A CBCT aided assessment for the location of mental foramen and the emergence pattern of mental nerve in different dentition status of the Saudi Arabian population / Avaliação auxiliada por CBCT para a localização do forame mentual e o padrão de emergência do nervo mentual em diferentes estados de dentição da população da Arábia Saudita

Objective: The anatomy of mental foramen (MF) is a noteworthy landmark during any surgical procedures in the inter-foraminal region. Thus, the study aims at evaluating the location of MF and the emergence pattern of MN in three status of dentition in Saudi Arabian population. Material and Methods: In a prospective study, we have analyzed 240 cone beam computed tomography (CBCT) for the location of MF and the emergence pattern of MN. The study comprising three groups, namely dentulous, partially edentulous and edentulous, each having eighty CBCT scans. We presented the data in percentages. The chi-square and McNemar's test were used for testing association and pair-wise analysis, respectively. Results: The most common location of MF was below the apex of the second premolar irrespective of dentition status, with 54.2% in right and 60% in the left side of the jaw. Among the dentition status, left side of the mandible has shown significant variation for the location of MF, whereas gender and age showed variation in the right side. Anterior loop (AL) (Type-III) the emergence pattern of MN was the highest in all dentition status, with 51.7% in right and 53.8% on the left side. The variation in the emergence pattern of MN in terms of gender and side of the jaw was statistically significant. Conclusion: In the Saudi Arabian population, the apex of second premolar and type III/AL was the most prevalent location of MF and the emergence pattern of MN, respectively (AU)

Introdução: Objetivo: A anatomia do forame mentual (FM) é de grande importância durante qualquer procedimento cirúrgico na região inter-foraminal. Por tanto, como objetivo o estudo visa avaliar a localização do FM e o padrão de emergência do NM em três estados de dentição na população da Arábia Saudita. Material e Métodos: Em um estudo prospectivo, analisamos 240 tomografias computadorizadas de feixe cônico (TCFC) para a localização do FM e o padrão de emergência de NM. O estudo compreendeu três grupos, a saber, dentados, parcialmente edêntulos e edêntulos, cada um com oitenta imagens de TCFC. Apresentamos os dados em porcentagens. O teste do Qui-quadrado e o teste de McNemar foram usados para testar associação e análise de pares, respectivamente. Resultados: A localização mais comum do FM foi abaixo do ápice do segundo pré-molar independente do estado da dentição, com 54,2% no lado direito e 60% no lado esquerdo da mandíbula. Dentre as condições da dentição, o lado esquerdo da mandíbula apresentou variação significativa para a localização dos FM, enquanto o sexo e a idade mostraram variação no lado direito. O padrão de emergência (Tipo III) da alça anterior (AL) do NM foi o mais alto em todos os estados de dentição, com 51,7% no lado direito e 53,8% no lado esquerdo. A variação no padrão de emergência de NM em termos de gênero e lado da mandíbula foi estatisticamente significativa. Conclusão: Na população da Arábia Saudita, o ápice do segundo pré-molar e tipo III / AL foi a localização mais prevalente de FM e o padrão de emergência de NM, respectivamente. (AU)

Características anatómicas del asa mandibular evaluada por tomografía computarizada de haz cónico / Anatomical characteristics of the mandibular loop evaluated by cone beam computed tomography

Introducción: El nervio dentario inferior es una estructura anatómica de la mandíbula, la cual presenta variaciones como el asa mandibular, ambas estructuras están relacionadas con iatrogenias con tratamientos como cirugías orales, regeneraciones óseas e implantes. El objetivo del presente estudio es evaluar las características del asa mandibular y el agujero mentoniano utilizando tomografía axial computarizada de haz cónico (CBCT) en pacientes del Postgrado de Periodoncia de la Universidad Autónoma de Nuevo León. Material y métodos: Se analizaron un total de 110 CBCT, de los cuales 61 entraron al estudio cumpliendo con los criterios de inclusión, se realizaron cortes transversales utilizando el software On Demand® para identifi car y medir el asa mandibular y localizar la posición del agujero mentoniano de ambos lados separando los grupos por género. Resultados: La prevalencia del asa mandibular fue de 32.8% de 61 CBCT que se analizaron, se observó más comúnmente en hombres y de manera bilateral, y cuando fue unilateral sólo se encontró en el lado derecho, la longitud promedio fue de 6 ± 1 mm. El agujero mentoniano se detectó en mayor porcentaje apical al segundo premolar inferior con un diámetro promedio de 3.5 ± 0.5 mm, alejándose de la raíz del diente adyacente en un promedio de 6 ± 1 mm y del borde de la mandíbula 12.5 mm ± 0.5 mm. Conclusión: Es de suma importancia identifi car las características anatómicas del asa mandibular y localizar la posición del agujero mentoniano durante la planifi cación del tratamiento para evitar complicaciones durante y después del acto quirúrgico (AU)

Introduction: The inferior dental nerve is an anatomical structure of the mandible which presents variations such as the anterior loop, both structures are related to iatrogenies with treatments such as oral surgeries, bone regenerations and implants. The aim of the present study is to evaluate the characteristics of the anterior loop and the mental foramen using cone beam computed tomography (CBCT) in patients of the Graduate Periodontics Program, School of Dentistry, Universidad Autónoma de Nuevo León. Material and methods: 110 CBCT were analyzed of which 61 entered the study fulfi lling the inclusion criteria, cross sections were made using the On Demand® software to identify and measure the anterior loop and locate the position of the mental foramen both sides separating our groups by gender. Results: The prevalence of the anterior loop was 32.8% of 61 CBCT that were analyzed, it was found more commonly in men and bilaterally, and when it was unilateral only found on the right side, the average length was 6 ± 1 mm. The mental hole was found in greater percentage apical to the second lower premolar with an average diameter of 3.5 ± 0.5 mm, moving away from the root of the adjacent tooth by an average of 6 ± 1 mm and from the edge of the mandible 12.5 ± 0.5 mm. Conclusion: It is very important to locate these anatomical structures during treatment planning and avoid complications during and after the surgical act (AU)

A Radiographic Study on the Visualization of the Anterior Loop in Darbhanga Population - An Original Research

Introduction: Knowledge of alveolar loop of inferior alveolarcanal is important to prevent any post operative complicationsafter mandibular surgery or any prosthesis placement inmandible parasymphysis region. The aim of this study wasto visualize anterior loop in Darbhanga (Bihar) populationon digital orthopantomogram radiographs and the objectivewas to evaluate the frequency of anterior loop in different agegroups on digital orthopantomogram radiographs.Material and Methods: The study was done in the Departmentof Oral Medicine and Radiology and Department of PublicHealth Dentistry. A total of 303 panoramic radiographs wereexamined by a single radiologist. Anterior loop was examinedin all 303 radiographs. The collected data were subsequentlyprocessed and analyzed using SPSS statistical package version17.Results: We found that anterior loop was visible in 39.6%of population. Anterior loop was most commonly seen inyounger age group. As the age advanced visibility of anteriorloop was reduced.Conclusion: In the present study, a total of 606 sites wereexamined on radiographs. Out of 156 male subjects, anteriorloop was visible in 68 subjects and out of 147 female subjects,anterior loop was visible in 52 subjects only. Visibility ofanterior loop in subjects aged 50 or more than 50 years wasseen in only 9 subjects.

3-dimensional reconstruction of mandibular canal at the interforaminal region using micro-computed tomography in Korean

PURPOSE: The purpose of this study was to identify the complex course of the mandibular canal using 3D reconstruction of microCT images and to provide the diagram for clinicians to help them understand at the interforaminal region in Korean. MATERIALS AND METHODS: Twenty-six hemimandibles obtained from cadavers were examined using microCT, and the images were reconstructed. At both the midpoint of mental foramen and the tip of anterior loop, the bucco-lingual position, the height from the mandibular inferior border, the horizontal distance between two points, and position relative to tooth site on the mandibular canal were measured. The angle that the mental canal diverges from the mandibular canal was measured in posteriorsuperior and lateral-superior direction. RESULTS: The buccal distance from the mandibular canal was significantly much shorter than lingual distance at both the mental foramen and the tip of anterior loop. The mandibular canal at the tip of anterior loop was significantly located closer to buccal side and higher than at the mental foramen. And the mental canal most commonly diverged from the mandibular canal below the first premolar by approximately 50° posterior-superior and 41° lateral-superior direction, which had with a mean length of 5.19 mm in front of the mental foramen, and exited to the mental foramen below the second premolar. CONCLUSION: These results suggest that it could form a hazardous tetrahedron space at the interforaminal region, thus, the clinician need to pay attention to the width of a premolar tooth from the mental foramen during dental implant placement.

Radiographic evaluation of anatomical variables in maxilla and mandible in relation to dental implant placement.

Introduction: Oral rehabilitation using implants is rapidly replacing tooth supported prostheses. The success of implants is largely dependent on the quality and quantity of alveolar bone. In this study, we assessed the location of limiting anatomical structures and the amount of alveolar bone available for implant placement. Materials and Method: Six hundred digital panoramic radiographs (300 males and 300 females) of dentate patients aged between 15-60 years were selected from the archives. The radiographs were subdivided into 3 groups with age interval of 15 years. Then the location of mental foramen, anterior loop, mandibular canal and maxillary sinus was determined. The amount of bone available was measured in both maxilla and mandible in the premolar and molar regions. Results: The mental foramen was most commonly located at the apex of the second premolar in both the genders. The anterior loop was more readily visible in the younger age group. The amount of bone available in the premolar and molar region of the mandible is nearly the same, while more bone is available in the premolar region of the maxilla. Conclusion: The location and morphology of anatomical structures of the jaws vary not only in different populations but also within the same population. The amount of bone available also showed variations in the same population and in the same individual on the right and left sides. The limiting anatomical structures govern the amount of bone available for possible implant placement.

Variaciones del canal mandibular con importancia clínica: reporte de caso / Anatomical variations of mandibular canal with clinical significance: case report

El canal mandibular y su contenido tienen un papel importante en el campo de la cirugía maxilofacial. Este puede presentar variaciones anatómicas, las cuales son clínicamente relevantes principalmente en los procedimientos de implantología. Su desconocimiento ha sido relacionado con complicaciones en la realización de procedimientos quirúrgicos y de anestesia en la práctica dental y maxilofacial. A razón de esto se presenta el reporte de caso de canal mental accesorio y bucle anterior del nervio alveolar inferior.

The mandibular canal and its contents have an important role in the field of maxillofacial surgery. This can present anatomical variations, which are clinically relevant mainly in implant procedures. Lack of knowledge regarding these variations has been linked to complications in carrying out surgical procedures and anesthesia in dental and maxillofacial practice. Therefore, we report this case of accessory mental canal and mental anterior loop.

Morphological assessment of the anterior loop of the mandibular canal in Koreans / 대한해부학회지

The mandibular canal divides into the mental and incisive canals at the premolar region, forms the anterior loop which crosses anterior to the mental foramen, and turns back to reach the mental foramen. The aim of this study was to elucidate the general anatomical structure of the anterior loop of the mandibular canal using morphometry. Twenty-six hemimandibles from 19 cadavers (16 males, 3 females; mean age at death, 54.4 years) were studied by meticulous dissection with the aid of a surgical microscope. The location of the anterior loop, the diameters of the mandibular, mental, and incisive canals, and their distances from bony landmarks were measured using digital calipers. The anterior loop of the mandibular canal was located 3.05+/-1.15 mm (mean+/-SD) anterior to the anterior margin of the mental foramen and 2.72+/-1.41 mm inferior to the superior margin of the mental foramen, and was 4.34+/-1.46 mm long. The diameters of the mandibular, mental, and incisive canals were 2.8+/-0.49, 2.63+/-0.64, and 2.22+/-0.59 mm, respectively. The distances between the inferior border of the mandible and each of these canals were 7.82+/-1.52, 10.11+/-1.27, and 9.08+/-1.66 mm, respectively. The anterior loop of the mandibular canal was located a mean of 3.1 mm anterior and 2.7 mm inferior to the mental foramen, and continued upward and backward into the mental canal, and forward into the incisive canal. These detailed morphological features of the anterior loop of the mandibular canal represent useful practical anatomical knowledge regarding the interforaminal region.

wPosition of mandibular canal determined by Cone-beam computed tomography examination in 83 Chinese people / 实用医学杂志

Objective To analyse the location of the mandibular canal,providing the theoretical basis for implanting and bone grafting. Methods Mandibular data of 83 Chinese people obtained by cone-beam computed tomography examination were collected. Results The distance from the mandibular canal to mandibular buccal wall was (5.32 ± 1.29)~(7.24 ± 1.29) mm. And the average distance from mandibular canal to mandibular lingual wall or inferior margin were respectively (3.43 ± .99) ~ (3.93 ± 1.17) mm and (8.81 ± 1.90) ~ (10.02 ± 2.19) mm. Significant differences between males and females were found in groups. The anterior loop was observed in 70.9%of all sides. The accessory mental foramen was observed in 10.84% of all sides. Conclusion For the remarkable mutation of the location of the mandibular canal in Chinese people, clinicians should be careful before implant or bone surgery procedures to minimize the risk of inferior alveolar nerve injury.

Observation of the anterior loop and mental foramen of the mandibular canal using cone beam computed tomography / 대한구강악안면방사선학회지

PURPOSE : To evaluate the anteroposterior length and buccal angle of the anterior loop, and the size and location of the mental foramen using cone beam computed tomography (CBCT). MATERIALS AND METHODS : 100 CBCT images from 87 adults (43 males and 44 females) ranging in age from 20 to 73 years (average 50 years) with edentulous ridge of the mandibular premolar region were obtained. Axial, sagittal, coronal images were reconstructed from Dental and Block Images of CBCT. The anteroposterior length, shape and buccal angle of the anterior loop, and the size and location of the mental foramen were calculated from reconstructed images of axial, sagittal and coronal CBCT. RESULTS : The anteroposterior length and buccal angle of the mental canal was 4.0+/-1.2 mm, 37.8+/-11.6 degrees respectively. The loop type with straight course was the most common shape of the mental canal. The location of the mental foramen below the apex of the lower second premolar (78%) was the most common. The maximum size of the mental foramen was 4.6+/-1.0 mm in width and 3.0+/-0.6 mm in height. The inner size of the mental canal was 2.6+/-0.6 mm in width and 2.1mm+/-0.4 mm in height. CONCLUSION : CBCT is useful to evaluate the anterior loop and mental foramen of the mandibular canal. Safe guideline of 4 mm from the most anterior point of the mental foramen is recommended for implant and surgical treatment.