Evaluation of the Relationship Between the Maxillary Sinus and Nasopalatine Canal of Maxillary Impacted Canines by Cone Beam Computed Tomography

Introduction. One of the critical parameters evaluated while planning orthodontic treatment for impacted canines in clinical practice is the relationship between impacted canines and adjacent anatomical structures. The nasopalatine canal (NPC) and maxillary sinus are anatomical formations that may be in close proximity to impacted canines. This study aimed to determine the relationship between palatally impacted canines, the maxillary sinus, and the NPC. Methods. A total of 105 impacted canines from 93 patients were evaluated using cone beam computed tomography (CBCT) images. The relationship between the impacted canine teeth, maxillary sinus, and NPC was assessed inside, outside, and at the border of the maxillary sinus floor and NPC walls. The millimetric distance between the impacted canine teeth and the borders of the maxillary sinus, the NPC, and the cortical bone of the palate was measured. Additionally, NPC morphology was assessed on the axial and sagittal CBCT images. Results. Of all the impacted teeth, 47.6% (3.8% inside, 43.8% at the border) were associated with the sinus, while 42.8% (15.2% inside, 27.6% at the border) were associated with the NPC. A significant moderate negative correlation (-0.32) was observed between age and the distance between impacted left canine teeth and the cortical bone of the palate. Additionally, when a Y-shaped NPC was present, the impacted canines were predominantly situated outside the canal. Conclusions. In this study, nearly half of the canines were located inside or at the border of the maxillary sinus and the NPC. Therefore, clinicians should carefully evaluate the relationship of impacted teeth with the maxillary sinus and the NPC during both orthodontic treatment and the extraction of impacted teeth.