Various treatment protocols of peri-implantitis involving surgical therapies with open flap debridement procedures, resective or reconstructive modalities have been documented to achieve variable success. Surgical non-reconstructive approaches have been suggested to have limited effectiveness in terms of the resolution of inflammation in the long term. Therefore, much more interest has been intensified regarding the efficacy of biomaterials used in reconstructive approaches. The aim of this study was to investigate the 3-year clinical/radiographic outcomes of reconstructive surgical therapy of peri-implantitis using a bone substitute combined with two different bioresorbable barrier membranes, either collagen membrane (CM) or concentrated growth factor (CGF). A total of 52 patients who had at least one implant diagnosed with peri-implantitis and needed to be scheduled for reconstructive therapy of a peri-implant infrabony defect were included. Peri-implantitis case was defined as increased probing depth (PD) compared to previous examinations with bleeding on probing (BOP) and/or suppuration and radiographic evidence of peri-implant bone loss beyond crestal bone level changes resulting from initial bone remodeling. The patients were randomly assigned to receive a bone substitute filling in combination with either CM or CGF. Intrabony components were filled with a bone substitute (BioOss spongiosa granules; Geistlich, Wolhusen, Switzerland) and covered with a CM (Bio-Guide, Geistlich Biomaterials) or CGF membrane. The plaque index (PI), gingival index (GI), BOP, PD, clinical attachment level (CAL), mucosal recession (MR) and radiographic vertical defect depth (VDD) values were evaluated at 1 and 3 years postoperatively.

Peri-implantitis is a plaque-associated pathological disease affecting the soft and/or hard tissues surrounding a dental implant and clinically characterized by bleeding on probing (BOP) and/or suppuration (Supp), increased probing depths (PDs) and/or mucosal marginal recessions (MRs) in addition to radiographic marginal bone loss (MBL) compared to previous examinations. Considering the increasing numbers of patients undergoing restorative treatment through dental implants and the corresponding increase in the prevalence of peri-implantitis, it is imperative to perform effective treatment methods for the management of these conditions. On the basis of evidence, the most reliable and predictable treatment of peri-implantitis has not yet been described, moreover, if the disease is left untreated, it progresses in a non-linear accelerating manner. Hence, peri-implantitis has been considered to be a major, unpredictable and growing problem for clinicians.

Various treatment protocols of this challenging problem involving non-surgical approaches and surgical therapies with open flap debridement procedures, resective surgeries, or reconstructive modalities, which include the use of bone substitutes with or without a membrane, decontamination methods of implant surfaces, antimicrobial prescriptions whether to use submerged or non-submerged techniques, have been proposed. Although non-surgical interventions have been reported to be effective in reducing BOP and PDs in peri-implantitis sites, these therapies have appeared to be unpredictable for the management of peri-implantitis, especially in most severe cases. As another treatment option, surgical non-reconstructive approaches, i.e. open flap debridement and surface decontamination alone, have been suggested to have limited effectiveness in terms of the resolution of inflammation for the long-term outcomes. Therefore, much more interest has been intensified regarding the efficacy of biomaterials used in reconstructive approaches. Several surgical augmentative therapy studies, including the use of bone substitutes with or without barrier membranes have demonstrated significant clinical and radiographic improvements for at least 3 years, especially in well-contained (three- or four-wall) intrabony defects. A systematic review evaluating long-term outcomes of reconstructive therapy for the management of peri-implantitis showed a mean PD reduction of 3 mm and a radiographic gain of 2.4 mm in bone level. However, as indicated by the last EFP Workshop, no evidence to support the superiority of a specific material, product or membrane in terms of long-term clinical outcomes of a reconstructive approach has been found. It has been strictly recommended that identification of peri-implantitis therapy success and disease resolution in the long-term management are required to allow adequate assessment of stable treatment outcomes.

Because of many studies indicating that growth factors have provided to transiently stimulate cells locally, accelerate angiogenesis, promote proliferation, differentiation, and regeneration, the additional use of them in the management of peri-implantitis has been proposed to improve the clinical outcomes and enhance soft and hard tissue regeneration. A recent systematic review and meta-analysis has been suggested that growth factors might be associated with better outcomes with regard to PD and BOP, whereas, they did not reveal statistically significant evidence for yielding additional benefits in the treatment of peri-implantitis. A randomized clinical trial (RCT) on the reconstructive surgical treatment of peri-implantitis evaluating concentrated growth factor (CGF) used as a bioresorbable barrier membrane in combination with a bone substitute, was performed recently by our study group and demonstrated significant improvements in both clinical and radiographic assessments at 1-year follow-up. Nevertheless, there is scarce information in the literature regarding the predictability and long-term stability of autologous growth factors in peri-implantitis management.

It is, therefore, the aim of this study to investigate the 3-year clinical/radiographic outcomes of reconstructive surgical therapy of peri-implantitis using a bone substitute combined with two different bioresorbable barrier membranes, either collagen membrane (CM) or CGF, and moreover, to identify prognostic indicators influencing the long-term reconstructive surgical treatment outcome using a multilevel statistical model.

Inclusion Criteria:

• age > 18 years,
• having at least one implant demonstrating two- or three-wall infrabony defect ≥3 mm, which presented a probing depth of ≥5 mm with BOP and/or suppuration,
• no implant mobility and no evidence of occlusal overload.

Exclusion Criteria:

• serious systemic diseases, medications or conditions that would contraindicate for periodontal surgery and compromise wound healing,
• a history of taking systemic antibiotic during the past 3 months, and
• placement, and prosthetic loading of implants within the past year.

Presence of bleeding on probing (BOP) and/or suppuration (SUP) on gentle probing, and a radiographic marginal bone loss (MBL) ≥ 2 mm based on baseline radiographs taken at the time of prosthesis delivery with increased probing depth (PD) compared to previous examinations.