Anatomy and Variations of the Floor of the Maxillary Sinus

The maxillary sinus is one of the paranasal sinuses along with the frontal, ethmoidal, and sphenoidal sinuses. It is located above the apical roots of the maxillary molars and is an important structure in fields such as endodontics, implant dentistry, and oral surgery. In planning for dental implant treatment, the distance between the alveolar ridge and the sinus floor, the existence of pathological features, and the septum in the maxillary sinus are of great importance. For example, a periapical lesion or penetration of the sinus floor membrane after tooth extraction can cause maxillary sinusitis. In this chapter, the anatomy, structure, and variations of the maxillary sinus are reviewed, and the sinus floor elevation procedure is introduced.