Accuracy of virtual models in the assessment of maxillary defects

PURPOSE: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning. MATERIALS AND METHODS: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) 60x60 mm FOV, 0.125 mm3 (FOV60); 2) 80x80 mm FOV, 0.160 mm3 (FOV80); and 3) 100x100 mm FOV, 0.250 mm3 (FOV100). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05. RESULTS: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements. CONCLUSION: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

course of the marginal mandibular branch of the facial nerve in adult cadavers; an anatomic study

Objectives: To observe the course of the marginal mandibular branch of the facial nerve [MMBFN] and its relation to the inferior border of the mandible and facial vessels

Methods: This cadaveric study was conducted at the Department of Anatomy, Gulhane Military Medical Academy, Ankara, Turkey from April to September 2012. The 44 facial halves of 22 adult cadavers were dissected under a stereomicroscope

Results: The nerve was found to be presented by one branch [36.4%], and 2 branches [63.6%]. The distance of the nerve from the inferior border of the mandible varied from 13.06-40.08 mm, with an average distance of 21.91 mm. There were communications with buccal branch only in 2 specimens [4.6%]. All the branches of the marginal mandibular branch ran laterally to the facial artery in 43 [97.7%] of the 44 specimens. In one specimen, the 2 marginal mandibular branches ran between the facial artery and vein

Conclusion: The MMBFN can occasionally be damaged during surgeries confined to the submandibular region due to its location and anatomical variant. The most common pattern of MMBFN was nerve with 2 branches. The maximum distance between the MMBFN and the mandible was 40.08 mm. This anatomical knowledge may be useful to surgeons of the head and neck in planning incisions and procedures in the submandibular region

Marginal mandibular branch of the facial nerve in human fetuses

To observe the course of the marginal mandibular branch [MMB] and its relation to the inferior border of the mandible and facial vessels. This study was conducted in the Department of Anatomy, Gulhane Military Medical Academy, Etlik, Ankara, Turkey from February 2009 to April 2010. The 44 hemi-face specimens of 22 fetuses were selected for this study, and dissected under a stereomicroscope. The MMB relationship was evaluated between adjacent structures [like vessels and muscles] and the lower border of the mandible. We found a number of one to 4 branches of the MMB. The MMB ran laterally to the facial vein in 42 [95.5%] of the 44 specimens. All the branches of the MMB ran laterally to the facial artery in 30 [68.2%] of the 44 specimens. In 2 specimens, it ran medially to the facial artery In 10 specimens, the facial artery ran between 2 branches of the MMB. In 2 specimens, the 2 branches of the MMB ran between facial artery and vein. There were no statistical differences between the left and right sides, and in both genders. The inferior border of the mandible may be an important landmark to avoid injury to the MMB of the facial nerve. It is for this reason, that surgeons who are willing to operate on this area should have a true knowledge and accurate judgement regarding the anatomy of this branch

Double Facial Nerve Trunk Emerged from the Stylomastoid Foramen and Petrotympanic Fissure: A Case Report

There are several studies concerning branches of the facial nerve, but we encountered less information about the trunk of the facial nerve in the literature. During the routine dissection of a 65-yr-old Caucasian male cadaver, double facial nerve trunk emerged from the stylomastoid foramen and petrotympanic fissure were encountered. Because of an extremely rare variation, we presented this case report. In addition this cadaver had two buccal plexuses. These plexuses and other branches were formed to structures like to polygon. These anatomic peculiarities were described, photographed and illustrated. Finally, magnetic resonance imaging was performed by using 1.5T scanner to this cadaver. The facial nerve trunk can be damaged during surgical procedures of the parotid gland tumours and submandibular region. Surgeons who are willing to operate on this area should be aware of the possible anatomical variations of the facial nerve trunk.