Comparative Evaluation Of The Micro-Osteoperforations And Piezocision On The Rate Of Canine Retraction: A Split Mouth Randomized Controlled Trial

AIM:Evaluate and compare the effect of micro-osteoperforation (MOP) and piezocision on the rate of orthodontic tooth movement in canine retraction.

OBJECTIVES:

1)     To evaluate the amount of canine movement on MOP side.

2)     To evaluate the amount of canine movement on piezocision side.

3)     To evaluate the amount of molar movement on MOP side.

4)      To evaluate the amount of molar movement on piezocision side.

5)      To evaluate the rotation and tipping of the canine on MOP side.

6)     To evaluate the rotation and tipping of the canine on piezocision side.

7)      To evaluate the rotation and tipping of the molar on MOP side

8)      To evaluate the rotation and tipping of the molar on piezocision side.

9)     To evaluate the root resorption of canine if any on the MOP side and piezocision side.

10)    To find out the best method for controlled canine movement.

Materials:

In thisstudy, following armamentarium will be required

1)     Mini-implant

2)     Piezotome Solo (Woodpecker, BS1 Insert)

3)     CBCT (Vatech A9)

4)     Alginate impression

5)     Transpalatal arch (TPA)

METHODOLOGY:

Pre-retraction (T0) alginate impression and Cone beam computed tomography scan (T0) will be taken for all subjects. All the selected subjects will require bilateral extraction of premolars.

Orthodontic treatment protocol for all the patients will be bonded with metal MBT(Leone) prescription of 0.022- 0.028 inch and trans bond XT. All the indicated first premolars will be extracted and alignment and levelling will be performed using 0.014-0.016 NiTi arch wires. This will progress to 0.016-0.022 stainless steel wires and single canine retraction will be performed using sliding mechanics

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MOP and Piezocision will be randomly allocated to the patients to choose the side of the procedure. Piezocision will involve gingival micro-incisions and vertical cortical cuts without flap reflection on randomly selected side. The Ultrasonic instrument (BS1 insert Piezotome) will be adjusted to deliver a low frequency ultrasonic waves (28-36 kHz) and used to perform corticotomy, the cortical alveolar incisions will be created inter proximally to a depth of 3mm. The 2 millimeters of marginal crestal bone will be held intact and the vertical groove will be extended along the entire length of canine root. The surgical site will be rinsed with normal saline.

On the other side of extraction, three MOPs will be performed. After disinfecting the area with betadine, the MOPs will be performed under local anesthesia using the TAD (1.8×8 mm).  The TAD will be screwed slowly into the alveolar bone, perpendicular to the bone surface till slight blanching of the surrounding soft tissue will be obtained to ensure full length penetration of the TAD, then the TAD will be unscrewed and removed.

MOPs will be created directly through the alveolar mucosa in the middle of the extraction space in the vertical direction and 3 mm apart. The first MOP will be located 5 mm away from the free gingival margin.

Canine retraction will be then commenced using NiTi closing coil springs applying 150 g extended between the first molar and canine hooks.

Follow-up visits will be scheduled every 3 weeks for re-calibrating the springs, and detecting any occlusal interferences that may arise during canine retraction. An upper alginate impression will be taken every visits. The study time will be continued till the completion of canine retraction, after which the final upper impression will be taken, and the patient will be referred to acquire the post-retraction CBCT (T1) image.

Evaluation of movements and rotation of canines and molar on both the sides, ie., MOP and piezocision side will be done both on the study model and by CBCT scan. The amount of canine movement will be measured in CBCT from the distal point of the lateral incisor to the mesial point of the canine that will be retracted.

For, amount of molar movement, incisive foramen will be marked, and a perpendicular to incisive foramen will be constructed in the transverse axis. The mesiobuccal cusp tip will be marked and a line will be constructed from the same to the true sagittal plane. Distance between the two transverse lines will be measured in pre and post retraction CBCT images.

The upper first molar and canine rotation will be measured as the angle between the molar horizontal axis and frontal plane in the axial view.

The long axis of the canine and molar will be marked, and angle will be formed with the true horizontal plane. The internal angle will be measured in pre and post retraction casesRoot resorption will be assessed using the multiplanar view of the EZ 3D software. The CBCT image will be adjusted using the re-orientation tool, such that the sagittal and the coronal cuts are parallel to the canine long axis. The two cross-sections showing the maximum canine root length will be selected for assessment using Malmgren index. Each canine will be given two scores (0–4) according to the root resorption severity detected from the labio-lingual and mesio-distal cross sections respectively. The difference between the pre and post-retraction scores for each canine will be calculated and evaluated statistically