Table 1 Assessments and definitions of oral hygiene and periodontal status

Simplified Oral Hygiene Index (OHI-S)

Examination protocol

Buccal surfaces of teeth 16, 11, 26

Lingual surfaces of teeth 31, 36, 46

Score

0: no plaque

1: plaque on the gingival third of the surface

2: plaque on the middle third of the surface

3: plaque on the occlusal third of the surface

Definition

Plaque-free was defined as all index teeth had OHI-S = 0

Pocket Depth Index (PDI)

Examination protocol

Random half–mouth protocol

Buccal surfaces of upper jaw

Lingual surfaces of lower jaw

Score

0: < 3.5 mm

1: 3.5 – 5.5 mm

2: > 5.5 mm

Definition

(1) Periodontal health was defined as all assessed teeth had pocket depth < 3.5 mm (PDI = 0)

(2) Deep pockets was defined as any assessed tooth had pocket depth > 5.5 mm (PDI = 2)