Abstract : This research aims to study the periodontal parameters after implementing the connective graft by tunnel- technique in patients with crowding in the mandibular anterior region. The randomized controlled clinical study sample consisted of 24 patients (12 patients in the control group and 12 patients in the experimental group), who were distributed into two groups according to the sequence of their admissions. Patients with single numbers were treated by implementing the connective tissue graft before the orthodontic. Patients with double numbers were treated with orthodontics only. The gingival recession and thickness were measured before and at the end of treatment. In addition, Little's irregularity index was measured every month until the end of treatment. The results showed an increase in gingival thickness in the experimental group. Gingival recession did not occur in the control or experimental group. The improvement in crowding was noticed in the experimental group's first and second treatment sessions. The implementation of connective tissue graft by tunnel technique is indicated before the orthodontic treatment in patients with thin gingival biotypes, where it increases the gingival thickness without accelerating the orthodontic movement in cases of crowding in the mandibular anterior region. Moreover, orthodontic treatment does not cause gingival recession.