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)