Bite marks are increasingly common in violent cases such as child abuse and sex crimes. Bite marks are often the result of a suspect's attack or a victim's self-defense. Because human teeth vary in size, shape and arrangement, bite marks on objects such as skin and food are characteristic. By using this principle, forensic odontology can identify or exclude suspects by comparing actual bite marks with the teeth marks in the mouth. In this paper, the practical application of bite mark evidence, the research status and problems of bite mark analysis are briefly reviewed, and the prospect of bite mark analysis is also discussed.
Bites, Human ; Child ; Child Abuse ; Face ; Forensic Dentistry ; Humans ; Tooth

Objective To discuss a new coding method for individual identification based on oral panoramic tomography, analyze the diversity of different coding modules in nonhomologous images and the consistency and the matching rate of the coding indexes of different coding modules in homologous images, and evaluate the application value of the different modules and the new coding method in individual identification. Methods The oral panoramic tomography images of 1 000 patients with permanent teeth were collected retrospectively. Each patient had two images taken at different times （called the Early database and the Late database according to the chronological order）. Each image was coded according to the designed coding method. A computer program was designed to compare the diversity of different modules, and calculate the diversity and consistency of different coding modules as well as the matching rate of the coding indexes. Results The diversity of the 4 modules that reflected teeth characteristics was much higher than that of other modules in the same database. The highest diversity was noticed in the module of right mandibular teeth in samples of both databases. The coding consistencies of the 4 modules were all above 50%. Besides, 90.2% of the matching rates of indexes of homologous images were over 80%. Conclusion The 4 modules have higher application value in individual identification, especially the right mandibular teeth. The coding method has a certain value in forensic individual identification.
Forensic Dentistry ; Forensic Medicine ; Humans ; Radiography, Panoramic ; Retrospective Studies ; Tooth/diagnostic imaging*

PURPOSE: It has been proposed that using new prediction methods, such as neural networks based on dental data, could improve age estimation. This study aimed to assess the possibility of exploiting neural networks for estimating age by means of the pulp-to-tooth ratio in canines as a non-destructive, non-expensive, and accurate method. In addition, the predictive performance of neural networks was compared with that of a linear regression model. MATERIALS AND METHODS: Three hundred subjects whose age ranged from 14 to 60 years and were well distributed among various age groups were included in the study. Two statistical software programs, SPSS 21 (IBM Corp., Armonk, NY, USA) and R, were used for statistical analyses. RESULTS: The results indicated that the neural network model generally performed better than the regression model for estimation of age with pulp-to-tooth ratio data. The prediction errors of the developed neural network model were acceptable, with a root mean square error (RMSE) of 4.40 years and a mean absolute error (MAE) of 4.12 years for the unseen dataset. The prediction errors of the regression model were higher than those of the neural network, with an RMSE of 10.26 years and a MAE of 8.17 years for the test dataset. CONCLUSION: The neural network method showed relatively acceptable performance, with an MAE of 4.12 years. The application of neural networks creates new opportunities to obtain more accurate estimations of age in forensic research.
Cone-Beam Computed Tomography ; Dataset ; Forensic Dentistry ; Humans ; Linear Models ; Methods ; Neural Networks (Computer)

Objective To apply Demirjian's and Cameriere's method for dental age estimation of adolescents from Hunan Han nationality, and compare the accuracy of the two methods. Methods A total of 480 orthopantomograms of?8-16 year?old adolescents from Hunan Han nationality?with no special diseases and good nutritional status were collected?by Xiangya Stomatological Hospital of Central South University from January, 2016 to July, 2017, among them 236 males and 244 females. The dental age of each adolescent was determined by Demirjian's method and Cameriere's method, respectively, and the paired t-test of the estimated dental age and the chronological age determined by the two methods was conducted by SPSS 20.0 software to compare the difference between estimated dental age and chronological age. Results Mean chronological age of males and females was 11.91 and 11.88 years, respectively. The estimated dental age determined by Demirjian's method showed an underestimate of chronological age by an average of 0.11 years （males） and 0.15 years （females）, while the estimated dental age determined by Cameriere's method showed an underestimate of chronological age by an average of 0.83 years （males） and 0.72 years （females）. Conclusion Demirjian's method is more accurate than Cameriere's method in dental age estimation of adolescents from Hunan Han nationality, therefore more suitable for dental age estimation of adolescents in this region.
Adolescent ; Age Determination by Teeth ; Asian People ; Child ; China ; Ethnicity ; Female ; Forensic Dentistry ; Humans ; Male ; Radiography, Panoramic ; Reproducibility of Results

In recent years, individual age estimation has gained increasing attention in forensic practice. Common age estimation methods mainly use developments of teeth and bones. Compared with bones, teeth are stronger and are highly resistant to external factors, therefore plays an important role in age estimation. Demirjian's method is one of the most commonly used methods to evaluate dental age and has been widely used in many countries. In this paper, the accuracy of its application in different populations is reviewed. It is found that compared with the chronological ages, most of the estimated ages are overestimated. By combining research results of many scholars and by analyzing, it can be assumed that this situation may be related with race, region, sex, etc.
Age Determination by Teeth ; Forensic Dentistry/standards* ; Research/trends* ; Tooth/anatomy & histology*

Age estimation is a hot and difficult issue in forensic practice. Teeth are the most solid organs in human body and can be kept in vitro for a long time. With age, the secondary dentin gradually generates and the volume of pulp cavity constantly decreases. Therefore, forensic dentists proposed that age-related changes of dentin-pulp complex could be used to estimate age, which has been widely applied in forensic practice over the years. Due to the development of imaging technology, a variety of methods have been advocated by forensic dentists to detect the age-related changes of dentin-pulp complex for age estimation. However, different methods have their own advantages and limitations, forensic scientists should combine the use of different methods for improving the accuracy of age estimation according to the actual situation. This paper reviews current research of age estimation based on dentin-pulp complex, so as to provide reference for related research.
Age Determination by Teeth ; Dental Pulp ; Dentin ; Forensic Dentistry/methods* ; Humans

Forensic dentistry is an interdiscipline of forensic medicine and stomatology, which provides legal information by collecting, testing and assessing the dental evidence scientifically. In this review, the present application of forensic dentistry has been described, such as the estimation of age, sex, species, occupation and living habit, as well as the identification of individual, domestic violence or abuse, which aims to enrich and improve forensic dentistry for making it be more useful in forensic medicine even in juridical practice.
Age Determination by Teeth ; Forensic Anthropology ; Forensic Dentistry/methods* ; Forensic Medicine ; Humans ; Tooth

PURPOSE: This study assessed the accuracy of age estimates produced by a regression equation derived from lower third molar development in a Thai population. MATERIALS AND METHODS: The first part of this study relied on measurements taken from panoramic radiographs of 614 Thai patients aged from 9 to 20. The stage of lower left and right third molar development was observed in each radiograph and a modified Gat score was assigned. Linear regression on this data produced the following equation: Y=9.309+1.673 mG+0.303S (Y=age; mG=modified Gat score; S=sex). In the second part of this study, the predictive accuracy of this equation was evaluated using data from a second set of panoramic radiographs (539 Thai subjects, 9 to 24 years old). Each subject's age was estimated using the above equation and compared against age calculated from a provided date of birth. Estimated and known age data were analyzed using the Pearson correlation coefficient and descriptive statistics. RESULTS: Ages estimated from lower left and lower right third molar development stage were significantly correlated with the known ages (r=0.818, 0.808, respectively, P≤0.01). 50% of age estimates in the second part of the study fell within a range of error of ±1 year, while 75% fell within a range of error of ±2 years. The study found that the equation tends to estimate age accurately when individuals are 9 to 20 years of age. CONCLUSION: The equation can be used for age estimation for Thai populations when the individuals are 9 to 20 years of age.
Age Determination by Teeth ; Asian Continental Ancestry Group* ; Forensic Dentistry ; Humans ; Linear Models ; Molar, Third* ; Parturition ; Radiography, Panoramic

OBJECTIVE: To explore the value of estimating chronologic age based on the grades of mandibular third molar development. To evaluate whether mandibular third molar could be used as an indicator for estimating the age under or over 18 years. METHODS: The mineralization status of mandibular third molar of 1 845 individuals aged 10 - 30 was graded and marked based on Demirjian's classification of grades reformed by Orhan. Gender difference was examined by t-test. A cubic regression model was established to analyze the correlation between third molar and chronologic age. Each grade of age cumulative distribution diagram and ROC curve was respectively performed to evaluate the relationship between third molar and the age of 18. Using Bayes discriminant analysis, an equation was established for estimating the age of 18. RESULTS: The inner-rater reliability was 0.903. Statistical analysis showed a moderate correlation between age and grade. Significant differences of both genders were found only in grade D and H (P < 0.05). Males at the grades from 1 to D and females at the grades from 1 to C were under 18 years old, and both males and females at grade H were over 18 years old. The area under the ROC curve was 0.797 (P < 0.05). CONCLUSION Third molar development shows a high correlation with age, and combined with other indicators, it can be used to estimate the age of 18.
Age Determination by Teeth/methods* ; Asian People ; Bayes Theorem ; China ; Female ; Forensic Dentistry ; Humans ; Male ; Molar, Third/diagnostic imaging* ; Radiography, Panoramic ; Reproducibility of Results ; Sex Characteristics

Dental identification was conducted on the putative body of a most wanted fugitive who was considered to be the de facto owner of the ferry MV Sewol. Postmortem examination showed many dental characteristics, including gold crowns, a porcelain-fused-to-metal crown, a gold fixed bridge, and resin restorations. The estimated age of the body was approximately 73 years. Antemortem data collected by the fugitive at private dentist showed that 10 teeth had dental features. When the antemortem data on the 10 teeth were compared with the corresponding teeth by using postmortem data, there was no discrepancy in the remaining teeth. The number of possible combinations was calculated, and the likelihood of this fugitive and any other person having the same dental features was one in 14 billion. Using the results of dental examination, the body was successfully identified.
Age Determination by Teeth ; Autopsy ; Crowns ; Dentists ; Denture, Partial, Fixed ; Forensic Dentistry ; Humans ; Tooth