Topographic anatomy of the inferior wall of the maxillary sinus in Koreans

Knowledge of the relationship between the root apex and the inferior wall of the maxillary sinus are crucial for diagnosing and treating a sinus pathosis as well as in assisting in dental implantation. Therefore, identifying the proximity between the root apex and the inferior wall of the sinus and clarifying the cortical thickness of the inferior wall of the sinus is essential for determining the topography of a spreading dental infection into the maxillary sinus. Accordingly, knowledge of the topography between the root apex and the inferior wall of maxillary sinus is important for diagnosing and planning dental implantation, endodontic procedures, and orthodontic treatment. This study was undertaken to clarify the morphological and clinical characteristics of the maxillary sinus, particularly the inferior wall of the sinus in Koreans, and to identify the relationship between the inferior wall of the maxillary sinus and the roots of the maxillary teeth. Twenty-four sides of the maxillae of hemi-sectioned Korean heads were used in this study. All specimens were decalcificated and sectioned coronally. On the sectioned specimens, 21 items were measured using an image analyzing system. The distances between the each root apex and the inferior wall of the maxillary sinus were measured. The distance from the root apex to the inferior wall of the sinus was the shortest in the second molar area and the longest in the first premolar area. The thickness of the cortical plate of the inferior wall of the maxillary sinus was thinnest in the first premolar area but it was thickest in the second premolar area. The vertical relationship between the inferior wall and the roots of the maxillary molars was classified into five types. Type I (the inferior wall of the sinus located above the level connecting the buccal and lingual root apices) dominated (54.5% in the first molar area, 52.4% in the second molar area). The horizontal relationship between the inferior wall of the sinus and the root apex was classified into three types. Type 2 (the alveolar recess of the inferior wall of then sinus was located between the buccal and lingual roots) was most common (80% in the first and second molar area). Overall this study demonstrated the many anatomical characteristics and determined the relationships between the maxillary sinus and their surrounding structures. These findings may have an impact on the clinical management of patients.