Single Versus Repeated Piezocision-assisted Orthodontic Tooth Movement

Primary outcomes

1. Measurement of canine retraction

   Time frame: 12 weeks

   Several landmarks will be identified on the dental arch, including the mid-palatal raphe, the most medial points on the third right and left rugae, and the cusp tips of the right and left maxillary canines. Perpendicular lines will be drawn from the medial points of the right and left third rugae, and the cusp tips of the right and left maxillary canines to the mid-palatal raphe. The antero-posterior measurements will be carried out between the canine lines and the third rugae lines bilaterally, to assess the rate of canine retraction.

2. Measurement of molar anchorage loss

   Time frame: 12 weeks

   Perpendicular lines will be drawn from the central fossae of both maxillary right and left first molars to the mid-palatal raphe. Consequently, molar anchorage loss will be calculated by measuring the distance between those lines, and the lines representing the third rugae as previously mentioned.

3. Measurement of canine root resorption

   Time frame: 12 weeks

   Root resorption of the maxillary canines will be evaluated and measured by comparing pre-retraction and post-retraction CBCT scans.

4. Bone Microstructure (Fractal Dimension)

   Time frame: 12 weeks

   Using the collected CBCT scans, the region of interest will be selected within the maxillary alveolar process, and the fractal dimension analysis will be performed using a special software for the maxillary canines in the experimental and control groups.

5. Alveolar bone density

   Time frame: 12 weeks

   From the acquired pre- and post-retraction CBCTs, bone density will be measured form a coronal cross-section of the maxillary arch around each canine in the experimental and control groups.

6. Alveolar bone thickness

   Time frame: 12 weeks

   The buccal bone thickness will also be measured at three points from the buccal bone to the root, at the coronal, mid-root, and apical level for each maxillary canine

7. Alveolar bone volume

   Time frame: 12 weeks

   From the pre- and post-retraction CBCTs (at T0 and T1), bone volume in areas of the maxillary alveolar process surrounding the canines will be measured using a special software.

8. Maxillary canine tipping

   Time frame: 12 weeks

   Tipping of the maxillary canine during retraction was evaluated by drawing vertical lines on the palatal surfaces of the lateral incisor and the canine that extend from the middle of the incisal edge of the lateral incisor and the cusp tip of the maxillary canine to the middle of the cervical line of each, thereby dividing each of them into equal halves. The distance between the lateral incisor and the canine was assessed at two points on their clinical crowns: incisal, and cervical, enabling the detection of crown tipping of the canine during retraction if there was a difference in the measurements between the both the assessed levels.