Table 2. Comparison of chronological and D7-O dental ages by gender and age group.

Gender	Age group (years)	N	CA	DA	DA-CA	p value#
			Mean ± SD (years)
GIRLS	5	24	5.46 ± 0.33	6.51 ± 0.36	1.05 ± 0.77	0.006
	6	39	6.57 ± 0.32	7.52 ± 0.18	0.96 ± 1.01	<0.001
	7	46	7.52 ± 0.26	7.99 ± 0.19	0.48 ± 1.32	0.020
	8	50	8.51 ± 0.31	8.76 ± 0.17	0.26 ± 1.11	0.556
	9	55	9.48 ± 0.30	10.23 ± 0.26	0.75 ± 1.93	0.010
	10	55	10.55 ± 0.32	11.37 ± 0.21	0.82 ± 1.62	<0.001
	11	40	11.44 ± 0.32	12.56 ± 0.27	1.12 ± 1.64	<0.001
	12	55	12.49 ± 0.32	13.15 ± 0.24	0.66 ± 1.86	0.004
	13	57	13.46 ± 0.30	14.56 ± 0.17	1.10 ± 1.19	<0.001
	14	59	14.48 ± 0.28	15.19 ± 0.18	0.71 ± 1.37	<0.001
	15	21	15.48 ± 0.27	15.64 ± 0.15	0.17 ± 0.64	0.192
	Total	501	10.68 ± 2.87	11.42 ± 0.14	0.75 ± 1.50	<0.001
BOYS	5	23	5.56 ± 0.29	6.90 ± 0.16	1.34 ± 0.76	< 0.001
	6	40	6.52 ± 0.31	7.62 ± 0.23	1.10 ± 1.37	< 0.001
	7	58	7.48 ± 0.29	8.11 ± 0.12	0.63 ± 0.88	< 0.001
	8	58	8.47 ± 0.29	9.25 ± 0.16	0.79 ± 1.24	< 0.001
	9	78	9.46 ± 0.28	9.80 ± 0.20	0.34 ± 1.68	0.156
	10	100	10.45 ± 0.29	11.00 ± 0.15	0.56 ± 1.53	0.001
	11	82	11.51 ± 0.30	12.20 ± 0.17	0.70 ± 1.44	< 0.001
	12	91	12.44 ± 0.30	12.98 ± 0.17	0.55 ± 1.62	0.012
	13	82	13.41 ± 0.31	13.92 ± 0.20	0.52 ± 1.73	0.005
	14	58	14.47 ± 0.31	15.39 ± 0.12	0.93 ± 0.93	< 0.001
	15	29	15.24 ± 0.25	15.41 ± 0.22	0.16 ± 1.17	0.051
	Total	699	10.81 ± 2.60	11.44 ± 0.11	0.64 ± 1.44	<0.001
Total sample		1200	10.75 ± 2.72	11.44 ± 0.08	0.69 ± 1.46	<0.001

^#Wilcoxon Signed Rank test: p ≤ 0.05 = significant