Comparing the accuracy of Demirjian and Nolla methods and establishing a new method for dental age estimation in northeastern Chinese children

Figures & data

Table 1. Age and sex distribution of training dataset and testing dataset from the study population.

Age groups (year)	Training dataset		Testing dataset		Total
	Males	Females	Males	Females
6.01–7.00	20	18	9	8	55
7.01–8.00	20	20	10	10	60
8.01–9.00	20	20	10	10	60
9.01–10.00	20	20	10	10	60
10.01–11.00	20	20	10	10	60
11.01–12.00	20	20	10	10	60
12.01–13.00	20	20	10	10	60
13.01–14.00	20	20	10	10	60
14.01–15.00	20	20	10	10	60
Total	180	178	89	88	535

Table 2. The mean CA, mean DA, MD and MAD of both sexes and all age groups for Demirjian method based on training dataset.

	Age group	CA(SD)	DA(SD)	MD(SD)	P-value	95%CI of MD	MAD(SD)
Males	6.01–7.00	6.74 (0.34)	7.40 (0.25)	0.66 (0.35)	0.00*	0.50–0.83	0.66 (0.35)
	7.01–8.00	7.54 (0.27)	7.67 (0.37)	0.13 (0.51)	0.85	(−0.11)−0.37	0.34 (0.40)
	8.01–9.00	8.70 (0.34)	8.60 (1.04)	−0.10 (1.00)	0.67	(−0.56)−0.37	0.74 (0.66)
	9.01–10.00	9.68 (0.31)	9.34 (1.26)	−0.35 (1.22)	0.22	(−0.92)−0.22	1.08 (0.62)
	10.01–11.00	10.82 (0.26)	11.13 (0.72)	0.32 (0.83)	0.07	(−0.07)−0.71	0.73 (0.47)
	11.01–12.00	11.51 (0.34)	11.73 (0.52)	0.23 (0.52)	0.06	(−0.01)−0.47	0.41 (0.38)
	12.01–13.00	12.36 (0.26)	12.55 (0.53)	0.19 (0.58)	0.09	(−0.08)−0.46	0.51 (0.31)
	13.01–14.00	13.29 (0.26)	13.22 (0.83)	−0.08 (0.82)	0.67	(−0.46)−0.31	0.64 (0.50)
	14.01–15.00	14.37 (0.26)	14.96 (0.72)	0.59 (0.70)	0.00*	0.26–0.91	0.73 (0.55)
Total males		10.56 (2.48)	10.73 (2.60)	0.18 (0.81)	0.00*	0.06–0.30	0.65 (0.52)
Females	6.01–7.00	6.76 (0.29)	7.17 (0.23)	0.41 (0.28)	0.00*	0.27–0.55	0.42 (0.27)
	7.01–8.00	7.76 (0.32)	7.85 (0.48)	0.09 (0.57)	0.51	(−0.18)−0.35	0.49 (0.28)
	8.01–9.00	8.87 (0.24)	8.21 (0.78)	−0.65 (0.82)	0.00*	(−1.04)–(−0.27)	0.89 (0.53)
	9.01–10.00	9.75 (0.30)	10.42 (1.38)	0.66 (1.30)	0.03*	0.06–1.27	1.04 (1.00)
	10.01–11.00	10.72 (0.32)	11.64 (0.98)	0.92 (0.99)	0.00*	0.45–1.38	0.94 (0.98)
	11.01–12.00	11.49 (0.25)	11.88 (0.34)	0.39 (0.41)	0.00*	0.20–0.58	0.47 (0.31)
	12.01–13.00	12.30 (0.15)	12.74 (0.82)	0.44 (0.78)	0.13	0.08–0.81	0.64 (0.62)
	13.01–14.00	13.36 (0.29)	13.83 (0.70)	0.47 (0.70)	0.01*	0.15–0.80	0.68 (0.49)
	14.01–15.00	14.32 (0.29)	14.33 (0.42)	0.01 (0.37)	0.92	(−0.16)−0.18	0.33 (0.14)
Total females		10.64 (2.40)	10.94 (2.59)	0.30 (0.86)	0.00*	0.18–0.43	0.66 (0.63)
Total samples	6.01–15.00	10.60 (2.43)	10.83 (2.59)	0.24 (0.84)	0.00*	0.15–0.33	0.65 (0.57)

CA: chronological age; DA: dental age; MD: mean differences (DA–CA); MAD: mean absolute differences; SD: standard deviation; CI: confidence Interval.

P-value: obtained using paired samples t-test or Wilcoxon signed rank test.

* Values that showed significant difference.

Table 3. The mean CA, mean DA, MD and MAD of both sexes and all age groups for Nolla method based on training dataset.

	Age group	CA(SD)	DA(SD)	MD(SD)	P-value	95%CI of MD	MAD(SD)
Males	6.01–7.00	6.74 (0.34)	6.81 (0.52)	0.07 (0.42)	0.44	(−0.12)–0.27	0.36 (0.21)
	7.01–8.00	7.54 (0.27)	7.22 (0.44)	−0.31 (0.45)	0.01*	(−0.53)–(−0.10)	0.44 (0.32)
	8.01–9.00	8.70 (0.34)	8.17 (0.64)	−0.53 (0.57)	0.00*	(−0.79)–(−0.26)	0.57 (0.53)
	9.01–10.00	9.68 (0.31)	9.21 (0.85)	−0.47 (0.88)	0.03*	(−0.89)–(−0.06)	0.81 (0.58)
	10.01–11.00	10.81 (0.26)	10.42 (0.77)	−0.40 (0.79)	0.04*	(−0.77)–(−0.02)	0.68 (0.56)
	11.01–12.00	11.51 (0.34)	11.32 (0.48)	−0.19 (0.44)	0.05	(−0.40)–0.02	0.36 (0.31)
	12.01–13.00	12.36 (0.29)	11.71 (0.37)	−0.65 (0.36)	0.00*	(−0.82)–(−0.48)	0.66 (0.35)
	13.01–14.00	13.29 (0.26)	12.59 (0.62)	−0.70 (0.62)	0.00*	(−0.99)–( −0.41)	0.71 (0.61)
	14.01–15.00	14.37 (0.26)	13.97 (0.49)	−0.40 (0.40)	0.00*	(−0.59)–(−0.21)	0.48 (0.30)
Total males		10.56 (2.48)	10.16 (2.41)	−0.40 (0.61)	0.00*	(−0.49)–(−0.31)	0.56 (0.46)
Females	6.01–7.00	6.76 (0.29)	6.31 (0.41)	−0.44 (0.38)	0.00*	(−0.63)–(−0.25)	0.46 (0.35)
	7.01–8.00	7.76 (0.32)	7.34 (0.68)	−0.42 (0.73)	0.02*	(−0.76)–(−0.07)	0.70 (0.46)
	8.01–9.00	8.87 (0.24)	7.87 (0.83)	−1.00 (0.85)	0.00*	(−1.40)–(−0.60)	1.11 (0.69)
	9.01–10.00	9.75 (0.30)	9.66 (0.87)	−0.09 (0.79)	0.15	(−0.46)–0.28	0.58 (0.54)
	10.01–11.00	10.72 (0.32)	10.62 (0.89)	−0.10 (0.79)	0.16	(−0.47)–0.27	0.59 (0.52)
	11.01–12.00	11.49 (0.25)	11.04 (0.39)	−0.44 (0.45)	0.00*	(−0.65)–(−0.24)	0.48 (0.41)
	12.01–13.00	12.30 (0.15)	11.91 (0.80)	−0.39 (0.74)	0.03*	(−0.74)–(−0.05)	0.72 (0.40)
	13.01–14.00	13.36 (0.29)	12.89 (0.56)	−0.47 (0.59)	0.00*	(−0.75)–(−0.20)	0.56 (0.50)
	14.01–15.00	14.32 (0.29)	14.04 (0.57)	−0.28 (0.45)	0.01*	(−0.49)–(−0.07)	0.39 (0.35)
Total females		10.64 (2.40)	10.23 (2.54)	−0.40 (0.70)	0.00*	(−0.51)–(−0.30)	0.62 (0.51)
Total samples	6.01–15.00	10.60 (2.43)	10.19 (2.47)	−0.40 (0.65)	0.00*	(−0.47)–(−0.33)	0.59 (0.49)

CA: chronological age; DA: dental age; DA: dental age; MD: mean differences (DA−CA); MAD: mean absolute differences; SD: standard deviation; CI: confidence Interval.

P-value: obtained using paired samples t-test or Wilcoxon signed rank test.

* Values that showed significant difference.

Figure 1. The comparison of mean absolute differences (MAD) for all age groups of males (A) and females (B) in testing dataset using Demirjian, Nolla and new adapted methods.

Table 4. The mean CA, mean DA, MD and MAD for males, females and total samples for Demirjian, Nolla and new method based on testing dataset.

Method		Males	Females	Total
Demirjian	CA (SD)	10.59 (2.48)	10.65 (2.40)	10.62 (2.44)
	DA (SD)	10.76 (2.66)	10.91 (2.45)	10.83 (2.55)
	MD (SD)	0.17 (0.76)	0.26 (0.68)	0.21 (0.72)
	MAD	0.61 (0.47)	0.58 (0.44)	0.60 (0.45)
Nolla	CA (SD)	10.59 (2.48)	10.65 (2.40)	10.62 (2.44)
	DA (SD)	10.17 (2.54)	10.20 (2.47)	10.18 (2.50)
	MD (SD)	−0.42 (0.66)	−0.46 (0.63)	−0.44 (0.64)
	MAD	0.59 (0.51)	0.60 (0.50)	0.59 (0.50)
New method	CA (SD)	10.59 (2.48)	10.65 (2.40)	10.62 (2.44)
	DA (SD)	10.60 (2.68)	10.64 (2.37)	10.62 (2.52)
	MD (SD)	0.01 (0.69)	−0.01 (0.59)	0.00 (0.64)
	MAD	0.52 (0.45)	0.45 (0.37)	0.49 (0.41)

CA: chronological age; DA: dental age; MD: mean differences (DA−CA); MAD: mean absolute differences; SD: standard deviation.