The accuracy of Cameriere methods in Turkish children: chronological age estimation using developing teeth and carpals and epiphyses of the ulna and radius.

The aim of the present study was to develop a specific formula by measuring the developing teeth, carpal bones, and epiphyses of the ulna and radius to determine the chronological age in Turkish children. The left developing permanent mandibular teeth were evaluated, and the number of teeth with closed apex was recorded. The distance between the inner sides of open apex/apices was measured by using the ImageJ program and divided by the tooth length. The sum of the normalized open apices was also calculated. The carpal area (Ca), covering the epiphyses of ulna and radius and the carpal bones, was measured on the X-rays of left hand. The areas of each carpal bone and epiphyses of the ulna and radius were measured, and these measurements were added together to obtain the bone area (Bo). The Bo/Ca ratio between the total area of carpal bones and the carpal area was calculated to normalize the measurements. The accuracy of the equations formulated by Cameriere was evaluated, and a new regression equation was developed accordingly. The new formula showed no statistically significant difference between the chronological and the estimated age for females, males, and total sample. The new formula, which hit the age with 72.80% accuracy, was more successful in predicting chronological age than other adjusted regression equations. The new regression model, created for the Turkish children by using both developing teeth and hand-wrist bones, was considerably successful in estimating the chronological age.

Ear identification: A multi-ethnic study sample.

The external human ear is considered to be highly variable among individuals. Hence, forensic applications could be explored for human identification. This research compares the usefulness of Cameriere's ear identification method, in samples originating from six different countries (Brazil, India, Japan, Russia, South Africa and Turkey) in order to examine possible differences in their accuracy values. A sample of 2,225 photographs of the external human ear (1,134 left and 1,091 right ears) from 1,411 individuals (633 females and 778 males) was collected. The samples included healthy subjects with no systemic disorders and without any craniofacial trauma, maxillofacial abnormalities, auricular anomalies, ear diseases or previous auricular surgery. Cameriere's ear identification method was applied and measurements were performed on the images of each ear, considering four anatomic regions: helix, antihelix, concha, and lobe. The quantified measurement values were converted into a proposed coded number system. A search for identical codes was accomplished to find out the distinctiveness of the morphology of the human ear. The combined codes of left and right ears of each of the 814 subjects were not repeated in this multi-ethnic study sample. Dirichlet's distribution and the inherent study equation showed that the probability of two different individuals having the same code (false-positive identification) was found to be <0.0007. Because of the distinctive metrics of the ratios of external human ears, studies with Cameriere's ear identification method may be valuable for human identification. Studying the differences between the left and right ears of the same individual and across different ethnic groups could contribute to the development of supplementary tools for human identification.

Age Classification in Forensic Medicine Using Machine Learning Techniques.

The aim of the study was to assess the capabilities of age determination (age group) at death using classification techniques by histomorphometric characteristics of osseous and cartilaginous tissue aging. Materials and Methods: The study material was a database containing the findings of morphometric researches of osseous and cartilaginous tissue histologic specimens from 294 categorized male corpses aged 10-93 years. For data analysis and classification we used modern machine learning methods: k-NN, SVM, logistic regression, CatBoost, SGD, naive Bayes, random forest, nonlinear dimensionality reduction methods (t-SNE and uMAP), and recursive feature elimination for feature selection. Results: The used techniques (algorithms) provided effective representation of a complex data set (76 histomorphometric features), allowing to reveal the cluster structure inside the low dimensional feature space, thus fitting the classifier becomes even more reasonable. During feature selection, we estimated their importance for age group classification and studied the relationship between classification quality and the number of features inside the feature space. Data pre-processing made it possible to get rid of noise and keep most informative features, thereby accelerating a learning process and improving the classification quality. Data projection showed more well-defined cluster structure in the space of selected features. The accuracy of establishing certain groups was equal to 90%. It proves high efficiency of machine learning techniques used for forensic age diagnostics based on histomorphometric findings.

Comparison of the third molar maturity index (I3M) between left and right lower third molars to assess the age of majority: a multi-ethnic study sample.

The diagnostic accuracy of the I3M 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 (I3ML and I3MR), 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 I3ML and I3MR, respectively. In addition, all these quantities were high when only the I3MR 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 I3ML and I3MR 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.

Study of the ethnicity's influence on the third molar maturity index (I3M) for estimating age of majority in living juveniles and young adults.

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 I3M 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 (I3M) 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 I3M 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.

A full Bayesian calibration model for assessing age in adults by means of pulp/tooth area ratio in periapical radiography.

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.

Age estimation in north east Brazilians by measurement of open apices.

Dental age (DA) estimation is an extensively investigated resource used by forensic science. This study aimed to evaluate the applicability of the Measurement of Open Apices for DA estimation in north east Brazilians. A total of 429 orthopantomographs of individuals aged 5 to 14.99 years were used. The sample was distributed according to the age groups 5-6.99, 7-8.99, 9-10.99, 11-12.99 and 13-14.99 years, and the data were analyzed descriptively and by linear regression (α= 5%). The majority of the radiographs were from females (n = 241; 56.2%), with an overall mean age of 12 years (± 2.12). A significant difference was observed between DA and chronological age (CA) in the total sample and specifically in females and males. The method underestimated CA by 0.31 year (total sample) and by 0.3 and 0.32 year in females and males, respectively. In contrast, the method overestimated CA in the groups 5-6.99 and 7-8.99 years, with a mean difference (MD) of 0.48 year (p = 0.007) and 0.17 year (p = 0.182), respectively. In the other groups, DA was predicted to be below CA, with a significant difference in the group 13-14.99 (0.75 year). Based on the regression analysis, a correction factor was proposed from the original formula for this population, thereby reaching a predictive power of approximately 80%. To conclude, this method is applicable to the study population aged 5 to 13 years as the estimates obtained did not exceed the error limit of ±1 year.

Child brides: the age estimation problem in young girls.

The aim of this work is to study a sample of girls from 15 different countries using Third Molar Maturity Index (I3M ), to assess the probability that a girl has reached the legal age of 18 years. The studied sample consisted of 3228 Orthopantomograms of healthy female subjects from 15 different countries. The cut-off value of I3M = 0.08 was tested to discriminate adults (≥18 years) and minors (<18 years). X-ray images were processed by computer-aided drafting program ImageJ. The information on sensitivity and specificity of I3M coming from the 15 countries was pooled together using a bivariate Bayesian modeling approach. Specificity of the I3M test did not change when the country was considered, and its value remains greater than 85% for each studied country. This method is useful to estimate the age of the girls involved in suspected early marriage because of the high probability of correctly identifying a minor with similar results observed among tested populations.

Evaluation of Cameriere and Willems age estimation methods in panoramic radiographs of Brazilian children.

The importance of age estimation in the forensic field is inherent to the process of establishing the biological profile of children, sub-adults and adults. The established profile might be useful for the identification of deceased victims or living individuals when it comes to age of legal interest. In parallel, age estimation is also investigated for clinical purposes, especially for the diagnosis of dental and bone maturation. Several studies were developed to provide accurate age estimation methods based on skeletal and dental development. This study aimed to apply and compare Cameriere's and Willems' methods for dental age estimation in a Brazilian sample. Two examiners performed image analysis and method application in 180 panoramic radiographs of Brazilian children aged 6-14 years old. The ages estimated with both methods revealed a good correlation with the chronological ages of Brazilian boys and girls. Cameriere's method showed a slight underestimation of 0.05 years for girls and 0.03 for boys. Willems' method, on the other hand, showed an overestimation of -0.47 years for girls and -0.39 for boys. Better age estimates were obtained combining the outcomes of both methods. In practice, Cameriere's and Willems' methods reached reliable outcomes and could be applied for dental age estimation purposes.

Age estimation by measuring open apices in teeth: a new formula for two samples of South African black and white children.

In this cross-sectional study, the accuracy of Cameriere's European formula was tested and a new specific model was developed for two samples of black and white South African children with known age and sex. For these purposes, 970 children of black South African ethnicity (girls 491, boys 479) and 974 with European ethnicity, living in South Africa (girls 493, boys 481), were retrospectively analyzed. The application of the European formula showed that there is a trend in the error estimates: the ages of the younger children are overestimated and those of the older children are underestimated, in both white and black children. A new model, based on the relationship between the apical width and the tooth length (maturity index) of the seven permanent mandibular teeth, was therefore constructed. The new developed equation for the South African population was able to explain 76% of total variance in white girls and 80% in white boys' subgroup. On the other side, the model explained 76% of total variance in black girls and 78% in the black boys' subgroup. The mean absolute error of the residuals (residuals = predicted age minus observed age) ranged from 0.718 to 0.769 years, with the interquartile range (IQRres) ranging from 1.19 to 1.31 years. Differently from the Cameriere's European formula, the plot did not tend to underestimate the chronological age significantly as the age increases. Cameriere's maturity index is reproducible in both samples of South African black and white children, for forensic purposes, and the Bayesian calibration approach is useful for a more accurate and precise estimation.

Validation of the third molar maturity index (I3M): study of a Dominican Republic sample.

This retrospective study aims to test the third molar maturity index (I3M) cut-off value of 0.08 for 18 years old in Dominican Republic population. Orthopantomograms of 513 subjects (284 females and 229 males) were evaluated, intra- and inter-observer agreement, ICC (intra-class correlation coefficient) values were 0.88% (95 % CI 0.86% to 0.91%), and 0.93% (95% CI 0.90% to 0.96%), for the intra- and inter-observer reliability, respectively. Accuracy in females was 0.96 (95% CI: 0.93-0.97); the sensitivity was 0.99 (95% CI: 0.96-0.99) and specificity was 0.92 (95% CI: 0.86-0.95). In males, the accuracy was 0.96 (95% CI: 0.93-0.98); the sensitivity was 0.94 (95% CI: 0.88-0.97) and specificity was 0.99 (95% CI: 0.95-0.99). The PPV (Positive Predictive Value) was 0.93 for females and 0.99 for males. The results of this study show that I3M can be used for discriminating adults from minors in Dominican Republic subjects around the legal age of 18 years old.

Is the third molar maturity index (I3M) useful for a genetic isolate population? Study of a Sardinian sample of children and young adults.

This work aims to assess the validity of the cut-off value (0.08) of the third molar maturity index (I3M) 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 I3M 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 I3M is a reliable method to distinguish between minors and adults even in such a genetic isolate population.

Third molar maturity index (I3M) for assessing age of majority: study of a black South African sample.

AIMS: The evaluation of the cutoff value of I3M = 0.08 for discriminating black South African minors from adults, and its relationship with chronological age. MATERIAL AND METHODS: A sample of 833 panoramic radiographs of healthy black South African subjects (500 females and 333 males), in the age range of 14 to 24 years (mean age 17.67 years in females and 17.42 years in males), was retrospectively evaluated. RESULTS: ICC values were 99.10% (95% CI 97.70 to 99.70%) and 99.20% (95% CI 98.00 to 99.60%), for the intra- and inter-observer reliability, respectively. I3M decreased as the real age gradually increased in both sexes. According to the logistic regression model, the variable sex was not significant when the probability that an individual is 18 years or older was calculated. The I3M = 0.08 was valuable in discriminating between adults and minors. The overall accuracy (ACC = fraction of accurately classified subjects) is 0.90 (95% CI 0.87-0.91); the proportion of correctly classified subjects (Se = sensitivity) is 0.80 (95% CI 0.76-0.84), and specificity (Sp) is 0.95 (95% CI 0.93-0.97). The PPV (predictive positive value) is 0.96 (95% CI 0.95-0.97), and the negative predictive value is 0.76 (95% CI 0.72-0.80). CONCLUSION: The results show that I3M is a valuable method to distinguish subjects who are around legal adult age in South Africa.

Age estimation in children by measurement of open apices in teeth with Bayesian calibration approach.

Age estimation from teeth by radiological analysis, in both children and adolescents, has wide applications in several scientific and forensic fields. In 2006, Cameriere et al. proposed a regression method to estimate chronological age in children, according to measurements of open apices of permanent teeth. Although several regression models are used to analyze the relationship between age and dental development, one serious limitation is the unavoidable bias in age estimation when regression models are used. The aim of this paper is to develop a full Bayesian calibration method for age estimation in children according to the sum of open apices, S, of the seven left permanent mandibular teeth. This cross-sectional study included 2630 orthopantomographs (OPGs) from healthy living Italian subjects, aged between 4 and 17 years and with no obvious developmental abnormalities. All radiographs were in digital format and were processed by the ImageJ computer-aided drawing program. The distance between the inner side of the open apex was measured for each tooth. Dental maturity was then evaluated according to the sum of normalized open apices (S). Intra- and inter-observer agreement was satisfactory, according to an intra-class correlation coefficient of S on 50 randomly selected OPGs. Mean absolute errors were 0.72 years (standard deviation 0.60) and 0.73 years (standard deviation 0.61) in boys and girls, respectively. The mean interquartile range (MIQR) of the calibrating distribution was 1.37 years (standard deviation 0.46) and 1.51 years (standard deviation 0.52) in boys and girls, respectively. Estimate bias was ßERR=-0.005 and 0.003 for boys and girls, corresponding to a bias of a few days for all individuals in the sample. Neither of the ßERR values was significantly different from 0 (p>0.682). In conclusion, the Bayesian calibration method overcomes problems of bias in age estimation when regression models are used, and appears to be suitable for assessing both age and age distribution in children according to tooth maturity.

Measurements of developing teeth, and carpals and epiphyses of the ulna and radius for assessing new cut-offs at the age thresholds of 10, 11, 12, 13 and 14 years.

The minimum age of criminal responsibility is the youngest age at which children may be held liable for infringements of penal laws. New cut-offs at the age thresholds of 10, 11, 12, 13 and 14 years were determined by applying three different methods: measurement 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 291 Italian children (152 boys, 139 girls), aged between 5 and 15 years. The sensitivity and specificity were established. As regards THW, specificity reached the maximum of 95% in boys aged 10, and the minimum of 87% in boys aged 11. The best score of the Positive Predictive Value (PPV) was obtained in boys at 10 years with the THW method and the worst in girls of 12 with the HW method.

The reliability of Cameriere's method in Turkish children: a preliminary report.

Dental age estimation in children is an important issue both legally and medically. Currently, however, there is a lack of contemporary dental age estimation standards for a Turkish population. This study assessed the accuracy of Cameriere's method by examining the panoramic radiographs of 573 healthy Turkish children between the ages of 8 and 15 years. Radiographs of the left permanent developing mandibular teeth, except wisdom teeth, were evaluated. All subjects were divided into 7 groups according to their chronological age. The Intra-class Correlation Coefficient was used to determine the intra- and inter-observer agreement error. A comparison of the distributions of estimation errors among age groups was performed using the Nemenyi test. There were no significant differences between inter-observer (p=0.352), and intra-observer readings after 2 weeks (p=0.275 and p=0.273, respectively). The dental age was underestimated when using Cameriere's method with a mean difference of -0.35 years (-0.24 years for girls and -0.47 years for boys). The median values of the differences between dental and chronological age were -0.44 years in boys (range: -3.70, 4.06) and -0.21 years in girls (range: -2.74, 3.29). In addition, the differences between dental and chronological ages in the different age groups decreased with increasing chronological age. Results from the Nemenyi test implied that Cameriere's method is more accurate for girls than for boys in this cohort of a Turkish population.

Age estimation in children and young adolescents for forensic purposes using fourth cervical vertebra (C4).

The aim of this study was to evaluate the applicability of using the growth of the body of C4 vertebra for the estimation of age in children and young adolescents. We used the fact that the proportions between the radiologic projections of the posterior and anterior sides of the C4 vertebral body, which forms a trapezoidal shape, differ with age: in younger individuals, the posterior side is higher, whereas in older individuals, the projections of the sides of the vertebral body form a rectangular shape with the two sides equal or with the anterior side slightly higher. Cephalograms of 444 Italian subjects (214 female and 230 male individuals) aged between 5 and 15 years and with no obvious development abnormalities were analyzed. The projections of the anterior side (a) and of the posterior side (b) of each C4 body were measured, and their ratio (Vba), as a value of the C4 body development, was used for age estimation. Distribution of the Vba suggested that it does not change after 13 years in female and 14 years in male subjects. Consequently, we restricted our analysis of the Vba growing model until 14 years in both sexes. We used a Bayesian calibration method to estimate chronological age as function of Vba as a predicting variable. The intra- and inter-observer agreement was satisfactory, using intra-class correlation coefficient of Vba on 30 randomly selected cephalograms. The mean absolute errors were 1.34 years (standard deviation 0.95) and 1.01 years (standard deviation 0.71), and the mean inter-quartile ranges of the calibrating distribution were 2.32 years (standard deviation 0.25) in male and 1.72 years (standard deviation 0.39) in female individuals, respectively. The slopes of the regression of the estimated age error to chronological age were 0.02 in male and 0.06 in female individuals, where both values did not result significantly different from 0 (p > 0.12). In conclusion, although our Bayesian calibration method might not really outperform the classical regression models in the precision of its estimates, it appears to be more robust, to greatly reduce the typical bias inherent in the regression model approach, and to have the ability to incorporate multiple predictors.

Adult or not? Accuracy of Cameriere's cut-off value for third molar in assessing 18 years of age for legal purposes.

AIM: The discovery of reliable means to determine the age of an individual is a fundamental objective in forensic medicine, in consideration of the constant increase of illegal immigration into the European community. In 2008 Cameriere et al. developed a method based on the relationship between age and the third molar index (I3m), which assesses the degree of maturation of the third molar through measurements made on orthopantomography. The purpose of this work was to test the accuracy of Cameriere's cut-off for I3m as a tool to assess full age (18) on a new sample of living subjects. METHODS: Orthopantomographs of 287 Italian living subjects aged between 13 and 22 years have been randomly selected and included in the study. Identification number, gender, date of birth and date of execution of the radiograph were recorded for each patient on a Microsoft Excel® spreadsheet. Radiographs were digitalized and analyzed using a computerized image-processing program (Adobe® Photoshop® CS4). RESULTS: The results show that the sensitivity of the test was 84.1% and the specificity was 92.5%. The estimated post-test probability was 90.1%, with a confidence interval of 95% (83.6%, 95.2%). Thus, the probability that a person being positive to the test has 18 or more years of age was 90.1%. CONCLUSION: The results highlight the contribution of Cameriere's cut-off value for the I3m in the assessment of full age, always remembering that the simultaneous employment of previously introduced complementary methods is essential for the purpose.

Accuracy and reliability of pulp/tooth area ratio in upper canines by peri-apical X-rays.

Due to the real need for careful staff training in age assessment, in order to improve capacity, consistency and competence, new research on the reliability and repeatability of methods frequently used in age assessment are required. The aim of this study was twofold: first, to test the accuracy of this method for age estimation; second, to obtain data on the reliability of this technique. A sample of 81 peri-apical radiographs of upper canines (44 men and 37 women), aged between 19 and 74years, was used; the teeth were taken from the osteological collection of Sassari (Sardinia, Italy). Three blinded observers used the technique in order to perform the age estimation. The mean real age of the 81 observations was 37.21 (CI95% 34.37 40.05), and estimated ages ranged from 36.65 to 38.99 (CI95%-Ex1 35.42; 41.28; CI95%-Ex2 33.89; 39.41; CI95%-Ex3 35.92; 42.06). The module differences found by the three observers were 3.43, 4.24 and 4.45, respectively for Ex1×Ex2, Ex1×Ex3 and Ex2×Ex3. The module differences observed among real and observed ages were 2.55 (CI95% 1.90; 3.20), 2.22 (CI95% 1.65; 2.78) and 4.39 (CI95% 3.80; 5.75), respectively for Ex1, Ex2 and Ex3. No differences were observed among measurements. This technique can be reproduced and repeated after proper training, since it was found high reliability and accuracy.

Twins and the paradox of dental-age estimations: a caution for researchers and clinicians.

The biological age difference among twins is frequently an issue in studies of genetic influence on various dental features, particularly dental development. The timing of dental development is a crucial issue also for many clinicians and researchers. The aim of this study was therefore to verify within groups of twins how dental development differs, by applying Demirjian's method, Mincer's charts of development of third molars and two of Cameriere's methods for dental age estimation, which are among the most popular methods both in the clinical and the forensic scenario. The sample consisted of 64 twin pairs: 21 monozygotic, 30 dizygotic same-sex and 13 dizygotic opposite-sex with an age range between 5.8 and 22.6 years. Dental age was determined from radiographs using the mentioned methods. Results showed that dental age of monozygotic twins is not identical even if they share all their genes. The mean intra-pair difference of monozygotic pairs was low and similar to the difference in dizygotic same-sex twins; the maximum difference between monozygotic twins, however, was surprisingly large (nearly two years). This should lead to some circumspection in the interpretation of systematic estimations of dental age both in the clinical and forensic scenario.