Pilot study on the clinical and microbiological effect of subgingival glycine powder air polishing using a cannula-like jet

To assess the efficacy of subgingival glycine powder air polishing (GPAP) during supportive periodontal therapy (SPT).

Each quadrant of 25 subjects was randomly assigned to the following treatments: subgingival scaling with hand instruments (SRP), GPAP, subgingival ultrasonic debridement (UD) and no subgingival treatment (NT). Clinical recordings included the following: probing pocket depth (PPD), gingival recession (RE), clinical attachment level (CAL), Gingival and Plaque Index. Subgingival plaque samples were taken from two sites >4 mm per quadrant. Therapy, recordings and microbial sampling were performed at baseline, 3 and 6 months, while at 1 month only clinical recordings and sampling were performed. Subgingival samples were analysed using 'checkerboard' DNA-DNA hybridization for Porphyromonas gingivalis, Tannerrella forsythia and Treponema denticola.

All groups were homogeneous at baseline for the clinical parameters assessed. The GPAP group displayed statistically significant higher PPD compared to SRP and UD at 1, 3 and 6 months and no statistical differences with the 'no treatment' group at all time points. At 1 month, the GPAP group displayed statistically significantly higher levels of CAL compared to SRP, while at 3 and 6 months statistically significant differences were observed with groups assigned to SRP and UD. No differences were observed among groups for RE, PI, GI and numbers of the investigated bacteria at any time point.

On the basis of clinical and microbiological data, this study does not support the superiority of GPAP as sole treatment over SRP or subgingival ultrasonic scaling.