Clinical and microbiological effect of frequent subgingival air polishing on periodontal conditions: a split-mouth randomized controlled trial

The objective of this study was to evaluate the clinical effects of repeated subgingival debridement by air polishing during supportive periodontal therapy. A double-blind, randomized controlled trial of 6 months in duration was conducted on 19 recall patients who were previously treated for chronic periodontitis. Three sites with probing pocket depths (PPD) of 4–9 mm in each of the patients were randomly assigned to the following treatments: Glycine powder/air polishing every 30 days (group 1), glycine powder/air polishing at baseline and on day 90 (group 2), or water irrigation every 30 days (group 3). Clinical parameters were recorded and microbiological sampling was performed at 0, 90, and 180 days post-treatment. Subgingival samples were analyzed using real-time PCR methods for Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Between baseline and 90 days, group 1 showed significantly more PPD reduction compared to group 3 and no significant differences with group 2. Between baseline and 180 days, group 1 displayed a significant increase in clinical attachment level compared with group 3. No differences were observed among the groups in numbers of total bacteria or percentage of investigated bacteria at any time point. This study revealed that routine subgingival air polishing at 30-day intervals had significant clinical effects in moderately deep pockets in patients who underwent supportive periodontal therapy.