Background: To our knowledge, no study evaluated the use of VCMX at multiple implant sites and compared its efficacy and safety to a SCTG with the same dimensions. Therefore, we propose in the present protocol to evaluate the efficacy of VMCX to increase the thickness and height of soft tissue when placed at the time of multiple implant placement, as compared to SCTG.

Material and Methods: This study will be conducted in the saint joseph university periodontology department on at least 5 to 10 patients. The studied sites are the edentulous posterior mandible in a split-mouth model. The test groups are the groups grafted with VCMX and the control groups are the groups grafted with SCTG.

Some studies have been reported to compare these two techniques. But the specificity of our study is soft tissue augmentation on multiple implant sites in a split-mouth design.

Inclusion Criteria:

• Adults ;18 years old.
• Patients with adequate oral hygiene (FMPI<20% and FMBI<20%).
• Healed implant sites (tooth extraction at least 8 to 12 weeks before enrolment).
• Patients who need prosthetic rehabilitation of at least two implants in the left and right posterior mandibular area.
• Inadequate amount of soft tissue where the implants are planned to be placed: thin mucosal tissues covering the edentulous alveolar ridge.
• Compliant patients are willing to sign an informed consent.

Exclusion Criteria:

• Uncontrolled periodontal disease.
• Heavy smoker (>10 cigarettes per day).
• General contraindications for dental surgical treatment.
• Insufficient bone volume for implant placement requiring bone augmentation procedures.
• History of malignancy, radiotherapy, or chemotherapy for malignancy within the past 5 years.
• Pregnancy or breastfeeding.
• Previous and concurrent medication affecting bone and mucosal healing.
• Disease affecting bone and connective tissue metabolism.
• Immediate implant placement.