Photodynamic therapy of persistent pockets in maintenance patients-a clinical study.

The aim of this study was to compare the short-term performance of a session of single photodynamic therapy (PDT) and of a conventional ultrasonic debridement (UST) in persistent pockets of maintenance patients. In a prospective, randomized, controlled, single-blind clinical study, patients with chronic periodontitis with at least two persistent pockets (>4 mm) were enrolled. They were treated either with UST (n = 29) or PDT (n = 25). Clinical and microbiological examinations were performed at baseline and after 3 months. For UST, the mean probing depth was reduced from 5.3 to 4.5 mm (p = <0.001) and for PDT from 5.3 to 4.7 mm (p < 0.001) with no difference between the two treatment modalities. Microbial counts were significantly reduced about 30% to 40% immediately after debridement but returned to baseline values a 3 months irrespective of treatment. PDT is not superior to conventional mechanical treatment of persistent pockets, but it may be a meaningful therapeutic alternative; the clinical effects were too minor to draw a definitive conclusion.