60 patients will be treated by extraction of maxillary first premolars by applying mini-screws between the maxillary second premolar and first molar as temporary skeletal anchorage devices (TSADs). They will be divided randomly into three groups in this trial. The prolonged duration of the treatment period can cause many side effects such as white spots, caries, periodontal diseases, and pain and discomfort. So many efforts have been made to reduce the treatment time. Many procedures have been introduced to accelerate orthodontic tooth movement, which can category as surgical or non-surgical. Piezocision is a minimally invasive surgical method for accelerating orthodontic tooth movement and shortening treatment time. Low-level laser therapy (LLLT) is one of the physical acceleration methods that have contributed to decreasing treatment time.

Closed nickel-titanium coil springs applying 250 g of force per side will be used for retraction of the maxillary anterior teeth.

The en-masse retraction will be obtained with two nickel-titanium coil springs placed between the mini-implants and the soldered hooks in a direction approximately parallel to the occlusal plane, a force of 250 g will be applied on each side to perform en-masse retraction. The retraction will be stopped when a Class I canine relation is achieved and a good incisor relation is obtained or spaces lateral to canines are closed.

Regarding the Piezocision, vertical soft-tissue incisions will be made on the buccal and palatal gingiva. One incision will be made between the roots of the six upper anterior teeth, and two incisions will be made between the upper canines and the second premolars. The incisions will be 5 mm long and start 4 mm apical to the interdental papilla. Then a piezosurgery knife will be inserted to perform the cortical alveolar incisions with 3-mm in-depth and 8 mm in length. No suturing will be needed.

Regarding the piezocision with the later application of low-level laser therapy (LLLT):

After seven weeks of piezosurgery, GaALAs diode laser (wavelength: 810 nm and exposure time of 10 seconds\point) 10 seconds per point will be applied on each tooth of the six maxillary anterior teeth according to this protocol: the root will be divided theoretically into 2 halves; gingival and cervical, and the laser will be applied in the centre of each half from both buccal and palatal sides which means 4 application points and total energy of 16 Joules per tooth. The LLLT will be applied 5 times in the first month of en masse retraction. After that, the irradiation will be repeated every two weeks, until the class, I canine relationship will be achieved and/or spaces lateral to incisors were closed

Inclusion Criteria:

1. Adult healthy patients, Male and female, Age range: 17-28 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. The patient had previous orthodontic treatment