Accuracy of a cut-off value based on the third molar index: Validation in an Australian population

A systematic overview of dental methods for age assessment in living individuals: from traditional to artificial intelligence-based approaches

Dental radiographies have been used for many decades for estimating the chronological age, with a view to forensic identification, migration flow control, or assessment of dental development, among others. This study aims to analyse the current application of chronological age estimation methods from dental X-ray images in the last 6 years, involving a search for works in the Scopus and PubMed databases. Exclusion criteria were applied to discard off-topic studies and experiments which are not compliant with a minimum quality standard. The studies were grouped according to the applied methodology, the estimation target, and the age cohort used to evaluate the estimation performance. A set of performance metrics was used to ensure good comparability between the different proposed methodologies. A total of 613 unique studies were retrieved, of which 286 were selected according to the inclusion criteria. Notable tendencies to overestimation and underestimation were observed in some manual approaches for numeric age estimation, being especially notable in the case of Demirjian (overestimation) and Cameriere (underestimation). On the other hand, the automatic approaches based on deep learning techniques are scarcer, with only 17 studies published in this regard, but they showed a more balanced behaviour, with no tendency to overestimation or underestimation. From the analysis of the results, it can be concluded that traditional methods have been evaluated in a wide variety of population samples, ensuring good applicability in different ethnicities. On the other hand, fully automated methods were a turning point in terms of performance, cost, and adaptability to new populations.

Third molar maturity index (I3M) assessment according to different geographical zones: a large multi-ethnic study sample

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_3ML and I_3MR) and the combination of both sides (I_3ML_I_3MR) 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_3ML; I_3MR; I_3ML_I_3MR, 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_3ML for male African people (91%) and the higher specificity (Sp) of all the parameters (I_3ML; I_3MR; I_3ML_I_3MR) 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.

Accuracy of different dental age estimation methods for determining the legal majority of 18 years in the Turkish population

OBJECTIVES

Radiographic evaluation of the third molar maturation is used to estimate dental age, especially in adolescence. This study aimed to assess the application of three age estimation methods (Cameriere's third molar maturity index (I_3M), Demirjian's maturation stages, and The London Atlas) to determine whether an individual is 18 years or older (adult) or younger than 18 years (minor).

MATERIALS AND METHODS

The dental age was estimated using the I_3M, Demirjian's maturation stages, and The London Atlas methods on panoramic radiograms of a total of 500 Turkish individuals aged 14-22 years. A logistic model was derived with an individual's adult or minor status as the dependent variable, and each method and sex as predictive variables. The adult status was determined using dental age estimation methods and the performance of these methods in differentiating adults from minors was evaluated. The three methods were compared case-wise for their accuracy in predicting adult status.

RESULTS

Logistic regression analysis showed that sex and each estimation method were statistically significant in discriminating adults and minors (p < 0.05). In the case-wise comparison for estimate adulthood, both Demirjian's stages and I_3M methods tended to perform better than the London Atlas method, with this trend reaching statistical significance (p < 0.05).

CONCLUSIONS

Cameriere's I_3M and Demirjian's development stages are useful methods for adult age assessment in the tested population.

CLINICAL RELEVANCE

In forensic medicine and legal practices, Cameriere's I_3M and Demirjian's maturation stage methods based on the development of the third molar teeth can be used to determine whether an individual is a minor or an adult.

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 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_3ML and I_3MR), 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_3ML and I_3MR, respectively. In addition, all these quantities were high when only the I_3MR 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_3ML and I_3MR 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 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.

Accurate age classification using manual method and deep convolutional neural network based on orthopantomogram images

Age estimation is an important challenge in many fields, including immigrant identification, legal requirements, and clinical treatments. Deep learning techniques have been applied for age estimation recently but lacking performance comparison between manual and machine learning methods based on a large sample of dental orthopantomograms (OPGs). In total, we collected 10,257 orthopantomograms for the study. We derived logistic regression linear models for each legal age threshold (14, 16, and 18 years old) for manual method and developed the end-to-end convolutional neural network (CNN) which classified the dental age directly to compare with the manual method. Both methods are based on left mandibular eight permanent teeth or the third molar separately. Our results show that compared with the manual methods (92.5%, 91.3%, and 91.8% for age thresholds of 14, 16, and 18, respectively), the end-to-end CNN models perform better (95.9%, 95.4%, and 92.3% for age thresholds of 14, 16, and 18, respectively). This work proves that CNN models can surpass humans in age classification, and the features extracted by machines may be different from that defined by human.

Age estimation in the living: A scoping review of population data for skeletal and dental methods

Age estimation of living individuals has become a crucial part of the forensic practice, especially due to the global increase in cross-border migration. The low rate of birth registration in many countries, hence of identification documents of migrants, especially in Africa and Asia, highlights the importance of reliable methods for age estimation of living individuals. Despite the fact that a number of skeletal and dental methods for age estimation have been developed, their main limitation is that they are based on specific reference samples and there is still no consensus among researchers on whether these methods can be applied to all populations. Though this issue remains still unsolved, population information at a glance could be useful for forensic practitioners dealing with such issues. This study aims at presenting a scoping review and mapping of the current situation concerning population data for skeletal (hand-wrist and clavicle) and dental methods (teeth eruption and third molar formation) for age estimation in the living. Two hundred studies on the rate of skeletal maturation and four hundred thirty-nine on the rate of dental maturation were found, covering the period from 1952 and 2020 for a total of ninety-eight countries. For most of the western and central African countries there are currently no data on the rate of skeletal and dental maturation. The same applies to the countries of the Middle East, as well as the eastern European countries, especially as regard the skeletal development.

Age Estimation Using the Cameriere Methods of Open Apices: A Meta-Analysis

PURPOSE

To evaluate the actual variability of the mean difference between chronological and dental age using the Cameriere method of open apices and to test its accuracy in variable age groups.

METHOD

We selected studies that contained data about the mean, standard deviation, and number of cases for chronological age, dental age and gender. We used a random-effects model. Statistical significance was estimated, at a p < 0.05, using prediction intervals. For the analysis of publication bias we used the funnel plot and Egger's regression test for plot asymmetry. I2 was used to test the presence of heterogeneity between studies. The Z test was used to test for statistical differences between subgroups, with p < 0.05 being considered statistically significant. We also used 95% for confidence intervals and prediction intervals.

RESULTS

In boys, the average difference between chronological and dental age was 0.44 (0.26-0.63) years, while in girls the average difference between chronological and dental age was 0.34 (0.19-0.49) years. In the 6-7 years age group and in the 14-15 years age group, there was a statistically significant difference between dental and chronological age. Our study shows that the Cameriere method is useful for estimating the chronological age, with errors of less than one year.

CONCLUSIONS

The Cameriere method of evaluating dental age using open apices is sufficiently accurate for forensic practice, at least in the 7-14 age-interval.

Forensic Validity of the Third Molar Maturity Index (I 3M) for Age Estimation in a Russian Population

The aim of this cross-sectional study was to test the accuracy of the third molar maturity index (I _3M) cut-off value (0.08) to distinguish between individuals above and below the adult age of legal responsibility (18 years) in a Russian population. A sample of 571 digital panoramic radiographs of healthy Russian minors and young adults (363 females and 208 males), aged between 14 and 24 years, was evaluated. The lower left third molars were analyzed by applying the cut-off value of 0.08 determined by Cameriere et al. (2008). Lin's concordance correlation coefficient (ρ _c) and Cohen's kappa coefficient (κ) showed that repeatability and reproducibility are high for both intra- and interobserver errors. The I _3M value decreased with age in both sexes. Age distribution gradually decreases as I _3M increases in both girls and boys. In the male group, molar maturity stages 0-0.04, 0.04-0.08, 0.08-0.3, 0.3-0.5, and 0.9-1.4 were reached slightly earlier than in the female group. The results demonstrated that sensitivity is 0.96 in boys and 0.93 in girls; associated specificity values were both 0.98. The cut-off value of I _3M is statistically robust and thus valid for forensic application in a Russian population to determine whether or not a subject has reached 18 years of age. Finally, we compared our results with those of other studies in which the same I _3M cut-off value was tested on different populations. The method is novel as it is reliable and easily reproducible, thus ensuring a universal way of comparing the results obtained (based on a cut-off value) among many populations, in order to develop an ever-increasing database.

Third molar maturity index and legal age in different ethnic populations: Accuracy of Cameriere's method

Molar development is widely accepted as a reliable indicator of chronological age in a forensic context. A quantitative method for age estimation has been proposed by Cameriere et al. based on the relationship between chronological age and the third molar maturity index (I_3M), which is the ratio between the two apical pulp widths and the total tooth length. Cameriere's cut off value of 0.08 was found to be a reliable tool in assessing the threshold of 18 years of age. The aim of this study was to evaluate the accuracy of the I_3M in different ethnic populations focusing on its specificity (subjects correctly classified as <18 years based on I_3M >0.08) and sensitivity (subjects correctly classified as ≥18 years based on I_3M <0.08). A review of 22 scientific articles was performed, representing data from panoramic radiographs of 12,286 individuals (5723 males and 6563 females) from all over the world, including some ethnical subgroups. The I_3M showed an overall sensitivity for both sexes ranging from 51.8% to 93.4% and a specificity ranging from 86.2% to 100%. The proportion of correctly classified individuals ranged from 74% to 95%. These results can be useful to refer the age estimation with the margin of error of subjects correctly classified as minors (specificity) or adults (sensitivity), according to sex, ethnicity and geographical distribution. The I_3M can be considered a suitable method for estimating adulthood in forensic settings, regardless of sex. However, ethnic group can affect the accuracy.

Validation of the Third Molar Maturation Index (I3M) to assess the legal adult age in the Portuguese population

Age estimation is a major step in forensic and legal procedures. Its relevance has been increasing due to growing society issues, such as identification of missing people, crimes against minors or lack of valid identification papers from locals or foreigners. Evaluation of the cut-off value of the Third Molar Maturation Index (I_3M) = 0.08 for discriminating minors from adults in the Portuguese population. The left lower third molars were analysed by applying a specific cut-off value of 0.08 determined by Cameriere et al. in 2008. A sample of 778 digital panoramic radiographs of a representative Portuguese sample (442 females and 336 males), in the age range of 12–24 years (mean age 17.7 ± 2.98 years in females and 18.1 ± 3.0 years in males), was retrospectively evaluated. I_3M decreased as the real age gradually increased in both sexes. The 0.08 cut-off score was valuable in discriminating adults from minors. According to the pooled results, the accuracy, by means of area under the curve, was 92.8% (95% confidence interval (CI) 91.0–94.6%). The proportion of correctly classified subjects (sensitivity) was 90.7% (95% CI 88.7–92.8%) and the specificity was 94.9% (95% CI 93.3–96.4%). The results show that I_3M is a valuable method to differentiate minors from adults in the Portuguese population.

Accuracy of the cutoff value of the third molar maturity index: an Egyptian study

Background

This study aimed to test the sensitivity and specificity of the third molar maturity index (I3M) cutoff value to discriminate between individuals above and below 18 years of age in an Egyptian sample.

Material and methods

Digital images of 247 orthopantographs (97 boys and 150 girls) were evaluated. The cutoff value of I3Mobtained from the results of Cameriere et al. (Int J Legal Med 122:493–497, 2008) was evaluated in both girls and boys.

Results

Sensitivity (the proportion of individuals being 18 years of age or older) was 95% and 73% in boys and girls, respectively. Meanwhile, specificity (the proportion of individuals younger than 18) was 100% in boys and 97% in girls. The proportion of correctly classified boys was 97% while it was 59% in girls.

Conclusion

It can be concluded that the third molar maturity index can discriminate between individuals who are 18 years and over and those under 18 with higher accuracy in boys.

Cameriere's third molar maturity index in assessing age of majority: a study of a French sample

Forensic age estimation is a challenging field in forensic sciences because of the increase of migratory flows. Medicolegal age assessment is a key point because it has many implications for authorities. Dental age estimation is an essential part of the global age assessment. The aim of this study was to evaluate and test the accuracy of Cameriere's cutoff values of the third molar maturity index (I3M) in assessing legal adult age of 18 years in a French population. The sample was constituted of 431 orthopantomograms performed between January 2014 and August 2017 on patients aged between 14 and 22 years. The reproducibility and repeatability of the method were high. Age distribution gradually decreases as I3M increases in both sexes. 0.08 seemed to be the best I3M cutoff. For females, the sensitivity and specificity of the test were 74.51% and 88.23%, respectively. The sensitivity and specificity for males were 92.19% and 88.35%, respectively. The accuracies were 80.74% for female, 90.57% for male. Estimated post-test probabilities were 0.879 for female and 0.899 for male. To conclude, the specific cutoff value of I3M ˂ 0.08 may be a useful additional tool in discriminating adults and minors in French population.

Validation of the Third Molar Maturation Index to estimate the age of criminal responsibility in Northeastern Brazil

The estimation of the age of majority is crucial to determine the legal accountability of an individual. With this purpose, the analysis of the dental development process has proven to be an effective, elucidatory method. This study investigated the applicability of the Third Molar Maturation Index (I_3M), proposed by Cameriere et al. (2008), to estimate the age of majority in a sample of Northeastern Brazilians using panoramic radiographs. Adobe® Photoshop® CS4 (Adobe Systems Incorporated, San Jose, California, USA) software was used to obtain the I_3M index measurements in a sample of radiographs from a dental radiology clinic located in Northeastern Brazil. Radiographs of individuals aged between 14 and 23 years were included in the sample, except if showing absence, distortions, pathological alterations or suspected pulp impairment of the tooth #38 (third lower left molar), as the method applies exclusively to this element. Of the total sample of radiographs previously obtained for diagnostic and/or orthodontic purposes (n=394), 185 were from males and 209 from females, of which 217 corresponded to 18 year-olds or older and 177 were from minors. Logistic regression and predictive values of sensitivity, specificity and Receiver Operating Characteristic (ROC) curve (α=0.05) were used. The cutoff point originally proposed for the I_3M index (0.08) presented a sensitivity of 88.4% and a specificity of 73.2%, with accuracy (area under the ROC curve) of 80.8% (95%CI: 76.4-85.3%) for the Northeastern Brazilian population, as well as a correct age classification in 80.2% of the sample. The method estimated accurately 73.7% of the cases corresponding to "18 years or older" and 88.1% of the cases "under 18years" (p=0.000). Among the sexes, the correct age classification rate of the method was 84.3% for males and 76.6% for females, with no statistically significant difference between the match and error rates and between the sexes (p≥0.05). In conclusion, the Third Molar Maturation Index could accurately distinguish the age of adolescents and young adults of both sexes aged 18 years or under/older in a Brazilian population.

Contribution of third molar eruption to the estimation of the forensic age of living individuals

Forensic age estimation of a living individual is frequently performed in clinical forensic medicine. Medicolegal physicians are usually called upon by the authorities to estimate the age of a living person requesting asylum or to determine whether a suspected offender is subject to juvenile or adult criminal law. Dental age is one of the parameters studied to estimate biological age. Several methods are used, and among these, analysis of the eruption of the third molar (M3) on an orthopantomogram (OPG) is one of the common methods. The objective of the study was to analyse the contribution of M3 eruption to age estimation, in particular with regard to the threshold of 18 years of age, in a sample of individuals examined in a French university hospital. The stage of wisdom tooth eruption of all individuals aged between 15 and 24 years, who had an OPG performed between 1 January 2013 and 31 December 2015, was interpreted using a three-stage scoring system. In total, 557 OPGs (340 males and 217 females) were included. None of the stage scores allowed a distinction between minors and majors, for either sex. Overall, 85% of females and 98% of males with four M3s in stage 3 (complete emergence in the occlusal plane) were majors.

Third molar maturity index for indicating the legal adult age in southeastern France

The estimation of age in living subjects is today a significant issue because of the increase in the situations in which it arises and its legal consequences. In line with the Study Group on Forensic Age Diagnostics of the German Association of Legal Medicine's recommendations, it is based on the concomitant use of physical examination and methods for estimating bone age and dental age. Given the variations between the populations, the use of the latter requires their validation on all the ethnic groups on which they can be used. This aim of this study was to access the interest of the Cameriere's third molar maturity index (I_3M) to indicate if an individual had reached the age of 18 in a sample of individuals from southeastern France. The studied sample consisted of OPTs 339 (184 females and 155 males) subjects aged between 14 and 22 years old. A logistic regression analysis with the adult age and minor age as dichotomous dependent variable and gender and I_3M as predictor variables showed that gender was not statistically significant in discriminating adults and minors. The receiver operating curve (ROC) analysis showed the best discrimination performance of the specific cut-off value of I_3M<0.08 in discriminating adults from minors. The proportion of accurate classification was 0.897 and 0.916 for females and males, respectively. The specificity (Sp) and sensitivity (Se) results for females were 0.962 and 0.813, respectively. Sp and Se for males were 0.953 and 0.871, respectively. The Bayes post-test probability was 0.961 and 0.955 in females and males respectively. Obtained results showed that a cut-off value of I_3M<0.08 may be an additional tool for indicating adult age in the tested population.

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 (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.

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 I_3M = 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. I_3M 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 I_3M = 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 I_3M is a valuable method to distinguish subjects who are around legal adult age in South Africa.

Accuracy of the third molar maturity index in assessing the legal age of 18 years: a systematic review and meta-analysis

The age estimation is a complex procedure required in the daily practice of legal medicine. The maturity of third molars stands out by the age of 18 because these teeth are still in development. This systematic review aimed to assess the accuracy of the third molar maturity index (I _3M), proposed by Cameriere et al. (2008), in discriminating whether an individual is under or over 18 years. Seven electronic databases were screened: PubMed, Scopus, ISI Web of Science, Cochrane Library, LILACS, SIGLE, and CAPES. Eligible studies included an assessment of I _3M accuracy at the 0.08 cut-off value. The quality assessment was performed by using QUADAS 2. Three meta-analyses (MA) were accomplished: overall, one for males and another for females. From 2397 articles identified, 16 met the eligibility criteria. Of these, two showed high risk of bias, one in the reference standard domain and the other in the flow and timing domain. The percentage of individuals correctly classified ranged from 72.4 to 96.0%. The overall MA showed pooled sensitivity of 0.86 (0.84 to 0.87; p = 0.0000) and pooled specificity of 0.93 (0.92 to 0.94; p = 0.0000). The AUC (area under the summary receiver operator characteristics curve) and DOR (diagnostic odds ratio) values were, respectively, 0.9652 and 104.68, indicating an overall high discrimination effect. Separately, better results of accuracy were found for males. High heterogeneity was achieved for both sensibility (94.6%) and specificity (88.8%). We conclude that the I _3M is a suitable and useful method for estimating adulthood regarding forensic purposes, regardless of gender.

The third molar maturity index in indicating the legal adult age in Kosovar population

The third molar tooth, known as the "wisdom tooth," is the only tooth that can be used to determine legal adult age. This study aimed to test the accuracy of Cameriere's third molar maturity index (I_3M) in assessing the legal adult age of 18 years in the Kosovar population. Orthopantomographs (OPTs) of 1221 healthy living Kosovar individuals, aged between 12 and 23 years and with no congenital or developmental anomalies, were analyzed. Intra-class correlation coefficients were 0.858 (95% CI, 0.786 to 0.906) and 0.852 (95% CI, 0.779 to 0.903) for intra-rater and for inter-rater agreement, respectively. The sample was divided into training dataset (800 OPTs) and test dataset (421 OPTs). The training dataset was used to generate the logistic regression model, while the test dataset was used to study the performance of the model. I_3M and gender as independent variables and adult age (≥ 18 years) or minor age (< 18 years) as the dependent variable were used for logistic regression analysis. The receiver operating curve (ROC) analysis was used to determine the specific cut-off value of I_3M for predicting adult age. The results showed that only I_3M statistically significantly contributed to discriminating adults and minors. ROC analysis showed that the cut-off value of I_3M < 0.08 was the best in discriminating adults and minors. An analysis of the test dataset (421 OPTs) showed that as I_3M decreased the age gradually increased. The performance of the cut-off value of I_3M < 0.08, to discriminate between adults and minors, was analyzed by contingency tables for both sexes. In males, the accurate classification (Acc) was 0.968 (95% CI, 0.926 to 0.985), the sensitivity (Se) was 0.962 (95% CI, 0.925 to 0.978), and the specificity (Sp) was 0.976 (95% CI, 0.929 to 0.995). The Bayes post-test probability (Bayes PTP) was 0.975 (95% CI, 0.905 to 1.00). In females, Acc was 0.909 (95% CI, 0.870 to 0.917), Se and Sp were 0.826 (95% CI, 0.787 to 0.834) and 0.991 (95% CI, 0.953 to 1.00) respectively, while Bayes PTP was 0.989 (95% CI, 0.926 to 1.00). Our data support the usefulness of I_3M < 0.08 to indicate legal adult age in a Kosovar population.