The purpose of this study is to compare the clinical and radiographic outcomes of two different barrier membranes-amnion-chorion membranes (ACM) and conventional collagen membranes-used in guided bone regeneration (GBR) procedures for the treatment of peri-implantitis. Both membranes are commonly used in clinical practice; however, this study aims to determine whether ACM offers greater benefits in terms of peri-implant probing depth reduction, radiographic bone fill, and patient-reported post-operative healing outcomes. The findings may help inform surgical decision-making and support the use of ACM as a more effective regenerative material for managing peri-implant bony defects.

Peri-implantitis is a common complication characterized by inflammation and progressive bone loss around dental implants. Guided bone regeneration (GBR) is a frequently employed surgical approach to manage peri-implant defects. Barrier membranes play a critical role in GBR by excluding soft tissue and supporting bone regeneration.

This randomized controlled clinical trial is designed to compare the outcomes of two commonly used barrier membranes: amnion-chorion membranes (ACM) and conventional collagen membranes. Although both are used in practice, ACM may offer additional biological benefits due to the presence of growth factors, anti-inflammatory properties, and native extracellular matrix components.

The study will enroll 56 participants across four clinical sites, with subjects randomly assigned to receive either ACM or a collagen membrane during peri-implant GBR surgery. Clinical parameters, including probing depths and peri-implant soft tissue health, will be recorded at baseline and follow-up visits. Patient-reported outcome measures (PROMs) will be collected using standardized questionnaires to evaluate post-operative healing, discomfort, and satisfaction. Standardized periapical radiographs will be taken at 3, 6, 12, 18, and 24 months to assess radiographic bone fill.

The primary objective is to determine whether the use of ACM results in improved clinical and radiographic outcomes compared to collagen membranes. Secondary objectives include evaluating patient-reported healing and long-term implant stability. Results from this study may inform clinical decision-making and potentially support the wider use of ACM in regenerative peri-implant therapy.

Inclusion Criteria:

• Systemically healthy adults (≥18 years) with a diagnosed peri-implantitis lesion requiring surgical intervention of any ethnicity
• Comprehension of treatment plan and research project.
• Presence of a single implant in function for at least one year.
• Radiographic evidence of peri-implant bone loss not exceeding one-third of the implant length.
• 2-3 wall defects amenable to guided bone regeneration (GBR).
• Screw-retained, posterior, self-cleansing implant prosthesis.
• Commitment to maintaining oral hygiene and attending follow-up visits.

Exclusion Criteria:

• Patients who have had a history of periodontitis, diabetes, smoking habit, or have been prescribed medications that may interfere with bone healing and metabolism
• Patients with allergies to any treatment devices
• Patients who have a lack of keratinized mucosa (<2 mm), or positioning for implants or restorative designs that compromise oral hygiene
• Peri-implant bone defects not attributable to peri-implantitis (e.g. surgical iatrogenic, trauma)
• Anterior implant restorations (#'s 6-11, #'s 22-27) or cement-retained restorations

This means the patient and the evaluator collecting outcome data (probing, PROMs, radiographs) are blinded. The only one that will not be blinded will be the surgeon.