The aim of this prospective clinical project will be to compare the effect of platelet rich fibrin versus low- intensity pulsed ultrasound on therate of different orthodontic tooth movements during clear aligner therapy.

The aim of this prospective clinical project will be to compare the effect of platelet rich fibrin versus low- intensity pulsed ultrasound on therate of different orthodontic tooth movements during clear aligner therapy.specifically canine retraction,incsiors levellingand aliggnment,maxillary molar distalizationand incisors intrusion

Inclusion Criteria:

- A- leveling and alignment Eligibility criteria

1. Age ranges from 14 to 17 years. 2. Bilateral Class II molar relationship. 3. Skeletal Class I or mild Class II relationship. 4. Normal or decreased vertical height. 5. No posterior crowding or spaces. 6. Fully erupted maxillary first and second molars. 7. Congenitally missing or extracted third molars. 8. Good oral hygiene. 9. Absence of any periodontal disease and alveolar bone loss. 10. Absence of medications that may inhibit orthodontic movement

Lower incisor leveling and alignment Inclusion criteria Complete permanent dentition (third molars not included); Moderate mandibular anterior crowding (with little's irregularity index score greater than 4 mm) who required non-extraction approach in the mandibular arch; No tooth size, shape or root abnormalities visible on the patient's radiographic records; No spaces in the mandibular arch; No blocked out tooth that did not allow for placement of the bracket at the

initial bonding appointment; 6. No required management with interproximal stripping, inter-maxillary elastics, open NiTi springs, and removable or extra-oral devices. Canine retraction Eligibility criteria

Age, 15 to 25 years; Class ii division 1 malocclusion with mild or no crowding; No previous orthodontic treatment; No systemic disease that might have affected bone formation or density, such as osteoporosis, hyperparathyroidism, or vitamin d deficiency; Adequate oral hygiene; Probing depth values not exceeding 3 mm across the Entire dentition; Adequate thickness of the attached gingiva (1-2 mm); No radiographic evidence of bone loss -

Exclusion Criteria:Patients who required surgery to correct skeletal discrepancies. Patients with congenital dentoskeletal disorders. Missed or mutilated teeth in maxillary arch. Patients with poor oral hygiene and/or periodontally compromised patients Severe dental crowding that necessitates an extraction approach 2. Abnormal anteroposterior and vertical relationships; 3. Patients with cleft lip and palate, anomalies, and syndromes; 4. Previous orthodontic 5. Treatment; 6. Regular medications intake that could interfere with otm. -

-