The current study Is a split-mouth Randomized Controlled Trial that was performed to investigate three dimensionally, using digital models and Cone Beam Computed Tomography imaging, the effect of micro-osteoperforations (MOPs) on the rate of tooth movement in a canine retraction model.

Sample size calculation was carried out and resulted in enrolment of 18 female patients requiring bilateral upper first premolars extraction and canine retraction with maximum anchorage. The sample was recruited from the outpatient clinic of the Orthodontic Department, Faculty of Dentistry, Cairo University.

After placement of the fixed orthodontic appliance, leveling and alignment proceeded till 0.016" × 0.022" NiTi upper archwire. Indirect skeletal anchorage was then prepared using TADs inserted bilaterally between the upper 1st molar and 2nd premolar, and the patient was referred for upper 1st premolars extraction.

Three months after extraction, 0.017" × 0.025" stainless-steel upper archwire was inserted and three vertically aligned MOPs were randomly allocated and performed in one side using a single TAD, while the other side served as control. The three MOPs were performed distal to the canine, equidistant in the extraction space. Bilateral canine retraction was then commenced using NiTi closing coil springs delivering 150 gms of force. Before leaving the clinic, a pain questionnaire was given to each patient.

Data were collected from monthly upper impressions, which were poured into stone models and scanned to obtain sequential digital models (T0, T1, T2, T3 & T4), in addition to pre- and post-retraction maxillary CBCT images.

The assessed outcomes were the rate of canine retraction per month, the total distance travelled by the upper canines, first molars anchorage loss, tipping, torque and rotation of upper canines and first molars, canine root resorption and finally the pain related to MOP procedure. Statistical analysis was performed on the gathered data and results were withdrawn.

Inclusion Criteria:

• Malocclusion that requires bilateral extraction of the maxillary first premolars and canine retraction with maximum anchorage; Class II division 1 and bimaxillary dentoalveolar protrusion cases.
• Full permanent dentition with exception of the third molars.
• Good oral hygiene and periodontal condition.

Exclusion Criteria:

• Medically compromised patients.
• Patients suffering from any congenital, hereditary or systemic diseases.
• Chronic use of any medications affecting orthodontic tooth movement (e.g. corticosteroids, hormonal therapy, NSAIDs)
• Patients with dental anomalies (e.g. enamel hypoplasia, root dilacerations in maxillary canines).
• Patients with medical conditions that contraindicate surgeries (e.g. bleeding tendency and immunocompromised patients).
• Radiographic evidence of bone loss.