Table 1.

Classification of experimental groups

Classification	Number (Male/Female)	Age (mean ± SD)	Evaluation basis of periodontal status
No-periodontitis (np) group	53 (22/31)	42.6 ± 12.0	Probing Pocket Depth (PPD) among all residual teeth < 3 mm
Mild-periodontitis (mip) group	103 (49/54)	51.1 ± 9.6	Less than four teeth showing PPD 4–6 mm among all residual teeth
Moderate-periodontitis (mop) group	113 (56/57)	55.3 ± 13.4	More than four teeth showing PPD 4–6 mm among all residual teeth
Severe-periodontitis (sp) group	22 (10/12)	54.3 ± 10.3	More than 9 teeth > PPD 6 mm or Rate of teeth > PPD 6 mm is over 30% among all residual teeth

Subjects were divided into four groups based on severity of periodontal disease.

Indicate the total number of people, the gender split in each group, mean age.