Platelet-rich fibrin (PRF) is a second-generation platelet concentrate used for tissue and bone regeneration. PRF releases growth factors such as TGF-β, PDGF, VEGF, IGF, and FGF, which are known to promote wound healing and bone regeneration. Thus, PRF may offer a promising therapeutic approach for peri-implantitis treatment. Numerous studies have reported beneficial effects of PRF on bone regeneration, bone augmentation, soft tissue healing, and ridge preservation. In infrabony periodontal defects, PRF has shown significant improvements in pocket depth reduction, clinical attachment level (CAL) gain, and bone fill.

However, a recent systematic review highlighted that evidence supporting PRF use in peri-implantitis remains limited, primarily due to a lack of adequately designed studies. Therefore, the aim of this project is to investigate whether PRF enhances regeneration in peri-implantitis defects. Specifically, it will assess whether surgical debridement of peri-implantitis defects-including electrochemical detoxification of implant surfaces using GalvoSurge-combined with PRF clot and membrane placement, improves treatment outcomes compared to surgical debridement and detoxification using GalvoSurge alone.

For this purpose, implants with peri-implantitis defects of comparable size will be randomly assigned to either the test or control group. After 12 months, implants will be clinically evaluated for radiographic defect fill, reduction in probing pocket depth (PPD), and bleeding on probing (BOP). The objective of this project is to verify, both radiographically and clinically, whether adjunctive PRF application enhances tissue regeneration and healing of peri-implantitis defects compared to open flap debridement (OFD) alone.

Peri-implantitis is a chronic inflammatory condition around dental implants, associated with biofilm-mediated infection. The initial stage involves the formation of a bacterial biofilm in the peri-implant tissue, resulting in mucositis, which is characterized by erythema, bleeding, exudation, and swelling. With continued biofilm accumulation, mucositis can progress to peri-implantitis, which is marked by bone destruction. Due to varying definitions of peri-implantitis, the VIII European Workshop on Periodontology established diagnostic criteria, specifying progressive bone loss of ≥ 2 mm with clinical signs of inflammation. Recently, the American Academy of Periodontology and the European Federation of Periodontology suggested a threshold of ≥ 3 mm. Based on these definitions, recent meta-analyses have shown the prevalence of peri-implantitis to be approximately 18.5% at the patient level and 12.8% at the implant level, highlighting an increasingly significant problem within the global adult population.

Currently, treating peri-implantitis is challenging, costly, and often unpredictable. The primary goals of therapy are to resolve soft-tissue inflammation and stabilize the bony attachment. This requires effective removal of bacterial biofilms and deposits from implant surfaces to enable healing on a biologically clean surface. Peri-implantitis therapy often necessitates a surgical approach that includes surface decontamination with or without the use of a bone substitute. Despite these interventions, surgically treated cases demonstrate a high failure rate, with approximately 60% of cases showing recurrence, underscoring the need for innovative therapeutic approaches.

PRF has recently emerged as a viable alternative to recombinant growth factors due to its ability to support healing naturally. It is obtained by centrifuging blood to create a coagulated plasma that includes a complex mixture of growth factors within a fibrin network. This plasma can be further processed to extract a PRF membrane by squeezing out the serum. PRF membranes are increasingly used to enhance clinical outcomes by delivering growth factors at surgical sites, either alone or in combination with dental implants and collagen membranes.

This project aims to determine whether PRF enhances regeneration in peri-implantitis defects and to compare the outcomes of surgical debridement and implant detoxification combined with PRF clot and membrane placement, against debridement and detoxification alone. For this purpose, implants with peri-implantitis defects of comparable size will be randomly assigned to either the test or control group.

Study Endpoints:

Radiographic defect fill after one year, with a cut-off level of > 1.0 mm Clinical parameters: probing pocket depth (PPD), bleeding on probing (BoP), and keratinized tissue amount in mm on the oral and buccal implant sides Soft tissue healing as assessed by the Early Wound Healing Index by Wachtel Composite clinical index based on criteria established by Renvert et al. (2018) Patient-reported outcomes assessed through a visual analog scale

Inclusion Criteria:

1. One or more peri-implant sites with PPD ≧ 5 mm combined with BOP/suppuration and
2. Peri-implant marginal bone loss, defined as a crater like defect ≧ 3 mm as assessed from intraoral radiographs
3. Good oral hygiene i.e. a plaque index <20%
4. Written informed consent

Exclusion Criteria:

1. History of chronic inflammatory disease
2. Severe systemic diseases
3. Medically confirmed diagnosis of diabetes mellitus
4. Anti-inflammatory prescription including prednisone
5. Smoking > 5 cigarettes
6. Pregnant or lactating women
7. < 18 years of age

A balanced randomisation is being performed.

Outcome measures are being assessed by a clinician blinded to the patient allocation.