Table 4. Comparison of chronological and D4-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	7.05 ± 0.27	1.59 ± 1.24	< 0.001
	6	39	6.57 ± 0.32	7.57 ± 0.13	1.00 ± 0.84	< 0.001
	7	46	7.52 ± 0.26	8.02 ± 0.17	0.50 ± 0.96	0.003
	8	50	8.51 ± 0.31	8.58 ± 0.15	0.07 ± 0.79	0.660
	9	55	9.48 ± 0.30	9.99 ± 0.26	0.51 ± 1.49	0.154
	10	55	10.55 ± 0.32	11.00 ± 0.22	0.45 ± 1.76	0.048
	11	40	11.44 ± 0.32	12.11 ± 0.29	0.67 ± 2.00	0.019
	12	55	12.49 ± 0.32	12.87 ± 0.25	0.38 ± 2.35	0.109
	13	57	13.46 ± 0.30	14.38 ± 0.20	0.92 ± 2.95	< 0.001
	14	59	14.48 ± 0.28	15.11 ± 0.19	0.63 ± 3.13	< 0.001
	15	21	15.48 ± 0.27	15.60 ± 0.16	0.12 ± 2.71	0.313
	Total	501	10.68 ± 2.87	11.27 ± 0.14	0.59 ± 2.77	< 0.001
BOYS	5	23	5.56 ± 0.29	7.22 ± 0.12	1.66 ± 0.55	< 0.001
	6	40	6.52 ± 0.31	7.78 ± 0.20	1.26 ± 0.93	< 0.001
	7	58	7.48 ± 0.29	8.10 ± 0.11	0.62 ± 0.59	< 0.001
	8	58	8.47 ± 0.29	9.28 ± 0.18	0.81 ± 1.16	< 0.001
	9	78	9.46 ± 0.28	9.72 ± 0.19	0.26 ± 1.58	0.541
	10	100	10.45 ± 0.29	11.02 ± 0.17	0.57 ± 1.68	< 0.001
	11	82	11.51 ± 0.30	12.40 ± 0.18	0.89 ± 1.87	< 0.001
	12	91	12.44 ± 0.30	13.42 ± 0.18	0.86 ± 1.97	< 0.001
	13	82	13.41 ± 0.31	14.24 ± 0.19	0.65 ± 1.85	< 0.001
	14	58	14.47 ± 0.31	15.16 ± 0.10	0.69 ± 0.90	< 0.001
	15	29	15.24 ± 0.25	15.50 ± 0.26	0.26 ± 1.08	0.051
	Total	699	10.81 ± 2.60	11.60 ± 0.11	0.79 ± 1.59	< 0.001
Total sample		1200	10.75 ± 2.72	11.47 ± 0.08	0.72 ± 2.30	< 0.001

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