This study will be done to compare the effectiveness of using coaxial tubular superelastic nickel-titanium and copper-nickel-titanium archwires during the initial phase of orthodontic treatment regarding alignment efficiency, pain perception, and root resorption.

This will be a prospective blinded non-stratified randomized clinical trial , parallel group trial with equal randomization (1:1 allocation ratio), different private clinics and general hospitals will allocate patients for this trial. The patients will be initially assessed for eligibility to be included in the study by the investigator. Those who will meet the inclusion criteria will be informed about the nature of the study verbally to take the initial approval for participation. The patients were asked to read the patient information sheet carefully at home and inform the investigator about their decision of participation at the subsequent appointment and to sign consent form sheet in case of agreement.

The patients will be treated using MBT prescription brackets with 0.022-inch slot (Pinnacle®, Ortho Technology, USA). Initially, teeth polishing will be performed with pumice and rubber cup, followed by water rinsing and air drying

All the participants will receive the same treatment. At the day of bonding, the first archwire will be placed for each group. Eight weeks later it will be replaced by the next size archwire for another eight weeks. Archwires will be tied to the bracket using elastomeric ligatures. Any debonding during treatment should be considered an emergency and re-bonded within 24 hours, otherwise the case will be dropout. A good alginate impression for the lower arch should be taken pre-treatment and after 4, 8, 12 and 16 weeks and a stone study model is obtained. Periapical X-ray for the mandibular central incisors will be taken pre-treatment and after 16 weeks. The participants will be given visual analog scale to record their pain p during the first week after each archwire placement.

Inclusion Criteria:

1. Patients indicated for fixed appliance orthodontic treatment with 5-9 mm crowding of mandibular anterior teeth according to Little's irregularity index (LII).
2. Presence of all the mandibular permanent teeth, except the third molars.
3. Overbite and overjet that do not interfere with bracket placement on mandibular anterior teeth.
4. No history of trauma or root resorption in the mandibular incisors.

Exclusion Criteria:

1. Previous orthodontic treatment.
2. Less than 5 mm of mandibular incisors crowding (LII).
3. Severe crowding which requires treatment by extraction of premolars in the mandibular arch.
4. Blocked-out teeth that cannot be engaged with the aligning archwire.
5. Prior experience of periodontal disease and loss of attachment.

Sequence Generation: A computer random generator will be used to develop a simple randomization with an equal allocation ratio (1:1) and without stratification.

Allocation Concealment: This will be achieved using sequentially numbered, opaque and sealed envelopes which will be numbered according to the study numbers. Each envelope includes the treatment allocation card (group 1 or 2) and the related archwires.

Blinding As the study will be conducted in different clinics, all data collection and measurement will be completed with the investigator being masked to the allocation groups, though blinding of the operator will not be possible during the archwire placement.