The purpose of this study is to assess the influence of two different flap designs (envelope Coronally Advanced Flap (eCAF) and Modified Tunnel Technique (MTT)) with the addition of a connective tissue graft (CTG) in treating soft tissue dehiscences at implant sites

The primary aim is to compare the test and control groups in terms of:

1. mean mid-facial recession coverage (mRC) measured as a percentage
2. the keratinized tissue (KT) gain measured in mm
3. the keratinized tissue thickness (KTT) gain measured in mm.

The secondary aims are to compare the two groups in terms of:

1. Esthetic score, using numeric values from 0 to 10
2. patient-reported esthetics, using numeric values from 1 to 5
3. patient-reported post-operative pain, based on Visual Analog Scale (VAS) scale, measured as numbers from 0 to 10.

Inclusion Criteria:

• Age ≥ 18 years
• Periodontally and systemically healthy
• Full-mouth plaque score and full-mouth bleeding score ≤ 20% (measured at four sites per tooth)
• Correct implant 3-dimensional position or buccal position ≤ 1 mm
• Buccal soft tissue dehiscence ≤ 4 mm
• Only osseointegrated implants
• The patient must be able to perform good oral hygiene

Exclusion Criteria:

• Contraindications for periodontal surgery
• Patients pregnant or attempting to get pregnant
• Malpositioned implant
• Soft tissue dehiscence (STD) > 4 mm
• Multiple adjacent implants with STD
• Existing of peri-implantitis
• Severe bone loss (≥4mm)
• Moderate-severe interproximal bone loss (implant fixture level to the alveolar bone > 3 mm)
• Moderate-severe papilla height loss (Nordland and Tarnow implant papillae index >1)
• Previous mucogingival surgery around the implant within the past six months or implant placement at the surgical site less than six months prior
• Smoking more than 10 cigarettes a day