Application of Lamendin's adult dental aging technique to a diverse skeletal sample

Lamendin et al. (1) proposed a technique to estimate age at death for adults by analyzing single-rooted teeth. They expressed age as a function of two factors: translucency of the tooth root and periodontosis (gingival regression). In their study, they analyzed 306 singled rooted teeth that were extracted at autopsy from 208 individuals of known age at death, all of whom were considered as having a French ancestry. Their sample consisted of 135 males, 73 females, 198 whites, and 10 blacks. The sample ranged in age from 22 to 90 years of age. By using a simple formulae (A = 0.18 x P + 0.42 x T + 25.53, where A = Age in years, P = Periodontosis height x 100/root height, and T = Transparency height x 100/root height), Lamendin et al. were able to estimate age at death with a mean error of +/- 10 years on their working sample and +/- 8.4 years on a forensic control sample. Lamendin found this technique to work well with a French population, but did not test it outside of that sample area. This study tests the accuracy of this adult aging technique on a more diverse skeletal population, the Terry Collection housed at the Smithsonian's National Museum of Natural History. Our sample consists of 400 teeth from 94 black females, 72 white females, 98 black males, and 95 white males, ranging from 25 to 99 years. Lamendin's technique was applied to this sample to test its applicability to a population not of French origin. Providing results from a diverse skeletal population will aid in establishing the validity of this method to be used in forensic cases, its ideal purpose. Our results suggest that Lamendin's method estimates age fairly accurately outside of the French sample yielding a mean error of 8.2 years, standard deviation 6.9 years, and standard error of the mean 0.34 years. In addition, when ancestry and sex are accounted for, the mean errors are reduced for each group (black females, white females, black males, and white males). Lamendin et al. reported an inter-observer error of 9+/-1.8 and 10+/-2 sears from two independent observers. Forty teeth were randomly remeasured from the Terry Collection in order to assess an intra-observer error. From this retest, an intra-observer error of 6.5 years was detected.     

Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition

Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.     

Age estimation using carpals: study of a Slovenian sample to test Cameriere's method

Carpals are often used as age indicators. In a recent study, Cameriere et al. studied the use of the ratio between the total area of carpal bones and epiphyses of the ulna and radius (Bo) and carpals (Ca) as age indicators. The present study, of a sample of 158 Slovenian children and adolescents aged between 6 and 16 years, focused on analysing the best regression for age estimation. The regression model yielded the following equation: age=-3.411+0.942 g+20.927(Bo/Ca), and explained 91.6% of total variance (R(2)=0.916). The median of the absolute values of residuals (observed age minus predicted age) was 0.09 years, with a quartile deviation of 0.786 years, and a standard error of estimate of 0.658 years. Comparisons between the previous equation referring to Slovenian children and the equivalent linear equation proposed by Cameriere et al. did not reveal any significant differences between the intercepts and slopes of the two linear models. These results suggested a common regression model for both Italian and Slovenian samples. The common regression model, describing age as a linear function of gender and Bo/Ca ratio, yielded the following linear regression formula: age=-2.907+0.408 g+20.757(Bo/Ca). This model explained 86% of total variance (R(2)=0.86). The median of the absolute values of residuals (observed age minus predicted age) was 0.02 years, with a quartile deviation of 1.02 years and a standard error of estimate of 0.96 years.     

Age estimation by a dental method: a comparison of Lamendin's and Prince & Ubelaker's technique

Lamendin et al. (J Forensic Sci 1992;37:1373) developed a general technique to estimate age of adults at death using two dental features: periodontosis and translucency of the tooth root. Prince and Ubelaker (J Forensic Sci 2002;47:107) modified this method, creating a formula for each sex and for different ancestries, and obtained more precise age estimations. In the present study, the validity of each method was tested in 45 males and 34 females of Spanish Caucasian origin, and a novel formula, based on Prince and Ubelaker method, was specifically developed for a population of mixed racial origin (mestizo) from Colombia, and findings obtained were again compared with those yielded by Lamendin adult dental aging technique. The Prince and Ubelaker method proved more accurate than the Lamendin technique in the Spanish Caucasian population, and our Prince and Ubelaker-based formula was also more accurate than the Lamendin et al. In both populations, the Lamendin method showed a higher mean error in estimations of the age of youngest and oldest individuals. These findings confirm the need to create specific formulas for each human group in order to obtain more accurate age estimates.     

A Two‐Level Model for Evidence Evaluation in the Presence of Zeros*

Abstract: Likelihood ratios (LRs) provide a natural way of computing the value of evidence under competing propositions. We propose LR models for classification and comparison that extend the ideas of Aitken, Zadora, and Lucy and Aitken and Lucy to include consideration of zeros. Instead of substituting zeros by a small value, we view the presence of zeros as informative and model it using Bernoulli distributions. The proposed models are used for evaluation of forensic glass (comparison and classification problem) and paint data (comparison problem). Two hundred and sixty‐four glass samples were analyzed by scanning electron microscopy, coupled with an energy dispersive X‐ray spectrometer method and 36 acrylic topcoat paint samples by pyrolysis gas chromatography hyphened with mass spectrometer method. The proposed LR model gave very satisfactory results for the glass comparison problem and for most of the classification tasks for glass. Results of comparison of paints were also highly satisfactory, with only 3.0% false positive answers and 2.8% false negative answers.     

Comparison of the validity of three dental methods for the estimation of age at death

The aim of the present study was to compare the accuracy, precision, and bias of two macroscopic and one histological age at death estimation methods on human teeth. The sample was comprised of 67 permanent teeth, obtained from 37 individuals aged 20-91 years. Age was predicted according to the methods proposed by Lamendin et al. (LAM), Bang and Ramm (BR), and the quantification of tooth cementum annulations (TCA). TCA was found to be most accurate in all age groups. Its mean absolute error of the estimated age was about half as high as the mean absolute error for both LAM and BR. BR achieved approximately the same mean absolute error as TCA for old adults only. LAM displayed the highest precision in the young and the old age group whereas TCA was more precise in the middle age group. TCA was found to be the most precise method when the precision was calculated for all ages. Considering the bias, all methods displayed a tendency to overestimate age in young and to underestimate it in old specimens. The exception to this rule was TCA, which provided unbiased estimates for young adults. The higher accuracy and precision recommends favouring TCA over LAM and BR, provided that the required know-how and equipment are available.     

Bone Mineral Density Adult Age Estimation in Forensic Anthropology: A Test of the DXAGE Application

Estimating age‐at‐death of individuals represented only by skeletonized human remains is a fundamental aspect of forensic anthropological casework. Recently, several researchers have proposed that bone mineral density (BMD) is a useful predictor of age‐at‐death in forensic contexts. Navega et al. (JFS 63(2):497–503) developed an online application called DXAGE for calculating age‐at‐death from BMD parameters. This study tests the utility of DXAGE by utilizing data from the National Health and Nutrition Examination Survey (NHANES). BMD data from a female subsample (n = 470) of the NHANES 2007–2008 dataset were analyzed, and the relationship between predicted age and real age was examined. Inaccuracy was 14.25 years, and bias was ?7.20 years. Results show that there is a weak correlation between predicted and actual age (r = 0.47) using the DXAGE application. While BMD data are potentially useful for predicting age age‐at‐death, the DXAGE application should be used cautiously in forensic anthropological contexts.     

Age estimation by measurements of developing teeth: accuracy of Cameriere's method on a Brazilian sample

Developing teeth are commonly the criteria used for age estimation in children and young adults. The method developed by Cameriere et al. (Int J Legal Med 2006;120:49-52) is based on measures of teeth with open apex, and application of a formula, to estimate chronological age of children. The present study evaluated a sample of panoramic radiographs from Brazilian children from 5 to 15 years of age, to evaluate the accuracy of the method proposed by Cameriere et al. The results has proven the system reliable for age estimation, with a median residual error of -0.014 years between chronological and estimated ages (p = 0.603). There was a slight tendency to overestimate the ages of 5-10 years and underestimate the ages of 11-15 years.     

Estimation of age-at-death for adult males using the acetabulum, applied to four Western European populations

Methods to estimate adult age from observations of skeletal elements are not very accurate and motivate the development of better methods. In this article, we test recently published method based on the acetabulum and Bayesian inference, developed using Coimbra collection (Portugal). In this study, to evaluate its utility in other populations, this methodology was applied to 394 specimens from four different documented Western European collections. Four strategies of analysis to estimate age were outlined: (a) each series separately; (b) on Lisbon collection, taken as a reference Coimbra collection; (c) on Barcelona collection, taken as a reference both Portuguese collections; and (d) on London collection taken as reference the three Iberian collections combined. Results indicate that estimates are accurate (83-100%). As might be expected, the least accurate estimates were obtained when the most distant collection was used as a reference. Observations of the fused acetabulum can be used to make accurate estimates of age for adults of any age, with less accurate estimates when a more distant reference collection is used.     

The Utility of the Samworth and Gowland Age‐at‐Death “Look‐up” Tables in Forensic Anthropology*

Abstract: Accurate age‐at‐death estimates are crucial to forensic anthropologists when onstructing biological profiles aimed at narrowing a missing‐persons list and to allow for timely and efficient identification of an unknown victim. The present contribution evaluates the utility of three new age‐at‐death estimation techniques recently proposed by Samworth and Gowland (2007). Results indicate that, in the samples under study, the Samworth and Gowland estimates from the pubic symphysis and auricular surface perform similar to alternate phase methods. The combined method does not appear to further enhance either the precision or the accuracy of the single pubic symphysis age‐at‐death estimate. In conclusion, these new methods seem to be more robust to distribution deviations than originally proposed by Samworth and Gowland (2007). They are therefore suitable for immediate and reliable forensic usage in the United States and worthy of further research for their use in North American forensic contexts.     

A Bayesian Approach to Age‐at‐Death Estimation from Osteoarthritis of the Shoulder in Modern North Americans

Osteoarthritis (OA) is a marker of degeneration within the skeleton, frequently associated with age. This study quantifies the correlation between OA and age‐at‐death and investigates the utility of shoulder OA as a forensic age indicator using a modern North American sample of 206 individuals. Lipping, surface porosity, osteophyte formation, eburnation, and percentage of joint surface affected were recorded on an ordinal scale and summed to create composite scores that were assigned a specific phase. Spearman's correlation indicated a positive relationship between each composite score and age (right shoulder = 0.752; left shoulder = 0.734). Transition analysis revealed a tendency toward earlier degeneration of the right shoulder. Bayesian statistics generated phase‐related age estimates based on highest posterior density regions. Best age estimates were into the seventh decade at the 90th and 50th percentile. The proposed method supplements traditional techniques by providing age estimates beyond a homogenous 50+ age cohort.     

Excretion of Delta9-tetrahydrocannabinol in sweat

The aims of this study were: first, to determine the accuracy of the Cameriere method for assessing chronological age in children based on the relationship between age and measurement of open apices in teeth and, second, to compare the accuracy of this method with the widely used Demirjian et al. method and with the method proposed by Willems et al. Orthopantomographs taken from white Italian, Spain and Croatian children (401 girls, 355 boys) aged between 5 and 15 years were analysed following the Cameriere, Demirjian and Willems methods. The difference between chronological and dental age was calculated for each individual and each method (residual). The accuracy of each method was assessed using the mean of the absolute values of the residuals (mean prediction error). Results showed that the Cameriere method slightly underestimated the real age of children. The median of the residuals was 0.081 years (interquartile range, IQR=0.668 years) for girls and 0.036 years for boys (interquartile range, IQR=0.732 years). The Willems method showed an overestimation of the real age of boys, with a median residual error of -0.247 years and an underestimation of the real age of girls (median residual error=0.073 years). Lastly, the Demirjian method overestimated the real age of both boys and girls, with a median residual error of -0.750 years for girls and -0.611 years for boys. The Cameriere method yielded a mean prediction error of 0.407 years for girls and 0.380 years for boys. Although the accuracy of this method was better for boys than for girls, the difference between the two mean prediction errors was not statistically significant (p=0.19). The Demirjian method was found to overestimate age for both boys and girls but the mean prediction error for girls was significantly greater than that for boys (p=0.024), and was significantly less accurate than the Cameriere method (p<0.001). The Willems method was better than that of Demirjian (p=0.0032), but was significantly less accurate than that of Cameriere (p<0.001).     

Effects of Parturition on Pelvic Age Indicators

This research assessed whether parity has a differential effect on age indicators of the pelvis. The data were collected from the William M. Bass Donated Skeletal Collection. Age indicators of the pubic symphysis and auricular surface were assessed using the Todd, Suchey–Brooks, Lovejoy et al., and Buckberry and Chamberlain scoring systems. A transition analysis was conducted, and scoring systems of the pubic symphysis showed the parous female group transitioning between eight and 14 years earlier than the nulliparous female and male groups, and 1 and 7 years earlier using the auricular surface methods. A likelihood ratio test produced significantly different results between parous and nulliparous females using the pubic symphysis (p < 0.01) but not the auricular surface (p > 0.05). Although parous females were inaccurately assessed more often than nulliparous females, no correction of methods is necessary at this time as current standards take parity into account by utilizing a lumped female sample.     

基于数据挖掘实现成人喉软骨和舌骨CT图像重组的年龄推断

目的 运用数据挖掘技术探索喉软骨和舌骨CT图像重组用于成人年龄推断的可行性.方法 收集413例颈部薄层CT图像,样本年龄范围18～<80岁,将样本随机分为测试集和训练集.参照TURK等的分级方法,对所有样本进行全方位综合阅片分级,将甲状软骨骨化过程分为6级,环状软骨骨化过程分为5级,舌骨大角和舌骨体的骨性结合分为3级....     

Pronasale Position: An Appraisal of Two Recently Proposed Methods for Predicting Nasal Projection in Facial Reconstruction

This study examines two recently proposed methods for predicting nose projection from the skull, those developed by Stephan et al. (Am J Phys Anthropol 122, 2003, 240) and Rynn et al. (Forensic Sci Med Pathol 6, 2010, 20). A sample of 86 lateral head cephalograms of adult subjects from Central Europe was measured, and the actual and predicted dimensions were compared. Regarding nose projection (the anterior and vertical position of the pronasale), in general, the method of Rynn et al. (Forensic Sci Med Pathol 6, 2010, 20) was found to perform better and with less error variance than the method of Stephan et al. (Am J Phys Anthropol 122, 2003, 240), but the mean difference between the actual and predicted values did not exceed 2.2 mm (6.5% of the actual dimension) in most of the variables tested. The vertical dimensions of the nose were predictable with greater accuracy than the horizontal dimensions. Although the mean error of both methods is not great in practice and thus both methods could be considered to be “accurate,” the real variance of error should not be overlooked.     

DXAGE: A New Method for Age at Death Estimation Based on Femoral Bone Mineral Density and Artificial Neural Networks

Age at death estimation in adult skeletons is hampered, among others, by the unremarkable correlation of bone estimators with chronological age, implementation of inappropriate statistical techniques, observer error, and skeletal incompleteness or destruction. Therefore, it is beneficial to consider alternative methods to assess age at death in adult skeletons. The decrease in bone mineral density with age was explored to generate a method to assess age at death in human remains. A connectionist computational approach, artificial neural networks, was employed to model femur densitometry data gathered in 100 female individuals from the Coimbra Identified Skeletal Collection. Bone mineral density declines consistently with age and the method performs appropriately, with mean absolute differences between known and predicted age ranging from 9.19 to 13.49 years. The proposed method—DXAGE—was implemented online to streamline age estimation. This preliminary study highlights the value of densitometry to assess age at death in human remains.     

A test of the differential accuracy of the maxillary versus the mandibular dentition in age estimations of immature skeletal remains based on developing tooth length

Liversidge and colleagues developed a method for predicting the age of immature skeletal remains based on the length of developing teeth. This quantitative method combines dental data from both jaws, except for the permanent lateral incisor, and because there are reasons to suspect that these two types of data are not identical and should not be combined, it raises concerns regarding the accuracy of the technique when applied differently to each jaw. In this study, the differential accuracy of the method was test when applied to the maxillary and mandibular dentition. The test sample is comprised of 57 Portuguese subadult skeletons of known age at death. Results suggest an overall high consistency between estimates obtained from both jaws, but for the permanent dentition only. In the deciduous dentition the age estimates obtained from the maxillary teeth tend to be greater than the age estimates obtained from the mandibular pair, and the differences are significant for the incisors and canine. Additionally, ages obtained from the maxillary deciduous canine also differ significantly from true chronological age. In the permanent dentition there were no differences between the ages provided by both jaws but both the maxillary and mandibular second molars show a significant tendency to underestimate true chronological age. Although this study cannot validate completely the method presented by Liversidge and colleagues, it does provide an important test to its accuracy and calls for further research into its overall performance, particularly with respect to the results obtained from both jaws.     

Orthodontic Treatment: Real Risk for Dental Age Estimation in Adults?

Dental age estimation becomes a challenge once the root formation is concluded. In living adults, one dental age indicator is the formation of secondary dentine, also associated with orthodontic treatment as well as root shortening. The aim of this study was to establish whether these secondary effects of orthodontic treatment could generate a statistically significant difference in dental age estimations when using Kvaal's method. The study sample included 34 pairs of pre‐ and postorthodontic panoramic radiographs, from different individuals with exactly the same age and sex distribution. Females 65%, median age 17.5 years, and males 35%, median age 22.5 years, were included. After data collection, dental age was estimated per tooth using formulae previously published. The risk of obtaining over‐estimation of age was calculated. (RR = 1.007). The changes caused by orthodontic treatment do not have any significant effect on age estimation when Kvaal et al.'s method is applied on panoramic radiographs.