Case Report Unilateral Absence of Mental Foramen with Surgical Exploration in a Living Human Subject Murat Ulu, 1 Elif Tarim Ertas, 2 Fatih Gunhan, 1 Meral Yircali Atici, 2 and Huseyin Akcay 1 1 Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Izmir Katip Celebi University, 35640 Izmir, Turkey 2 Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Izmir Katip Celebi University, 35640 Izmir, Turkey Correspondence should be addressed to Fatih Gunhan; fatihgunhan44@hotmail.com Received 5 November 2015; Revised 17 January 2016; Accepted 28 January 2016 Academic Editor: Asja Celebi´ c Copyright © 2016 Murat Ulu et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te mental foramen (MF) is an important anatomic landmark of the mandible, in which the somatic aferent sensory nerve of the mandibular nerve emerges as mental nerve and blood vessels. Te identifcation and actual location of MF are important in order to avoid sensory dysfunction or paresthesia due to mental nerve injury. In the literature there are some rare reports on the anatomical variations of the MF such as its location or presence of accessory foramina. Te present report describes the absence of mental foramina on the lef side of the mandible, as detected by cone-beam computed tomography before impacted tooth removal and observed directly during surgery. 1. Introduction Te mental foramen (MF) nerves divide into several branches to provide sensorial innervation of the angle of the mouth with its angular branch: the skin of the lower lip, oral mucosa, and gingiva up to the second premolar with its medial and lateral inferior labial branches and the skin of the mental region with its mental branch [1]. MF is generally located in the area of premolar region as bilateral oval or round openings, although race and ethnicity may afect its location [2]. Radiographically, the MF can be seen as a round or oval radiolucent area on both the right and lef sides of the mandible [3, 4]. Te identifcation and actual location of MF are impor- tant in order to avoid sensory dysfunction or paresthesia during any surgical procedures in this area, as well as achieving efective anesthesia [3, 5, 6]. Since the conventional radiographs such as periapical and panoramic flms provide two-dimensional images of the mandible [2, 7], the MF may not be observed in some cases due to the superimposition of anatomic landmarks [5, 8], the pattern of trabecular bone [4], and the thinning of the mandible [5]. In the literature, variations of the MF such as its location or presence of accessory foramina are reported in several articles but the absence of MF is extremely rare [5, 5]. We present here a case of unilateral absence of the mental foramen in a living patient detected on cone-beam computed tomography (CBCT) images and surgical exploration during lower impacted 2nd and 3rd molar extraction. According to our knowledge there is a very extremely rare case report in the literature which indicates absence of mental foramen with CBCT image and by surgical exploration. 2. Case Report A 20-year-old male patient was referred to Izmir Katip Celebi University Faculty of Dentistry with a chief complaint of pain in lef posterior mandible. A panoramic radiograph disclosed the presence of fully impacted mandibular 2nd and 3rd lef molars with horizontally overlapped position (Figure 1). A radiolucent area around impacted molars and bone resorption distal side of 1st molar was observed. Extraction was decided for both of the impacted teeth. In order to evaluate the relation between the impacted 2nd molar and inferior alveolar nerve, CBCT (NewTom 5G®, QR, Verona, Italy) examination was performed before surgery. All axial, coronal, and 3D images were carefully explored. During CBCT examination an uncommon anatomic variation drew our attention. In the lef mandible MF could not be seen Hindawi Publishing Corporation Case Reports in Dentistry Volume 2016, Article ID 1971925, 4 pages http://dx.doi.org/10.1155/2016/1971925