The purpose of the study is to assess the efficacy and the safety of Chlorhexidine Gluconate chip (Periochip®) versus Placebo Chip in treatment of symptoms in patients with Peri-Implantitis.

This is a Phase 2a study assessing the safety and efficacy of Chlorhexidine Gluconate chip (Periochip®) versus Placebo Chip in treatment of symptoms in patients with Peri-Implantitis

Inclusion Criteria:

1. Signed and dated Informed Consent Form.
2. Good general health.
3. Male or female patients aged >21 years old.
4. Availability for the 25 week duration of the study.
5. Peri-implantitis is characterized by the presence of at least 1 implant with periodontal pockets of 6-10 mm in depth (potential target implant) demonstrating Bleeding on Probing without involving the apex of the implant and confirmed radiographically.
6. Females of childbearing potential must be non-pregnant and non-lactating at entry and agree to use an adequate method of birth control during the study.

Exclusion Criteria:

1. Presence of oral local mechanical factors that could (in the opinion of the Investigator) influence the outcome of the study.
2. Presence of orthodontic appliances, or any removable appliances, that impinges on the tissues being assessed.
3. Presence of soft or hard tissue tumours of the oral cavity.
4. Horizontal inter implant distance ≤2 mm (if an adjacent implant exists).
5. Selection of the following dental implant types as target implant/s: hydroxylapatite (HA) and/or Titanium Plasma-sprayed (TPS).
6. History of allergy to Chlorhexidine.
7. Patients treated with systemic antibiotic therapy or periodontal/mechanical/local delivery therapy within 6 weeks prior to study entry and throughout the study duration.
8. Patients treated with non-steroidal anti-inflammatory drugs (NSAIDs) within 14 days prior to entry into the study and throughout the study duration (excluding treatment of acetylsalicylic acid ≤100 mg /day).
9. Patients taking Phenytoin, calcium channel blockers drugs (CCBs) and/or cyclosporine, which might influence the pattern of tissue response.
10. Presence of any of the following conditions: Type 1 diabetes, major recurrent aphtae stomatitis, abscesses and related oral pathologies.
11. The presence of any medical or psychiatric condition or any other condition that, in the opinion of the Investigator, could affect the successful participation of the patient in the study.
12. Patient participates in any other clinical study 30 days prior to the start of the study and throughout the study duration.
13. Patient uses Chlorhexidine oral rinses/ mouthwashes on a regular basis.

Baseline through Week 24

All patients who receive study drug and have at least one follow-up assessment after beginning treatment