Statistical analysis
EMD
Assuming a fairly normal distribution of the sample and a clinically significant difference in PPD of 0.7 mm with a standard deviation of 0.5 mm between EMD + and EMD-, the calculation showed that at least 10 patients per group would achieve a power of 85% at a significance level of α = 0.05. To compensate for the possible loss of patients, a sample size of 22 patients with 11 patients in each group were recruited.Descriptive statistic was used to present patient characteristics. Data distribution was assessed by visual inspection of histograms and the Kolmogorov–Smirnov test, and the Levene’s test was used for the equality of variances. All continuous data were presented as means with standard deviation and categorical variables as proportions and frequency counts.Independent 