Injury Risk Estimation in Mandible-Related Surgical Procedures: A CBCT Study Based on Vital Interforaminal Anatomical Structures.

The mandibular interforaminal region has been considered safe for surgical procedures; nevertheless, the risk of injury to neurovascular structures, such as the mental foramen (MF) and its related structures (anterior loop [AL] and lingual foramina [LF]) should not be overlooked. The study aimed to evaluate the relative risk of injury to these structures during surgical procedures in the anterior region of the mandible based on cone-beam computed tomography (CBCT) scans. A retrospective cross-sectional and observational study was performed on 250 CBCTs from adults (18-69 years) with dentate jaws. Linear measurements of the MF, AL, and LF were evaluated to estimate the risk of injury to these structures during chin-related surgical procedures. The most frequent distance between the base of the mandible (BM) and MF was 8 mm (30.2%). In addition, 20.4% of the CTs had 6 mm from the vestibular cortical bone to the LF. The commonly found measurement from LF to the apex of the nearest tooth was 7 mm (24.0%); 64.2% of the CTs showed a 2-mm distance between the most distal point of the dental implant site to the most anterior point of the AL. Safety distances for genioplasty techniques (MF to mandible base > 6 mm, 96.6% [CI 95%, 95.0%-98.2%]) were observed. Considering the 5-mm cut-off point between the lower limit of a hypothetical bone graft and the chin, 65.4% (CI 95%, 58.9%-71.9%) of CTs were within this distance. Regarding the safety margin of 8 mm, 85.6% (CI 95%, 80.8%-90.4%) were up to this value. This study found safety margins for genioplasty and chin bone grafting surgical techniques that adopt a 5-mm cut-off point. Further similar studies assessing other surgical methods and employing larger samples from different geographical origins may contribute to this field of investigation.

Accessory lingual mental foramen: A case report of a rare anatomic variation.

INTRODUCTION: The mandibular nerve and the mental foramen have occasionally shown variations in its anatomy. This report aims to present a case of lingual mental foramen recognised on three-dimensional cone beam computed tomographic imaging (CBCT). CASE REPORT: Routine Orthopantomogram (OPG) and CBCT images were evaluated to assess the status of impact third molars in a 31-year-old female who had visited the dental clinics in our institution. The OPG image failed to reveal any anatomic variation in the position of the mental foramen. On tracing the course of the mandibular canal in CBCT images, two foramina were traced at the region of premolar. One opened towards the buccal cortical plate at the normal position of the mental foramen and an accessory lingual mental foramen had an opening on the lingual cortical bone at the same level as the mental foramen. CONCLUSION: Understanding variations of the mental foramen is extremely essential in dentistry to carry out successful anaesthetic or surgical interventions and to avoid complications such as nerve damage or excessive bleeding.

Interexaminer agreement between two dental specialties for the detection of bifid mandibular canal and accessory mental foramen in cone-beam computed tomography / Concordancia inter-examinador entre dos especialidades odontológicas para la detección del canal mandibular bífido y foramen mental accesorio en tomografía computarizada de haz cónico

Introduction: The aim of this study was to assess the agreement between oral and maxillofacial radiologists (OMFR) and oral and maxillofacial surgeons (OMFS) for the detection of bifid mandibular canal (BMC) and accessory mental foramen (AMF) using cone-beam computed tomography (CBCT). Material and Methods: This retrospective study involved 22 examiners (11 OMFR and 11 OMFS) who independently assessed 30 CBCT volumes from patients (n = 60 hemi-mandibles) under preoperative radiographic evaluation for implant placement. The examiners scored the presence of BMC and AMF in each hemimandible. The interexaminer agreements were assessed using Fleiss' kappa statistics. Results: For intra-examiner agreement, 40% of the sample was reevaluated. The interexaminer agreement between OMFR and OMFS was slight (0.12) for the detection of BMC and fair (0.24) for AMF. The agreement among OMFR for detection of BMC was fair (0.22), and it was slight among OMFS (0.15). The agreement among OMFR for detection of AMF was substantial (0.61), and among OMFS it was fair (0.22). Agreements between OMFR and OMFS were slight for BMC and fair for AMF, independently of the years of experience. Intraexaminer agreement ranged from 60% to 90% among OMFR and from 55% to 90% among OMFS. Conclusion: A slight and a fair agreement between OMFR and OMFS was found for the detection of BMC and AMF, respectively. In general, OMFR obtained higher agreement among themselves, mainly for detection of AMF.

Introducción: El objetivo de este estudio fue evaluar la con-cordancia entre los radiólogos orales y maxilofaciales (ROMF) y los cirujanos orales y maxilofaciales (COMF) para la detección del canal mandibular bífido (CMB) y el foramen mentoniano accesorio (FMA) mediante tomografía computarizada de haz cónico. CBCT). Material y Métodos: Este estudio retrospectivo involucró a 22 examinadores (11 ROMF y 11 COMF) que evaluaron de forma independiente 30 volúmenes CBCT de pacientes (n = 60 hemimandíbulas) bajo evaluación radiográfica preoperatoria para la colocación de implantes. Los examinadores puntu-aron la presencia de CMB y FMA en cada hemimandíbula. Los acuerdos entre examinadores se evaluaron utilizando las estadísticas kappa de Fleiss. Resultados: Por concordancia intraexaminador se reeva-luó el 40% de la muestra. El acuerdo entre examinadores entre ROMF y COMF fue ligero (0,12) para la detección de CMB y regular (0,24) para FMA. La concordancia entre ROMF para la detección de CMB fue regular (0,22) y leve entre COMF (0,15). El acuerdo entre ROMF para la detección de FMA fue sustancial (0,61), y entre COMF fue justo (0,22). Los acuerdos entre ROMF y COMF fueron leves para CMB y justos para FMA, independientemente de los años de experiencia. La concordancia entre examinadores varió del 60 % al 90 % entre ROMF y del 55 % al 90 % entre COMF. Conclusión: Se encontró un acuerdo leve y justo entre ROMF y COMF para la detección de CMB y FMA, respec-tivamente. En general, se obtuvo mayor acuerdo entre ROMF, principalmente para la detección de FMA.

Structural Features of the Mental Foramen in a Saudi Subpopulation: A Retrospective CBCT Study.

INTRODUCTION: Accurate and precise knowledge about the position, size, and shape of the mental foramen (MF) are critical in avoiding procedural complications. The MF's anatomical features vary among different ethnic groups, and various radiographic techniques have been used to determine these variations. AIMS: To evaluate the MF's shape, vertical and horizontal positions, and distance from the border of the mandible. To evaluate the differences among genders as they pertain to the right and left sides of the mandible and research the bilateral symmetry regarding the same variables. MATERIALS AND METHODS: Cone beam computer tomography (CBCT) scans of 155 Saudi patients (69 males and 86 females) who visited the college of dentistry's clinics were obtained from the college database for this retrospective study. All the scans were analyzed by 3 calibrated examiners. The data collected was analyzed statistically, and results were obtained. RESULTS: The MF was located under the mandibular second premolar in 56.9% of cases, whereas in 26.9% of cases, it was located between the first and second mandibular premolar. The most prevalent position was below the level of the apices of the mandibular premolar teeth (87.2%). The round shape was most frequent (44.9%) compared to the H-oval (34.7%) and V-oval (20.4%). The V-oval shape was more frequent in males, while the H-oval shape was more frequent in females. The average distance from the center of the MF to the mandibular border was 14.03 ± 1.58 mm, with males exhibiting a greater distance than females. Overall, there were no significant differences between the bilateral symmetry and the right and left sides for all parameters. CONCLUSION: The most common position of the MF was under the root apex of the mandibular second premolar, with an average distance of about 14 mm from the border of the mandible. The position and shape of the MF were the same bilaterally in the majority of individuals.

Prevalence and morphometric analysis of double mental foramen and double mandibular foramen from digital panoramic radiographs / Prevalencia y análisis morfométrico de foramen mental y foramen mandibular dobles a través de radiografías panorámicas digitales

The morphological variations of the mental foramen (MF) and mandibular foramen (MBF) have been studied for several years, and the prevalence and morphometric characteristics of double and triple foramina have been reported. The objective of this study was to establish the prevalence of variations in the MF and MBF, and to carry out a morphometric analysis of a Chilean population using digital panoramic radiographs. The study included 927 radiographs; the observed prevalence of double MF was 2.58 %, while the prevalence of double MBF was 1.51 %. No cases of triple foramina were found. In men, double MF was found more frequently in the left hemiarch (64.28 % of cases), while in women it was more frequent in the right hemiarch (80 %). Double MBF was found more frequently in the right hemiarch in women (80 % of cases), while the distribution between left and right in men was even. The mean area, width and height of the double MF were 5.46 mm2, 2.77 mm and 2.57 mm respectively. The means of the same morphometric measurements in double MBF were 6.37 mm2, 2.27 mm and 3.19 mm respectively. In both foramina, statistically significant differences were only found between the height of the foramen and the age of the subjects, with the observation that the greater the subject's age, the smaller the height. Dental surgeons must take these anatomical variants into consideration in clinical and surgical actions; timely diagnosis by radiograph is important to avoid possible complications.

Las variaciones morfológicas del foramen mental (FM) y mandibular (FMB) han sido estudiadas durante varios años, reportándose su prevalencia y las características morfométricas de forámenes dobles y triples. El objetivo de este estudio fue establecer la prevalencia de variaciones de los FM y FMB y realizar un análisis morfométrico a través de radiografías panorámicas digitales de una muestra de población chilena. En el estudio se incluyeron 927 radiografías y se observó una prevalencia de FM doble de 2,58 %, mientras que la prevalencia de FMB doble fue de 1,51 %. No se encontraron casos de forámenes triples. En hombres, el FM doble se encontró mayoritariamente en la hemiarcada izquierda (64,28 % de los casos), mientras que en mujeres fue en la hemiarcada derecha (80% de los casos). Para el caso de los FMB dobles, en mujeres se presentó mayoritariamente en la hemiarcada derecha (80 % de los casos), mientras que en hombres fue equitativo en ambos lados. El promedio del área, ancho y alto de los FM dobles fue de 5,46 mm2, 2,77 mm y 2,57 mm, respectivamente. Asimismo, los promedios de estas medidas morfométricas para el FMB doble fueron 6,37 mm2, 2,27 mm y 3,19 mm, respectivamente. Para ambos forámenes sólo se encontraron diferencias estadísticamente significativas entre el alto y la edad de los sujetos, observando que, a mayor edad menor era el alto del foramen. Los cirujanos dentistas deben tener en consideración estas variantes anatómicas para la realización de distintas acciones clínicas y quirúrgicas, su diagnóstico radiográfico oportuno es importante para prevenir posibles complicaciones.

Localización anatómica del foramen mentoniano mediante tomografía computarizada cone-beam en una población de Chile: estudio observacional / Anatomical localization of the mental foramen using cone-beam computed tomography in a population in Chile: observational study

La ubicación del foramen mentoniano (FM) varía desde el canino hasta el primer molar. La confirmación de la ubicación del FM es fundamental para evitar lesiones nerviosas durante procedimientos odontológicos. La distancia del FM al diente adyacente se puede evaluar mediante tomografía computarizada cone beam (CBCT) de forma segura y precisa. El objetivo fue determinar la distancia promedio entre la cortical superior del FM y el ápice dentario más cercano. Se realizó un estudio descriptivo que midió la distancia en milímetros (mm) desde FM al ápice dentario más cercano de 99 exploraciones CBCT. La medición se realizó en un corte que intercepta el FM y el ápice adyacente. Se evaluaron un total de 99 casos (72 mujeres/ 27 hombres), con una edad promedio de 34,7 años, (rango de 18-73 años). La distancia promedio se ubicó a 3,22 mm del ápice dentario más cercano al FM, la distancia mínima encontrada fue de 0,81 mm y la máxima de 6,99 mm. Se relaciona con el segundo premolar en un 79 % de los casos, y primer premolar en un 17 %. El FM se ubica cercano a la zona de premolares, su localización puede variar en relación a los ápices de estos dientes. Este estudio confirma la importancia de ser cautelosos durante los tratamientos endodónticos y/o quirúrgicos, para prevenir lesiones nerviosas en relación a esta estructura anatómica.

The location of the mental foramen (MF) varies from the canine to the first molar. The confirmation of the location of the MF is essential to avoid nerve injuries during dental procedures. The distance from the MF to the adjacent tooth can be assessed by cone beam computed tomography (CBCT) safely and accurately. The objective was to determine the average distance between the upper cortex of the MF and the nearest dental apex. A descriptive study was carried out, where the distance in millimeters (mm) from MF to the nearest dental apex was measured in 99 CBCT exploration. The measurement was realized in a slice that intercepts the MF and the adjacent apex. A total of 99 cases were evaluated (72 women / 27 men), with an average age of 34.7 years (range of 18-73 years). The average distance was located at 3.22 mm from the nearest dental apex to MF, the minimum distance found was 0.81 mm and the maximum was 6.99 mm. It is related to the second premolar in 79 % of cases, and first premolar in 17 %. The MF is located close to the premolar area, its location can vary considerably in relation to the apices of these teeth. This study confirms the importance of being cautious during endodontic and / or surgical treatments to prevent nerve injuries in relation to this anatomical structure.

Clinical and anatomical study of foramen locations in jaw bones and adjacent structures.

This study aims to find and locate foramens exactly in maxilla and mandible in case of complications during surgeries.Computer topographic angiography (CTA) images of 120 cases were reviewed. The measurements were performed on coronal, sagittal and axial planes after the 3 dimension volume reconstruction. The distances among foramens, bony landmarks, teeth, and facial artery were all measured with the angles as adjustments.The incisive foramen (IF) was measured 20.55 ±â€Š2.81 mm to margo inferior of incisor, and 45.27 ±â€Š5.27 degree from the axial midline. The greater palatine foramen located 43.17 ±â€Š2.55 mm from the IF, while 21.08 ±â€Š3.75 degree from the midline in axial plane. The lesser palatine foramina located 44.56 ±â€Š5.74 mm from the IF and 20.05 ±â€Š3.59 degree to the midline. The Mandibular foramen (MBF) was 91.15 ±â€Š1.86 mm horizontally to the margo inferior of incisor. The angle that the MBF-margo inferior of incisor line made with the axial midline was 31.25 ±â€Š2.89 degree. The shortest horizontal distance from the mental foramen (MF) to the facial artery in sagittal plane was 21.90 ±â€Š1.86 mm, while it became 13.00 ±â€Š2.05 mm in coronary section. The horizontal distance from the MF to the margo inferior of incisor in sagittal plane was 22.04 ±â€Š3.22 mm. It turned out to be 25.78 ±â€Š5.23 mm between MF and mid-sagittal line in coronary section. The vertical distance was 25.20 ±â€Š3.06 mm from the upper margin of the second premolar to the MF.The foramens were clearly seen through CTA. Moreover, linear and angular measurements were presented, which makes it safer and wiser for surgeons to consider the biometric data before operations.

Variation in accessory mental foramen frequency and number in extant hominoids.

Nerves providing sensation to the lower face and jaw exit the mandibular canal via the mental foramen. In humans, there are many documented occurrences of additional foramina (accessory mental foramina, AMFs) on the lateral mandibular surface that may also contain nervous structures. There are large discrepancies in the literature regarding how often AMFs occur in humans, and investigations of non-human hominoid AMFs are rare. Consequently, the causes of interspecific diversity in this variable have not been explored. This project seeks to compare the frequency and number of AMFs between males and females, and among human regional groups and hominoid subspecies and species, and to investigate possible causal factors for any differences identified. No significant differences were found between males and females in any group. Gorillas and orangutans had the highest percentages of individuals with AMFs and the highest mean number of foramina, while modern humans and siamangs had the lowest figures for these variables. Significant differences (p < .05) were found for the mean number of foramina between most pairs of species. The results also showed that species with mandibles that are larger overall, have a larger area anterior to mental foramen, and a longer mandibular canal typically present more AMFs. The strongest correlation was found between the mean number of mental foramina and mandibular canal length. We suggest that these results provide preliminary support for the hypothesis that increasing mandibular canal length increases the likelihood that that nerves will ramify, leading to greater frequencies of accessory mental foramina.

Double mandibular canal and triple mental foramina: detection of multiple anatomical variations in a single patient.

Having complete information about a patient's mandibular canal and mental foramen is fundamental to performing safer procedures and avoiding intraoperative and postoperative complications. Cone beam computed tomography (CBCT) produces accurate images for the analysis of maxillomandibular bone structures and is widely used in dentistry. The aim of this study is to report a case of mandibular bifid canal associated with triple mental foramina that was revealed with CBCT images. A 45-year-old woman was referred for a CBCT scan of remaining bone quantity to assist in preoperative implant planning. The patient had reported problems related to anesthesia during extraction of the mandibular right second and third molars. Examination showed bilateral bifurcation of the mandibular canal, from the mandibular foramen to the gonial angle. In addition, exteriorization of the mandibular canal was noticed in 3 regions; that is, there were 3 distinct mental foramina. Clinicians must be aware of these anatomical variations in the mandibular region during dental procedures to avoid complications such as difficulty in obtaining anesthesia or postoperative sensory dysfunction.

Evaluation of bone texture imaging parameters on panoramic radiographs of patients with Sheehan's syndrome: a STROBE-compliant case-control study.

Sheehan's syndrome (SHS) is a rare condition related to the risk of osteoporosis and evaluation of bone texture imaging features on panoramic radiographs would be suitable for this condition, which was the aim of the present study. Fractal dimension, lacunarity, and trabecular morphologic aspects were significantly altered in these patients. INTRODUCTION: SHS is an important public health problem particularly in developing countries. It is characterized as postpartum hypopituitarism secondary to obstetric complications-related ischemic pituitary necrosis that shows significant systemic metabolic repercussions. Thus, this study aimed to evaluate bone texture parameters in digital panoramic radiographs of patients with SHS. METHODS: A case-control study was conducted with 30 SHS patients from an Endocrinology and Diabetology Service of reference in Brazil, and 30 age- and sex-matched healthy controls. A custom computer program measured fractal dimension, lacunarity, and some morphologic features in the following mandibular regions of interest (50 × 50 pixels): below the mental foramen (F1), between the first and second molars (M1), and at the center of the mandibular ramus (R1). RESULTS: The fractal analysis showed a statistically significant difference between the studied groups in all regions of interest. The fractal dimension in F1 (p = 0.016), M1 (p = 0.043), and R1 (p = 0.028) was significantly lower in SHS group, as well as lacunarity in R1 (p = 0.008). Additionally, several morphologic features were statistically significant in the SHS group (p < 0.05). CONCLUSION: Therefore, individuals with SHS showed altered imaging texture parameters on panoramic radiographs, which reflect a smaller spatial organization of the bone trabeculae and, possibly, a state of reduced mineral bone density.

Prevalence of Accessory Mental Foramina: A Study of 4,000 CBCT Scans.

The presence of accessory mental foramina (AMF) is an important consideration prior to any dental implant and surgical treatment to avoid injury to the neurovascular bundle and subsequent postoperative complications. The aim of this retrospective study was to determine the prevalence of AMF from a substantially large sample of the Australian population. The cone beam computed tomography (CBCT) scans of 4,000 patients showing the mandible were examined. All mental foramen (MF) were visualized and no cases were excluded. The number of MF/AMF, sex, and age were recorded. The prevalence of AMF was found to be 6.4% (254 patients) in this study. Twelve patients exhibited bilateral AMF, and 11 had three mental foramina on one side. One case had a total of five mental foramina with three on the right and two on the left side. No significant sex preference was discovered. This is the largest study ever to be conducted to evaluate the prevalence of AMF. With nearly one in 15 individuals found to have AMF, clinicians must be acutely aware of this anatomical variation and treatment plan for each case accordingly. Clin. Anat. 32:1048-1052, 2019. © 2019 Wiley Periodicals, Inc.

Ubicación de agujeros mentonianos y sus accesorios en adultos peruanos / Location of the Mental Foramen and Their Accessories in Peruvians Adults

Resumen El objetivo del estudio fue determinar la ubicación de los agujeros mentonianos, sus accesorios y las relaciones con los rebordes alveolares y basales en adultos peruanos. Se realizó un estudio descriptivo, transversal y retrospectivo. La muestra estuvo conformada por 100 tomografías computarizadas cone beam de pacientes entre 20 y 55 años de edad que acudieron a la clínica de la Facultad de Odontología de la Universidad Nacional Mayor de San Marcos. Se consideraron tomografías de pacientes dentados mandibulares tomadas durante el 2015, las cuales se clasificaron de acuerdo a edad y sexo, identificando en ellas la ubicación de los agujeros mentonianos y agujeros accesorios en relación con una pieza dentaria inferior, según la clasificación de Al Jasser-Nwoku. La distancia del agujero mentoniano en el lado izquierdo al reborde alveolar fue de una media de 12,62 mm y en el lado derecho tuvo una media de 12,90 mm y la distancia con respecto al reborde mandibular en el lado izquierdo mostró una media de 14,14 mm y en el lado derecho fue de 13,91mm. La relación del agujero mentoniano con respecto a los dientes estuvo ubicado por debajo de la 2da premolar inferior. El 14% presentó agujero accesorio, predominando la posición 4 (altura de la segunda premolar).

Abstract The aim of the present study was the determine the location of the mental foramen and accessories, their relationships with the alveolar and basal rims found in Peruvians adults. A descriptive, transverse and retrospective study was carried out. The sample was composed of 100 cone beam CT scans of patients, between the ages of 20 to 55 years of age, these patients were attended at the clinic of the Faculty of Dentistry of Mayor National University of San Marcos UNMSM. Were considered tomograms of mandibular dentate patients taken during 2015, classified according to age and sex, identifying in them the location of the mental foramen and accesories in relation to a lower tooth, according to the classification of Al Jasser- Nwoku.The distance of the mental foramen on the left side to the alveolar ridge had an average of 12.62 mm and on the right side it had a mean of 12.90 mm and the distance from the mandibular ridge on the left side showed an average of 14.14 mm and on the right side was 13.91 mm. The relationship of the mental foramen to the teeth was located below the second mandibular premolar. The 14% presented accessory hole, predominating position 4 (at the level of the second premolar).