Thirty two patients requiring extraction of maxillary first premolars and en-masse retraction of upper anterior teeth will participate in the study. They will be divided randomly into two groups: electrical group and control group. In each group, en-masse retraction will be initiated after completion of the leveling and alignment phase via closed nickel-titanium coil springs applying 250 g of force per side, Mini-implants will be used as an anchor unit.

The overall retraction duration will be calculated. The skeletal, dental and soft tissue changes will be detected using panoramic and lateral cephalometric radiographs which will be obtained pretreatment, pre and post en-masse retraction of the anterior teeth.

Prior to enrollment of each subject into the study, they will be examined completely to determine the orthodontic treatment plan. The operator will inform them about the aim of the study and ask them to provide a written informed consent.

Self-drilling titanium mini-implants (1.6mm diameter and 8mm length) will be used. They will be inserted between the maxillary second premolar and first molar at approximately 8-10 mm above the archwires at the mucogingival junction and will be checked for primary stability (mechanical retention). Then the maxillary first premolar will be extracted. The maxillary arch will be levelled and aligned. The rectangular stainless steel archwires (0.019" × 0.025") with anterior 8mm height soldered hooks distal to the canines will be inserted.

A removable device containing a small electrical circuit will be applied to each patient to supply the required electric current.

Each patient in the electrical group will be asked to wear a removable device containing a small electrical circuit that will supply the required electric current for five hours a day until the completion the retraction of the upper anterior teeth.

(250-300) g force will be applied on each side using two NiTi springs attached between the mini-implants and the soldered hooks in a direction approximately parallel to the occlusal plane for conducting an en-masse retraction. The force level will be measured every 2 weeks. Retraction will be stopped when a class I canine relationship will be achieved and a good incisor relationship will be obtained.

The duration of retraction will be calculated by calculating the time required to achieve complete retraction of the upper anterior teeth through clinical examination.

Panoramic and lateral cephalometric radiographs will be obtained pretreatment, pre and post en-masse retraction of the anterior teeth, to assess the skeletal, dental and soft tissue changes.

Periodontal health will be assessed at the beginning of orthodontic treatment, before and after en-masse retraction by evaluating the following parameters: plaque index, gingival index, bleeding index, probing depth and gingival recession.

Inclusion Criteria:

1. Adult healthy patients, Male and female, Age range: 15-27 years.

2. Class II Division 1 malocclusion :

   • Mild / moderate skeletal Class II (sagittal discrepancy angle ≤7)
   • Overjet ≤10
   • Normal or excessive facial height (Clinically and then cephalometrically assessed using these three angles : mandibular/cranial base angle, maxillary/mandibular plane angle and facial axis angle)
   • Mild to moderate crowding ≤ 4

3. Permanent occlusion.

4. Existence of all the upper teeth (except third molars).

5. Good oral and periodontal health:

   • Probing depth < 4 mm
   • No radiographic evidence of bone loss.
   • Gingival index ≤ 1
   • Plaque index ≤ 1

Exclusion Criteria:

1. Medical problems that affect tooth movement (corticosteroid, nonsteroidal anti-inflammatory drugs (NSAIDs), …)

2. Presence of primary teeth in the maxillary arch

3. Missing permanent maxillary teeth (except third molars).

4. Poor oral hygiene or Current periodontal disease:

   • Probing depth ≥ 4 mm
   • radiographic evidence of bone loss
   • Gingival index > 1
   • Plaque index > 1

5. Patient had previous orthodontic treatment