Regenerative Treatment of Peri-implantitis

The purpose of this study is to study the use of a new type of d-PTFE membrane called reinforced PTFE Mesh (RPM) with dental surgery. The regenerative outcomes of RPM membranes and collagen membrane for surgical reconstructive treatment of peri-implantitis (gum disease around implants) will be compared.

Inclusion Criteria: * Age ≥ 18 years * Physical status according to the American Society of Anesthesiology (ASA) I or II, which include patients who are systematically healthy or may suffer from mild to moderate, however well-controlled systemic diseases. * Subjects having at least one dental implant with peri-implantitis according to the definition proposed by the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions (Berglundh et al., 2018): * Full-mouth plaque score and full-mouth bleeding score ≤ 20% (measured at four sites per tooth) * Correct 3-dimensional implant positioning, or buccal position ≤ 1 mm * Implants which have been in function for at least 6 months Exclusion Criteria: * A clearly mal-positioned dental implant * Significant interproximal horizontal bone loss (more than 50% of implant fixture length) * A mobile dental implant * Presence of uncontrolled or untreated periodontal disease * More than 2 weeks usage of antibiotics in the past two months * Subjects taking medications known to modify bone metabolism or those that can interfere with the normal wound healing (such as bisphosphonates, corticosteroids, hormone replacement therapy, parathyroid hormone, denosumab, strontium ranelate, etc.), or those with uncontrolled systemic diseases or conditions that may similarly affect the patient's healing (osteoporosis, osteopenia, hyperparathyroidism, Paget's disease, uncontrolled diabetes (HBA1c \> 8)). * Pregnant subjects or individuals attempting to get pregnant (self-reported) * Subjects smoking more than 10 cigarettes a day, or those with a history of drug or alcohol abuse (self-reported) * Subjects unable to maintain adequate oral hygiene (O'Leary plaque index more than 50%) (O'Leary et al., 1972) * Any other contraindications for undergoing periodontal surgery