Table 1.

Numbers and percentage (%) of surfaces coded 1 or 2 at the first examination that retained the same code (1 → 1, 2 → 2), transited to lower (1 → 0, 2 → 0, 2 → 1) or higher (1 → 2, 1 → 3, 2 → 3) visual code 6 months after debonding, according to allocation to study groups

	1 → 0	1 → 1	1 → 2	1 → 3	2 → 0	2 → 1	2 → 2	2 → 3
	p = .542	p = .134	p = .956		p = .628	p = .373	p = .598	p = .130
Test group (N = 293)	45 (15.4)	6 (2.0)	20 (6.8)	2 (0.7)	65 (22.2)	8 (2.7)	143 (48.4)	4 (1.4)
Control group (N = 313)	38 (12.1)	4 (1.3)	23 (7.3)	0 (0)	68 (21.7)	12 (3.8)	165 (52.7)	3 (1.0)
Total (N = 606)	83 (13.7)	10 (1.7)	43 (7.1)	2 (0.3)	133 (21.9)	20 (3.3)	308 (50.8)	7 (1.2)