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

Progress in Orthodontics

Table 7 Independent t-tests comparing the gingival margin-papillae measurements for the normal wear and severe wear subsets for the combined four groups

Tooth class	Group	n	Mean	SD	t	p
U6	Normal wear	107	2.51	0.82	− 1.33	0.187
U6	Severe wear	12	2.87	1.04	− 1.33	0.187
U5	Normal wear	110	2.62	0.82	1.07	0.285
U5	Severe wear	16	2.40	0.53	1.07	0.285
U4	Normal wear	109	3.22	0.82	1.51	0.134
U4	Severe wear	9	2.78	0.47	1.51	0.134
U3	Normal wear	110	4.39	1.08	0.46	0.649
U3	Severe wear	18	4.27	0.99	0.46	0.649
U2	Normal wear	106	3.39	1.01	0.96	0.341
U2	Severe wear	11	3.08	1.19	0.96	0.341
U1	Normal wear	97	3.90	1.14	0.17	0.868
U1	Severe wear	22	3.86	0.81	0.17	0.868
L6	Normal wear	78	2.62	0.88	0.06	0.950
L6	Severe wear	44	2.61	0.76	0.06	0.950
L5	Normal wear	104	2.90	0.74	0.31	0.761
L5	Severe wear	17	2.93	0.98	0.31	0.761
L4	Normal wear	107	3.45	0.71	− 0.10	0.920
L4	Severe wear	10	3.48	0.86	− 0.10	0.920
L3	Normal wear	103	4.20	1.01	1.59	0.114
L3	Severe wear	29	3.87	0.91	1.59	0.114
L2	Normal wear	102	2.98	0.88	0.19	0.851
L2	Severe wear	23	2.94	0.87	0.19	0.851
L1	Normal wear	97	2.99	0.74	1.32	0.189
L1	Severe wear	26	2.77	0.78	1.32	0.189

p < .05, indicating that the gingival margin-papillae measure comparing the normal wear and severe wear subgroups was not different because of tooth wear—a true negative value
Reprinted with permission from Eltink et al. [17, 27]