A cone-beam computed tomography study to assess anterior loop and other anatomic variations in mental foramen area in an iranian population / Un estudio de tomografía computarizada de haz cónico para evaluar el asa anterior y otras variaciones anatómicas en el área del foramen mentoniano en una población iraní

Purpose: This study aimed to determine the prevalence and length of the anterior loop (AL) of the inferior alveolar nerve, and evaluate the emergence direction of the mental nerve and the location of mental foramen in a group of Iranian patients. Material and Methods: This study was carried out on CBCT scans of 150 patients (57 males and 93 females; mean age 40.8 ±14.33 years). The presence and extent of the AL was determined in reconstructed images. The emergence path of the mental nerve was classified into three groups: anteriorly directed emergence, right-angled pattern of emergence, and posteriorly directed emergence. The location of mental foramen relative to adjacent premolars was determined. Results: AL was identified in 14.7% of the cases with a mean length of 1.39± 0.91 mm (range 0.25 to 3.50 mm). No significant differences were observed in the prevalence and extent of the AL between genders (p>0.05). The right-angled pattern of emergence was more dominant (43.7%). The most prevalent location of mental foramen was between the first and second premolars (68.3%). There was no significant association between the presence of AL with the path of emergence of the mental nerve (p=0.627) or the location of the mental foramen (p= 0.10 0). Conclusion: The prevalence of anterior loop was relatively low in the present sample (14.7%) with a length range of 0.25 to 3.5 mm. Due to the importance of this anatomic variation in implant surgery, it is suggested to carefully assess CBCT images before the surgical procedure to avoid neurosensory complications.

Propósito: Este estudio tuvo como objetivo determinar la prevalencia y la longitud del loop anterior (LA) del nervio alveolar inferior, y evaluar la dirección de emergencia del nervio mentoniano y la ubicación del foramen mentoniano en un grupo de pacientes iraníes. Material y Métodos: Este estudio se llevó a cabo en exploraciones de tomografía computarizada de haz cónico de 150 pacientes (57 hombres y 93 mujeres; edad media 40,8 ± 14,33 años). La presencia y extensión de la LA se determinó en imágenes reconstruidas. La vía de emergencia del nervio mentoniano se clasificó en tres grupos: emergencia dirigida anteriormente, patrón de emergencia en ángulo recto y emergencia dirigida posteriormente. Se determinó la ubicación del foramen mentoniano en relación con los premolares adyacentes. Resultados: Se identificó LA en el 14,7% de los casos con una longitud media de 1,39± 0,91 mm (rango 0,25 mm a 3,50 mm). No se observaron diferencias significativas en la prevalencia y extensión de la AL entre sexos (p>0,05). El patrón de emergencia en ángulo recto fue más dominante (43,7%). La localización más prevalente del foramen men-toniano fue entre el primer y segundo premolar (68,3%). No hubo asociación significativa entre la presencia de AL con la vía de emergencia del nervio mentoniano (p=0,627) o la ubicación del foramen mentoniano p=0,100).Conclusión: La prevalencia de asa anterior fue rela-tivamente baja en la presente muestra (14,7%) con un rango de longitud de 0,25 mm a 3,5 mm. Debido a la importancia de esta variación anatómica en la cirugía de implantes, se sugiere evaluar cuidadosamente las imágenes de tomografía computarizada de haz cónico antes del procedimiento quirúrgico para evitar complicaciones neurosensoriales.

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.