Table 1 Diagnostic test scores and definitions in this study

Tongue coating

0: Not apparent

1: <1/3 of the dorsum coated

2: 1/3 to 2/3 of the dorsum coated

3: >2/3 of the dorsum coated

OLT

0: No odor present

1: Slight malodor (barely noticeable)

2: Moderate malodor

3: Offensive malodor (strongly noticeable)

BANA test

0: negative (no blue color)

1: weakly positive (faint blue color; corresponding to 10⁴–10⁵ colony-forming units)

2: strongly positive (definite blue color; corresponding to ≥10⁶ colony-forming units)

Chronic periodontitis

Presence of four or more teeth with at least one site having PPD ≥ 4 mm or CAL ≥ 3 mm.

Severity of periodontitis

Percentage of sites affected by periodontal disease (the number of involved sites divided by the total number of sites measured)