Characteristics and dimensions of the Schneiderian membrane and apical bone in maxillary molars referred for apical surgery: a comparative radiographic analysis using limited cone beam computed tomography.

Introduction: The purpose of the present study was to evaluate the thickness and the anatomic characteristics of the Schneiderian membrane and cortical bone using limited cone beam computed tomography (CBCT) scannning in patients referred for planning of apical surgery of maxillary molars.

Methods: This controlled study included 2 cohorts of patients (n = 50 for each group). For patients in group 1 (with apical pathology), 3 measurements in millimeters were performed using coronal and sagittal CBCT slices: the dimension of the apical lesion in the axis of the root, the width of the cortical bone in the axis of the root, and the thickness of the Schneiderian membrane perpendicular to the underlying cortical bone.