Radiographical characteristics and traction duration of impacted maxillary canine requiring surgical exposure and orthodontic traction: a cross-sectional study

Abstract

This cross-sectional study aimed to classify the radiographical characteristics of impacted maxillary canines that were surgically exposed following orthodontic traction and to find out which factor is most closely related to traction duration. This study enrolled 74 patients with 87 maxillary canines. Cone-beam computed tomography images, panoramic radiographs, and medical records were analyzed. Cystic-appearing lesion and resorption of adjacent roots were observed in 26.4% and 23.0% of cases, respectively. Impacted maxillary canines were mostly distributed in the lateral incisor area. The mean (± standard deviation) traction duration for the 47 teeth that met the study criteria was 13.9 (± 8.9) months. Impacted maxillary canines treated with surgical exposure and orthodontic traction showed increasing possibilities of palatal impaction and resorption of the adjacent root as they were located mesially (p < 0.05). The distance from the occlusal plane to the impacted maxillary canine showed the strongest positive correlation with traction duration (r = 0.519, p < 0.01). When establishing treatment plans for patients with impacted maxillary canines, distance from the occlusal plane to the impacted canines, rather than the angle, should be considered in predicting the duration of treatment.

Figure 1

CBCT findings associated with impacted maxillary canines. CBCT findings associated with impacted maxillary canines. (a) Bucco-palatal position of impacted maxillary canine (b) Cystic-appearing lesion (c) Resorption of adjacent root.

Figure 2

Sector measurement using panoramic radiography. Sector measurement using panoramic radiography. Each sector was divided according to the proximal contact point of adjacent teeth. Impacted maxillary canines were classified by the sector where their cusp tips were located. The figure above shows ‘sector A’.

Figure 3

Angular measurements using panoramic radiography. Angular measurements using panoramic radiography. The occlusal plane is defined as the plane which connects the mesiobuccal cusp of the maxillary first molar and the mid-point of incisal edge of the maxillary central incisor. The midline is defined as the line which connects the proximal contact of the maxillary central incisors and anterior nasal spine. (a) 3^OP. The angle between the long axis of the canine and the occlusal plane. (b) 3^ML. The angle between the long axis of the canine and the midline.

Figure 4

Linear measurements using panoramic radiography. Linear measurements using panoramic radiography. (a) 3c-OP. The distance from the cusp tip of the impacted maxillary canine to the occlusal plane. (b) 3c-ML. The distance from the cusp tip of the impacted maxillary canine to the midline.