Reference and target sample age distribution impacts between model types in dental developmental age estimation

Accuracy of age estimation of radiographic methods using developing teeth

Age estimation based on the mineralized morphology of teeth is one of the important elements of forensic anthropology. To explore the most suitable age estimation protocol for adolescents in the South China population, 1477 panoramic radiograph images of people aged 2–18 years in the South were collected and staged by the Demirjian mineralization staging method. The dental ages were estimated using the parameters of the Demirjian and Willems. Mathematical optimization and machine learning optimization were also performed in the data processing process in an attempt to obtain a more accurate model. The results show that the Willems method was more accurate in the dental age estimation of the southern China population and the model can be further optimized by reassigning the model through a nonintercept regression method. The machine learning model presented excellent results in terms of the efficacy comparison results with the traditional mathematical model, and the machine learning model under the boosting framework, such as gradient boosting decision tree (GBDT), significantly reduced the error in dental age estimation compared to the traditional mathematical method. This machine learning processing method based on traditional estimation data can effectively reduce the error of dental age estimation while saving arithmetic power. This study demonstrates the effectiveness of the GBDT algorithm in optimizing forensic age estimation models and provides a reference for other regions to use this parameter for age estimation model establishment, and the lightweight nature of machine learning offers the possibility of widespread forensic anthropological age estimation.

Estimation of dental age is an important part of forensic age estimation in living persons. As the quality of the values given in population-specific reference studies has a great impact on the estimation, the aim of this study was to validate reference data for wisdom teeth mineralization and eruption of a German population concerning the diagnosis of the age limit of 18years in persons with known age. Mineralization and eruption was evaluated in 307 orthopantomograms of Central European subjects aged 17.5-18.5years. Dental age was estimated using reference data and compared to chronological age. Statistical methods were used to analyze the differences and to propose adjusted reference values. Estimation of dental age relying on mineralization resulted in overestimations of 2years on average in 76% of the males and 82% of the females. Using eruption, all men and 75% of the women were overestimated by up to 7years. The differences between estimated and chronological age in both men and women were associated with the mineralization and eruption stage, respectively. The higher the stage, the higher was the risk of overestimation. The mineralization stages up to stage E were associated with underestimations. Using the proposed adjusted reference values resulted in more accurate estimations of dental age. Validation of reference values for dental age estimation showed great overestimations resulting in high error rates with numerous persons being younger than the estimated dental age. Adjustments are proposed which reduce differences between estimated dental age and chronological age.

Dental age estimation is very important for individual identification in criminal and civil forensic investigations. One of the methods for age estimation is studying age related changes in pulp volume of teeth. The objective of the current study was to estimate dental age from the pulp volume of five different categories of teeth of a Peruvian sample using cone beam computed tomography (CBCT). Retrospective CBCT records of 231 patients [females (134), males (97), age: 12-60 years] were included in the study, categorized into five different age groups (12-19, 20-29, 30-39, 40-49, 50-59, 60 years and older). Dental pulp volume of five categories of teeth(upper canines, left upper central incisors, left upper first molars, lower left first premolars, first molars) were analyzed using Romexis® 5.3.3.5 software for each patient. There was a reduction in the pulp volume of upper right and left canine with age. The pulp volume was lowest in people aged 60 years and over. Linear regression analysis of the pulp volume and chronological age showed a coefficient of determination of 30%, suggesting a weak correlation. A weak correlation between dental pulp and age is derived. But, a robust large homogenous sample of teeth in future for different age groups may establish a reliable regression equation.

Dental age and tooth development in children with molar-incisor hypomineralization: A case-control study

Introduction: Dental age estimation using orthopantomogram is very useful in pediatric dentistry, orthodontics in clinical diagnosis and treatment planning and also has forensic application. Demirjian method is widely used for age estimation and Willems method has been suggested to be accurate than Demirjian in various populations. To estimate the dental age of children in a specific population of Nepal by Demirjian and Willems method, compare them with the chronological age and assess their applicability. Materials and Method: Digital orthopantomograms of 5 to 14 years of children were used to estimate the dental age by Demirjian’s 7- teeth method and Willems method. Descriptive statistics was used and mean with standard deviation was calculated for gender and age of the samples. Paired t-test was used for comparison of chronological age with dental age. P < 0.05 was considered as statistically significant.Pearson correlation was used to assess the correlation between chronological and dental age in both the genders. Result: By Demirjian method, there was an underestimation of 0.276 years in males and 0.194 in females and by Willems method, 0.652 in males and 0.847 in females which were statistically significant. There was an underestimation of dental age in all the age groups except in the age group of 5,7 and 14 for Demirjian age which was statistically nonsignificant. Pearson correlation demonstrated strong positive correlation between chronological age and dental age. Conclusion: The underestimation of dental age was more by Willems method as compared to Demirjian method. There was a strong positive relationship between chronological age and dental age in both the genders. Demirjian’s 7- teeth method was more applicable as compared to Willems method when tested in selected Nepalese children population

Development of a Reference Data Set (RDS) for dental age estimation (DAE) and testing of this with a separate Validation Set (VS) in a southern Chinese population

Previous research on archaeological skeletal remains in Bosnia and Herzegovina rarely included odontological analysis. The objective of this research was biological profiling through odontological analysis (dental morphological characteristics, estimation of sex and dental age at death) in medieval archaeological skeletal remains samples from Krešića greblje in Paoča (Čitluk municipality, Bosnia and Herzegovina). After the excavations of the archaeological site, odontological analysis was performed before genetic analysis. The sample comprised 22 permanent teeth from 6 individuals. Odontological analysis included odontometric estimation of sex, estimation of age at death by two morphological methods, and an analysis of dental traits and dental pathology. Genetic analysis was used for sex determination. The results of odontological analysis classified all individuals as adults, with estimated age at death 20-25 in one individual, 30-35 in three individuals, 35-45 in one individual, and one individual older than 45 years of age. Odontometric sex estimation was in high concordance with sex determination by genetic analysis, and correctly classified five individuals’ sex (four females and one male). In one individual odontometric sex was assessed as female while genetic analysis revealed male. Morphological dental traits and dental pathology were investigated as well, adding to a better understanding of the odontological characteristics of the medieval population in the area of Bosnia and Herzegovina. Sex and dental age estimation given by odontological analysis provide fast and cost-effective information, and should be performed as an auxiliary before genetic analysis.

One or more missing teeth, such as hypodontia, make it difficult to obtain accurate results in age estimation methods. This paper aims to test the accuracy of the models developed by Bedek et al. that can estimate age with fewer than seven teeth for Turkish children. Panoramic radiographs of 1118 children (540 girls and 578 boys) aged between 6 and 16years were evaluated using the Willems method and Bedek models for the entire sample and for different ages and sexes. Differences between dental age (DA) and chronological age (CA) calculated for all methods for each sex and all age groups were analyzed the paired sample t-test and Wilcoxon signed rank test. The accuracy of the DA estimation methods was determined by the proximity of DA to CA by calculating mean absolute error (MAE). While all Bedek models underestimated CA by 0.2 to 0.1years, the Willems method overestimated CA by 0.3years. DA-CA difference in the total sample and girls was statistically significant in all methods. In the total sample, the seven- and four-teeth models had the lowest MAE, while the one-tooth model had the highest MAE. Seven- and four-teeth models were the most suitable for age estimation, and all models except the one-tooth model were found to be more accurate than the Willems method in northwestern Turkish children. Especially in children with hypodontia, it may be possible to estimate DA with the use of Bedek models.

Introduction: The Demirjian's method has been advocated since 1973 as a universal method in dental age (DA) estimation. Several studies in different populations have shown that DA was overestimated compared with chronological age (CA). The Objective of the Study: The aim of this study was to assess the DA in Jordanian children aged 4–17 years using the Demirjian method and compare it with the standard values provided by Demirjian. Design of the Study: This was a cross-sectional study. Subjects and Methods: Five hundred and eighty four panoramic radiographs of healthy children of both genders. The CA was scored from the medical record of the child and the dental age scored on all seven left mandibular teeth in the panoramic radiograph based on demirjian's method. Statistical Testing: All data were collected, tabulated, and statistically analyzed using SPSS version 25. The statistical analyses were performed using an independent samples t-test and a correlation coefficient to analyze quantitative data and a scatter plot. Results: The DA was overestimated than CA, especially in the intervals between 6–7, 14–15, and 16–17 years in females, and in the interval 12–13 and 16–17 years in males. Furthermore, there were significant correlations between CA and DA according to the girls in the intervals 9–14 years, and there were significant correlations between CA and DA related to boys in the intervals 6–7, 8–11, and 15–16 years. The results from this study have shown that Demirjian “s method cannot be applicable to be used to determine the estimated DA of the Jordanian population. Conclusion: The Demirjian's method for dental estimation is not valid for the Jordanian population, and there should be another method for dental age estimation.

The aim of this study was to test the accuracy of an age estimation method using the radiographs of permanent mandibular third molar teeth in a Southern Thai population. Digital panoramic radiographs of 480 Thai samples (240 males and 240 females) aged from 8 to 23 years were selected and divided into 16 age groups. The permanent mandibular third molar teeth were separated into nine developmental stages according to the Demirjian et al. classification. The developmental stage was evaluated and then converted into a developmental score. Accuracy of the dental age estimation was tested using regression equations according to the Duangto et al. study. Our results showed that dental age was close to the chronological age within one year for both sexes. In conclusion, the age estimation equations according to the Duangto et al. study provide an accurate age estimation in a Southern Thai population. Keywords: Dental age estimation, Demirjian et al. classification, Mandibular third molar teeth, Thai population

I describe a technique for comparing two simple accounts of a distribution of response times: A mixture model and a generalized-shift model. In the mixture model, a target distribution is assumed to be a mixture of response times from two other (reference) distributions. In the generalized-shift model, the target distribution is assumed to be a quantile average of the reference distributions. In order to distinguish these two possibilities, quantiles for the target distribution are estimated from the quantiles of the reference distributions assuming either a shift or a mixture, and the predicted quantiles are used to calculate the multinomial likelihood of the obtained data. Monte Carlo simulations reported here demonstrate that the index is relatively unbiased, is effective with moderate sample sizes and modest spreads between the reference distributions, is relatively unaffected by changes in the number of bins or by data trimming, can be used with data aggregated across subjects, and is relatively insensitive to a range of subject variations in distribution shape and in mixture or shift proportion. As an illustration, the index is applied to the interpretation of three effects from distinct paradigms: residual switch costs in the task-switching paradigm, the psychological refractory period effect, and sequential effects in the Simon task. I conclude that the multinomial likelihood index provides a useful and easily applied tool for the interpretation of effects on response time distributions.

Background: Age is the prime factor in the identification of the individual. Among the age estimation methods, dental age estimation from the volume ratios of tooth and pulp is gaining importance due to its accuracy. Objective: To assess the dental age using the ratio of pulp volume (PV) and tooth volume (TV) of extracted mandibular premolars using CBCT and to correlate with chronological age. Methods: Mandibular premolars extracted for orthodontic and periodontic purposes were collected and prepared for CBCT exposure. The data obtained was analyzed using ITK SNAP for manual segmentation. Linear regression analysis was performed separately for the first and second premolars. Pearson’s correlation was used to correlate dental age and odontological parameters with chronological age. Results: Statistical analysis of the data yielded the following equation: estimated age = 76.42-817.4*PV/TV of the first premolar and 75.11-758.94*PV/TV of the second premolar. The coefficient of determination (R2) was 0.908 and 0.755, respectively. Conclusion: Predicted age from the volumes of first mandibular premolars is more accurate producing reliable estimates with chronological age.

Introduction Accurate age estimation is required in the field of health sciences, as it is relevant to the timing of various treatment procedures. Differences in the development among children of the same chronological age have led to the concept of physiologic age as a means to define progress toward completeness of development or maturity in the individual child. The most common dental age estimation methods are Nolla &Demirjin’s.Demirijan’s being the more result oriented method of age estimation. 
 Aim and Objective: To evaluate the Dental age estimation using Demirijan’s 8 teeth method and 7 teeth method. 
 Materials and methods: The sample for the study consisted of 400 individuals aged between 618 years. The chronological age of the patient will be obtained by official birth certificate. Radiographic age estimation of the selected sample was done after analyzing Orthopantomographs using both Demirijan’s 7 teeth and 8 teeth method. The chronological age was then statistically compared with the results obtained by the radiographic age using SPSS v16 software. 
 Results: The estimation of dental age estimation using Demirijan’s 7 teeth method showed overestimation compare with Demirjian 8 teeth method. 
 Conclusion: Dental age estimation using Demiijan’s 8 teeth method reduces the margin of error in correctly estimating age

Accuracy of the estimation of dental age in comparison with chronological age in a Spanish sample of 2641 living subjects using the Demirjian and Nolla methods