The objective of the study is to evaluate the safety and effectiveness of Arestin (minocycline HCl) 1 mg Microspheres in the treatment of subjects with peri-implantitis, when used in combination with mechanical debridement.

The hypothesis of the study is that Arestin in combination with mechanical debridement is more effective in the treatment of peri-implantitis when compared to mechanical debridement alone. The primary efficacy measure will be the reduction of probing depth at Day 180 as measured at qualifying implant sites.

Inclusion Criteria:

• A minimum of one osseointegrated implant with a diagnosis of peri-implantitis
• Absence of any significant oral soft tissue pathology
• At least one peri-implant site with an average of 2 probing depth readings between 5mm and 7mm (inclusive) when using a light force and with bleeding on probing within 30 seconds of the probing
• Confirmed evidence of pathologic bone loss
• At least 1mm of keratinized gingiva present around the implant

Exclusion Criteria:

• Pregnancy
• Allergy to tetracycline-class drug(s)
• Systemic medical condition(s) requiring antibiotic prophylaxis prior to invasive dental procedures
• Presence of active systemic infectious disease such as hepatitis, HIV, history of tuberculosis
• Diagnosis of clinically significant or unstable organic disease, or compromised healing potential
• Signs of untreated advanced periodontal disease and/or poor oral hygiene
• Subjects having a probing depth greater than 8mm at time of enrollment
• Subjects presenting with mobility of any dental implant
• Subjects having a qualifying implant under occlusal trauma or overloaded (as determined by the investigator)