This is a pivotal, prospective, randomized, blinded, multicenter study to evaluate two treatments of photodynamic disinfection in adults with chronic periodontal disease. The study is expected to enroll a total of up to 105 subjects.

The key question is whether scaling and root planing (SRP) followed by one or two doses of photodynamic disinfection using 0.01% MB result in improved outcomes that persist over time in adults with chronic periodontitis when compared with subjects with SRP alone. This study is meant to be pivotal in nature in the evaluation of photodynamic disinfection.

Primary Endpoint

The primary outcome of interest in this study is improvement in or stabilization of clinical attachment level. The clinical attachment level is the distance in mm from the cemento-enamel junction to the base of the sulcus or periodontal pocket as measured with a periodontal probe. In order to prevent study bias all endpoint measurements will be performed by a single examiner throughout the course of the study. A clinically significant difference will be considered as:

1) A measurement difference of 0.4 mm between treatment groups

Secondary Endpoints

The secondary objectives are to assess the effects of photodynamic disinfection on clinical symptoms including reductions in probing depth and decreases in bleeding on probing.

Inclusion Criteria:

1. The subject is capable of giving informed consent
2. The subject is willing to sign a consent form
3. The subject is an adult male or female > 18
4. The subject is diagnosed with chronic periodontitis
5. The subject has >18 fully erupted teeth
6. The subject has at least 4 measurement sites with pocket depth of 6-9 mm in at least two quadrants of the mouth.
7. Subject is willing and able to return for treatment and evaluation procedures scheduled throughout the course of this clinical study

Exclusion Criteria:

1. The subject is pregnant or nursing or who plans to become pregnant in the next 4 months
2. The subject has significant liver disease by subject report
3. The subject has an active malignancy of any type by subject report
4. The subject has chronic disease or diminished mental capacity that would mitigate the ability to comply with the protocol
5. The subject has any significant disease (either acute or chronic) or who is taking a medication with concomitant oral manifestations that in the opinion of the investigator would interfere with evaluation of safety or efficacy of PERIOWAVE®
6. The subject has an active periapical abscess or periodontal abscess or a history of acute necrotizing ulcerative gingivitis
7. The subject has been treated with antibiotics within the 1-month period prior to beginning the study or any systemic condition which requires antibiotic coverage for routine periodontal procedures (e.g. heart conditions, joint replacements, etc.) by report of the subject
8. The subject has a known allergy to Methylene Blue
9. Has glucose-6-phosphate dehydrogenase (G6PD) deficiency by subject report
10. The subject currently uses anti-coagulant therapy at therapeutic doses
11. The subject is currently using any photosensitizing medications
12. The subject has participated in investigational treatment in the last 30 days or has the expectation for using a separate investigational treatment during the time of the study