Dental Age Estimation Using the Demirjian Method: Statistical Analysis Using Neural Networks / 대한법의학회지

In children and adolescents, dental age estimation is performed with the development of the teeth. Various statistical analysis methods have been used to determine the relationship between age and dental maturity and develop an accurate method of age calculation. This study attempted to apply a neural network model for the statistical analysis of dental age estimation in children and evaluated its applicability. This study used 1196 panoramic radiographs of patients aged 3–16 years, and 996 and 200 were randomly classified into training and test sets, respectively. The dental maturity of the mandibular left teeth was evaluated using Demirjian's method, the neural network model using the backpropagation algorithm was derived using training sets, and the errors were evaluated using 100 radiographs of each male and female as test sets. In addition, multiple linear regression analysis was conducted on the same training set, and the error was calculated by applying it to the test set and comparing it with the error of the neural network model. In the neural network model, the mean absolute error (MAE) and root mean squared error (RMSE) were 0.589 and 0.783 in male subjects and 0.529 and 0.760 in female subjects, respectively. In the multiple linear regression model, the MAE and RMSE were 0.600 and 0.748 in male subjects and 0.566 and 0.789 in female subjects, respectively. When applying the neural network model to the statistical analysis of the dental developmental stage, the results were as accurate as those of conventional statistical analysis methods. This study’s approach is expected to be useful for estimating the ages of children.

Harris lines observed in human skeletons of Joseon Dynasty, Korea / 대한해부학회지

The Harris line (HL), caused by bone-growth arrest and manifesting on X-rays as a radiopaque transverse line in the metaphysis of the long bones, is an indicator reflecting stress conditions such as disease or malnutrition. HL frequency has been assumed to differ between pre-modern and modern societies, as reflective of increased caloric intake and overall nutritional improvements attendant on industrialization. To determine if such a change occurred in Korea, in the present study we compared the respective HL statuses in medieval Joseon and modern Korean population samples. HLs were found in 39.4% (28/71) of the Joseon Koreans. Whereas only 27.5% (11/40) of the males showed an HL, fully 54.8% (17/31) of the females exhibited it. Notably, HLs were observed in only 16.4% (35/213) of the modern Koreans; more remarkably still, the HL rate was almost the same between the sexes, 16.7% (20/120) for the males and 16.1% (15/93) for the females. The HL frequency was much higher in the Joseon Koreans than in their modern counterparts, reflecting the improvement of nutritional status that had been achieved in the course of South Korea's modernization. This HL-frequency decrease was much more obvious in the female populations. The higher HL frequency among the Joseon females might reflect the relatively poor nutritional condition of females in pre-modern Korean society.

A Rapidly Skeletonized Dead Body in Late Summer: A Case Report / 대한법의학회지

In the following report, we describe the case of a rapidly skeletonized corpse discovered in late summer. On the first day of September, a 57-year-old man was found almost completely skeletonized on a hill behind his house. His body lay prone, accompanied by a brush cutter at the entrance to the graveyard where his friend's parents were buried. His cap, clothes, and rubber boots were all intact and undamaged. Upon autopsy, no definite abnormalities were identified except for an old linear fracture on the frontoparietal bone. According to his friends and neighbors, he had likely died 8 or 9 days prior to the discovery of his body.

Long bone fractures identified in the Joseon Dynasty human skeletons of Korea / 대한해부학회지

Fracture is one of the pathological signs most frequently encountered in archaeologically obtained bones. To expand the paleopathological knowledge on traumatic injuries, it is desirable to secure data on long bone fractures from as wide a geographic and temporal range as possible. We present, for the first time, evidence of long bone fractures in a 16th-18th century Joseon skeletal series (n=96). In this study, we found 3 Colles' fractures of the radius in 2 individual cases. The pattern of fractures was unique. Although previous reports show that the ulna is broken more often than the radius, ulnar fracture associated with fending off a blunt attack was rare in our series (1/7 cases). Transverse fractures, typically caused by intentional violence, were also very rare (1/7 cases) in this study. These results may reflect the relatively tranquil lives of the Joseon people in 16th-18th century Korea. We also found post-fracture complications such as deformations, bone length shortening, and osteomyelitis. The present study would be of interest to medical scientists in related fields because it is one of the few studies conducted on long bone fractures among pre-modern societies in East Asian countries, thus far.

Application of 3D Surface Scanners in Forensic Science and Medicine ( I ): Digital Storage of Human Skeletons and Development of Appraisal Methods for Incident Scenes / 대한법의학회지

The aim of this project was to use 3D scanning data collected at incident scenes and various evidence to 1) develop surveying methods based on 3D data consisting of overall and detailed scene evidence, captured by long-range and micros-canner, which can be shared by personnel working in different fields such as forensic medicine, video analysis, physical analysis, traffic engineering, and fire investigation; 2) create digital storage for human skeletons and set the foundation for virtual anthropology; and 3) improve the credibility of 3D evidence by virtual remodeling and simulation of incident scenes and evidence to provide a basis for advanced and high-tech scientific investigation. Two complete skeletons of male and female were scanned using 3D micro-scanner. Each bone was successfully reproduced and assembled in virtual space. In addition, recreating evidence scheduled for invasive examination by creating RP (rapid prototype) was possible. These outcomes could play an important role in setting up the new field of virtual anthropology. Case-specific surveying methods were developed through analysis of 3D scanning data collected by long-range surface scanners at the scenes of vehicular accidents, falls, shootings, and violent crimes. A technique and recording method was also developed for detecting forged seals by micro-scanning the pressure exerted on the seal. Appraisal methods developed in this project could be utilized to secure 3D data of human skeletal remains and incident scenes, create a standard for application, and increase objectivity, reproducibility, and accuracy of scanning methods. We plan to develop case-specific 3D data analysis techniques to improve the credibility of analysis at the NFS and to establish a 3D data collection and analysis team.

A Statistical Analysis on Forensic Odontological Examination at the NFS from 2007 to 2010 / 대한법의학회지

Analysis of the cases registered for the Forensic Odontology Lab of the National Forensic Service (NFS) from April 6th, 2007 to December 2010 was performed to observe the trend and pattern of the cases, in order to propose measures for improvement in future cases both in quantity as well as quality. High rate of cases were observed from the capital area, especially in ground and mountains during warmer season from June to October. Most of the cases were of human remains requested and examined for the estimation of age, sex, stature and identification. However, some of the requested criteria were applied forensic methods such as postmortem interval, cause of death, and facial reconstruction which could not be conducted. To better fulfill the needs of the society, reform of the current registration-examination system by introducing a multi-disciplinary team for processing the scene, education of the law enforcement personnel, research and acquiring funds for the relevant areas, developing antemortem dental record database are recommended for improvement in quantity and quality of the information produced by odontology lab.