Table 2. Association between toothbrushing frequency and toothbrushing at night.

	Toothbrushing frequency
	≤1 time	2 times	≥3 times	P-value
	(n = 1,332)	(n = 2,361)	(n = 844)
Toothbrush at night				<0.001
Yes	437 (32.8)	2,284 (96.7)	844 (100)
No	895 (67.2)	77 (3.3)	0 (0)

n (%), Chi-square test.