Sex estimation based on the anthropometric measurements of thyroid cartilage using discriminant analysis

Abstract Background The morphometric analysis of the individual bones of the human skeleton can be used to estimate the sex of unidentified corpses. Our aims were as follows: to test whether thyroid cartilage can be used for forensic purposes as a predictor of biological sex; to establish the level of sexual dimorphism of the thyroid cartilage in a sample of adult subjects from a population of European Russia; and to test the accuracy of the morphometric parameters obtained from the thyroid cartilage. Results The thyroid cartilage from 100 adults of known age (50 males and 50 females) was obtained during forensic examination; morphometric tests were conducted using Vernier Digital ROKTOOLS ABS DIN 862 0-200/6 inch with measurement accuracy ± 0.01 mm. The measured parameters were N = 31 for each subject. Intra- and inter-observer reproducibility was tested. Multivariate statistical analysis was applied to the measurements. To check the data set for normal distribution, the Kolmogorov-Smirnov test was used. Finally, to estimate the sex of the observed individuals, a stepwise discriminant analysis was conducted, using the Wilks' lambda selection method. The most significant parameters were the outer distance between bases of inferior horn; the inner distance between distal ends of inferior horns; distance between distal ends of left superior and inferior horns; left superior horn length (distance between left superior horn distal end and base); distance between superior and inferior notches; thyroid angle; left lamina height (vertical line along left lamina middle); horizontal distance between anterior intermedium line and the right lamina posterior edge; distance between inferior thyroid notch and line connecting left and right thyroid laminae; and left superior horn thickness at mid-line. The stepwise discriminant analysis resulted in an equation with ten parameters. Conclusions The results of the current study indicated that in the European Russian population, the equation obtained in the stepwise discriminant analysis makes it possible to predict sex with a probability of 100% on the validation set. On the test set, the resultant accuracy was 100% for females and 100% for males. Our findings confirm the scientific evidence that the thyroid cartilage has a pronounced sexual dimorphism

Age estimation in children by measurement of open apices in teeth

This paper concerns a method for estimating the age of children based on their teeth. The sample consisted of 455 Italian white children (213 boys, 242 girls) aged between 5 and 15 years. The purpose of the present investigation was to present a method for assessing chronological age based on the relationship between age and measurement of the open apices in teeth. Pearson\u2019s correlation coefficients between age and these variables showed that the correlations between age and the open apices in teeth were significant and negative. Furthermore, gender and the number of teeth with the apical end of the root canals completely closed (N0) showed a significant correlation with chronological age. With the aid of a stepwise multiple regression model, a linear relationship between open apices, N0, and age was shown. Statistical analysis indicated that these morphological variables explain 83.6% of the variations in estimated chronological age. The median of residual errors between the actual and estimated ages was 120.035 years [interquartile range (IQR)=1.18 years]

Variations in pulp/tooth area ratio as an indicator of age: a preliminary study

This paper details for age determination of adult from single rooted theeth. The sample consisted of 100 Italians white Caucasioan patients (46 men, 54 womwn) aged between 18 and 72 years. The single rooted maxillary right canine was utilized in this preliminary study. Pulp/root ration, tooth length ratio, pulp/root area and pulp/root width ratios at three different levels were computed. Pearson's correlation coefficients between age and these variables showed that the ratio between pulp and tooth area correlated best with age (r2 = 0,85). Stepwise multiple regression models yielded a linear relationship between pulp/root width at mid-root level and chronological age and a linear relationship when pulp/tooth area was compared to age. Statistical analysis indicated that these two variables explain 84,9% of variations in estimated chronological age. The median of the absolute value of residual errors between actual and estimated ages was less than four years

Carpals and epiphysis of radius and ulna as age indicators

Estimation of skeletal age using radiographic images is widely used for assessing biological growth in clinical and auxological studies. The most frequent areas used for age estimation in children and adolescents are tooth and wrist/hand, both giving good results with only a low level of radiation. In particular, ossification of the carpals shows good agreement with chronological age. This study of a sample of 150 Italian children and adolescents aged between 5 and 17 years focused on analyzing the possible applications of the proportion of carpal area (Ca) mineralization as a criterion of age estimation. The ratio between the total area of carpal bones and epiphyses of the ulna and radius (Bo) andCa was calculated. This ratio (Bo/Ca) was used for linear regression analysis. The regression model, describing age as a linear function of the ratio Bo/Ca, yielded the following equation: Age= 123.253+0.719g+20.610 Bo/Ca, and explained 83% of the total variance (R2=0.83). The median of the absolute values of residuals (observed age minus predicted age) was 0.08 years, with a quartile deviation of 1.59 years, and a standard error of estimate of 1.19 years

Age estimation in children by measurement of open apices in teeth: an Indian formula.

The aim of this paper is twofold: first, to evaluate an Indian sample by Cameriere\u2019s European formula; and second, if this formula turns out to be unsuitable, to study a specific formula for Indian children. Orthopantomographs taken from 480 Indian children (227 girls and 253 boys) aged between 3 and 15 years were analyzed. Following the pilot study, subjects\u2019 age was modeled as a function of gender (g), region of country (C), and morphological variables (predictors: x5, the distance between the inner sides of the open apex of the second premolar divided by the tooth length; s \ubc x1 \ufe x2 \ufe x3 \ufe x4 \ufe x5 \ufe x6 \ufe x7, sum of normalized open apices; N0, the number of teeth with root development complete. Results showed that all these variables except gender and second premolar contributed significantly to the fit so that all were included in the regression model, yielding the following linear regression formula: Age \ubc 9:402 0:879 C \ufe 0:663 N0 0:711 s 0:106s N0 where C is a dummy variable equal to 0 for the center or north of India and 1 for the south. The above equation, with the variables considered, explained 89.7% (R2=0.897) of total deviance. The median of the residuals (observed age minus predicted age) was \u20130.063 years, with an interquartile range of 1.10 years

Age estimation using carpals: study of a Slovenian sample to test Cameriere\u2019s 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 + 0.942g + 20.927(Bo/Ca), and explained 91.6% of total variance (R2 = 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 + 0.408g + 20.757(Bo/Ca). This model explained 86% of total variance (R2 = 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

Third molar maturity index by measurements of open apices in a Libyan sample of living subjects

In most countries, forensic age estimation in living subjects has become increasingly important in the last few years. In addition, as the age of legal majority ranges from 14 to 18 in many countries, and in Libya it is 18 years, radiographic assessment of the degree of third molar development is essential for forensic age estimation of adolescents and young adults. The aim of this paper is to assess the accuracy of the cut-off value of 0.08, by measurements of third molar index (I3M), in determining if a subject is adult or not in Libyan population. Digital panoramic radiographs of 307 healthy subjects (163 girls, 144 boys), aged between 14 and 22, were analysed. The I3M, the age and the sex of the subjects were used as predictive variable for age estimation. Using a cut-off of 0.08, the sensitivity of the test for boys was 90.9% and the specificity 100%. The proportion of correctly classified individuals was 95.1% (95% CI: 91.5–98.7%). The sensitivity for girls was 90.6% and the specificity 100%. The proportion of correctly classified individuals was 94.5% (95% CI: 90.9–98.1%). Estimated post-test probability in boys and girls was 100%. Further analyses, performed using a cut-off of 0.09, do not affect the specificity (100%) while they improve the sensitivity for both boys and girls

Age estimation in children by measurement of open apices in teeth: a European formula

The aim of the present paper was to improve and expand research with a larger number of children from various European countries and to provide a common formula useful for all these countries. Orthopantomographs taken from 2,652 European Caucasian children (1,382 boys, 1,270 girls) aged between 4 and 16 years were analyzed. The children came from Croatia, Germany, Kosovo, Italy, Slovenia, Spain, and the UK. Following the pilot study, subjects’ age was modeled as a function of gender (g), morphological variables (predictors)×5 (second premolar), s (sum of normalized open apices) N0, and the first-order interaction between s and N0. The results showed that all these variables contributed significantly to the fit, so that all were included in the regression model, yielding the following linear regression formula: Age=8.387+ 0.282 g−1.692×5+0.835 N0−0.116 s−0.139 s×N0, where g is a variable, 1 for males and 0 for females. The equation explained 86.1% (R2=0.861) of total deviance. The median of the residuals (=observed age minus predicted age) was −0.114 years, with (RefB.2) interquartile range=1.22 years

The measurement of open apices of teeth to test chronological age of over 14-year-olds in living subjects

Age determination in living subjects is a problem of increasing interest in our community, due to the increasing numbers of individuals without identification papers, who have immigrated illegally or committed crimes, and for whom it is necessary to verify whether they have reached the age of 14 years in order to be charged legally. Although the most widespread methods for age estimation refer to skeletal or dental analysis, these methods do present some drawbacks for identification of the age of 14. The aim of the present study is to discriminate between children who are or are not 14 years of age or older by measuring the open apices of teeth. We evaluated the OPGs of 447 persons aged between 12 and 16 years, of Italian, Croatian and Slovenian nationality. For each individual, dental maturity was estimated using the number of the seven left permanent mandibular teeth with root development complete, and normalized measurement of the open apices of the third molar. The results revealed that an individual is considered to be 14 years of age or older if all seven left permanent mandibular teeth have closed apices and the normalized measurement of open apices of the third molar is lower than 1.1