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Identification of living undocumented individuals highlights the need for accurate, precise, and reproducible age estimation methods, especially in those cases involving minors. However, when their country of origin is unknown, or it can be only roughly estimated, it is extremely difficult to apply assessment policies, procedures, and practices that are accurate and child-sensitive. The main aim of this research is to optimize the correct classification of adults and minors by establishing new cut-off values for four different continents (Africa, America, Asia, and Europe). For this purpose, a vast sample of 10,701 orthopantomographs (OPTs) from four continents was evaluated. For determination and subsequent validation of the new third molar maturity index (I 3M ) cut-off values by world regions, a cross-validation by holdout method was used and contingency tables (confusion matrices) were generated. The lower third molar maturity indexes, from both left and right side (I 3M L and I 3M R) and the combination of both sides (I 3M L_I 3M R) were calculated. The new cut-off values, that aim to differentiate between a minor and an adult, with more than 74.00% accuracy for all populations were as follows (I 3M L; I 3M R; I 3M L_I 3M R, respectively): Africa = (0.10; 0.10; 0.10), America = (0.10; 0.09; 0.09), Asia = (0.15; 0.17; 0.14), and Europe = (0.09; 0.09; 0.09). The higher sensitivity (Se) was detected for the I 3M L for male African people (91%) and the higher specificity (Sp) of all the parameters (I 3M L; I 3M R; I 3M L_I 3M R) for Europeans both male and female (> 91%). The original cut-off value (0.08) is still useful, especially in discriminating individuals younger than 18 years old which is the goal of the forensic methods used for justice., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The diagnostic accuracy of the I 3M to assess the legal age of 18 years has already been tested in several specific-population samples. The left lower third molar has been extensively used for discriminating between minors and adults. This research aimed to compare the usefulness of lower third molar maturity indexes, from both left and right side (I 3M L and I 3M R), in samples originating from four distinct continents in order to examine possible differences in their accuracy values. For this purpose, a sample of 10,181 orthopantomograms (OPGs), from Europe, Africa, Asia and America, was analysed and previously scored in other studies. The samples included healthy subjects with no systemic disorders with both third molars and clear depicted root apices. Wilcoxon Signed Rank test for left and right asymmetry did not show any significant differences. Data about sensitivity, specificity, predictive values, likelihood ratio and accuracy were pooled together and showed similar results for I 3M L and I 3M R, respectively. In addition, all these quantities were high when only the I 3M R was considered to discriminate between adults and minors. The present referable database was the first to pool third molar measurements using panoramic radiographs of subjects coming from different continents. The results highlighted that both I 3M L and I 3M R are reliable indicators for assessing the legal age of 18 years old in those jurisdictions where this legal threshold has been set as the age of majority., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Estimation of age of majority has important applications in the forensic daily practice because of the increasing demand for age estimates of unaccompanied minors. Diagnostic accuracy of I 3M to assess legal adult age of 18 years has been already tested in several specific population samples. The aim of this work was to compare the available data about sensitivity and specificity of the third molar maturity index (I 3M ) from five different regional groups' radiographic samples to study possible ethnical difference. For this purpose, a sample of 6157 orthopantomograms (OPGs), coming from 15 countries, was analysed. Data about sensitivity and specificity were pooled using a bivariate modelling approach. The one-way MANOVA analysis was applied to assess the likelihood that sensitivity and specificity of the five regional groups are sampled from the same population. The result of the one-way MANOVA showed that both sensitivity and specificity did not depend from the regional groups. The obtained sensitivity was 84% (95% CI: 82% and 85%), and its specificity was 94% (95% CI: 93% and 95%). Based on these results, the I 3M was a useful statistical tool to identify whether a subject has reached the legal age of 18 years old, regardless of his or her ethnicity., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The Bayesian approach is being a fundamental tool in forensic and legal field where inferences and decisions are made. In this study, a full Bayesian calibration model was developed to make probabilistic inferences about age estimation in a reference sample of 891 periapical X-rays of upper and lower canines. These teeth belonged to both deceased and living adult subjects, aged between 20 and 86 years, coming from five different countries (Turkey, Italy, Portugal, Japan and Mexico). For this purpose, the narrowing of pulp chamber due to the apposition of secondary dentine was analysed by means of the pulp/tooth area ratio. To determine the agreement of the method, intra- and inter-observer differences for measuring process were calculated by means of the intraclass correlation coefficient (ICC) analysis. Observer error tests showed excellent agreement between observers and between repeated assessments. According to the results of the ANCOVA, neither nationality nor sex was associated to the secondary dentine apposition while it is associated with individual's age. The results of the present study indicated that the concept of probability is intrinsically linked to the assessment of age in a forensic context, and the Bayesian approach could be considered a robust tool to overtake the bias generated by traditional regression models, thus helping the decision-making process in a legal framework.

This work aims to assess the validity of the cut-off value (0.08) of the third molar maturity index (I 3M ) for discriminating minors from adults in Sardinian population. A sample of 336 digital panoramic radiographs of healthy Sardinian children and young minors (165 females and 171 males), aged between 15 and 23 years (mean age, 19.35 years in females and 18.80 years in males), was retrospectively evaluated. The left lower third molars were analysed by applying a specific cut-off value of 0.08 determined by Cameriere et al. in 2008. The reliability and reproducibility of the test was also studied: the intra-class correlation coefficients (ICC) were 0.91 (95% CI, 0.89-0.93) and 0.88 (95% CI, 0.86-0.90), for the intra- and inter-observer reliability, respectively. The I 3M gradually decreased as the real age gradually increased in both sexes. According to the pooled results of the diagnostic test, the accuracy (ACC) was 0.86 (95% CI, 0.82-0.89); the proportion of correctly classified subjects (Se = sensitivity) was 0.82 (95% CI: 0.76-0.86); and specificity (Sp = specificity) was 0.95 (95% CI, 0.89-0.97). The positive predictive values (PPV) and the negative predictive values (NPVs) were 0.97 (95% CI, 0.94-0.99) and 0.70 (95% CI, 0.62-0.77). The LR+ and the LR- were 17.12 (95% CI, 7.27 to 40.36) and 0.19 (95% CI, 0.14 to 0.25). In spite of this, significant differences in the early mineralisation of the third molar were found between sexes as well as in the results of the diagnostic test, showing a better sensitivity in males than in females. The results showed that, although the third molar teeth are highly variable in development, and with differences between females and males as compare to other teeth, the I 3M is a reliable method to distinguish between minors and adults even in such a genetic isolate population.

This study provides regression equations for estimation of age of infants from the dimensions of their developing deciduous teeth. The sample comprises 97 individuals of known sex and age (62 boys, 35 girls), aged between 2 days and 1,081 days. The age-estimation equations were obtained for the sexes combined, as well as for each sex separately, thus including "sex" as an independent variable. The values of the correlations and determination coefficients obtained for each regression equation indicate good fits for most of the equations obtained. The "sex" factor was statistically significant when included as an independent variable in seven of the regression equations. However, the "sex" factor provided an advantage for age estimation in only three of the equations, compared to those that did not include "sex" as a factor. These data suggest that the ages of infants can be accurately estimated from measurements of their developing deciduous teeth., (© 2017 American Academy of Forensic Sciences.)

Deliberate falsification of age was considered to be one of the main reasons for forensic age estimation of the living individuals. This posed to be a challenging task during criminal and legal proceedings, and ultimate care must be taken not to classify juveniles as adults. Third molars are the only developing teeth during late adolescence and early adulthood. Our study was designed to analyze the usefulness of the third molar maturity index (I 3M ) specific cut-off value (I 3M  < 0.08) to discriminate adults (≥18 years) and juveniles (<18 years) in South Indian children. 216 panoramic radiographs (114 females and 102 males) of living subjects aged between 14 and 21 years were analyzed. Our results demonstrated high sensitivity (83.3% and 90.2%) and specificity (98.3% and 95.1%) for females and males respectively. The positive likelihood ratios of being adult were 50.00 and 18.35 while the negative likelihood ratios were 0.17 and 0.10 in females and males respectively. The estimated posttest probability was 98.0% in females and 94.8% in males. The obtained results showed that the specific cut-off value of I 3M  < 0.08 may be a useful additional tool in discrimination of individuals who are around 18 years of age., (Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

Dental age estimation was recognized as an imperative issue in clinical and medico-legal practice. However, very few studies on dental age estimation in children have been published in Colombia. This study evaluated the accuracy of Cameriere's method of measurement of open apices on tooth roots in a sample of 526 digital panoramic radiographs (OPTs) of children (274 boys and 252 girls), aged between 6 and 14 years, from Bogotá, Valle del Cauca, Buga and Villavicencio, in Southwest Colombia. Only first seven permanent lower teeth, except third molar, from the left side of mandible were studied. Difference between dental age and chronological age was evaluated for boys and girls across nine age classes. Intra-class correlation coefficient and Kappa score was used to test intra- and inter-observer agreement error rate. Dental age was overestimated by 0.08 years and standard deviation (±SD) of 0.68 years in boys which was not statistically significant (p = 0.06), while in girls dental age underestimated by -0.25 ± 0.65 years which was statistically significant difference (p < 0.001). The absolute difference between DA and CA or mean prediction error (ME) was 0.57 ± 0.38 years in boys and 0.57 ± 0.41 in girls (p = 0.966) which implies that Cameriere's European formula is similarly accurate in both sexes in this sample of Colombian children., (Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

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 (I 3M ), 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 I 3M, 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., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

In the last few years, forced and unregistered child marriage has widely increased into Turkey. The aim of this study was to test the accuracy of cut-off value of 0.08 by measurement of third molar index (I3M) in assessing legal adult age of 18 years. Digital panoramic images of 293 Turkish children and young adults (165 girls and 128 boys), aged between 14 and 22 years, were analysed. Age distribution gradually decreases as I3M increases in both girls and boys. For girls, the sensitivity was 85.9% (95% CI 77.1-92.8%) and specificity was 100%. The proportion of correctly classified individuals was 92.7%. For boys, the sensitivity was 94.6% (95% CI 88.1-99.8%) and specificity was 100%. The proportion of correctly classified individuals was 97.6%. The cut-off value of 0.08 is a useful method to assess if a subject is older than 18 years of age or not., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

The aim of this cross-sectional study was to test the accuracy of cut-off value of 0.08 by measurement of third molar index (I3M) in assessing legal adult age of 18 years in a sample of Colombian children and young adults. Digital orthopantomographs of 288 Colombian children and young adults (163 girls and 125 boys), aged between 13 and 22 years, were analysed. Concordance correlation coefficient (ρc) and κ statistics (Cohen's Kappa coefficient) showed that repeatability and reproducibility are high for both intra- and inter-observer error. κ statistics for intra- and inter-observer agreement in decision on adult or minor was 0.913 and 0.877, respectively. Age distribution gradually decreases as I3M increases in both girls and boys. For girls, the sensitivity test was 95.1% (95% CI 87.1%-95%) and specificity was 93.8% (95% CI 87.1%-98.8%). The proportion of correctly classified individuals was 95.1%. For boys, the sensitivity test was 91.7% (95% CI 85.1%-96.8%) and specificity was 90.6% (95% CI 82.1%-97.8%). The proportion of correctly classified individuals was 89.7%. The cut-off value of 0.08 is highly useful to determine if a subject is 18 years of age or older or not., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

The aim of this study is to analyse the age-predicting performance of third molar index (I3M) in dental age estimation. A multiple regression analysis was developed with chronological age as the independent variable. In order to investigate the relationship between the I3M and chronological age, the standard deviation and relative error were examined. Digitalized orthopantomographs (OPTs) of 975 Italian healthy subjects (531 female and 444 male), aged between 9 and 22 years, were studied. Third molar development was determined according to Cameriere et al. (2008). Analysis of covariance (ANCOVA) was applied to study the interaction between I3M and the gender. The difference between age and third molar index (I3M) was tested with Pearson's correlation coefficient. The I3M, the age and the gender of the subjects were used as predictive variable for age estimation. The small F-value for the gender (F = 0.042, p = 0.837) reveals that this factor does not affect the growth of the third molar. Adjusted R(2) (AdjR(2)) was used as parameter to define the best fitting function. All the regression models (linear, exponential, and polynomial) showed a similar AdjR(2). The polynomial (2nd order) fitting explains about the 78% of the total variance and do not add any relevant clinical information to the age estimation process from the third molar. The standard deviation and relative error increase with the age. The I3M has its minimum in the younger group of studied individuals and its maximum in the oldest ones, indicating that its precision and reliability decrease with the age., (Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

The methodology used to identify individuals in forensic anthropology requires a minimum degree of precision and accuracy and should be based on identified and representative samples. Achievement of these objectives in infant skeletons is hampered by the scarcity of appropriate samples. The dental age estimation methods of Liversidge et al. (Am J Phys Anthropol 90: 307-313, 1993) and Deutsch et al. (Growth 49: 207-17, 1985) were applied to the Granada osteological collection of identified infants (Granada, Spain) in order to evaluate its applicability in a Mediterranean population. Significant differences were found between the estimated and real ages in both cases. Based on the measurements obtained in 140 fetuses and infants, new regression formulas were developed to estimate age from the metric study on deciduous teeth. Independent functions are provided for each deciduous maxillary and mandibular tooth in each sex, along with the margin of error (95% confidence interval). These formulas appear to offer one of the best methods available for estimating the age of Mediterranean infants in forensic anthropology settings.

The aim of this cross-sectional study was to test the accuracy of Cameriere's European formula for age assessment in a large sample of Mexican children. The accuracy of dental age estimation was defined as how closely real age, measured as the difference between chronological age (CA) and dental age (DA), could be predicted. Digitalized orthopantomographs of 502 Mexican children (254 girls and 248 boys), aged between 5 and 15 years, were analyzed. The seven left permanent mandibular teeth were evaluated using Cameriere's method. Intra- and inter-observer variability for this technique was tested on a small random sample. Dental age was estimated for each individual and compared with known chronological age. Accuracy was measured as the difference between known chronological age and dental age and tested for significance with the mean prediction error (ME). The standard deviation and 95% confidence interval of the mean difference were also calculated. ME was 0.63 years for girls and 0.52 years for boys. ME was found to be slightly overestimated by 0.10 years for girls, but was correctly estimated for boys with an accuracy of 0.00. In conclusion, this method is very useful and may be recommended for practical application both in clinical dentistry and forensic procedures on the Mexican population., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

The aim of this study was to compare the accuracy of three methods for age estimation in children: the measurements of open apices in tooth roots (T), the ratio between the total area of carpal bones and epiphyses of the ulna and radius (HW), and the combined method (THW). The sample consisted of 288 Caucasian Italian children (152 boys and 136 girls) aged between 5 and 15 years. Accuracy was determined as the difference between estimated age and chronological age, and accuracy was assessed by analyzing individuals' orthopantomograms and hand-wrist radiographs. Accuracies were 0.41 years for girls and 0.54 years for boys with the THW method; for the HW method, 1.00 years for girls and 0.92 years for boys; and for the T method, 0.62 years for girls and 0.71 years for boys. THW is the most accurate technique for age estimation in these children., (© 2012 American Academy of Forensic Sciences.)

Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Since 2004, in order to examine patterns of secondary dentine apposition, Cameriere et al. have been extensively studying the pulp/tooth area ratio of the canines by panoramic and peri-apical X-ray images. The main aim of this paper is to examine the relationship between age and age-related changes in the pulp/tooth area ratio in monoradicular teeth, with the exception of canines, by orthopantomography. A total of 606 orthopantomograms of Spanish white Caucasian patients (289 women and 317 men), aged between 18 and 75 years and coming from Bilbao and Granada (Spain), was analysed. Regression analysis of age of monoradicular teeth indicated that the lower premolars were the most closely correlated with age. An ANCOVA did not show significant differences between men and women. Multiple regression analysis, with age as dependent variable and pulp/tooth area ratio as predictor, yielded several formulae. R(2) ranged from 0.69 to 0.75 for a single lower premolar tooth and from 0.79 to 0.86 for multiple lower premolar teeth. Depending on the available number of premolar teeth, the mean of the absolute values of residual standard error, at 95% confidence interval, ranged between 4.34 and 6.02 years, showing that the pulp/tooth area ratio is a useful variable for assessing age with reasonable accuracy., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Cameriere et al. studied the pulp/tooth area ratio by peri-apical X-ray images of the canines, to observe the apposition of secondary dentine. The present study examines the application of this technique in a Mexican identified sample coming from the Department of Physical Anthropology of the INAH, at Mexico City. The main aim of this work is to test the reliability of this method in a skeletal sample of a specific population, different from the samples used for its development. The obtained regression model explained 96.2% of total variance (R(2) = 0.962) with a standard error of estimate of 1.909 and a standard deviation of 1.947. These results demonstrate great reliability and that the age/secondary dentine relationship is not variable in this specific population., (© 2011 American Academy of Forensic Sciences.)