Sample size calculation
PD
Sample size calculation determined that 10 subjects per treatment group would provide an 80% power to detect a true difference of 1.0 mm between the test and control groups using probing depth (PD) reduction as the primary outcome variable. Assuming that the common standard deviation would be 0.8 mm and compensating for a 20% drop-out during the study period, a sample of 12 subjects per group (24 in total) was determined.