Estimate the Age of Han Adult Based on the Pulp Chamber Volume and Pulp Dentinal Index of Right First Molars Using Oral and Maxillofacial CBCT

doi:10.12116/j.issn.1004-5619.2023.230705

Abstract

Abstract:

Objective To explore the correlation between the actual age and the pulp chamber volume （PCV） and pulp dentinal index （PDI） of the right first molars based on cone beam computed tomography （CBCT） technology, and to construct an accurate and convenient model for age estimation. Methods CBCT image data of 1 857 Han adults （883 males and 974 females） from the Department of Stomatology, Affiliated Hospital of North Sichuan Medical College were collected. The data were divided into training and validation sets at a ratio of 8∶2. A total of 1 485 training samples were used to construct the age estimation model, and 372 samples were used to validate the accuracy of the model. The Mimics 21.0 software was used to measure the PCV and calculate the PDI of the right first molars. Their correlations with age and the differences between different sexes and tooth positions were analyzed. Results Both the PCV and the PDI of the first molars showed strong negative correlations with the actual age （r values ranged from 0.82 to 0.89）. The differences in PCV and PDI between different sexes and tooth positions were statistically significant （P<0.05）. The age estimation model based on PDI was superior to that based on PCV. The model based on the PDI values of the two right first molars （y=73.72-44.15 x₃-28.27 x₄, where x₃ and x₄ are the PDI values of the right maxillary and mandibular first molars, respectively） was the best, with the R² of 0.79 and the mean absolute error of 4.90 years. Conclusion Both PCV and PDI of the first molars are effective indicators for age estimation. The age estimation model based on the PDI is more convenient and accurate than that based on the PCV, providing a more effective method for age estimation in forensic practice.

Key words: forensic anthropology, age estimation, cone beam computed tomography （CBCT）, first molar, pulp chamber volume, pulp dentinal index

CLC Number:

Yan-jie DING, Xiao ZHANG, Wen-li SHI, Zi-yi LI, Wei WANG, Shi-lin ZHANG, Gen-jie YANG, A-ji GUO, Bo JIN. Estimate the Age of Han Adult Based on the Pulp Chamber Volume and Pulp Dentinal Index of Right First Molars Using Oral and Maxillofacial CBCT[J]. Journal of Forensic Medicine, 2025, 41(1): 59-65.

Figures/Tables 5

Fig. 1 Construction of the three-dimensional model of the pulp chamber

Fig. 2 Schematic diagram of the PDI parametermeasurement plane

Tab. 1 Correlations between various measurement indexes and age

测量指标	最小值	最大值	$x ¯$ ±s	r
右上颌第一磨牙髓室体积（x₁）/mm³	6.53	55.00	21.19±6.74	0.86
右下颌第一磨牙髓室体积（x₂）/mm³	6.39	48.43	18.37±6.10	0.82
右侧第一磨牙髓室体积（x₁和x₂的均值）/mm³	6.39	55.00	19.78±6.58	0.87
右上颌第一磨牙PDI（x₃）	0.09	0.96	0.43±0.18	0.86
右下颌第一磨牙PDI（x₄）	0.14	1.19	0.50±0.17	0.82
右侧第一磨牙PDI（x₃和x₄的均值）	0.09	1.19	0.46±0.18	0.89

Tab. 1 Correlations between various measurement indexes and age

测量指标	最小值	最大值	$x ¯$ ±s	r
右上颌第一磨牙髓室体积（x₁）/mm³	6.53	55.00	21.19±6.74	0.86
右下颌第一磨牙髓室体积（x₂）/mm³	6.39	48.43	18.37±6.10	0.82
右侧第一磨牙髓室体积（x₁和x₂的均值）/mm³	6.39	55.00	19.78±6.58	0.87
右上颌第一磨牙PDI（x₃）	0.09	0.96	0.43±0.18	0.86
右下颌第一磨牙PDI（x₄）	0.14	1.19	0.50±0.17	0.82
右侧第一磨牙PDI（x₃和x₄的均值）	0.09	1.19	0.46±0.18	0.89

Tab. 2 Statistical analysis in various measurement indexes of the right first molars betweendifferent sexes and tooth positions （x¯±s）

测量指标	总样本（n=1 857）	男性（n=883）	女性（n=974）
右上颌第一磨牙髓室体积（x₁）/mm³	21.19±6.74	22.34±6.78	20.14±6.52^1）
右下颌第一磨牙髓室体积（x₂）/mm³	18.37±6.10^2）	19.29±6.03^2）	17.54±6.04^1）2）
右侧第一磨牙髓室体积（x₁和x₂的均值）/mm³	19.78±6.42	20.82±6.59	18.84±6.42^1）
右上颌第一磨牙PDI（x₃）	0.43±0.18	0.42±0.18	0.44±0.18^1）
右下颌第一磨牙PDI（x₄）	0.50±0.17^2）	0.49±0.17^2）	0.50±0.17^1）2）
右侧第一磨牙PDI（x₃和x₄的均值）	0.47±0.18	0.46±0.17	0.47±0.18^1）

Tab. 3 Estimation model of the right first molar measurement indexes with the actual age

测量指标	推断模型	R²	MAE/岁
右上颌第一磨牙髓室体积（x₁）/mm³	y=69.92-1.48 x₁	0.74	5.71
右下颌第一磨牙髓室体积（x₂）/mm³	y=67.29-1.56 x₂	0.67	6.24
右侧第一磨牙髓室体积（x₁、x₂）/mm³	y=70.98-0.59 x₁-1.01 x₂	0.76	5.59
右上颌第一磨牙PDI（x₃）	y=69.17-66.47 x₃	0.75	5.61
右下颌第一磨牙PDI（x₄）	y=73.65-65.79 x₄	0.68	6.16
右侧第一磨牙PDI（x₃、x₄）	y=73.72-44.15 x₃-28.27 x₄	0.79	4.90

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