This study reports mtDNA polymorphisms in both hypervariable segments HV1 and HV2 of the non coding D-loop region from 60 unrelated Koreans. In contrast to two previous Korean data base studies, mtDNA was extracted separately from pulp tissue and root dentin of teeth obtained from dentists. Dentin turned out to be a reliable source of mitochondrial DNA. This can be of practical importance in forensic identification case work after a long post-mortem interval since pulp decomposes rapidly. The extraction method is explained in detail. The mtDNA polymorphisms obtained from 60 teeth of unrelated Koreans were compared with the already existing Korean data base.

The accuracy of forensic age estimation based on the chronology of second (M2) and third molar (M3) development was investigated using 2,087 orthopantomograms of Korean men and women aged between 3 and 23 years. The developmental stages of M2s and M3s in these subjects were classified using the criteria of Demirjian. Inter-observer reliability and statistical data on each stage of mineralization of M2s and M3s were evaluated. The left-right symmetries of the maturation degrees in the M2s and M3s were observed in both sexes, between which no arch differences were found, but statistically significant sex-specific differences were observed in some stages of M2 and M3 development. In multiple regression analysis, a strong positive relationship was observed between age and mineralization of M2s and M3s. The regression formulas for estimating the age of Koreans were presented based on sex and combination of teeth. These results suggest that the developments of second and third molars can be considered as valuable age indicators in Korean adolescents and young adults.

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.

The primary aim of this study was to evaluate the utility of orthopantomography for human identification. Three hundred orthopantomograms were randomly selected from those stored at Dental Hospital of Yonsei University in Seoul. Dental patterns observed in orthopantomogram were converted into eight codes and their diversity was calculated. The diversity of dental patterns in orthopantomogram was 99.92% for full dentition and the diversity of mandible (99.28%) was slightly higher value than that of maxilla (98.22%). In the case of molars and premolars in both jaws, the diversity values ranged from 92.13% to 96.04%. It was founded that the orthopantomography is a valuable means of personal identification not only based on full dentition but also when only the posterior teeth are available. The present study indicates that orthopantomography is excellent means of forensic identification.

No abstract

This correlational study investigated the direct and indirect effects of instructional factors and motivational and cognitive components of self-regulated learning on scientific inquiry performance in a sample of scientifically gifted middle school students. A total of 166 students were selected from nine gifted classes in the public school system with after-school enrichment programs in Korea. Students responded to self-report measures of mastery-oriented learning goals, self-efficacy, self-regulatory strategy use, and inquiry activities in science class. Performance data were obtained from work on a scientific inquiry task. Results of a path analysis revealed that students' self-efficacy and perceived degree of inquiry activities in science class were the only factors directly influencing their scientific inquiry skills. Whereas open inquiry learning that allows for choices and decisions in students' inquiry procedure directly influenced use of self-regulatory strategies, the extent of inquiry activities directly influenced self-efficacy. Self-regulatory strategy use was not a significant predictor for scientific inquiry skills. Based on the results, implications for future science gifted education are discussed. Putting the Research to Use: This study, by incorporating instructional factors in the framework of self-regulated learning of gifted students, extended the previous research that had examined the relationships among the components of self-regulated learning in relation to achievement. Also, it explored such relationships in a much less studied area, science, and extended the scope of science achievement by including scientific inquiry skills as a criterion of academic performance. In general, it reveals that inquiry learning increases gifted students' scientific inquiry skills while open inquiry does not contribute much to this process and that the only learner characteristic influencing scientific inquiry skills is self-efficacy. For educators working with scientifically gifted students, this study urges them to plan open inquiry learning more systematically and make it accessible to students, by providing assistance and guidance with the inquiry process at the outset of learning and increasingly incorporating the open nature of inquiry. Motivational beliefs of gifted students in their abilities also need to be encouraged and fostered in the classroom.

In order to study if mitochondrial DNA (mtDNA) could be retrieved from isolated human dentine, small pieces of dentine were cut out from the central part of the apical half of wisdom teeth from 21 individuals aged 15 to 85 years. The dental pulp was used as a control. After extraction, amplification and agarose gel electrophoresis the amount of mtDNA was semi-quantified from the intensity of the stained bands in the gel. Mitochondrial DNA was retrieved from all samples and the sequences were identical in pulp and dentine from each individual. There was a clear age-dependent decrease in the amount of amplified mtDNA. Since the odontoblastic processes in the apical dentine undergo degeneration with age and the dentinal tubules subsequently become occluded with calcium phosphate crystals, the conclusion was drawn that even after dissolution of the odontoblastic processes, at least remains of the mtDNA are trapped in the dentine. This well protected mtDNA could thus be regarded a good source of DNA in identification cases with severe degradation.

Genomic DNA was isolated from buccal swabs by the QIAamp DNA Mini Kit (QIAGEN). The primers used for amplification and sequencing of exon 6 and 7 of ABO gene were suggested by Lee and Chang (1), and Ogasawara et al. (2), respectively. About 1-2 ng of genomic DNA was used for PCR in 25 μL reaction volume. PCR mixture contained 10 mM Tris-HCl pH 8.5, 50 mM KCl, 1.5 mM MgCl2, 200 μM of each dNTP, 0.25 μM of each primer, and 1 U of AmpliTaq Gold DNA Polymerase (Applied Biosystems). Thermal cycling was performed initially at 95°C for 10 min, then 35 cycles consisting of 95°C for 1 min, 60°C for 1 min for exon 6 and 63°C for 1 min for exon 7, 72°C for 1 min, followed by 10 min extension at 72°C in a GeneAmp PCR System 9600 (Perkin Elmer).