Anterior loop of the mental nerve: a morphological and radiographic study

• Published in: Clinical oral implants research 2003-08, Vol.14 (4), p.464-471
• Main Authors: Kuzmanovic, Dusan V, Payne, Alan GT, Kieser, Jules A, Dias, George J
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; anatomical dissection; anterior loop of mental nerve; Bone Density; Cadaver; Chin - innervation; Dentistry; Dissection; Female; Humans; implant treatment planning; Male; Mandible - innervation; Mandibular Nerve - anatomy & histology; Mandibular Nerve - diagnostic imaging; Middle Aged; Patient Care Planning; radiography; Radiography, Dental, Digital; Radiography, Panoramic
• ISSN: 0905-7161; 1600-0501
• DOI: 10.1034/j.1600-0501.2003.00869.x

: Treatment planning for dental implant patients is often complicated by the unknown extent of the anterior loop of the mental neurovascular bundle. The aim of this study was to determine the correlation between the visual interpretation of the panoramic radiographs and the anatomical dissection findings in a cadaveric sample. Panoramic radiographs of the 22 randomly selected coronally sectioned human head specimens were taken using the Scanora® (Soridex, Orinon Corporation Ltd, Helsinki, Finland) radiographic unit jaw panorama (Programme 001, magnification 1.3) and dental panorama (Programme 003, magnification 1.7) and interpreted by two calibrated observers. Bilateral anatomical dissection was then performed on all specimens. The anterior loop of the mental canal was only identified in six panoramic radiographs (27%) (range 0.5–3 mm). There was a significant positive correlation between both observers of the radiographs and between the two radiographic programmes used. Anatomical measurements of the anterior loop of the mental neurovascular bundle revealed its presence in eight dissected specimens (range 0.11–3.31 mm; mean 1.20, ± 0.90). Fifty percent of the radiographically observed anterior loops of the mental canal were misinterpreted by observers with both radiographic programmes and 62% of the anatomically identified loops were not observed radiographically. Clinicians should not rely on panoramic radiographs for identifying the anterior loop of the mental nerve during implant treatment planning. However, a safe guideline of 4 mm, from the most anterior point of the mental foramen, is recommended for implant treatment planning, on the basis of our anatomical findings. Résumé Le plan de traitement pour les patients désirant des implants est souvent compliqué par la méconnaissance de l'emplacement de la boucle antérieure du nerf dentaire inférieur. Le but de cette étude a été de déterminer la relation entre l'interprétation visuelle de radiographies panoramiques et les découvertes effectuées par dissection anatomique sur cadavres. Des radiographies panoramiques de 22 humains ont été prises par Scanora®, panoramique mâchoire (programme 001, grandissement 1,3) et panoramique dentaire (programme 0,03, grandissement 1,7) et interprétées par deux observateurs calibrés. La dissection anatomique bilatérale a ensuite été effectuée. La boucle antérieure du canal n'a seulement été identifiée que dans six radiographies panoramiques (27%)(de 0,5 à 3 mm). Il y ava