Soft Peri-implant Tissue Around Different Abutment Materials

Inclusion Criteria: * Age ≥ 18 years * Absence of Systemic Diseases / Disorders * Smoking ≤ 5 cigarettes per day * Periodontally healthy or treated * Full-mouth plaque score (FMPS) ≤ 15% at baseline * Full-mouth bleeding score (FMBS) ≤ 15% at baseline * Presence of edentulous space needing an all on four or all on six treatment with overdenture * Width of the keratinized gingiva ≥ 2 at the level of the crest Exclusion Criteria: (I) • Pregnancy / lactation * Use of systemic antibiotics in the last 3 months * Use of systemic antibiotics as prophylaxis for endocarditis * A chronically treated patient (i.e. 2 weeks or longer) with medicines known to affect periodontal tissues (e.g. phenytoin, calcium antagonists, cyclosporine, warfarin and non-steroidal anti-inflammatory drugs) the last month before starting the study * Radiotherapy in the neck-head region * HIV, TB, hepatitis or other infectious diseases * Abuse with drugs or alcohol * Smoked cigarettes\> 5 cigarettes per day * Untreated periodontitis * FMPS\> 15% at baseline * FMBS\> 15% at baseline * Implants with peri-implant history * Width of keratinized tissue over crest \<2 mm * Need for bone reconstruction around implants to be inserted