Anatomical Variation of the Maxillary Sinus in Cone Beam Computed Tomography

Purpose. The aim of this paper is to report a case in which the cone beam computed tomography (CBCT) was important for the confirmation of the presence of maxillary sinus septum and, therefore, the absence of a suspected pathologic process. Case Description. A 27-year-old male patient was referred for the assessment of a panoramic radiograph displaying a radiolucent area with radiopaque border located in the apical region of the left upper premolars. The provisional diagnosis was either anatomical variation of the maxillary sinuses or a bony lesion. Conclusion. The CBCT was important for an accurate assessment and further confirmation of the presence of maxillary septum, avoiding unnecessary surgical explorations. 1. Introduction Maxillary sinuses (MS) are facial pyramidal cavities with thin walls corresponding to the orbital, alveolar, facial, and infratemporal aspects of the maxilla. The size, shape, and wall thickness of this anatomic structure vary from one individual to another [1]. Some maxillary sinuses present septa, consisting of thin walls of bone inside the sinus, which are variable in thickness, length, and number [2]. According to the literature, the incidence of maxillary sinus septa is between 16 and 58% [1]. Acknowledgement of the anatomic variations of the MS is very important for surgeons, specially prior to surgical procedures, such as insertion of maxillary dental implants or maxillary sinus lifting. MS septa may be more accurately diagnosed using computed tomography (CT) or more recently cone beam computed tomography (CBCT). The information offered by these imaging resources is used to predict sinus volume and the degree of septation, when present [3–5]. This paper reports a case in which the CBCT was important for the confirmation of the presence of maxillary sinus septum and, therefore, the absence of a suspected pathologic process. 2. Case Presentation A 27-year-old male patient was referred to our institution for the assessment of a radiolucent area surrounded by radiopaque border located in the periapical regions of upper left first and second premolars (Figure 1). Figure 1: Panoramic radiograph showing radiolucent area surrounded by radiopaque halo located in the periapical region of the upper first and second premolars. The intraoral examination showed integrity of the mucosa and no bone expansion was noticed. Pulp vitality test was positive for all teeth in the region. The provisional diagnosis was an anatomic variation of the MS or a bony lesion. In order to visualize the region in 3D, CBCT scan was performed (i-CAT