Statistical analysis
PD
The primary outcome variable was considered to be the change in PD. The percentage of closed pockets (PD < 4 mm and BOP-) was also calculated. PD was stratified in shallow to moderate (initial PD < 6 mm) and deep (initial PD ≥ 6 mm) pockets. Discrete variables (reported as percentages of all sites) were analysed by the Fisher exact test. Continuous variables (reported as means and standard deviations) were compared by the Mann–Whitney 