Outcome measures
lateral incisors, orthodontic, tooth
SECONDARY, ROOT RESORPTION, IMPACTION
For all patients, two cone-beam computed tomography (CBCT) images of the maxillary jaw were obtained. The first CBCT image was obtained two weeks before the beginning of treatment while the second image was obtained right on the day the fixed appliance was removed. The CBCT system was a CBCT Picasso
The principal researcher (MRM) performed the measurements and evaluated all variables. The primary outcomes were (1) traction duration, (2) total treatment duration, and (3) the velocity of traction movement. The traction duration is measured as the interval between the onset of orthodontic traction on the impacted canine and the emergence of half of its clinical crown. The total treatment duration calculated as the time between the bonding of the fixed orthodontic appliance until it is removed. The velocity of traction movement is determined by dividing the depth of impaction, which is defined as the distance from the impacted canine cusp tip to the occlusal plane, by the traction duration.The secondary outcomes were (1) bone support of the aligned canine (BS-IC), (2) bone support of the contralateral naturally erupting canine (BS-CON), (3) bone support of the adjacent lateral incisor (BS-LI), (4) bone support of the adjacent first premolar (BS-PR), and (5) root resorption of the adjacent lateral incisor (RR-LI). Bone support was evaluated on the posttreatment CBCT scans. It was assessed on the mesial, distal, buccal, and palatal aspects of the canines, lateral incisors and first premolar. The total bone support ratio was calculated by averaging the four measurements made on each tooth. The alveolar bone level was measured from the root apex of the evaluated tooth to the alveolar crest, whereas the root length of the evaluated tooth was measured from root apex to the midpoint of a line connecting the mesial and distal points on the cemento-enamel junction of this tooth. The ratio of alveolar bone level to the root length was considered the percentage of bone support.
