Can canines alone be used for age estimation in Chinese individuals when applying the Kvaal method?

Mujia Li; Jiamin Zhao; Wenjie Chen; Xin Chen; Guang Chu; Teng Chen; Yucheng Guo

doi:10.1080/20961790.2020.1717029

Can canines alone be used for age estimation in Chinese individuals when applying the Kvaal method?

Forensic Sci Res. 2020 Mar 18;7(2):132-137. doi: 10.1080/20961790.2020.1717029. eCollection 2022.

Authors

Mujia Li^{1

2}, Jiamin Zhao^{1

2}, Wenjie Chen¹, Xin Chen¹, Guang Chu^{1

2}, Teng Chen³, Yucheng Guo^{1

2}

Affiliations

¹ Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China.
² Department of Orthodontics, Stomatological Hospital of Xi'an Jiaotong University, Xi'an, China.
³ College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, Xi'an, China.

Abstract

Due to the secondary dentin formation, the dental pulp undergoes changes in shape throughout life. Based on this phenomenon, the Kvaal method has been applied to various populations for age estimation, and its usefulness has been verified. When applying the Kvaal method to Chinese subjects, we observed a relatively strong correlation between mandibular canines and age. This study notes the correlation between canines and chronological age and is the first to identify which canine is most closely related to chronological age. In addition, a new, simpler formula is determined based on canines according to Kvaal's methodology. The radiographs of 360 individuals from northern China were selected, from which the widths and lengths of the pulp from four canines were measured according to the Kvaal method. Next, inter- and intra-observer reliabilities were analyzed in order to assess the repeatability of these measurements. The correlation between measurements and age was examined, and Chinese-specific age estimation formulae were derived. The results revealed that the ratios from the left maxillary canine exhibited the strongest correlation with age compared to the other canines, whereas the left mandibular canine showed the weakest correlation, which may contribute to the overall poor correlation of mandibular canines with age. What's more, the formula derived from the left maxillary canine in this study displayed the highest coefficients of determination, and the formula derived from all canines showed the lowest residuals. Both of these formulae performed better than the Chinese-specific formula derived from six different types of teeth in our previous study, which had formerly possessed the highest coefficients of determination and the lowest residuals. Thus, we concluded that canines do play an important role in age estimation in the Chinese population, and the correlation between maxillary canines and chronological age is stronger than that of mandibular canines, although no distinct trend as to which side is better correlated with age was established. Going forward, we recommend the analysis of additional samples from different geographical regions and populations to further verify the importance of canines in age estimation.

Keywords: Chinese subjects; Forensic sciences; Kvaal method; age estimation; canine; forensic odontology; secondary dentine.

Grants and funding

This work was supported by the National Natural Science Foundation of China [grant number 81701869], the China Postdoctoral Science Foundation [grant number 2019M653664] and the Fundamental Research Funds for the Central Universities [grant number xjj2017168].