Peri-implantitis is a infectious disease that resides in the mucosa surrounding dental implants and also affects the supporting bone. Because the number of implants placed in everyday clinical practice is continuously increasing, is it reasonable to anticipate an increasing prevalence of peri-implantitis. This underlines the necessity for a predictable therapy. However, from the literature there is very little reliable evidence suggesting which could be the most effective interventions for treating periimplantitis.

The primary objective of this controlled clinical study is to evaluate the clinical effect of decontamination of the implant surface during the surgical treatment of peri-implantitis using a 2% chlorhexidine solution or a 0.12% chlorhexidine solution. The secondary objective is to assess the microbiological effect of decontamination of the implant surface during the surgical treatment of peri-implantitis using a 2% chlorhexidine solution or a 0.12% chlorhexidine solution.

The primary study parameter is the change from baseline in modified bleeding index. Secondary study parameters are: change in microbial composition of the biofilm covering the dental implant surface; microbiological composition of the peri-implant sulcus; change in probing pocket depth;change in suppuration on probing; change in radiographic marginal bone level on standardized intraoral radiographs; change in modified plaque index; implant failure, defined as implant mobility of previously clinically osseointegrated implants and removal of non-mobile implants because of progressive marginal bone loss or infection; complications and adverse events. It is hypothesized that decontamination of the implant surface with 2% chlorhexidine leads to a greater decrease in modified bleeding index than decontamination with a 0.12% chlorhexidine solution.

Inclusion Criteria:

• The patient is at least 18 years of age;
• The patient has at least one endosseous implant in the oral cavity with clinical and radiographical signs of peri-implantitis. Peri-implantitis is defined as a loss of marginal bone more than or equal to 2 mm as compared to a fixed reference point on the dental implant, in combination with bleeding and/or suppuration on probing and a peri-implant probing depth more than or equal to 5 mm;
• The implants have been exposed to the oral environment for at least two years;
• The patient is capable of understanding and giving informed consent.

Exclusion Criteria:

• Medical and general contraindications for the surgical procedures;
• A history of local radiotherapy to the head and neck region;
• Pregnancy and lactation;
• Insulin dependent diabetes;
• Systemic use of antibiotics during the last 2 months;
• Long-term use of anti-inflammatory drugs;
• Incapability of performing basal oral hygiene measures as a result of physical or mental disorders;
• Active, uncontrolled periodontal pathology of the remaining dentition;
• Local use of antibiotics or use of other anti-septic / antimicrobial therapies in the oral cavity during the last 2 months;
• Bruxism;
• Implants placed in skin grafted areas;
• Implants with bone loss due to other reasons than bacterial infection (e.g. loose screw, inadequate positioning of the implant);
• Implants with bone loss exceeding 2/3 of the length of the implant or implants with bone loss beyond the transverse openings in hollow implants;
• Implant mobility;
• Implants at which no position can be identified where proper probing measurements can be performed;
• Previous surgical treatment of the peri-implantitis lesions;
• Previous non-surgical treatment of the peri-implantitis lesions during the last 6 months (scaling or curettage).