Peri-implantitis is an 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, it is reasonable to anticipate an increasing prevalence of peri-implantitis. However, from the literature there is very little reliable evidence suggesting which could be the most effective interventions for treating peri-implantitis.

The primary objective of this controlled clinical study is to evaluate the microbiological effect of decontamination of the implant surface during the surgical treatment of peri-implantitis using a chlorhexidine or placebo solution. The secondary objectives are to assess both the clinical and the microbiological effectiveness of treatment of peri-implantitis.

It is hypothesized that rinsing of the implant surface using a 0.12% chlorhexidine solution does not lead to better microbiological and clinical results compared to rinsing with a placebo solution.

The present study is a double-blind, placebo-controlled, randomized clinical trial.

Adult patients with at least one endosseous implant in the oral cavity with clinical and radiographical signs of peri-implantitis will be included in this study.

Implants with peri-implantitis lesions will be surgically exposed, followed by mechanical cleansing using curettes and gauzes and cotton pellets soaked in saline followed by either 1 minute of rinsing with a placebo solution (saline with appearance of chlorhexidine) (control group) or 1 minute of chemical cleansing using 0,12% chlorhexidine + cetylpyridinium chloride (CPC) without alcohol (Perio-aid®) (test group). After 1 minute of saline rinsing the gingival flap will be returned slightly apical (in order to reduce pockets) and will be firmly sutured. For both groups the surgery is followed by 2 weeks of mouthrinses with 0,12% chlorhexidine + Cetylpyridinium Chloride (CPC) without alcohol (Perio-aid®) two times daily during 30 seconds.

The main study parameter is the microbial composition of the biofilm on the dental implant surface. Secondary study parameters are bleeding on probing, probing pocket depth, suppuration on probing, microbiological composition of the peri-implant sulcus, radiographic marginal bone level on standardized intraoral radiographs, presence of plaque, presence of calculus, marginal soft tissue recession implant failure, complications and adverse events.

Inclusion Criteria:

• The patient is ≥ 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 ≥ 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 ≥ 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;
• Diabetes;
• Systemic use of antibiotics during the last 3 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 3 months;
• Use of mouthrinses;
• 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 curretage).