Table 1. Difference between the estimated dental age (DA) and chronological age (CA) among various age groups.

Female
3-‐3.9	3.68	3.55		-‐0.13	0.459
4-‐4.9	4.60	4.96		0.36	0.346
5-‐5.9	5.56	5.70		0.14	0.575
6-‐6.9	6.66	7.24		0.58	0.008*
7-‐7.9	7.52	7.69		0.16	0.297
8-‐8.9	8.30	9.09		0.79	0.068
9-‐9.9	9.54	10.00		0.46	0.307
10-‐10.9	10.63	11.66		1.03	0.075
11-‐11.9	11.33	11.65		0.32	0.565
12-‐12.9	12.57	13.36		0.79	0.098
13-‐13.9	13.48	13.92		0.43	0.244
14-‐14.9	14.89	14.15		-‐0.74	0.392
15-‐15.9	15.51	14.10		-‐1.41	0.036
Average	8.92	9.28		0.36	0.001*
Male
3-‐3.9	3.57	4.36		0.79	0.001*
4-‐4.9	4.45	4.47		0.02	0.949
5-‐5.9	5.61	6.90		1.29	0.000*
6-‐6.9	6.41	7.49		1.07	0.006*
7-‐7.9	7.23	7.74		0.51	0.002*
8-‐8.9	8.50	9.00		0.50	0.160
9-‐9.9	9.58	9.30		-‐0.28	0.405
10-‐10.9	10.80	11.54		0.74	0.123
11-‐11.9	11.51	12.43		0.92	0.307
12-‐12.9	12.60	13.45		0.85	0.008*
13-‐13.9	13.40	14.92		1.52	0.013
14-‐14.9	14.54	14.50		-‐0.04	0.227
15-‐15.9	15.30	13.65		-‐1.65	0.340
Average	8.93	9.55		0.62	0.000*

* P value < 0.01 
CA, chronological age; DA, dental age