Periodontitis are infectious and inflammatory diseases of gum and tooth supporting tissues leading to tooth loss and oral disability. Twenty to 30 percents of patients treated for periodontal diseases display more or less pronounced persistence of periodontal tissue infection, inflammation, and destruction. The therapeutic additional value of photodynamic anti-infectious treatment remains controversial. The objective of this study is to evaluate the mid-term effect of the photodynamic device Fotosan®630 on severe periodontitis treatment outcomes and to define its specific therapeutic indications.

Inclusion Criteria:

• aged 40 years
• signed informed consent
• generalized severe chronic periodontitis
• patient with at least 24 teeth
• more than 30% of sites with clinical attachment loss >5mm- at least 5 sites with pocket depth >4mm per quadrant- at least one molar per quadrant- evidenced bone loss on radiographs- bleeding on probing ≥30%

Exclusion Criteria:

• aggressive periodontitis
• smoking more than 10cig/day
• patient with endocarditis risk or need of antibiotic prophylaxis
• pregnant women
• patient included in other trials
• patient under guardianship
• patient treated with antibiotics, anti-inflammatory, and other drugs (inhibitors of calcium channels…) influencing periodontal status within 6 months before examination
• patient suffering from diseases influencing periodontal status (diabetes…)
• patient periodontally treated with root planing or periodontal surgery within 1 year before examination
• patient with scheduled extensive prosthetic treatment
• patient with a high haemorrhagic risk (INR>4)
• impossible patient cooperation