Bond Strength Survival of a Novel Calcium Phosphate-Enriched Orthodontic Self-Etching System after Various Ageing Protocols: An In Vitro Study

Table 5

Descriptive and inferential statistics of adhesive remnant index (ARI) scores of bracket debonding at four ageing protocols: 24 h water storage (24 HW); 30 min (initial), one-month water storage (1 MW), and one-month acid challenge (1 MA).

Groups	Ageing method	N	ARI scores				Kruskal–Wallis test	Mann–Whitney test (control versus nHAp-SEP)
			0	1	2	3
Control	24 HW	20	1	14 (3EC+2 EF)	2 (1EC)	3	H = 6.803; df = 3	24HW, initial, 1MW, 1MA
Control	Initial	20	1 (1EC)	14 (2EC)	4	1
Control	1 MW	20	1 (1EF)	7 (2EC)	5 (1EC)	7
Control	1 MA	20	1 (1EC)	10 (2EC+2EF)	4	5
nHAp-SEP	24 HW	20	15	5	0	0	H = 4.086; df = 3
nHAp-SEP	Initial	20	13	7	0	0
nHAp-SEP	1 MW	20	17	3	0	0
nHAp-SEP	1 MA	20	18	2	0	0

The control group resulted in significantly more adhesive residue left on the enamel surface after all ageing methods. EC, enamel crack; EF, enamel fracture. indicates significant differences among groups at the 0.001 level.