A cone-beam computed tomographic assessment of the proximity of the maxillary canine and posterior teeth to the maxillary sinus floor: Lessons from 4778 roots

Abstract

When tooth roots protrude into the maxillary sinus, apical root resorption and tipping may occur during horizontal tooth movement across the sinus floor. Three-dimensional cone-beam computed tomography (CBCT) images may provide detailed information without distortion and overlap. We evaluated the relationships between the maxillary tooth root apices and the maxillary sinus floor using CBCT. We evaluated 4778 roots from 76 men (aged 27.6±10.4 [mean±standard deviation] years; range, 18-69years), and 225 women (aged 30.4±12.0years; range, 18-68years). The positional relationships between the maxillary tooth root apices, including the canine, premolar (first and/or second), and molar (first and/or second), and the inferior wall of the maxillary sinus were comprehensively evaluated on 2 cross-sectional CBCT images (ie, the sagittal and coronal planes). These distances were measured in both images simultaneously. The sagittal plane distances were significantly larger than coronal plane distances, except for the distobuccal root of the first molar. Pearson correlation test revealed a significant negative correlation between the distance and the patient's age. Our study provides valuable information for planning orthodontic tooth movement through the maxillary sinus, which may help to predict the occurrence and severity of root resorption.