Abstract Statement of the problem: Peri-implant soft-tissue augmentation procedures can be broadly divided into two groups, depending on their primary therapeutic objective: (1) Peri-implant soft-tissue phenotype modification and (2) Treatment of peri-implant marginal mucosa defects (PMMDs), also known as peri-implant soft-tissue dehiscences.

Aim of the study: The aim of this study will be to evaluate the efficacy of the Omega roll envelope flap (OREF) technique compared to the conventional envelope split-thickness flap technique combined with an autogenous connective tissue graft, in enhancing Peri-implant soft tissue phenotype defined by the gingival thickness, keratinized tissue width, mucosal margin level and interproximal papilla height around implant.

Materials and Methods: 24 patients complaining of a single missing tooth in the with adjacent intact natural teeth and demanding replacing it with the best possible esthetics will be enrolled and recruited from the outpatient clinic, Faculty of Dentistry, Ain Shams University according to eligibility criteria. They will be randomly allocated to two equal groups. Group A (test group, n=12) will have a single implant placed after receiving non-surgical periodontal therapy and then after 12 weeks at the uncovering of the implant and placement of healing abutment, an Omega roll envelope flap (OREF) technique will be carried out for soft tissue augmentation, while Group B (control group, n=12) same procedures will be done but, soft tissue augmentation will be done by an envelope split-thickness flap combined with a sub-epithelial connective tissue graft. After 3 and 6 months Peri-implant soft tissue phenotype defined by gingival thickness, keratinized tissue width, mucosal margin level and interproximal papilla height around implant will be clinically assessed (1ry outcome). The 2ry outcomes will include comparing between the probing depth and clinical attachment level. Postoperative pain and swelling will be recorded by the patient for the 1st two weeks post-surgically. Postoperative instructions and medication will be given to the patient. All readings will be carried out by a calibrated outcome assessor who will be blinded. Data collected will be tabulated and statistically analyzed.

Inclusion Criteria:

• Systemically free patients (American Society of Anesthesiologists (ASA) I. Patients between 18 - 50 years of both genders and able to understand the nature of the proposed surgery and to sign the informed consent. Ability to comply with the study related procedures such as maintaining good oral hygiene and attending all follow-up scheduled appointments. Patients who complained of a single missing tooth bounded with two adjacent natural sound teeth diagnosed with clinical periodontal health. Necessity for soft tissue augmentation in a single tooth gap determined by a concavity that was present in the edentulous area or tissues with thin biotype being ≤2 mm or with inadequate width of ≤4mm. Adequate bone width for implant placement without need for bone augmentation (confirmed by a single pre-operative cone-beam computed tomography) (CBCT).

Exclusion Criteria:

• Previous soft tissue augmentation in the area. Need for major soft or hard tissue augmentation procedures. Smokers. Patients taking medications that might affect the healing of soft and hard peri-implant tissues.