M. Săndulescu 1, M. Trăistaru 1, Mihaela Niţescu 1, I. Sîrbu 1
1 University of Medicine and Pharmacy “Carol Davila”, Bucharest, Romania, Faculty of Dental Medicine. Department of Oral Implantology
Abstract
Background: The inferior alveolar nerve is the one of the largest branches of the mandibular division of the trigeminal nerve and it is vulnerable during surgical procedures of the mandible, especially during impacted third molar removal and implant placement procedures. Purpose: The present study aims to clarify the 3-dimensional positioning of the mandibular canal in partially edentulous patients by evaluating a series of Cone-Beam Computed Tomography (CBCT) data. Material and method: For this study we evaluated 136 patients (66 women, 70 male), aged 18-86, who consecutively presented to the Oral Implantology Clinic from the Central Clinical Emergency Military Hospital, Bucharest, Romania, between November 2008 – December 2009 for various dental treatments. The inclusion criteria were: presence of terminal bilateral mandibular edentations (group 1) or presence of lateral edentations on one side of the mandible associated with terminal edentations on the opposite side (group 2). Within the two groups, we analyzed the shape of the mandibular body, dividing it into two mandibular morphological types, and we determined the mandibular canal’s position through the quantification of the distances to the superior border of the alveolar process, to the buccal cortical plate and to the oral plate. Results: In group 1, the average bone height above the mandibular canal was 11.98 mm, while in group 2 it was 13.07 mm for the mandibular morphological type 1 and 16.88 for the mandibular morphological type 2. Regarding the bucco-lingual position of the mandibular canal, in group 1, the mean distance from the mandibular canal to the buccal plate was 4.14 mm, while the mean distance to the lingual plate was 3.20 mm. In group 2 we found slightly higher distances. Conclusions: In order to avoid injury of the inferior alveolar neurovascular bundle during surgical implant placement procedures, both the vertical distance to the mandibular canal and the buccal-oral positioning of the mandibular canal need to be determined pre-operatively. Patients with termino-terminal mandibular edentations present a significant vertical bony resorption compared to the patients with latero-terminal edentation. This study provides essential data for developing a clinical algorithm of preoperative risk assessment in patients undergoing implant surgery within both the posterior and the anterior mandible, in order to minimize intra- or post-operative complications, such as inferior alveolar nerve damage.