Table 7.

Association between brush type (manual or power) and the number of subjects with recession (at least 1 site ≥1 mm, ≥2 mm, ≥3 mm)

Type of recession	Total number (%) of subjects with recession	Brush type	Number (%) of subjects with recession	Association: P-value*
None	4 (2.2)	Manual	1 (1.1)	Not applicable
		Power	3 (3.3)
At least 1 site ≥1 mm	177 (97.8)	Manual	89 (98.9)	0.621
		Power	88 (96.7)
At least 1 site ≥2 mm	88 (48.6)	Manual	49 (54.4)	0.119
		Power	39 (42.9)
At least 1 site ≥3 mm	18 (9.9)	Manual	10 (11.1)	0.602
		Power	8 (8.8)

^*Fisher's exact test for recession type at least 1 site ≥1 mm; chi-square test for recession type at least 1 site ≥2 and ≥3 mm.