Inclusion Criteria:  Patient satisfying the following criteria will be included in this clinical study:  Patients with age between 16-25 years Patients with either Angle's class I or class II malocclusion with moderate crowding in the anterior mandible(LII- 4-6mm) who requires extraction in the lower arch (tooth-size-arch-length discrepancy>5 mm) Permanent dentition Existence of all tooth in the mandibular arch (except third molars which may or may not be present) Good oral hygiene and periodontal health No smoking habit.  Exclusion Criteria:  medical conditions that would affect tooth movement (corticosteroid treatments, NSAIDs consumption, bisphosphonates, hyperparathyroidism, osteoporosis, uncontrolled diabetes) Contraindication to oral surgery (medical, social, psychological) Missing tooth in the mandibular arch Presence of primary or supernumerary tooth in mandibular arch Previous orthodontic treatment Poor oral hygiene and current periodontal disease Smoking habit.