Quantitative measures of gingival recession and the influence of gender, race, and attrition

Progress in Orthodontics

Table 5 Independent t-tests comparing the measure of clinical recession in the normal wear and severe wear subsets

Tooth class	Group	n	Mean	SD	t	p
U6	Normal wear	107	0.29	0.59	0.12	0.906
U6	Severe wear	12	0.27	0.47	0.12	0.906
U5	Normal wear	110	0.22	0.41	1.88	0.062
U5	Severe wear	16	0.03	0.12	1.88	0.062
U4	Normal wear	109	0.27	0.48	0.86	0.393
U4	Severe wear	9	0.13	0.35	0.86	0.393
U3	Normal wear	110	0.32	0.54	0.55	0.581
U3	Severe wear	18	0.25	0.43	0.55	0.581
U2	Normal wear	106	0.16	0.36	0.65	0.515
U2	Severe wear	11	0.09	0.30	0.65	0.515
U1	Normal wear	97	0.18	0.43	1.92	0.058
U1	Severe wear	22	0.00	0.00	1.92	0.058
L6	Normal wear	78	0.11	0.42	− 0.82	0.415
L6	Severe wear	44	0.18	0.48	− 0.82	0.415
L5	Normal wear	104	0.18	0.40	0.59	0.557
L5	Severe wear	17	0.12	0.33	0.59	0.557
L4	Normal wear	107	0.21	0.44	− 0.63	0.532
L4	Severe wear	10	0.31	0.70	− 0.63	0.532
L3	Normal wear	103	0.26	0.51	1.48	0.141
L3	Severe wear	29	0.12	0.28	1.48	0.141
L2	Normal wear	102	0.09	0.30	0.78	0.439
L2	Severe wear	23	0.04	0.20	0.78	0.439
L1	Normal wear	97	0.19	0.41	1.14	0.256
L1	Severe wear	26	0.09	0.28	1.14	0.256

p < .05, comparing the normal wear and severe wear subgroups; no significant difference was found in the clinical recession due to tooth wear
Reprinted with permission from Eltink et al. [17, 27]