Radiographically, the floor of the maxillary sinus appears as a thin radiopaque line (1). If there is little pneumatization of the alveolar process, the floor of the sinus may be seen superior to the roots of the maxillary posterior teeth, or it may not be visible on periapical radiographs. If the maxilla is extensively pneumatized, the floor of the sinus will appear to drape around the roots of the teeth or be superimposed over the roots of the teeth, giving the appearance of the roots penetrating the sinus floor. In these cases, the lamina dura of maxillary posterior teeth.
