CBCT study of root apices distance to mandibular canal in peruvian population

The purpose of this study was to compare the average distances from the root apices of the first molars, second molars, and second premolars to the mandibular canal according to sex in the Peruvian population using cone-beam computed tomography (CBCT). Eighty CBCT scans of Peruvian patients aged from 15-80 years were examined. After locating the mandibular canal, measurements of the vertical distances from the mandibular canal to the apices of the second premolars, as well as the first molars and second molars, were made. For the statistical analysis, Student's t test was used for both paired and unpaired samples, with a significance level of p0.05) between the distances from the apices of the second premolars and the first and second molars to the mandibular canal. However, for the second premolars and second molars on the left side, the values were higher, with averages of 5.52mm and 3.75mm, respectively. The mesial roots of the second molars were closer to the mandibular canal. In addition, women showed shorter distances than men.

El propósito de este estudio fue comparar las distancias promedio desde los ápices radiculares de primeros molares, segundos molares y segundos premolares al canal mandibular según sexo en la población peruana mediante tomografía computarizada de haz cónico (TCHC). Se examinaron 80 tomografías CBCT de pacientes peruanos con edades comprendidas entre los 15 y 80 años. Luego de ubicar el canal mandibular, se realizaron mediciones de las distancias verticales desde el canal mandibular hasta el ápice de los segundos premolares mandibulares, así como de los primeros molares y segundos molares. Para el análisis estadístico se utilizó la prueba t de Student para muestras pareadas y no pareadas con un nivel de significación de p0.05) entre las distancias desde los ápices de los segundos premolares mandibulares y los primeros y segundos molares al canal mandibular. Sin embargo, para los segundos premolares y segundos molares en el lado izquierdo, los valores fueron más altos con un promedio de 5,52mm y 3,75mm, respectivamente. Las raíces mesiales de los segundos molares estaban más cerca del canal mandibular. Además, las mujeres mostraron distancias más cortas que los hombres.

The anatomical limit and strategies for molar movement during orthodontic treatment / 口腔疾病防治

@#In many cases, tooth movement over a considerable distance is needed to meet the major goal of orthodontic treatment, which has always been to correct malocclusion and improve the facial profile in patients with skeletal malocclusion. However, tooth movement over a considerable distance also carries risks of dehiscence, fenestration, root exposure, and so forth. The reason lies in neglecting many limits for tooth movement, especially anatomical characteristics. This review focuses on structural limits for orthodontic molar movement, such as the alveolar cortex, the maxillary sinus floor, and the mandibular canal. In addition, we set the strategy in clinical orthodontics. For the alveolar cortex and the mandibular canal, orthodontists are recommended to move the root away from the cortical bone initially and formulate personalized molar movement plans according to clinical examination and cone-beam computed tomography (CBCT) and other imaging examinations. First, the molar root was controlled by torque away from the bone plate, and then, the molar movement amount and direction were controlled according to the personalized movement path. In regard to the maxillary sinus floor, light and continuous forces and scientific biomechanics are suitable for bodily tooth movement. In summary, better therapeutic efficacy and long-term stabilization could be achieved by circumventing the limits and risks caused by anatomical limitations and characteristics.

Panoramic radiography and cone-beam computed tomography to measure distances between root apexes and anatomical structures / Radiografía panorámica y tomografía computarizada de haz cónico para medir distancias entre ápices radiculares y estructuras anatómicas

Aim: To compare the accuracy of the panoramic radiography with cone-beam computed tomography (CBCT) scans in measuring the distances between root apexes and the adjacent anatomical structures including the maxillary sinus and the mandibular canal. Material and Methods: A total of 200 CBCT scans (100 maxillary and 100 mandibular) from patients who also had corresponding panoramic radiography were selected. Linear measurements (in mm) presenting centralized image were made between the apexes of the maxillary teeth and the inferior wall of the maxillary sinus, and between the apexes of the mandibular teeth and the superior border of the mandibular canal by using specific software for panoramic radiography and the measurements on the coronal sections in CBCT scans. Data were submitted to inferential statistical analysis and Student's t-test for comparison between measurements. Results: CBCT scans were significantly more accurate than panoramic radiography to measure the distances between the apexes of the maxillary teeth and the inferior wall of the maxillary sinus (p<0.05) and between the apexes of the mandibular teeth and the superior border of the mandibular canal or mental foramen (p<0.05). Conclusion: CBCT scans present more accurate measurements than panoramic radiography.

Objetivo: Comparar la precisión de la radiografía panorámica con las exploraciones de la tomografía computarizada dental de haz en cónico (CBCT) para medir las distancias entre los vértices radiculares y las estructuras anatómicas adyacentes, incluidos el seno maxilar y el canal mandibular. Material y Métodos: Se seleccionaron un total de 200 tomografías CBCT (100 maxilares y 100 mandibulares) de pacientes que además tenían la correspondiente radiografía panorámica. Se realizaron mediciones lineales (en mm) que presentaban imagen centralizada entre los ápices de los dientes maxilares y la pared inferior del seno maxilar, y entre los ápices de los dientes mandibulares y el borde superior del canal mandibular mediante software específico para radiografía panorámica. y las mediciones en las secciones coronales en escaneos CBCT. Los datos se sometieron a análisis estadístico inferencial y prueba t de Student para comparación entre mediciones. Resultados: Las exploraciones CBCT fueron significativamente más precisas que la radiografía panorámica para medir las distancias entre los ápices de los dientes maxilares y la pared inferior del seno maxilar (p<0,05) y entre los ápices de los dientes mandibulares y el borde superior de los dientes mandibulares. canal o agujero mentoniano (p<0.05). Conclusión: Las exploraciones CBCT presentan mediciones más precisas que la radiografía panorámica.

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.

Análisis comparativo de la visualización del canal mandibular mediante tomografía computarizada cone beam en humanos / Comparative analysis of the visualization of the mandibular canal by cone beam computed tomography in humans

RESUMEN: Una de las estructuras de mayor interés en la región maxilofacial es el canal mandibular, donde su preservación optimiza el éxito de los procedimientos clínicos. Por su disposición al interior de la mandíbula, la visualización in vivo requiere el uso de técnicas radiográficas, entre las que destaca el Cone Beam CT (CBCT). El objetivo de este trabajo es comparar la visualización del canal mandibular humano mediante imágenes en CBCT con distintos observadores y programas de radiación. Mediante imágenes generadas con CBCT en mandíbulas secas con distintos programas de adquisición, se obtuvieron cortes coronales en los sectores anterior, medio y posterior del canal mandibular, con un total 240 mediciones, las que incluyeron dos tamaños de voxel y dos dosis de radiación distintos. Cada una de las imágenes fue evaluada por un Cirujano Dentista, Máster en Anatomía y Especialista en radiología Máxilofacial. Se obtuvieron porcentajes de visualización según observador para cada programa de adquisición de imágenes. La prueba de Q de Cochran arrojó diferencias entre los observadores (p0,05). El grado de experticia del observador influye en la visualización y su precisión. A su vez, utilizar un programa de adquisición de imagen con distinto voxel y/o dosis no afecta a la visualización, siendo esta dependiente de la anatomía propia de la estructura. Podría utilizarse un protocolo con menor radiación para el usuario cumpliendo con la premisa ALARA (As Low As Reasonably Achievable).

SUMMARY: One of the structures of greatest interest in the maxillofacial region is the mandibular canal, where its preservation optimizes the success of clinical procedures. Due to its disposition inside the mandible, in vivo visualization requires the use of radiographic techniques, among which the Cone Beam CT (CBCT) stands out. The objective of this work is to compare the visualization of the human mandibular canal by means of CBCT images with different observers and radiation programs. Using images generated with CBCT in dry mandibles with different acquisition programs, coronal slices were obtained in the anterior, middle and posterior sectors of the mandibular canal, with a total of 240 measurements, which included two voxel sizes and two doses different radiation sources. Each of the images was evaluated by a Dentist, an Anatomy Master's degree and a specialist in Oral & Maxillofacial Radiology. Percentages of visualization according to observer were obtained for each image acquisition program. The Cochran Q test yielded differences between the observers (p 0.05). The degree of expertise of the observer influences the visualization and its precision. In turn, using an image acquisition program with a different voxel/radiation dose not affect the visualization, since it depends on the anatomy of the structure itself. A protocol with less radiation could be used in patients complying with the ALARA ("As Low As Reasonably Achievable") premise.

Imaging study of the mandibular forward canal in adults based on cone beam CT / 口腔疾病防治

Objective @#To explore the imaging characteristics of the mandibular nerve canal in adults to provide a reference for clinical mandibular surgery.@*Methods@# One thousand adult patients in Guiyang Stomatological Hospital from January 2018 to January 2021 were randomly selected. Cone beam CT (CBCT) was used to observe the anterior mandibular canal and other branches, and the incidence of anterior canal in the mandibular ramus area, posterior molar area and molar area and the distance to each point of the mandible were measured.@*Results@#Of the 901 patients (1 802 sides) included in the study, 386 patients (42.84%) found branches of the mandibular canal, and 182 patients (97 males and 85 females) found the Anterograde Canal 20.20% (182/901). In total, 225 mandibles were found to have anterior canals. There were 101 cases of left mandible and 124 cases of right mandible. The forward canal mainly occurred in the molar area, the molar posterior area and the ascending branch area, and the ascending branch area was the best starting point of the forward canal and the molar stopping point (P < 0.05). The average length of the forward canal (L1) was (10.364 ± 3.833) mm, the average height of the forward canal to the main trunk of the mandibular nerve (L2-RRB) was (3.623 ± 2.035) mm, and the average height of the forward canal to the crest of the alveolar ridL3 (l3) was (9.280 ± 3.240) mm.@*Conclusion@#Mandibular nerve canal branches are common, and there were no differences in male, female and lateral distribution. In this study, the incidence of mandibular anterior canal was the highest, and it often occurred in the molar area.

Assessment of the relationship of the distance between mandibular first and second molars with the inferior alveolar canal and cortical bone plate in an Egyptian subpopulation: a CBCT study

Abstract: The aim of the current cone beam computed tomography (CBCT) study was to evaluate the proximity of mandibular first and second molar roots to the inferior alveolar canal (IAC) and mandibular cortex in an Egyptian subpopulation. Scans of 120 patients (480 molars, 960 roots) were obtained from the College of Dentistry database at the Suez Canal University, Egypt. Buccal and lingual bone plates and root thickness were measured at the specified resected root end 3 mm from the radiographic apex, and so was the proximity of the root apices to the IAC. Measurements of the right and left mandibular first and second molars were recorded for each root. Three examiners performed the measurements separately. ANOVA was used to compare the different roots. Bonferroni's post-hoc test was used for pair-wise comparisons when ANOVA was significant. The significance level was set at p ≤ 0.05. The findings displayed a closer proximity of the mandibular second molar apices to the IAC, as compared to the mandibular first molars. The mesial roots were at a shorter distance than the distal ones. Moreover, the mandibular second molars revealed the thickest total bone width including the root. So, it is beneficial for endodontists to be aware of the relation of the mandibular first and second molars to the surrounding cortical bone plates and the IAC before starting either nonsurgical or surgical endodontic treatment.

The usage of the terms mandibular canal, inferior alveolar canal, and inferior dental canal in the academia: a bibliometric analysis / El uso de los términos canal mandibular, canal alveolar inferior y canal dental inferior en la academia: un análisis bibliométrico

SUMMARY: A recent study found that the mandibular canal might be preferably called the inferior alveolar canal in recent publication years, certain journal categories, countries and departments with which the authors were affiliated. The canal can also be called the inferior dental canal that was not included in that study. This bibliometric analysis was conducted to evaluate the entire relevant literature, and to investigate if inferior alveolar canal was trending over the years. The Web of Science Core Collection electronic database was searched to identify publications exclusively mentioning mandibular canal, inferior alveolar canal, inferior dental canal, and publications mentioning them in combinations. Publication year, country of contributing authors, journal category, journal title, and citation count were recorded for the resultant publications. There were 1152 publications analyzed. Mandibular canal has always been the dominating term since the 1990s, whereas inferior alveolar canal seemed to become slightly more popular in the 2010s than in the past. Journals from dentistry, surgery, radiology, anatomy, and medicine all showed a preference towards mandibular canal. Leading dental surgery journals had a higher ratio of inferior alveolar canal usage than their dental radiology counterparts. Top 20 countries showed a preference towards mandibular canal except Saudi Arabia, which had 57.7 % of publications using inferior alveolar canal exclusively. Publications mentioning mandibular canal, inferior alveolar canal, and inferior dental canal did not differ in averaged citation count. The term mandibular canal was still dominating in all academic fields. The term inferior alveolar canal showed increased usage in the 2010s without an increasing trend. The argumentation of renaming mandibular canal as inferior alveolar canal has yet to accumulate considerable traction.

RESUMEN: Un estudio reciente encontró que el canal mandibular ha sido llamado en los últimos, canal alveolar inferior en ciertas categorías de revistas, países y departamentos con algunos autores asociadas a estas. El canal también se puede denominar canal dental inferior término que no se incluyó en ese estudio. Este análisis bibliométrico se realizó para evaluar la literatura relevante e investigar la frecuencia del uso de canal alveolar inferior en el tiempo. Se buscó en la base de datos electrónica de Web of Science Core Collection para identificar publicaciones que mencionan exclusivamente canal mandibular, canal alveolar inferior, canal dental inferior y publicaciones que las mencionan en combinaciones. El año de publicación, el país de los autores contribuyentes, la categoría de la revista, el título de la revista y el recuento de citas se registraron para las publicaciones resultantes. Se analizaron 1152 publicaciones. Desde la década de 1990, canal mandibular siempre ha sido el término predominante, mientras que canal alveolar inferior pareció volverse algo más popular en la década de 2010. Las revistas de odontología, cirugía, radiología, anatomía y medicina mostraron una preferencia por canal mandibular. Las principales revistas de cirugía dental tenían una proporción más alta de uso de canal alveolar inferior que sus contrapartes de radiología dental. Los principales 20 países mostraron una preferencia por canal mandibular, excepto Arabia Saudita, que tenía un 57,7 % de las publicaciones que usaban exclusivamente canal alveolar inferior. Las publicaciones que mencionan canal mandibular, canal alveolar inferior e canal dental inferior no difirieron en el recuento promedio de citas. El término canal mandibular todavía predomina en todos los campos académicos. El término canal alveolar inferior mostró un mayor uso en la década de 2010 sin una tendencia creciente, sin embargo el argumento de cambiar el nombre de canal mandibular a canal alveolar inferior en el futuro deberá ser ratificado.

Análisis comparativo de la biometría del canal mandibular mediante disección anatómica y tomografía computarizada cone beam en humanos / Comparative analysis of the biometry of the mandibular canal by anatomical dissection and cone beam computed tomography in humans

El canal mandibular es una estructura de especial interés considerando que es vital su preservación durante actos clínicos. Por encontrarse al interior del hueso requiere un estudio in vivo mediante el uso rayos X, involucrando técnicas entre las que destaca la TC Cone Beam (TCCB). El objetivo de este trabajo es comparar la biometría del canal mandibular humano obtenida en la disección anatómica con la morfometría de las imágenes generadas en TCCB. A partir de cortes coronales realizados en los sectores anterior, medio y posterior del canal mandibular en mandíbulas secas, y mediante imágenes generadas en la TCCB, se obtuvieron 216 mediciones en cada una de técnicas aplicadas. Las mediciones lineales del canal mandibular se efectuaron utilizando marcadores radiopacos que fueron dispuestos en relación a las paredes vecinas que corresponden a las corticales alveolar/residual, basal, interna y externa. Se midió el diámetro vertical y transversal del canal, junto con las distancias entre la cortical alveolar/residual y basal, y entre la cortical interna y externa. Se obtuvieron los valores promedio de cada una de las mediciones lineales, tanto de la biometría en la mandíbula seca como de la morfometría realizada en la TCCB. Luego se determinó las diferencias estadísticas de cada medición (L1-L6 y D1-D2) entre ambas técnicas, utilizando la prueba de correlación de Pearson, donde se obtuvo una correlación positiva muy alta (p›0,987). Adicionalmente se determinó que las mediciones no se ven afectadas por el sector del canal analizado (p›0,987). En las mediciones realizadas L1-L6 y D1-D2, no se encontraron diferencias significativas entre la biometría con respecto a las medidas de morfometría hechas en las imágenes de la TCCB. Las medidas L4 y L5 son las que ofrecen menor diferencias porcentuales con otras investigaciones, debido a una menor absorción de las corticales involucradas.

The mandibular canal is a structure of special interest, considering that its preservation during clinical procedures is vital. Given its location inside the bone, in vivo studies including X-rays and Cone Beam CT (CBCT) analysis are among the techniques required for an evaluation. The aim of this paper is to compare biometrics of the human mandibular canal from an anatomic dissection, with the morphometry of images obtained with CBCT. In this study, 216 measurements were obtained from cross sections carried out in the anterior, middle and posterior sectors of the mandibular canal in dry jaws, through CBCT images. Linear measurements of the mandibular canal were carried out using radiopaque markers that were arranged with respect to the outlying walls that correspond to the alveolar/residual, basal, internal and external corticals. The vertical and transverse diameters of the canal was measured, along with the distances between the alveolar/residual and basal cortex, and between the internal and external corticals. The average values of each of the linear measurements were obtained, both of the biometrics in the dry jaw and the morphometry performed in the CBCT. Then the statistical differences of each measurement (L1-L6 and D1-D2) between both techniques were determined, using the Pearson correlation test, where a very high positive correlation was obtained (p ›0.987). Additionally, it was determined that measurements are not affected by the sector of the analyzed channel (p ›0.987). The measurements made L1-L6 and D1-D2, no significant differences were found between the biometrics with respect to the morphometry measurements made in the CBCT images. Measures L4 and L5 are those that offer the lowest percentage differences with other research, due to lower absorption of the corticals involved.

Cross-Sectional Study of Mandibular Canal Branching in Regions Affected by Dental Inflammation with Cone Beam Computed Tomography / Estudio Transversal de la Ramificación del Canal Mandibular en Regiones Afectadas por Inflamación Dental con Tomografía Computarizada de Haz Cónico

ABSTRACT: The present study aimed to investigate the occurrence of mandibular canal alterations in regions with dental inflammation by means of cone beam computed tomography (CBCT). A database of 2,484 CBCTs was reviewed for identifying dental inflammation in mandibular alveolar ridges. The final sample consisted of 150 CBCTs, including 91 females and 59 males, with ages ranging from 13 to 89 years (mean age of 47.06; ± SD=18.722). The presence and location of dental inflammation, gender, age, as well as presence and location of mandibular canal branching (MCB) were evaluated. The Kolmogorov-Smirnov, Chi-square, and T-test were applied to verify the statistical relationship of the data. There were 178 images of dental inflammation on 150 CBCTs, mainly located at molars' region (75 %). Apical lesions were the most common type of dental inflammation found (79 or 44.4 % of the sample), followed by pericoronitis (32; 18.0 %). This study identified 135 mandibular canal branches in the exams that presented dental inflammation. The MCB were also most commonly located at molars' region (74.07 %). No statistical difference was identified regarding the distribution of mandibular canal branching in relation to the sites with dental inflammation (p=0.370).The MCB found were mostly single (86 or 63.7 % of the total). Sex had no influence on mandibular canal branching occurrence (p=0.308), not did age (p=0.728). A high prevalence of mandibular canal branching was observed in the regions where dental inflammation were identified, most commonly found in the molar region.

RESUMEN: El presente estudio tuvo como objetivo investigar la ocurrencia de ramificación del canal mandibular (RCM) en regiones con inflamación dental mediante tomografía computarizada de haz cónico (TCHC). Se revisó una base de datos de 2.484 TCHC para identificar la inflamación dental en las crestas alveolares mandibulares. La muestra final consistió en 150 TCHC, incluidas 91 mujeres y 59 hombres, con edades comprendidas entre 13 y 89 años (edad media de 47,06 ± DE = 18,722). Se evaluaron el sexo, la edad, la presencia y la ubicación de la inflamación dental, así como la presencia y ubicación de RCM. KolmogorovSmirnov, Chi-cuadrado y prueba-T se aplicaron para verificar la relación estadística de los datos. Hubo 178 imágenes de inflamación dental en 150 TCHC, ubicados principalmente en la región de los molares (75 %). Las lesiones apicales fueron el tipo más común de inflamación dental encontrada (79 o 44,4 % de la muestra), seguidas por pericoronitis (32; 18,0 %). Este estudio identificó 135 ramas del canal mandibular en las regiones que presentaron inflamación dental. El RCM también se localizó con mayor frecuencia en la región de los molares (74,07 %). No se identificaron diferencias estadísticas con respecto a la distribución de la ramificación del canal mandibular en relación con los sitios con inflamación dental (p = 0,370). Las RCM encontrados fueron en su mayoría solteros (86 o 63,7 % del total). El sexo no tuvo influencia en la ocurrencia de la ramificación del canal mandibular (p = 0,308), no la edad (p = 0,728). Se observó una alta prevalencia de ramificación del canal mandibular en las regiones donde se identificó la inflamación dental, que se encuentra con mayor frecuencia en la región molar.

A Radiographic Study to Evaluate the Course and Visibility of the Mandibular Canal in Darbhanga Population: An Original Research

Introduction: Mandibular canal or inferior alveolar canal isan important anatomical landmark in mandible which containsneurovascular bundles. Mandibular canal is considered asreference anatomical landmark in maxillofacial surgeries.The aim of this study was to evaluate the course and visibilityof the mandibular canal in Darbhanga (Bihar) populationon digital panoramic radiographs, and the objective was toassess the normal variation of mandibular canal on panoramicradiographsMaterial and Methods: A total of 500 panoramic radiographswere selected from the archives of our department as softcopies. The course of mandibular canal was evaluated onpanoramic radiographs. The collected data were subsequentlyprocessed and analyzed using SPSS statistical package version17.Results: We found that elliptic curve is most common curve.Visibility of mandibular canal is more in the third molarregion compared to first molar region. Conclusion: In thepresent study, most common curve was elliptic curve (64.8%)followed by linear curve (22.2%). Visibility of mandibularcanal in third molar region was 98.1%. In both gender, ellipticcurve was most common curve.

Сross-sectional anatomic study of direct positional relationships between mandibular canal and roots of posterior teeth using cone beam computed tomography

Objectives: to establish the frequency of the various types of direct contacts of the root apices with the wall of the mandibular canal and to determine gender differences in number of such contacts in a selected belarusian population using cone beam computed tomography. methodology: one hundred and two cone beam computed tomography scans were analyzed to classify the types of contact and three-dimensional relationship between the mandibular teeth and the mandibular canal. results: the direct contact between the teeth and the mandibular canal was observed in 63.7 percent of patients. overall 300 roots of 189 teeth were in direct contact with the mandibular canal: 9.3 percent were second premolars, 14.7 percent were first molars, 33.8 percent were second molars and 50.0 percent were third molars. there were no statistically significant differences in the number of teeth with direct contact with the mandibular canal between males and females. conclusion: the direct contact of the root apices with the mandibular canal was most often found in the second and third molars. the root apices of the third molars had the greatest variability of location relatively to the mandibular canal.

Estudio de las variantes anatómicas del conducto dentario inferior en el sector posteroinferior mediante tomografía de haz cónico en pacientes desdentados / Study of the anatomical variants of the mandibular dental canal in the lower posterior sector by cone-beam tomography in edentulous patients

Objetivo: Determinar las variantes anatómicas producidas entre el conducto dentario inferior y las corticales alveolares superior, inferior, externa e interna en pacientes desdentados con respecto a pacientes dentados posteroinferiores en tomografía axial computarizada (TAC). Métodos: Se estudiaron 15 tomografías en pacientes edéntulos y 15 en pacientes dentados en el sector posteroinferior, de ambos sexos en pacientes con un rango de edad entre los 50 hasta los 65 años. Se midieron en cortes oblicuos a partir del agujero mentoniano realizando 5 cortes posteriores cada 4 milímetros. En cada corte se realizaron mediciones desde el conducto dentario inferior hasta las corticales superior, inferior, interna y externa. Resultados: Se pudo observar que en los pacientes desdentados se hallan diferencias signifi cativas entre las mediciones del conducto dentario inferior y las corticales óseas, con respecto a los pacientes dentados. Conclusión: Según este estudio se pudo comprobar que el hueso sufre mayor resorción en los pacientes desdentados observándose más acentuada la pérdida ósea entre el conducto dentario y las corticales superior e interna con respecto a los pacientes dentados (AU)

Objective: To determine the anatomical variants produced between the mandibular canal and the superior, inferior, external and internal alveolar cortices in edentulous patients with respect to dentate patients posteroinferior in computed tomography (CBCT). Methods: Fifteen tomographies were studied in edentulous patients and 15 in dentate patients in the posteroinferior sector, of both sexes in patients with an age range between 50 and 65 years. They were measured in oblique cuts from the mental foramen making 5 posterior cuts every 4 millimeters. In each cut, measurements were made from the mandibular canal to the upper, lower, internal and external cortices. Results: It was observed that in the edentulous patients there are signifi cant diff erences between the measurements of the mandibular canal and the bone cortical, with respect to the dentate patients. Conclusion: According to this study it was possible to verify that the bone undergoes greater resorption in the edentulous patients, with more marked loss of bone between the mandibular canal and the superior and internal cortices with respect to the dentate patients (AU)

The relative location between the mandibular third molar and inferior alveolar canal studied by CBCT / 实用口腔医学杂志

Objective: To determine the positional relationship between impacted mandibular third molar(IMTM) and mandibular canal(MC) by CBCT. Methods: 664 IMTMs with root apexes contacted to MCs on panoramic radiograph were further examined by CBCT,the exact positional relationship between IMTMs and MCs was observed and analyzed by I-Dixel software. Results: The 664 cases were divided into lowly(6. 3％),intermediately(60. 7％) and highly(33. 0％) impacted groups by the depth of IMTMs in mandibulae showed on CBCT images. The distance(mm) from the root apexes of IMTMs to the intact superior wall of MCs(n = 329) in lowly, intermediately and highly impacted cases were 1. 39 ± 1. 38,1. 28 ± 1. 03 and 1. 79 ± 1. 54 respectively(P ＜ 0. 05). MCs on the buccal side,lingual side,under the IMTMs and between the root apexes were found in 49. 8％,12. 0％,36. 6％ and 1. 5％ of the cases; the MC wall deffect was found in 65. 8％,27. 5％ and 95. 0％ of the cases with the MCs under,on buccal and lingual side of the IMTMs, respectively(P ＜ 0. 001). Conclusion: CBCT examination is necessary for the determination of the positional relationship between MC canal and IMTM with the root apex cotacted or overlapped to MC.

Anatomic relationships of mandibular canal: a cone beam CT study / Relaciones anatómicas del canal mandibular: un estudio en tomografías computarizadas de haz de cono

SUMMARY: It is critical to know the precise location and configuration of the mandibular canal (MC) to avoid damages in the alveolar inferior nerve during an invasive dental treatment. The aim of this study was to provide anatomic relationships of the mandibular canal in its entire pathway related to cortical walls and dental roots to serve as basic knowledge for dental clinical procedures performed in this area. We analyzed 50 CBCT images assessing the specific location of MC at the retromolar space as related to inferior teeth roots. Data were analyzed by side using descriptive statistics (median: mean [M], standard deviation [SD], 95 % confidence interval: lower endpoint [IC] and upper endpoint [IC']). The MC length and pathway were measured from the mandibular foramen up to the mental foramen. MC was closer from lingual cortical than buccal at the retromolar space as well the distal root of the second molar and the root of the second premolar are closest to MC. A mean length for the MC of 70.8 (±5.3 mm) for the right side and 71 (±5.8 mm) for the left side were observed. In conclusion, it is critical for clinicians to know three-dimensionally the topographic relationships between the inferior teeth roots and the mandibular canal before proceeding to any invasive dental or surgical procedure at this region.

RESUMEN: Es crítico conocer la ubicación exacta y la configuración del canal mandibular (MC) para evitar daños en el nervio inferior alveolar durante un tratamiento dental invasivo. El objetivo de este estudio fue proporcionar relaciones anatómicas del MC en toda su trayectoria relacionada con paredes corticales y raíces dentales para servir como un conocimiento básico para los procedimientos clínicos dentales realizados en esta región. Se analizaron 50 imágenes CBCT evaluando la localización específica del MC en el espacio retromolar, así como las raíces de los dientes inferiores. Los datos se analizaron por lado, utilizando estadística descriptiva (mediana: media [M], desviación estándar [SD], 95 % intervalo de confianza: punto final inferior [IC] y extremo superior [IC]). La longitud y vía del conducto mandibular se midieron desde el foramen mandibular hasta el foramen mentoniano. El MC estaba más cerca de la cortical lingual que bucal en el espacio retromolar, así como la raíz distal del segundo molar y la raíz del segundo premolar están más cerca del MC. Se observó una longitud media para el MC de 70,8 (± 5,3 mm) para el lado derecho y de 71 (± 5,8 mm) para el lado izquierdo. En conclusión, es fundamental que el clínico conozca tridimensionalmente las relaciones topográficas entre las raíces de los dientes inferiores y el conducto mandibular antes de proceder a cualquier procedimiento invasivo dental o quirúrgico en esta región.

Frequency and position of the mental foramen in panoramic X-rays: literature review / Frecuencia y posición del foramen mental en radiografías panorámicas: revisión bibliográfica

The mental foramen (MF), located in the body of mandible in the region below the inferior premolars, is the anatomical structure through which the mental neurovascular bundle emerges. The MF can be seen clearly in panoramic X-rays. The object of the present study was to carry out a literature review in order to identify the frequency and position of the MF in panoramic X-rays. We looked for articles in the SCiELO, Pubmed, Scopus, LILACS, Web of Science and EBSCOhost databases, for the years 2006 to 2016. The key words used were "mental foramen", "mandibular canal", "inferior alveolar nerve", "anatomy" and "panoramic X-ray". Once the articles had been selected, an analysis was made of their methodological quality; poor-quality articles were excluded. In each article the frequency and position of the MF in each hemi-mandible was analyzed. We found 82 articles, of which 20 were retained after application of the exclusion criteria. The MF was found in 4,824 hemi-mandibles (95.2 %), with greater presence on the left side (50.29 %) than the right (49.71 %). The MF is most commonly located between the apices of the inferior premolars (42.22 %), coincident with the root of the second inferior premolar (33.98 %) or distal of the root of the second inferior premolar (10.98 %). The MF is a very frequent anatomical structure. Knowledge of its location is fundamental for reducing the risk of accidents and unexpected events during clinical and surgical manoeuvres.

El foramen mental (FM), ubicado en el cuerpo de la mandíbula, inferiormente a la región de los dientes premolares inferiores, es la estructura anatómica por donde emerge el paquete vásculonervioso mental. El FM se logra visualizar con buena precisión en una radiografía panorámica. El objetivo del presente estudio fue realizar una revisión de la literatura para identificar la frecuencia y posición del FM en radiografías panorámicas. Se buscaron artículos en las bases de datos SCiELO, Pubmed, Scopus, LILACS, Web of Science y EBSCOhost, entre los años 2006 y 2016. Las palabras clave utilizadas fueron "foramen mental", "canal mandibular", "nervio alveolar inferior", "anatomía" y "radiografía panorámica". Tras la selección de los artículos se realizó un análisis de la calidad metodológica de los mismos, donde se excluyó artículos de baja calidad. Se analizó en cada artículo la frecuencia y posición del FM en cada hemimandíbula. Se encontraron 82 artículos, de los cuales quedaron sólo 20 al aplicar criterios de exclusión. El FM fue encontrado en 4824 hemimandíbulas (95,2 %), siendo el lado izquierdo donde hubo mayor presencia de forámenes (50,29 %) en comparación al lado derecho (49,71 %). El FM se localiza entre los ápices de los premolares inferiores en 42,22 %, es coincidente con la raíz del segundo premolar inferior en 33,98 %, y es distal a la raíz del segundo premolar inferior en 10,98 %, siendo éstos los más relevantes. El FM es una estructura anatómica muy frecuente, ubicada en general inferiormente a los premolares inferiores. Es una estructura de gran importancia clínica, por ello el conocimiento detallado de sus características y variaciones anatómicas es muy importante para evitar complicaciones y disminuir el riesgo de accidentes durante procedimientos clínico-quirúrgicos en la región. Además, a pesar de que la RP presenta buena precisión en la identificación del FM hay condiciones clínicas que requieren otros métodos imagenológicos para su identificación.

Measurement and analysis of mandibular canal course by cone-beam computed tomography / 安徽医科大学学报

Objective To measure the course of the mandibular canal in mandibula posterior area by cone-beam computed tomography ( CBCT ) , to provide a theoretical support for implant preoperative assessment. Methods Mandibular data of 65 people measured by CBCT were collected, measured the distance between mandibular canal around the bone wall and analyzed the differences by gender and the differences between the left and the right. Results The average distance of mandibular canal outer edge to the buccal bone plate by former backward in-creased gradually,at least in the area of the mental formen, at largest in the area of the mental foramen after 18 mm. The average distance between mandibular canal inner edge to lingual bone plate by former backward reduced gradually, at largest in the area of the mental foramen,at least in the area of the mental foramen after 18 mm. The average distance between mandibular canal upper edge to alveolar crest by former backward reduced gradually,at largest in the area of the mental foramen, at least in the area of the mental foramen after 18 mm. The average dis-tance between the edge of mandibular canal to the edge of mandible by former backward reduced previous,then in-creased, at least in the area of the mental foramen after 6 mm, at largest in the area of the mental foramen after 18 mm. All the results had no significant statistical differences between the male and the female, and had no significant statistical differences between the left and the right. Conclusion The trajectory of the mandibular canal from front to back is downward first, then upward in the mesial of the first molar in the vertical, and whose from the buccal side to the lingual side. That has significance for assessment before implant in mandibular posterior area.

Cone beam computed tomography evaluation of bifid mandibular canals in the adult population in Sichuan Province / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the incidence of bifid mandibular canals (BMC), and analyze the types, courses, and anatomic features of the variant canals in the adult population in Sichuan Province.</p><p><b>METHODS</b>Five hundred patients (1 000 hemimandibles) underwent cone beam computed tomography (CBCT) were included in this study. The incidence, bifurcate types and courses of the BMC were evaluated.</p><p><b>RESULTS</b>The incidence of BMC was 13.8% (69/500) in the study, 9.2% in terms of total hemimandibles. The most frequently type was retromolar canals, followed by the dental and buccolingual type, meanwhile the lowest was the forward type. The mean diameter of the accessory canals was 0.90 mm and the mean length was 9.39 mm.</p><p><b>CONCLUSIONS</b>CBCT used in this study has shown that the incidence of BMC assessed by CBCT was significantly higher than panoramic radiography. Furthermore, CBCT can depict the position, course, size and the branches of the mandibular canals.
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Localization of mandibular canal and assessment of the remaining alveolar bone in posterior segment of the mandible with single missing tooth using cone-beam computed tomography: a cross sectional comparative study

OBJECTIVES: Localization of the mandibular canal (MC) and measurement of the height and width of the available alveolar bone at the proposed implant site in the posterior segment of the mandible using cone-beam computed tomography (CBCT) in patients with a single missing tooth. MATERIALS AND METHODS: A cross-sectional study was performed where CBCT scans of the patients with a single missing tooth in the posterior segment of the mandible—premolar, I (1st) molar, and II (2nd) molar were used. The scans were assessed using OnDemand3D software (version 1.0; CyberMed Inc., Seoul, Korea) for localization of the MC asnd remaining alveolar bone both vertically (from the superior position of the MC to the crest of the alveolar ridge) and horizontally (buccolingual, 3 mm below the crest of the alveolar ridge). The findings were statistically analyzed using independent t-test. RESULTS: A total of 120 mandibular sites (40 sites for each of the three missing premolar, I molar, and II molar) from 91 CBCT scans were analyzed. The average heights (from the alveolar crest to the superior margin of the MC) at the premolar, I molar, and II molar areas were 15.19±2.12 mm, 14.53±2.34 mm, and 14.21±2.23 mm, respectively. The average widths, measured 3 mm below the crest of the alveolar ridge, at the premolar, I molar, and II molar areas were 6.22±1.96 mm, 6.51±1.75 mm, and 7.60±2.08 mm, respectively. There was no statistically significant difference between males and females regarding the vertical and horizontal measurements of the alveolar ridges. CONCLUSION: In the study, the measurements were averaged separately for each of the single missing teeth (premolar, I molar, or II molar), giving more accurate information for dental implant placement.

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.