determined with the x, y, and x coordinates of the root apex of mandibular premolars and the MF. Student's t-test and chi-square were performed. The most common horizontal location (52%) was position 2, which means between the premolars (p < 0.05). The relative location of the MF to the root apex of the second premolar was closer than the first premolar (p < 0.05). The distance between the root tip of the second premolar and the MF was 5.27 mm, with a minimum value of 1.87 mm. Clinicians should be aware of the possible neural results to the mental nerve of an endodontic infection and the extrusion of irrigation solutions.

The mental foramen, anatomical parameters through a radiographic approach to aid in dental implantology: A retrospective analysis in a sample of a Palestinian population

Purpose

This study aims at analyzing the mental foramen (MF) structure, dimension, position, and emergence profiles among a sample of a Palestinian population.

Methods

212 mental foramina (106 patients) were analyzed on two panoramic views (CBCT reformatted (CRP) & conventional (CP)) and CBCT coronal views. The visibility score, position, size, presence of loop & supplementary foramina, distances coronal and apical to the foramen, and the emergence profiles of the mental canals with associated course angles were all noted.

Results

No statistically significant relationship was found between the type of panoramic radiographic view used (i.e., CP & CRP) and the resultant visibility level and position of MF. The majority of the MF showed an intermediate visibility score on both CP & CRP. The highest percentage of MF's position was under the 2nd mandibular premolar. The emergence profile was shown to be, in most, superior (S) in 47.6% of the sample and posterosuperior (PS) in 28.3%. The MF mean height and width were 4.08 mm & 4.11 mm, respectively. The coronal and axial angles averages were 46.25° and 91.49°, respectively. The distance superior and inferior to the MF showed averages of 12.39 mm and 13.52 mm, respectively. 28.3% of the sample presented with a mental loop, with a mesial extension average of 2 mm.

Conclusion

On both panoramic views (CBCT & conventional), the majority of the mental foramina displayed an intermediate visibility level, with no significant difference between the two techniques. The MF was found mostly under the second premolar. The majority of the examined mental canals had a superior emergence profile.

Validation of different protocols of inferior alveolar canal tracing using cone beam computed tomography (CBCT)

OBJECTIVES

The objective of this study was to evaluate, compare and validate different protocols of inferior alveolar canal tracing.

METHODS

60 DICOM files with a total of 80 inferior alveolar canals were retrieved and imported to a third-party software where all proposed protocols can be performed. Initially, inferior alveolar canal was traced by two oral and maxillofacial radiologists together on cone beam CT cross-sectional images and considered as the baseline for future comparisons. Oral and maxillofacial surgeon performed the proposed different protocols. The protocols were color-coded differently by the surgeon before being compared with the baseline canal by the radiologists through a 5-point scale.

RESULTS

Results showed that no single protocol was successful in all cases, even the cross-sectional protocol. According to the present study, the hybrid protocol was the most accurate while the automatic protocol was the least accurate.

CONCLUSIONS

The hybrid protocol was reliable and showed the highest number of successful applications followed by the commonly used cross-sectional protocol. Dental practitioners should be aware of the application of multiple protocols and their pros and cons as no single protocol was successful in all the cases. Applying the same protocols on a larger sample size using different cone beam CT and multislice CT machines with different exposure parameters is recommended.

Evaluation of the Course of Inferior Alveolar Canal and its Relation to Anatomical Factors on Digital Panoramic Radiographs

Statement of the Problem

The inferior alveolar canal (IAC) is a bony canal that starts from mandibular foramen at the inner surface of the mandibular ramus and extends along the ramus and body of mandibular bone in forward and downward directions to the mental foramen. Inside the mandibular canal, there are lower alveolar artery and a nerve with the same name. Understanding the anatomical details of the lower alveolar canal, including position, pathway and morphology to prevent complications in surgical procedures in the lower jaw such as mandibular impacted molar surgeries, mandibular nerve block injection, or even root canal treatment of mandibular teeth is important.

Purpose

The purpose of this study was to investigate the course and direction of IAC in mandibular bone and its relation to anatomical factors such as gonial angle and location of entrance of IAC in the mandibular ramus.

Materials and Method

This cross-sectional study evaluated a sample of 280 digital panoramic images. All samples were Iranian. The pattern and direction of the IACs were recorded according to age and gender and the relation of these patterns to the gonial angle of mandible and the entry point of the IAC in mandibular ramus were evaluated.

Results

The results showed that the course of canal, the entrance point of the canal and the gonial angle were the same between different age groups and between two genders. There was no significant relation between the course of canal and the two anatomical variables mentioned (p> 0.05).

Conclusion

Considering the increasing frequency of implant surgeries and presence of different courses of the mandibular canal and concerning the important complications such as paresthesia caused by damage to the mandibular nerve, panoramic radiography is necessary before any surgery in this area to avoid unwanted injuries to the neurovascular system if other advanced modalities are not available.

Location of the Mandibular Incisive Canal Related to the Placement of Dental Implants: A Case Report

Cone-beam computerized tomography (CBCT) can show an uncommon mandibular incisive canal that cannot be detected by panoramic radiography, which is used preoperatively to form the initial plan of the size and length of an implant fixture for surgical placement in the mandibular interforaminal area. Determination of the position and anatomical configuration of the mandibular incisive canal is challenging. The purpose of this case report is to discuss anatomical variations in the mandibular incisive canal and the mental canal by reviewing previous studies. Furthermore, we propose that the anterior loop length of the mental canal near the mental foramen, as well as the diameter of the mandibular incisive canal, should be verified by CBCT prior to performing implant surgery in the anterior mandibular area to prevent possible nerve damage.

Localization of the Mandibular Canal in a Turkish Population: a Retrospective Cone-Beam Computed Tomography Study

Objectives

The aim of this study was to determine the location of the mandibular canal at the mental foramen region that is essential in order to prevent injuries to the inferior alveolar neurovascular bundle during mandibular surgical procedures.

Material and Methods

The position of the mandibular canal was analysed using cone-beam computed tomography images from 300 Turkish patients, who were referred to Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Izmir Katip Celebi University for various complaints. The distances of the mandibular canal to the outer superior (D1), inferior (D2), buccal (D3), and lingual (D4) cortical margins were measured at 2 mm distal to the mental foramen.

Results

There were 148 (49.3%) males and 152 (50.7%) females with ages ranging from 15 to 74 years (39.15 [SD 17.8]). D1 was significantly greater than D2 and D3 was significantly greater than D4 on both left and right sides. While the mean D1, D2, and D4 in males were significantly greater than in females on both left and right sides. There was no significant difference between D3 in males and females on both left and right sides.

Conclusions

The results showed that the mandibular canal was vertically located nearer to the inferior cortical border and horizontally nearer to the lingual cortical border of the mandible at the mental foramen region. Knowledge of the distances of mandibular canal to the outer cortical margins at this region of the mandible will be helpful for surgical procedures.

The mental foramen: A cone beam CT study of the horizontal location, size and sexual dimorphism amongst living Jordanians

Accurate information regarding the horizontal location and size of mental foramen (MF) has a well-known clinical importance. In addition, these variables have been reported to exhibit inter-population variation. The aims of the present study were to study the horizontal position and size of MF, as seen on cone beam CT (CBCT) images, and to assess sexual dimorphism in these variables. Total of 139 CBCT images of a random Jordanian sample (50 males, 89 females, average age = 43.5, SD = 13.0, range = 23-69 years) were included. The most frequent horizontal locations of MF were found to be: between the two lower premolars (50%), and in line with lower second premolar (40%). The average long diameter of MF was 3.08 mm, SD = 0.65 mm in males (n = 50, range = 1.5-4.8 mm) and 2.46 mm, SD = 0.58 mm in females (n = 89, range = 1.2-4.0 mm), and the difference was statistically significant. Very weak positive correlation was found between age and MF diameter in females (r = 0.161) and the correlation was approaching statistical significance (p-value = 0.066), while a weak negative correlation was found between these two variables in males (r = -0.276) and the correlation was statistically significant (p-value = 0.038). It could be inferred from the results of the present study that about 95% success rate for mental nerve block anesthesia is expected when the anesthetic solution is administered between the two premolars; however this needs to be tested experimentally. It appears that there is a tendency for an increase in MF size with age in females as opposed to a tendency for size reduction with age in males; this might suggest a role for sexual hormones in influencing MF size.

Mandibular Canal Course and the Position of the Mental Foramen by Panoramic X-Ray in Chilean Individuals

The object of this study was to analyse the morphology and morphometry of the mandibular canal (MC) course and the mental foramen (MF) position in relation to the inferior teeth by panoramic X-ray (PAN). Vertical linear measurements were taken of each hemimandible to obtain the length of the distances analysed. We studied the MF position in relation to inferior premolar roots and the relation between the MC and mandibular teeth roots (MCR). The MF was usually located between the apices of the first and second premolars in younger individuals and immediately below the apex of the inferior second premolar in older individuals. The MC evinced proximity to the third molar, and this relation was not affected by sex or age group. The distances analysed in this study presented a marked difference between gender, with larger values in males than in females. The variations which may occur between individuals and different populations make it essential for dentists and surgeons to plan carefully before procedures involving this region.

3D CBCT morphometric assessment of mental foramen in Arabic population and global comparison: imperative for invasive and non-invasive procedures in mandible

BACKGROUND

Recent advancements in clinical dentistry have increased the possibilities of surgical procedures in the mental region. A detailed knowledge of mental foramen (MF) morphometry is significant to preserve integrity of the mental nerve trunk in surgical interventions such as orthognathic surgery, implant placement and anaesthetic block.

OBJECTIVE

The aim of this study was to determine the most accurate position of the mental foramen by using new assessment approach in a sample of dental patients presenting to the specialist dental clinic, College of Dentistry, Al Jouf University, Saudi Arabia.

STUDY DESIGN

A retrospective study was performed using cone beam computed tomography (CBCT) of 600 patients (40.1 ± 11.78 years old). Following inclusion and exclusion criteria, 395 CBCT were finally obtained and analyzed for the most accurate position of the mental foramen (MF) by OnDemand 3D software (Seoul, Korea). Prevalence of shape of MF and accessory MF were also assessed. Pearson chi-square test was employed to test significant differences between genders and races.

RESULTS

The most common horizontal and vertical position of the mental foramen was in line with the long axis of 2nd premolar (41.3%) and below the root apex level (93.2%), respectively. The most common shape of MF was round type (72.66%). The prevalence of accessory 2MF and 3MF was 2.28% and 0.25%, respectively.

CONCLUSION

New information about MF presented in this article can help anatomists, prosthodontists, orthodontists, surgeons, forensic odontologists and paleoanthropologists to predict the position of the MF and perform safer surgeries.

Predictive factors of the dimensions and location of mental foramen using cone beam computed tomography

Objective

The mental foramen (MF) hosts main neurovascular structures, making it of crucial importance for surgical procedures. This study aimed to analyze the factors influencing the dimensions and location of the MF.

Materials and methods

Cone beam computed tomography (CBCT) scans of 344 patients were examined for MF dimensions, as well as for the distances from the MF to the alveolar crest (MF-MSB), and to the inferior mandibular border (MF-MIB).

Results

Gender, mandibular side and presence of accessory mental foramina (AMF) significantly influence MF area. Males, left hemimandibles, and hemimandibles with no AMF had a higher rate of large MF areas (B = − 0.60; p = 0.003, females; B = 0.55; p = 0.005; B = 0.85; p = 0.038). Age, gender and dental status significantly influence MF-MSB distance. The distance decreased as age increased (B = −0.054; p = 0.001), females showed a lower rate of long MF-MSB distances (B = −0.94, p = 0.001), and dentate patients showed a higher rate of long MF-MSB distances (B = 2.27; p = 0.001). Age, gender and emerging angle significantly influenced MF-MIB distance. The distance decreased as age and emerging angle increased (B = −0.01; p = 0.001; B = −0.03; p = 0.001), and females had a lower rate of long MF-MIB distances (B = −1.94, p = 0.001).

Conclusions

General and local factors influence the dimensions and location of MF. MF dimensions are influenced by gender, mandibular side, anteroposterior position, and the presence of AMF. Distance from MF to alveolar crest is influenced by gender, age and dental status, while the relative MF position is influenced by age and dental status. CBCT images make it possible to analyze the MF in order to avoid complications during surgical procedures.

Tracking of the inferior alveolar nerve: its implication in surgical planning

OBJECTIVES

The objective of the study is to assess the correlation between the mandibular canal tracing done on cone beam CT (CBCT) data, with the size, shape, and position of the neurovascular bundle (NB) obtained by magnetic resonance imaging (MRI).

MATERIAL AND METHODS

Six human cadaver mandibles were scanned with a CBCT Promax® scanner (Planmeca, Helsinki, Finland) and with an Ingenia® 3.0 T MR system (Philips, Amsterdam, The Netherlands). The NB was segmented from the MRI dataset, while the mandibular canal (MC) tracing was done on the CBCT images. Quantitative 3D analysis was made for the full-segmented nerves and for three defined regions of specific clinical interest, namely angle, body, and mental region.

RESULTS

From the 3D MRI analysis, the nerve thickness (for the angle, body, and mental region) ranges from 0.8 to 5.2 mm, while the thickness of the mandibular canal tracing is approximately 2.00 mm on both sides as chosen in the tracing software. The mean volume of the NB on the left is 828.49 ± 215.54 mm³ and on the right 792.98 ± 264.57 mm³. For the nerve tracing, the mean value is 351.92 ± 16.42 and 339.69 ± 16.12 mm³ on the left and right sides, respectively. Wilcoxon signed-rank test showed significant differences between NB and MC volume measurements (p = 0.0005). The Bland-Altman plots show an increasing slope for thickness and volume, indicating that the absolute differences between neurovascular bundle, estimated by MRI, and the mandibular canal, drawn on the CBCT images, increase with larger mean values.

CONCLUSIONS

Surgeons should be aware of the shortcomings of nerve tracing in the different regions of the mandible.

CLINICAL RELEVANCE

Tracing of the inferior alveolar nerve (IAN) underestimates shape and volume. Whenever nerve tracing instead of well-recognizable anatomical bony landmarks is used for surgical planning that need precision, a wider safe margin is recommended.

The Ultrasonographic Determination of the Position of the Mental Foramen and its Relation to the Mandibular Premolar Teeth

INTRODUCTION

The position of the mental foramen has been well researched in cadaver specimens, radiographically as well as intraoperatively. To our knowledge, this landmark study is the first to make use of ultrasonography in a study population to determine the position of the mental foramen in relation to the mandibular premolar teeth. Ultrasonography has great potential to further revolutionize the practice of medicine and dento-maxillofacial surgery.

AIM

To make use of ultrasound to determine the position of the mental foramen and its relation to the mandibular premolar teeth.

MATERIALS AND METHODS

One hundred Black and Caucasian subjects were enrolled. A high frequency (8MHz) transducer (PLF.805ST) of a diagnostic ultrasound system (model SSA-510A) was applied above the inferior border of the mandible, just lateral to the mentum. With the marker of the transducer pointing cranially, the position of the mental foramen in relation to the closest mandibular premolar tooth was determined. The position was compared across race, sex and age groups.

RESULTS

All mental foramina (100%) were visualised. Overall the most frequent position of the mental foramen was in line with the long axis of the second premolar on the right (44%) and between the first and second premolars on the left (44%). There were no statistical differences (p >0.05) between race groups, sex and age groups with regard to the position of the mental foramen in relation to the mandibular premolars. However, in Blacks, the most frequent position of the mental foramen was in line with the long axis of the second premolar and in Caucasians the most common position was between the first and second premolars. The most frequent position of the mental foramen in females was in line with the long axis of the second premolar on the right and between the first and second premolars on the left. In males, the most frequent position of the mental foramen was in line with the long axis of the second premolar bilaterally. The most common position of the mental foramen in the age group category 18-30 years was between the first and second premolars. In patients aged 31-60 years the most frequent position was in line with the long axis of the second premolar.

CONCLUSION

Ultrasound is a sensitive modality to locate the mental foramen. There are differences in the most common position of the mental foramen with regard to the long axis of the premolar teeth. Ultrasonography has the potential to revolutionize the practice of dento-maxillofacial surgery.

Evaluation of the mandibular canal visibility on cone-beam computed tomography images of the mandible

BACKGROUND

The mandibular canal (MC) is an important and necessary landmark that should be considered before any surgery in the posterior region of the mandible. This study is aimed to evaluate the visibility and position of the MC in an Iranian population using cone-beam computed tomography.

METHODS

In this cross-sectional study, cone-beam computed tomography images of 69 patients, which were available as soft copies in the archives of the databases in the Department of Oral Radiology at Hamadan University of Medical Sciences (Hamadan, Iran), were analyzed. The visibility, corticalization, and position of the MC were assessed by 2 expert oral radiologists independently. The χ2 test, unpaired t test, and 1-way analysis of variance were used for analysis.

RESULTS

The right and left MCs were clearly visible in 89.6% and 84.7% of the cases, respectively. Among 87.5% of cases, the MC was observed simultaneously in 2 sides. Position of the MC in relation to surrounding structures showed lowest asymmetry at the second premolar area. There were no statistically significant difference between sex and the evaluated parameters.

CONCLUSIONS

Cone-beam computed tomography was successful in most cases in displaying the MC. The areas with most MC visibility in the right and left sides were the second and third molar regions, respectively. This visibility declined forwardly in both sides.

Assessment of position and bilateral symmetry of occurrence of mental foramen in dentate asian population

INTRODUCTION

The mental foramen shares its significance in various fields of dentistry. Being a strategically eminent landmark, an understanding of the variation of its position is important Aim: To radiographically evaluate frequently occurring position of mental foramen and its distance with reference to the lower premolars and the lower border of mandible on standardized panoramic radiographs.

METHODS

The inferior alveolar canal, upto the mental foramen, was traced over 300 orthopantomographs (OPGs) which were selected by using specific criteria. The mandibular plane and the long axis of the premolars were used as references to measure perpendicular distance of foramen.

RESULTS

The most common position was found to be between the two premolars (63% cases), which scaled approximately 15.46mm above the lower border of the mandible, with an average proximity to the 2nd premolar (5.51mm) than the 1(st) premolar (8.21mm). This was followed by position behind the second premolar, which scored 20.67%. Both the foramina were noted in the same vertical plane of reference, and they showed bilateral occurrence of the most common position of the mental foramen, with respect to 45.67% cases.

CONCLUSION

The most common location was reported to be between the two premolars, with a definite bilateral symmetry on both left and right sides. No gender preferences were observed. An average distance of 15mm from the lower border of the mandible was calculated.

Mandibular third molar impaction: review of literature and a proposal of a classification

Objectives

The purpose of present article was to review impacted mandibular third molar aetiology, clinical anatomy, radiologic examination, surgical treatment and possible complications, as well as to create new mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results.

Material and Methods

Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular third molar, impacted mandibular third molar, inferior alveolar nerve injury third molar, lingual nerve injury third molar. The search was restricted to English language articles, published from 1976 to April 2013. Additionally, a manual search in the major anatomy and oral surgery journals and books was performed. The publications there selected by including clinical and human anatomy studies.

Results

In total 75 literature sources were obtained and reviewed. Impacted mandibular third molar aetiology, clinical anatomy, radiographic examination, surgical extraction of and possible complications, classifications and risk factors were discussed. New mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results was proposed.

Conclusions

The classification proposed here based on anatomical and radiological impacted mandibular third molar features is promising to be a helpful tool for impacted tooth assessment as well as for planning for surgical operation. Further clinical studies should be conducted for new classification validation and reliability evaluation.

Clinical and radiological classification of the jawbone anatomy in endosseous dental implant treatment

Objectives

The purpose of present article was to review the classifications suggested for assessment of the jawbone anatomy, to evaluate the diagnostic possibilities of mandibular canal identification and risk of inferior alveolar nerve injury, aesthetic considerations in aesthetic zone, as well as to suggest new classification system of the jawbone anatomy in endosseous dental implant treatment.

Material and Methods

Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandible; mandibular canal; alveolar nerve, inferior; anatomy, cross-sectional; dental implants; classification. The search was restricted to English language articles, published from 1972 to March 2013. Additionally, a manual search in the major anatomy and oral surgery books were performed. The publications there selected by including clinical and human anatomy studies.

Results

In total 109 literature sources were obtained and reviewed. The classifications suggested for assessment of the jawbone anatomy, diagnostic possibilities of mandibular canal identification and risk of inferior alveolar nerve injury, aesthetic considerations in aesthetic zone were discussed. New classification system of the jawbone anatomy in endosseous dental implant treatment based on anatomical and radiologic findings and literature review results was suggested.

Conclusions

The classification system proposed here based on anatomical and radiological jawbone quantity and quality evaluation is a helpful tool for planning of treatment strategy and collaboration among specialists. Further clinical studies should be conducted for new classification validation and reliability evaluation.

The prevalence, length and position of the anterior loop of the inferior alveolar nerve in Chinese, assessed by spiral computed tomography

PURPOSE

This study used spiral computed tomography to identify the anterior loop of the inferior alveolar nerve, and to measure its length and position in Chinese. This information may be useful to safely install endosseous implants in the most distal area of the interforaminal region.

METHODS

Sixty-eight Chinese patients were included in this retrospective study. Patients were scanned by 64-slice spiral computed tomography, and the prevalence, length, and position of the anterior loop were assessed using the multiplanar capabilities of software.

RESULTS

An anterior loop could be identified in 83.1% of the cases, with a mean length of 2.09 mm (range 0-5.31 mm). The mean distance from the superior border of the mental foramen to the alveolar crest was 13.00 mm, and the mean distance from the superior border of the origin of the anterior loop to the alveolar crest was 17.83 mm.

CONCLUSIONS

The anterior loop was highly prevalent in Chinese, and the length of the anterior loop was highly variable. Therefore, we recommend that drilling commences from a location approximately 5.5 mm mesially from the mental foramen, when installing implants in the most distal interforaminal area.

Visibility of mandibular canal on panoramic radiograph after bilateral sagittal split osteotomy (BSSO)

PURPOSE

This study aimed to assess the visibility of the mandibular canal (MC) on panoramic radiographs after bilateral sagittal split osteotomy (BSSO), and to investigate what factors affect this MC visibility.

METHODS

We assessed MC visibility on panoramic radiographs of 200 BSSO patients. Images were acquired preoperatively (T0), immediately postoperatively (T1), 6 months postoperatively (T2), and 1 year postoperatively (T3), from three different predetermined regions of the mandible: the angle (Angle), distally to the second molar (M2), and mesially to the first molar (M1). All analyses were performed using SAS version 9.22.

RESULTS

The visibility of the MC was registered preoperatively in over 96 % (387/400) of the measurements at the angle of the mandible, 79 % (317/400) at M2, and <63 % (251/400) at M1. MC visibility decreased immediately after the operation and increased thereafter. Region of the mandible (P ≤ 0.0001), plate removal (P ≤ 0.0001), time of assessment (P ≤ 0.0001), and age (P = 0.0034) were the important predictors of whether MC would be radiographically visible.

CONCLUSIONS

The visibility of the MC decreased immediately after BSSO, especially at the operation site (M2 and M1), while maximum MC visibility was achieved at 12 months postoperatively in our series. Since MC was not visible at the operation site after BSSO for 50 % of the subjects, it may be necessary to use additional visualization modalities for postoperative patient assessment in this region.

Identification of the mandibular vital structures: practical clinical applications of anatomy and radiological examination methods

Objectives

The purpose of this article was to review the current available clinical techniques and to recommend the most appropriate imaging modalities for the identification of mandibular vital structures when planning for oral implants.

Material and Methods

The literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular canal, mandibular incisive canal, mental foramen, anterior loop of the mental nerve, radiography, dental implants. The search was restricted to English language articles, published from January 1976 to January 2010.

Results

In total 111 literature sources were obtained and reviewed. The peculiarities of the clinical anatomy of mandibular canal, mandibular incisive canal, mental foramen and anterior loop of mental nerve were discussed. Radiological diagnostic methods currently available for the identification of the mandibular vital structures when planning for oral implants were presented. Guidelines for the identification of the mandibular vital structures in dental implantology were made.

Conclusions

The proposed guideline provides clinicians a tool in proper identifying the important mandibular vital structures thus minimizing the potential complications during implant surgery.

Effect of ageing towards location and visibility of mental foramen on panoramic radiographs

Mental foramen is an opening of the mental canal onto the lateral surface of the mandible. In this pilot radiographical study, in Malay population the effects of ageing towards the location and visibility of the mental foramen were determined. Most of the mental foramina were found to be located inferior to the apex of the second premolar. Non-visibility of the foramen was greatly increased in patients aged 50 years and above (Pearson Chi-square; p = 0.00). This finding may provide a guide to dental surgeries in Malay patients of different age groups.

Anatomy of mandibular vital structures. Part I: mandibular canal and inferior alveolar neurovascular bundle in relation with dental implantology

Objectives

It is critical to determine the location and configuration of the mandibular canal and related vital structures during the implant treatment. The purpose of the present study was to review the literature concerning the mandibular canal and inferior alveolar neurovascular bundle anatomical variations related to the implant surgery.

Material and Methods

Literature was selected through the search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular canal, inferior alveolar nerve, and inferior alveolar neurovascular bundle. The search was restricted to English language articles, published from 1973 to November 2009. Additionally, a manual search in the major anatomy, dental implant, prosthetic and periodontal journals and books were performed.

Results

In total, 46 literature sources were obtained and morphological aspects and variations of the anatomy related to implant treatment in posterior mandible were presented as two entities: intraosseous mandibular canal and associated inferior alveolar neurovascular bundle.

Conclusions

A review of morphological aspects and variations of the anatomy related to mandibular canal and mandibular vital structures are very important especially in implant therapy since inferior alveolar neurovascular bundle exists in different locations and possesses many variations. Individual, gender, age, race, assessing technique used and degree of edentulous alveolar bone atrophy largely influence these variations. It suggests that osteotomies in implant dentistry should not be developed in the posterior mandible until the position of the mandibular canal is established.

Anatomy of Mandibular Vital Structures. Part II: Mandibular Incisive Canal, Mental Foramen and Associated Neurovascular Bundles in Relation with Dental Implantology

Objectives

The purpose of the present study was to review the literature of how to identify the mental foramen, mandibular incisive canal and associated neurovascular bundles during implant surgery and how to detect and avoid the damage of these vital structures during implant therapy.

Material and Methods

Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular incisive canal, mental foramen, mental nerve, anterior mental loop. The search was restricted to English language articles, published from 1979 to November 2009. Additionally, a manual search in the major anatomy, dental implant, and periodontal journals and books was performed.

Results

In total, 47 literature sources were obtained and reviewed. The morphology and variations of the mandibular incisive canal, mental foramen and associated neurovascular bundles were presented as two entities. It suggested that clinicians should carefully assess these vital structures to avoid nerve/artery damage.

Conclusions

The mandibular incisive canal, mental foramen and associated neurovascular bundles exist in different locations and possess many variations. Individual, gender, age, race, assessing technique used and degree of edentulous alveolar bone atrophy largely influence these variations. It suggests that the clinicians should carefully identify these anatomical landmarks, by analyzing all influencing factors, prior to their implant surgical operation.

Atypical trigeminal neuralgia of the mental nerve: a case study

Any division or branch of the trigeminal nerve can exhibit signs and symptoms of neuralgia. Those who treat patients suffering with craniofacial pain are frequently charged with determining the cause of illusive pain complaints and if objective signs are not discovered, the patient may not be treated and may be forced to seek help elsewhere. Trigeminal neuralgia-like pain is often seen in the mental nerve region of the mandible, but frequently, there is no radiographic evidence for the source of such pain. In the current case report, it was discovered that the patient's mental nerve pain was cause by an irregular surface of the anterior portion of the mental foramen. Successful treatment was provided by surgically recontouring the edge or lip of the mental foramen without injury to the mental nerve.