A Reappraisal of Developing Permanent Tooth Length as an Estimate of Age in Human Immature Skeletal Remains

This study expands on existing juvenile age prediction models from tooth length by increasing sample size and using classical calibration. A sample of 178 individuals from two European known sex and age skeletal samples was used to calculate prediction formulae for each tooth for each sex separately and combined. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. An ANCOVA was used to test sex and sample differences. Tooth length for age does not differ between the samples except for the canine and second premolar, and no statistically significant sex differences were detected. The least prediction error was found in the incisors and the first molar, and the highest prediction error was found in the third molar. Age prediction formulae provided here can be easily used in a variety of contexts where tooth length is measured from any isolated tooth.     

Using the National Incident-Based Reporting System (NIBRS) to Test Estimates of Arrestee and Offender Characteristics

National-Incident Based Reporting System (NIBRS) information for 1993 iscompared with two other sets of homicide data to assess the acuracy ofprocedures for estimating age-, sex-, and race-specific arrest counts fromtraditional Uniform Crime Report (UCR) data. The simultaneous age, race, andsex characteristics of offenders provided in the NIBRS arrest and offender segmentsare compared with estimates of the same characteristics derived from summaryUCR arrest data. The results suggest that using UCR marginal totals toestimate arrest counts by race and sex produces reasonably accurateestimates of the number of black and nonblack male arrests for murder andother offenses. Estimates of arrests of females by race and sex are lessaccurate, probably because of the relatively small number of arrests ofwomen and girls. Estimating male arrest counts for specific age groups alsoproduces reasonably accurate estimates. The results suggest that previousresearch employing such estimates may have been misleading in the estimatesof female arrests by race but accurate in the estimates of male arrests byrace. Although the use of summary UCR-based estimates in futurecross-sectional research will become increasingly unnecessary as the NIBRSreplaces the current UCR program, time series research designs on arrest andcrime trends will continue to require estimates.     

根据双刃刺器刺创口推断刺器宽度

解决根据皮肤创口推断刺器宽度的问题。实验在自愿捐献的12具男性尸体的胸部,用不同宽度和厚度的双刃匕首致创221个。应用法医学、解剖学及数理统计的理论和技术对创口形成机理、影响因素及其与刺器宽度的相关关系进行分析,得出了以下结论：刺器厚度与创口长度无明显相关,刺器宽度与创口长相关,创口回缩程度与创口方向及刺器宽度相关。并建立了两个最优回归方程,提出了一个根据皮肤双刃利器创口推断刺器宽度的方法。     

Minor or adult? Introducing decision analysis in forensic age estimation

Nowadays, forensic age estimation takes an important role in worldwide forensic and medico-legal institutes that are solicited by judicial or administrative authorities for providing an expert report on the age of individuals. The authorities’ ultimate issue of interest is often the probability that the person is younger or older than a given age threshold, which is usually the age of majority. Such information is fundamental for deciding whether a person being judged falls under the legal category of an adult. This is a decision that may have important consequences for the individual, depending on the legal framework in which the decision is made. The aim of this paper is to introduce a normative approach for assisting the authority in the decision-making process given knowledge from available findings reported by means of probabilities. The normative approach proposed here has been acknowledged in the forensic framework, and represents a promising structure for reasoning that can support the decision-making process in forensic age estimation. The paper introduces the fundamental elements of decision theory applied to the specific case of age estimation, and provides some examples to illustrate its practical application.     

The effects of certain intermediary target materials and their proximity to ballistic gelatin on jacketed hollow point bullet expansion

Expanding bullets are preferred by law enforcement because of their wounding potential and ability to avoid over-penetration which could result in unintended targets being struck by bullets that perforate their intended targets. Expansion failure for jacketed hollow point (JHP) bullets is commonly attributed to several causes including damage to the bullet's cavity, velocity loss, bullet destabilization and materials from intermediate targets filling the bullet's cavity which can cause expansion failure when the bullet subsequently impacts a soft, fluid-based target such as human tissue or ballistic gelatin. In this study, JHP bullets were fired into ballistic gelatin after passing through selected intermediate targets representing items common to shooting incidents. Velocity loss and bullet destabilization were not factors that contributed to the JHP bullets that experienced expansion failure; however, materials obstructing the bullets' cavities and damage to the bullets' cavities were considered causes for some of the JHP bullet expansion failures. It was determined through this research that most of the target materials caused JHP bullet expansion failure when shored against the ballistic gelatin, but when placed at distances of 7 ft. from the ballistic gelatin, bullets fired through the same target materials did expand. This original and unique study produced findings that are of significant value to shooting incident reconstruction experts and other forensic professionals as shooting incidents can call into question a victim's proximity to a wall or door when a bullet(s) perforated such a target material.     

对女性肋骨进行组织形态测量推断年龄

探讨人类密质骨的年龄变化规律 ,为法医学、人类学利用骨骼推断年龄提供新方法。收集 6 7例中国北方汉族女性右侧第六肋骨的中 1/3段 ,制作脱钙骨切片 ,在计算机图像分析仪上测量 9项组织形态学参数 ,并进行多元逐步回归分析 ,得到一个推断年龄的多元回归方程 :^Y =31 2 6 4+0 86 8X2 +2 86 6 93X4 +0 6 89X7-778 874X8-0 0 0 6X9,复相关系数和标准误分别是 0 92 3和 4 0 8。经 2 5例已知年龄的标本检验 ,预测年龄的误差在± 5岁以内的可达 84% ,误差在± 8岁以内的可达 10 0 %。结果表明 :应用肋骨的组织结构特征可准确推断死者年龄     

Estimating age in Maori, Pacific Island, and European children from New Zealand

The islands of New Zealand are populated by persons of European, Maori, and Pacific Island extraction. The purpose of this research is to quantify the levels of dental maturation of each of these three populations, in order to obtain data that will be useful in forensic identification and age estimation. The sample consisted of 1383 orthopantomographs (660 males, 723 females) of 477 Maori, 762 European, and 144 Pacific Island children between the ages of 3 and 14 years. Each radiograph was digitized and the stages of mineralization of the seven left mandibular permanent teeth were assessed using the eight stages described by Demirjian. Values for 1, 3, 5, 50, 95, 97, and 99% confidence intervals are listed for each maturity score. Intra-observer reliability was evaluated using Bland-Altman's method on data from re-scoring one out of every 20 radiographs and standard dental maturation curves were constructed for the three populations by means of a quantile regression method. Despite the fact that quantile regression analysis showed that across the age group investigated there were differences between boys and girls, knowledge of the sex does not increase the accuracy of the age estimate, simply because the magnitude of the error of age estimation is greater than the difference between the sexes. Our analysis also shows that population divergence is most marked after the age of 9 years, with a peak difference seen at age 10.     

Morphometric analysis of third molar root development by an experimental method using digital orthopantomographs

Abstract:  The aim of the study was to conduct a morphometric analysis of the root development of the third molar, with the purpose of overcoming the limits of an exclusively morphological analysis. The study was divided in two phases. The first one was the verification of the existence of a constant crown-root (C/R) ratio on a sample of 100 third molars, characterized by a complete root development. The value obtained was used in the second phase to predict the final root's length, knowing the crown height. So we have calculated, on a sample of 322 third molars with developing roots, the final ratios between incomplete roots and complete roots. Statistical analysis was then made with 90%, 95%, and 99% confidence intervals. The results showed a significant difference according to the age of the subject and the limit values, lower and upper, for subjects aged 16 and 17 years versus those aged 18 and 19. For each analysis, the width of the class of tolerance and other statistical indicators were calculated. The results we obtained support the advantage of a morphometric study as opposed to an exclusively morphological study, but all the techniques used to determine the age of a living subject can provide only indications of the biological age, but no certainties as regards chronological age.     

Application of three dental methods of adult age estimation from intact single rooted teeth to a Peruvian sample

Methods of estimating adult age at death from such dental features as root translucency, root length, and the extent of periodontosis in intact single rooted teeth have proven useful in studies of modern individuals, especially in estimating age in older adults. Questions remain however, concerning the impact of regional and population variation on accuracy. To examine this issue, three approaches to age estimation were applied to a diverse sample of 100 individuals from Peru. Mean errors of estimation for all three approaches were similar to those originally reported, suggesting minimal impact of population variation of the features measured. A new regression equation, specifically for Peruvian samples, is provided.     

Third molar development according to chronological age in populations from Spanish and Magrebian origin

Spain is frequently the entrance country into the European Union for undocumented immigrants, especially those from the Magreb (Northern Africa). Forensic age estimates for these persons are difficult because systematic studies of dental maturity are lacking. Three different populations were analyzed to determine the pattern of development of third molars as a tool for age estimation in people of different ethnic and geographic origin. Orthopantomograms from two different populations of Spanish origin (Galicia in northwestern continental Spain, and Ceuta, a Spanish province in Northern Africa) were compared to radiographs of molars from a Magrebian population (Northern Africa) resident in Ceuta. Orthopantomograms were obtained from a private dental clinic (n=344) in Galicia and from the Public Oral Health Services (n=228) in Ceuta. We looked for differences in third molar mineralization (determined with the Demirjian scale) that might serve as age indicators (older versus younger than 18 years). Differences in maturation patterns were found between sexes and populations of origin. Mineralization of tooth 38 was more advanced in males than females among subjects 18 years of age and older in all three populations. Moreover, mineralization of tooth 38 in subjects aged 18 years and older was significantly slower in the Spanish-Galicia population than in the Magrebian-Ceuta population. We found no significant differences between Magrebian and Spanish individuals from Ceuta. We conclude that differences in tooth 38 mineralization may be related more with socio-geographical than ethnic origin (ancestry), and thus constitute evidence of the relevance of socio-geographic rather than genetic factors in third molar development. We used ROC analysis to determine the accuracy of the examiner's ability to correctly estimate age as younger or older than 18 years. The results suggest that Demirjian stage for tooth 38 can be considered a good indicator of age in all three populations.