Table 2.

Results of the pairwise comparison by the Mann–Whitney U-test for all indices and groups

Index	A versus B	A versus C	B versus C
API
t0	P < 0.001	P < 0.001	n.s.
tl	P < 0.001	n.s.	n.s.
t2	P < 0.001	n.s.	n.s.
PI
t0	P < 0.001	P = 0.003	n.s.
tl	n.s.	n.s.	n.s.
t2	n.s.	n.s.	n.s.
mSBI
t0	P < 0.001	P < 0.001	n.s.
tl	P < 0.001	P < 0.001	n.s.
t2	P < 0.001	n.s.	n.s.
BOB
t0	P = 0.006	P < 0.001	n.s.
tl	P < 0.001	P < 0.001	n.s.
t2	P < 0.001	P < 0.001	P < 0.001

Group A adopted interdental brushes, group B served as the control group (no interdental hygiene) and group C used dental floss. t0, baseline; t1, 2 weeks; t2, 4 weeks.The indexes evaluated were the Approximal Plaque Index (API, %), the Plaque Index (PI, mean value), the modified Sulcus Bleeding Index (mSBI, %) and the Bleeding on Brushing Index (BOB, %). n.s., no significant difference.