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.     

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.     

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.     

Age estimation of teenagers from Monterrey (Mexico) by the evaluation of dental mineralization after multi-slice helical computed tomography

Current social conditions require more accurate methods to determine the age of people, either living or deceased. The aim of this study was to determine chronological age by measuring the mineralization of third molars. Volunteers (n = 137), aged between 14 and 22 years and of either gender, were recruited from north-eastern Mexico. Sampling was probabilistic and at random. The mineralization stage of third molars was evaluated with the use of multi-slice helical computed tomography and the Mincer-modified Demirjian amended scale. The correlation coefficient, mean difference and linear estimation were determined. There was a linear correlation between age and the mineralization of third molars. Third molars of adults had a degree of mineralization above Demirjian stage F, whereas the third molars of minors had stages between A and F. Hence, a method was obtained to determine the chronological age from the evaluation of dental mineralization of third molars by multi-slice helical tomography. These results are useful as a diagnostic support in forensic dentistry.     

Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults

Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15–23?years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22?years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars’ eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.     

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.     

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.     

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.     

Bone age assessment: comparison of children from two different regions with the Greulich–Pyle method In Turkey

The aim of this study was to identify and compare bone age assessments of Turkish children in regions of Central Anatolia and Eastern Anatolia using the Greulich-Pyle (GP) method. Evaluation was made of 849 (375 boys, 514 girls) adolescents aged between 9 and 17 years, who lived in two geographically different regions of Turkey. The selection criteria included normal growth and development, a state of good physical and mental health with no previous history of chronic or acute illnesses, no past trauma or injury to the hand-wrist region, no congenital or acquired malformations of the hand-wrist area, no hormonal disorders, and good quality hand-wrist radiographs. Bone age (BA) was evaluated using the GP method from definitive radiographs of the left hand-wrist. The total mean differences between BA and chronological age (CA) for girls and boys were found to be 1.19 ± 1.2 (p < 0.05) and 0.90 ± 1.2 (p < 0.05) years in the Eastern Anatolia region and 0.28 ± 0.6 (p > 0.05) and –0.10 ± 0.3 (p > 0.05) years in the Central Anatolia region. There were significant differences between BA and CA in all age groups for girls and boys in Malatya (a city in the Eastern Anatolia region) and in 10 and 13 year olds for girls and 12, 13, 15, and 16 year olds for boys in Sivas (a city in the Central Anatolia region). Statistically significant differences were determined between the BA and CA of the subjects living in Malatya and Sivas (p < 0.05). The results of this study using the Greulich–Pyle atlas indicate that bone development is completed earlier in adolescents living in Malatya compared with those in Sivas.     

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.     

Chronological age estimation based on third molar development in a Portuguese population

Third molar development was assessed using a sample of 1,131 orthopantomograms from a Portuguese population. The methodology applied was the eight stages (A–H) method described by Demirjian et al. The final sample was made of 739 orthopantomograms, 387 (52.5%) of which belonging to females; age ranged between 6.1 and 22.5 years old (mean age = 14.49, S.D. = 4.37). For each developmental stage, mean age, standard deviation, and minimal and maximal age was assessed; evaluation of the rate formation of each tooth, according to sex, was calculated and data distribution expressed in percentiles for each stage; the probability of an individual being 16 was also evaluated. The relationship between tooth development and chronological age had a statistical significance for all teeth and both sexes (p < 0.0001). The data described may provide reference for forensic application and agree with the thesis that each population need specific data.     

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.     

Determining the effectiveness of adult measures of standardised age estimation on juveniles in a Western Australian population

The estimation of chronological age through assessment of dental radiographs is well-established and a useful method to assist in the identification of persons in forensic and anthropological scenarios. The objective of our investigation was twofold: (i) to validate the Kvaal et al. age-estimation method on a sample of Western Australian subjects, and (ii) to increase the range of chronological ages to which the Kvaal et al. method can be applied. Our sample size included panoramic radiographs from 74 subjects (aged 12–28 years). A set of ratios were calculated and then used to apply different statistical models of linear regression, in order to generate a final formula to estimate age. The most accurate estimations were obtained from the models generated by the mandibular canine measurement (SEE ± 3.708 years), and for the three mandibular teeth (SEE ± 3.388 years). The results indicate that inclusion of juveniles did not affect final results, and the method still produced estimates acceptable in a forensic framework.     

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.     

Sonographic assessment of the ossification of the medial clavicular epiphysis in 616 individuals

Establishing radiation-free imaging methods for the assessment of clavicular ossification in forensic age determination is desirable as it reduces radiation exposure in living individuals. For this purpose the stage of ossification of the right medial clavicular epiphysis was determined prospectively using sonography in 309 male and 307 female healthy volunteers. The classification of stages according to Schulz et al. was used for this purpose. Stage 2 was first noticed at the age of 14.4 years in males, and at the age of 14.1 years in females. Stage 3 was first achieved by males at the age of 17.6 years and by females at the age of 17.4 years. Stage 4 first occurred in males at the age of 19.3 years and at the age of 18.9 years in females. The mean age for stage 1 was 13.6 years. The mean age of stage 2 ranged between 17.3 and 17.6 years. For stage 3 the mean age varied from 20.7 to 21.2 years, and for stage 4 from 23.3 to 23.5 years. It was concluded that sonographically determined stage 4 clavicular ossification provides evidence for the completion of the nineteenth year of life in males and the eighteenth year of life in females. In order to increase the reliability of age determination using this method it is recommended that findings be recorded by at least two experienced independent examiners who then reach a consensus.     

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.     

Accuracy of the London Atlas,Haavikko’s Method and Cameriere’s European Formula of dental age estimation in Turkish children

Age estimation is a mandatory procedure when the chronological age is unknown or uncertain. Dental development is the preferred characteristic for estimating a child's age. There are many methods for dental age estimation, but their reliability can differ between populations. This study compared the accuracy of three of these methods—the London Atlas (LA), Haavikko's method (HM), and Cameriere's European formula (CF)—in Turkish children living in northwestern Turkey. Panoramic radiographs of 980 children from northwestern Turkey aged between 6.00 and 14.99 years were examined for the whole study group and separately for different ages and sexes by all three methods. Statistical differences between chronological age and dental age were tested using the paired sample t-test and the Wilcoxon signed-rank test. The LA, HM, and CF accuracies were determined based on the mean absolute error. Spearman's rank correlation coefficient showed that the correlation between chronological age and dental age for both sexes was linear for all methods. The LA overestimated the chronological age by 0.09 years, while HM and CF underestimated it by 0.49 and 0.11 years, respectively. The difference between dental age and chronological age was significant in all samples, for all methods, except for the LA in boys. When boys, girls, and the total sample were evaluated, values with the lowest mean absolute error were obtained by HM and were statistically significant in all three groups. Therefore, HM is more accurate than the LA and CF for dental age estimation in Turkish children living in northwestern Turkey.     

Assessment of the accuracy of the Greulich and Pyle hand-wrist atlas for age estimation in a contemporary Australian population

Age estimation of living individuals is topical, and is particularly important globally, owing to increasing migration of undocumented individuals. Radiographic skeletal analysis of hand-wrist skeletal development is often used to infer chronological age based on direct comparison to standards such as the Greulich and Pyle atlas. However, this atlas has been criticised for being applied to foreign populations without due consideration of accuracy. The aims of the current study are to assess the precision and accuracy of the atlas in a contemporary Western Australian population and to develop population specific standards based on the latter system. The study sample comprised 360 individuals (equal sexes) and aged from birth to 25 years; a hold-out group comprising a further 50 individuals was used for model validation. Age estimation was performed through the visual comparison of the study radiographs against the atlas standards; statistical analyses were performed to assess the relationship between estimated skeletal and actual age. Prediction models were formulated; mean SEE values were ±0.005–0.90 (male) and ±0.25–0.421 years (female). Comparisons with prior research demonstrates the importance of contemporary population standards. The models presented here have forensic utility in a Western Australia jurisdiction, albeit the level of accuracy achieved is not suitable for the specific determination of legal majority.