Discrepancy between chronological age and evaluated dental age using the Demirjian system in Western Australian children

The aims of this work were to assess dental age using the Demirjian system and to evaluate the discrepancy between chronological and dental age among children residing in Western Australia. Forty panoramic radiographs of 5- to 11-year-old children taken at the paediatric clinic of a dental hospital in Western Australia were selected. The developmental stage of each left permanent mandibular tooth excluding the third molar was assessed by three trained examiners. Estimated dental age using the Demirjian system was compared with the chronological age of each child. The accuracy of the Demirjian system in this group of children was 42.5%. The difference between chronological age and dental age was significant (t = 4.066, df = 39, p < 0.001). Dental age estimation for Caucasian children had greater accuracy (χ² = 5.013, df = 1, p = 0.025). Gender and orthodontic concerns were not related to the accuracy of the Demirjian system (p ≥ 0.481). The discrepancy between chronological and dental age using the Demirjian system was significant when assessing the Western Australian population although it was more accurate for Caucasian children. The accuracy was similar between subjects with and without orthodontic concerns.     

The influence of impaction to the third molar mineralization in northwestern Chinese population

Age estimation by third molar mineralization has been developed for a period of time. Recent studies showed that impaction status has an influence on the rate of the third molar mineralization in Europids and male Black African populations. In this regard, the present study was conducted to determine whether the impaction status could delay the chronological process of third molar mineralization in northwestern Chinese population too. A total of 3,512 digital orthopantomograms of 1,255 male and 2,257 female northwestern Chinese subjects aged from 11 to 26 years were assessed based on the formation stages described by Demirjian et al. with two modifications. Mineralization stage and impaction status were determined for all third molars. Statistical measures were calculated at stages C–H in the male and female gender for both impacted and non-impacted third molars. It was ascertained that the mean ages with impacted third molars at stages C–H were 0.02–1.42 years higher in males and 0.04–1.52 years higher in females than those with non-impacted third molars, but statistical differences were only found at stages C, D, and E in males and stages D and E in females. The probabilities of being under 14, 16, or 18 years of age with non-impacted third molars were all higher than those with impacted third molars. The results prove that impacted third molars show significant slower mineralization than non-impacted ones at stages D and E in both males and females of northwestern Chinese population. It is recommended to consider the influence of impaction on the rate of third molar mineralization for dental age estimation.     

Validation of common classification systems for assessing the mineralization of third molars

One major criterion for dental age estimation is the evaluation of third molar mineralization. There are various methods for evaluating tooth mineralization based on classification by stages. The aim of the present work is to assess the validity of the common classification systems. To this end, we analyzed 420 conventional orthopantomograms of German females aged 12–25 years old. The mineralization status of tooth 38 was determined using the stages defined by Gleiser and Hunt, Demirjian et al., Gustafson and Koch, Harris and Nortje and Kullman et al., respectively. Of the methods tested, the most accurate results were obtained with Demirjian et al.s classification system, which performed best not only for observer agreement but also for the correlation between estimated and true age. It is argued that this is due to the fact that Demirjian et al.s classification is based on a sufficient number of stages which are defined independently of speculative estimations of length. This leads to the conclusion that the method devised by Demirjian et al. should be used for evaluating the mineralization of third molars for purposes of forensic age determination.     

The usage of third molars to determine legally relevant age thresholds in Turkey

From a forensic perspective, attaining the ages of 12, 15 and 18 is particularly important with respect to the Turkish Penal Code (TPC). The aim of this study is to obtain data regarding third molar development in the Turkish population for age estimation and to investigate the contribution of third molar development to age estimation in relation to the TPC. The study was applied with panoramic radiography on 379 male and 405 female subjects. The mineralization status of the third molars were evaluated on the basis of Demirjian’s classification system. It was determined that ‘0’ and ‘A’ stages for under-12 years of age, ‘B’ and ‘C’ stages for under-15, ‘D’ stage for under-18, ‘E’ and ‘F’ stages for over-12, ‘G’ stage for over-15 and ‘H’ stage for over-18 were specific stages for both genders. Specific stages that are detected according to the developmental stages of the third molars were not found to be adequately precise for distinguishing legal age thresholds. However, this study shows that matured third molars (reaching H stage) are indicative of an individual’s being over 18 years of age for both genders in Turkey.     

Validity of different dental age estimation methods in Pakistani orthodontic patients

This research aims to evaluate the validity of Demirjian’s (1973), Nolla’s (1960) and Willem’s (2001) methods of dental age (DA) estimation in Pakistani orthodontic patients (8–16.9 years). It also addresses the validity of these methods in determining dental maturity across the gender and compares the difference between original Demirjian tables (based on French-Canadian standards) and Pakistani tables formulated by Sukhia et al. (2012). Orthopantomograms of 403 subjects (males?=?176, females?=?227) were examined for DA assessment by different methods. Paired t-test and Wilcoxon signed-ranked tests were used to determine significant differences between mean dental and chronological age among different age groups. Correlation between DA and CA were assessed by the Spearman’s correlation (p?=?≤0.05). Nolla’s method under-estimated the DA by 1.00 ± 1.54 in males and over-estimated by 0.21 ± 1.64 in females. DA was significantly advanced using Pakistani tables (males?=?0.32 ± 1.17, females?=?0.38 ± 1.33 years) and Willem’s method (males?=?0.31 ± 1.09, females?=?0.29 ± 0.48 years). DA correlated better with CA using Pakistani tables compared with the French-Canadian standards. Earlier dental maturation was reported in females compared with males using Demirjian’s and Nolla’s methods. Strong correlations were found between CA and DA according to all methods (p < 0.001). Overall, Willem’s method was identified as the most valid method for DA estimation in the Pakistani sample.     

Validity of a modified Demirjian system based on an Australian dataset – simple maturity score in age estimation

This pilot study is a validation of a modified Demirjian’s System developed for the Australian population by Blenkin and Evans. The study sample comprised orthopantomographs of 230 individuals aged 2.5 to 14.5 years. Seven right mandibular teeth (excluding the wisdom tooth) were assessed and graded according to the Demirjian’s stages of tooth development. Corresponding modified numeric scores for the stages were summed to form a simple maturity score from which age estimates were derived. The mean difference between the estimated and chronological age for girls was 0.02 years, 95% CI [-0.13, 0.17]. Paired-sample t-test results found this difference not to be statistically significant p = 0.81, <0.05. For boys, the method underestimated the age with a mean difference of –0.24 years 95% CI [–0.4, –0.08]. Paired t-test found this to be significantly different (p = 0.003). This study found that the modified Demirjian’s System of Blenkin and Evans is valid for use in the Australian population.     

Investigation into stutter ratio variance

The number of criminal cases involving Turkish juveniles has increased in recent years. To date, there is no method for chronological age estimation according to third-molar mineralization in Western Turkish children and adolescents. The aim of this study was to investigate the mandibular third molar development according to the eight stages (A–H) of the Demirjian method and to compare third-molar development according to gender and age with previous data. The digital orthopantomograms of 1120 white Turkish children (406 boys, mean age 15.17 ± 3.80 years, and 714 girls, mean age 16.83 ± 3.59 years) aged 7 to 22 years, from the Western Anatolia region were retrospectively reviewed. The Turkish population reached stage H at a mean age of 20 years in both genders. Dental mineralization in Western Turkish children was delayed at stages D–G but advanced at stage H compared with that in Turkish children in other regions. Third molar root development can reliably estimate the mean age and age range for a juvenile of unknown chronological age, especially compared with the standard deviation obtained using other techniques for calculating the skeletal age of the hand-wrist or long bones.     

Comparative study on the chronology of third molar mineralization in a Japanese and a German population

In Germany, a sharp increase in forensic age estimations of living persons has been observed in recent years. German law defines four legally relevant age limits: 14, 16, 18 and 21 years. In these age groups, radiographic assessment of the mineralization status of third molars is of particular importance. So far, the influence of ethnicity on the mineralization rate has been insufficiently analyzed. A total of 3031 orthopantomograms of 1597 Japanese and 1434 Germans aged between 12 and 26 years were examined. The mineralization status of third molars was evaluated on the basis of the classification proposed by Demirjian. For the individual mineralization stages, the study presents the mean values and standard deviations (SD) separately for both populations and sexes. The majority of probands from both the Japanese and the German population achieved the C stage and the late G and H stages of third molar development at similar ages. Significant differences between Japanese and Germans were observed, however, with regard to the D, E and F stages defined by Demirjian. Japanese men and women achieved the D, E and F stages approximately 2-3 years later than German men and women. In addition to forensic age determination in living persons, the presented reference data can also be used for age estimations of unidentified deceased persons and skeletons.     

The chronological age estimation of third molar mineralization of Han population in southwestern China

The purpose of the study was to estimate the chronology of third molar mineralization in Han population of southwestern China and find its unique characteristics so that it would provide a reference in several legal cases like forensic age estimation. The study used Demirjian's staging method to study 2192 orthopantomograms of 984 male and 1208 female subjects aged between 8 and 25 years. The statistical data was analyzed by Student's t test and ANOVA.The conclusions of the study are: (1) The chronological mineralization age of third molars of Han population in Southwestern China is similar to the Turkish and the Japanese, was earlier than the Austrian and Han of South China, but later than the Spanish. (2) The mineralization timing of the third molars between two sides in maxilla or mandible has no significant differences in the same gender group. (3) There is no significant difference in mineralization of third molars between male and female, except for tooth 48 in Demirjian's stage E. (4) The mineralization of third molar in maxilla is earlier than mandible.     

Age estimation using third molar maturation based on Demirjian’s criteria

Dental age estimation is routinely used in human identification, in both the living and the dead. Teeth follow a predictable pattern of eruption and maturation that can be assessed radiographically in the living, allowing experts to estimate an individual’s age. Third molars develop much later than the other permanent teeth, and can be used to estimate age of individuals nearing the age of maturity. Ability of third molar maturation when graded using Demirjian’s method in ascertaining whether an individual has attained the medicolegal ages of 16 and 18 years has not yet been verified. The present study involved assessing the third molar maturation of 220 individuals of a training set using Demirjian’s scoring system, generating regression models to estimate age using the third molar maturity scores, applying these models on a test set of 40 individuals, and calculating the mean difference (MD) and the mean absolute error (MAE) between the chronological and estimated ages of the test set participants. It was observed that the lowest mean difference and mean absolute error was observed for the maturation of the left mandibular third molar (MD = 1.05 years, MAE = 2.09 years). Boxplots generated in the study report that the third molar maturation stages given by Demirjian can identify whether an individual has attained the medicolegally significant ages of 16 and 18 years of age.     

Chronological age estimation of third molar mineralization of Han in southern China

In order to study the chronology of age of third molar mineralization of Han in southern China, Demirjian staging method was used to determine the stage of four third molars (18, 28, 38, 48) mineralization in 3,100 Han in southern China aged 4.1–26.9 years based on radiological evidence from digital orthopantomograms. The mean age of the 3,100 patients was 15.96 ± 4.73 years, including 1,200 male (mean age, 15.32 ± 4.62) and 1,900 female (mean age, 16.35 ± 4.76). Results show that there was no significant difference in mineralization between 18 and 28 and 38 and 48 of male or female. However, significant difference was observed between 28 and 38 of female at stage C; 28 was 0.25 years earlier than 38. In male, at stage G, 38 was 0.61 years earlier than 28, and 48 was 0.62 years earlier than 18. At stages D, E, F, G, and H, male 48 was 0.34, 0.66, 0.72, 1.34, and 0.76 years earlier than that of female, respectively. At stages A, D, E, F, G, and H, male 38 was 0.73, 0.26, 0.56, 0.91, 1.29, and 0.70 years earlier than that of female, respectively. At stages B, E, F, G, and H, the mineralization mean age of male 18 was 0.54, 0.50, 0.76, 0.92, and 0.58 years earlier than that of female, respectively. At stages E, F, G, and H, the mineralization mean age of male 28 was 0.51, 0.76, 0.92, and 0.49 years earlier than that of female, respectively. After reviewing the literature, the chronological mineralization age of 48, at stages D to G, of Han in southern China was 1 to 4.6 years earlier than that of Japanese and 1 to 3 years earlier than that of German. The mean age at stage H of 48 of Han in southern China was similar to Turkish, Black African, Japanese, and German, but was later than Spanish. Finally, the conclusions are: (1) in the same gender group of Han in southern China, the mineralization ages between two sides in upper or lower jaw are very similar, and (2) the chronology mean age and complete time of third molar mineralization of male were earlier than that of female.     

Comparative assessment to determine the accuracy of Demirjian and DARLInG methods of dental age estimation in western Indian children

The aim of this study is to compare the accuracy of Demirjian and Dental Age Research London Information Group (DARLInG) methods of dental age estimation in western Indian children. A total of 485 dental panoramic radiographs of children aged between 4 and 15 years were included in this study. Dental age was estimated based on the degree of mineralization of permanent teeth in the left side of the arch. Dental age was estimated from the scores obtained from the Demirjian and DARLInG’s United Kingdom Caucasian datasets respectively. The difference between the chronological age (CA) and dental age (DA) in each range (CA-DA) was analysed using paired t-test. The age and sex-based differences of the estimated age using the two methods were tested using ANOVA and Pearson correlation co-efficient analysis. The overall mean CA was 8.74 years and 9.00 years for boys and girls respectively. The overall mean difference (CA-DA) using the Demirjian’s method for boys and girls were −0.68 years and −0.52 years respectively (p < 0.05). Using the DARLInG’s method, the overall mean difference (CA-DA) was −0.31 years and −0.34 years for boys and girls respectively (p < 0.05). Between the two methods, significant differences were observed in different age groups (p < 0.05). Pearson correlation coefficient showed significant positive correlation between dental age estimated from the Demirjian and DARLInG methods (p < 0.05). The DARLInG method provided better estimate of age compared to Demirjian method in the western Indian population. However, an ethnic specific reference dataset specific to this population would likely produce accurate age estimates.     

Dental age estimation in Malay children based on all permanent teeth types

The applicability of the Willems et al. model was verified on a collected sample of Malay (Malaysian nationality) children. This sample was split in a reference sample to develop a Malay-specific prediction model based on the Willems et al. method and in a test sample to validate this new developed model. Next, the incorporation of third molars into this model was analyzed. Panoramic radiographs (n?=?1,403) of Malay children aged between 4 and 14.99 years (n?=?702) and subadults aged between 15 and 23.99 years (n?=?701) were collected. The left mandibular seven permanent teeth of the children were scored based on the staging technique described by Demirjian and converted to age using the Willems et al. method. Third molar development of all individuals was staged based on the technique described by Gleiser and Hunt modified by Kohler. Differences between dental age and chronological age were calculated and expressed in mean error (ME), mean absolute error (MAE), and root mean square error (RMSE). The Willems et al. model verified on the collected Malay children overestimated chronological age with a ME around 0.45 year. Small differences in ME, MAE, and RMSE between the verified Malay-specific prediction model and the Willems et al. model were observed. An overall neglected decrease in RMSE was detected adding third molar stages to the developed permanent teeth model.     

Untersuchungen zum zeitlichen Verlauf der Weisheitszahnmineralisation bei einer deutschen Population

In Germany a sharp increase in forensic age estimations of living individuals has been observed in recent years. With regard to the relevant age group, radiological assessment of the mineralization stage of the third molars is of particular importance. However, the influence of ethnicity on the rate of mineralization has been insufficiently analyzed. A total of 1,437 orthopantomograms from 860 female and 577 male Germans aged between 12 and 26 years were examined. The mineralization stage of the third molars was evaluated based on the classification of stages proposed by Demirjian. For the individual mineralization stages, the study presents the means and standard deviations for the genders separately. Statistically significant differences in the chronology of third molar mineralization between maxilla and mandible or between the two sides could not be observed. A comparison between genders did not reveal significant differences either.     

Dental age estimation from the developmental stage of the third molars in Iranian population

A sharp increase in forensic age estimation of living persons has been observed in recent years. However, ethnic populations residing in different countries have been insufficiently analyzed. The aim of this study was to achieve a referral database and regression equations for dental age estimation of unaccompanied minors of Iran nationality. A total of 1200 orthopantomograms were collected from original Iran and equally divided in age categories between 10 and 27 years. On the radiographs, the developmental stage of the third molars was scored applying a Demirjian et al. scoring technique. Inter- and intra-observer reliabilities were tested using kappa statistics. Correlation between the scores of all four wisdom maxillary and mandibular third molars teeth and left/right symmetry were evaluated with spearman correlation coefficient. Student’s t-test on asymmetry was performed and regression formulas were calculated. The present database was the first to assemble third molar developmental scores on radiographs of Iran individuals and provided more appropriate dental age estimation of unaccompanied Iran minors. To enhance the accuracy of forensic age estimates based on third molars mineralization, the use of population-specific standards is recommended.     

Einfluss der Retention auf die Mineralisationsgeschwindigkeit dritter Molaren

Third molars are of special interest concerning legally relevant age groups in forensic age estimation by means of examination of dental mineralization. This study investigated the influence of wisdom tooth impaction on the mineralization rate. A total of 1,198 orthopantomograms from 629 female and 569 male German individuals (age range 15-40 years) were examined. After assessing the dental mineralization of the third molar in cases with stage H according to Demirjian, wisdom tooth impaction was determined. Females with complete wisdom tooth impaction were 0.7-4.0 years older than those females with incomplete wisdom tooth impaction, in the male group the age difference was 1.6-2.6 years, the lower level for stage H according to Demirjian was between 18 and 20 years in both genders. It was concluded that in German individuals with stage H according to Demirjian it is most likely that these persons have reached a minimum age of 18 years.     

The chronology of second and third molar development in Koreans and its application to forensic age estimation

The accuracy of forensic age estimation based on the chronology of second (M2) and third molar (M3) development was investigated using 2,087 orthopantomograms of Korean men and women aged between 3 and 23 years. The developmental stages of M2s and M3s in these subjects were classified using the criteria of Demirjian. Inter-observer reliability and statistical data on each stage of mineralization of M2s and M3s were evaluated. The left–right symmetries of the maturation degrees in the M2s and M3s were observed in both sexes, between which no arch differences were found, but statistically significant sex-specific differences were observed in some stages of M2 and M3 development. In multiple regression analysis, a strong positive relationship was observed between age and mineralization of M2s and M3s. The regression formulas for estimating the age of Koreans were presented based on sex and combination of teeth. These results suggest that the developments of second and third molars can be considered as valuable age indicators in Korean adolescents and young adults.     

Evaluation of chronological age based on third molar development in the Spanish population

A cross-sectional study was carried out to assess chronological age estimation based on the stages of third lower molar development, following the eight stages (A–H) method of Demirjian et al. The final sample consisted of 1,054 orthopantomograms from Spanish individuals of known chronological age (range 14–21 years) and gender (462 males and 592 females). Results showed a stronger correlation for males (r²=0.54) than for females (r²=0.45). Root formation occurred earlier in males than females, in stages 5, 6 and 7. The mean difference between chronological and estimated age was –0.10 years (±1.23 SD) for left third molar, and –0.07 years (±1.22 SD) for right third molar, with slight variations regarding sex. Comparative tables are provided regarding medicolegal questions concerning age 18 prediction in the Spanish population, showing that legal age is reached in stage 7 (G) by women and in stage 8 (H) by men. No differences have been observed between sides (p<0.0001). Differences were observed between Spaniards and other previously studied populations. Third molar maturity takes place earlier in the Spanish than French-Canadian, Scandinavian, American, German, Japanese and South African populations and is more similar to US Hispanics in root development.