Developing an eyeball positioning method in the eye orbit for craniofacial identification in Korean population.

We analysed the skulls and faces of Korean subjects using anthropometric methods to understand the anatomical characteristics of the eyeball and eye orbit region of Korean population and to determine the correlations between the hard and soft tissues around the eyeball and eye orbit region. In total, 82 sections in the region were measured to determine the correlations; among them, 34 showed significant differences by sex, and 6 showed significant differences by age. As the distance from the centre of the eye lens to the eye orbit is calculated as a ratio, we determined that the centre of the eye lens is located relatively on the lateral and superior position in each eye orbit in front view. Fourteen sections that could be used for craniofacial reconstruction/approximation in men and women were selected. Regression equations were derived according to the correlation of each section, and their reliabilities were verified by out of sample validation tests. Therefore, our results increase the accuracy of eyeball position determination, which would be useful for more efficient craniofacial reconstruction/approximation of the Korean population and should improve the efficiency of facial recognition.

Validation of London Atlas for forensic age estimation in Koreans by comparing with Lee's and Willems' methods.

This cross-sectional study aimed to evaluate the applicability of the London Atlas for age estimation in the Korean population by comparing with Lee's and Willems' methods. Dental ages of 475 orthopantomographs from Korean individuals aged 4-15 years (mean 10.32 ± 3.31 years) were estimated using the London Atlas, Lee's and Willems' methods. Correlation between dental and chronological age was determined using Pearson's correlation coefficient, and the statistical difference between dental and chronological age was analyzed using a paired t-test. The bias (mean differences), mean absolute error, and root mean square error between dental and chronological age, stratified by age groups and estimation methods, were calculated. Differences in bias and absolute error between sexes were scrutinized using an independent-samples t-test. Age estimates of the three tested methods were combined and compared to those of each individual method. The London Atlas and Willems methods resulted in overestimations, whereas the Lee method led to an underestimation on the entire sample. The overall accuracy was observed in the order of Lee's method, the London Atlas, and Willems' method. The London Atlas demonstrated superior consistency of estimation performance across age groups and no significant differences in estimation performance between sexes. The combination of estimates from the London Atlas and Lee's method resulted in an enhancement in bias and accuracy. We conclude that the London Atlas, due to its bias and accuracy comparable to Lee's and Willems' methods, is applicable for forensic practice in the Korean population.

Craniofacial anthropometric investigation of relationships between the nose and nasal aperture using 3D computed tomography of Korean subjects.

This study investigated the relationships of morphology and locations of the nose and nasal aperture by using major craniofacial landmarks on the human skull and face for craniofacial reconstruction/approximation of Koreans. In the frontal view, the positions of bony landmarks on the skull, including the nasal aperture, were correlated with the positions of nasal landmarks vertical to the transverse plane. In profile, the positions of bony landmarks on the skull were correlated with the positions of nasal landmarks horizontal to the coronal plane. Overall, 26 of the 76 measurements demonstrated significant correlations between the corresponding landmarks on the nose and nasal aperture. Simple regression equations were produced from the results. This study showed that the nose and nasal aperture are significantly related to each other in terms of their morphology and location in Koreans. The prediction guidelines, produced as regression formulas, can be applied to craniofacial reconstruction/approximation and bio-anthropological research of Korean skulls. The study results can also be used clinically in rhinoplasty and nasal reconstruction surgery.

Analysis of forensic odontological examinations at the National Forensic Service of Korea from 2011 to 2015.

The National Forensic Service (NFS) of Korea is a government agency responsible for examining and evaluating evidence obtained at crime scenes. The Section of Forensic Odontology of the Medical Examiner's Office conducts forensic odontological analyses of human remains, and mainly criminal cases are handled. In this study, 588 forensic odontological cases referred to NFS during 2011-2015 were analyzed for referral pattern, evidence material, examination criteria, and other factors and were compared with respective data from 2007 to 2010. Majority of the requests were internal (further dental examinations after autopsy) rather than external (direct requests from other agencies such as police departments). Regarding evidence materials, "Teeth" (including teeth and resected jaws) were dominant evidences. Due to the seasonal effects in Korea, the highest number of requests was in September of each year, but the number of requests in April has recently increased. Evidence materials were mostly found in suburban and rural area, especially in mountainous area due to the geographic characteristics of Korea. Regarding specific examinations, profiling, including age estimation, accounted for majority of the requests; this number had increased relative to the findings of a previous study, whereas the number of requests for dental identification and bite mark analysis had decreased. With this analysis, trends in forensic odontology can be observed, and we expect that these trends would be served as a reference for designing study and making training protocol for forensic odontology.

The application of the Kvaal method to estimate the age of live Korean subjects using digital panoramic radiographs.

Dental age estimation of the living is limited because observing the histological structure of teeth is difficult. Therefore, several methods have been proposed to estimate age by observing changes on dental radiographs of pulpal size caused by secondary dentin deposition. This study aims to evaluate the validity of the Kvaal method to estimate the ages of Korean subjects using digital panoramic radiographs and formulate regression equations for use in Korean subjects. We included 266 Korean subjects (age 21-69 years) visiting Chosun University Dental Hospital (Gwangju, South Korea). The pulpal size and width of six tooth types (maxillary central incisor, lateral incisor, second premolar, mandibular lateral incisor, canine, and first premolar) were measured on digital panoramic radiographs according to the Kvaal method. Statistical interobserver/intraobserver reliabilities were calculated to evaluate the reproducibility of the measured values, and correlations between actual ages and measured values were identified. The differences between the predicted ages and the actual age were analyzed. Paewinsky method was also applied and its validity was evaluated. In addition, a series of new regression equations for the age estimation of Korean subjects was produced. When both methods were applied directly to the teeth of the subjects, significant differences were observed between the estimated and chronological ages. The length-related parameters of the teeth of subjects calculated by the original Kvaal method showed no significant correlation. A regression equation derived from the width parameters without the length ratios is proposed for use in Korean subjects.