OPG-based dental age estimation using a data-technical exploration of deep learning techniques

Dental age estimation, a cornerstone in forensic age assessment, has been extensively tried and tested, yet manual methods are impeded by tedium and interobserver variability. Automated approaches using deep transfer learning encounter challenges like data scarcity, suboptimal training, and fine-tuning complexities, necessitating robust training methods. This study explores the impact of convolutional neural network hyperparameters, model complexity, training batch size, and sample quantity on age estimation. EfficientNet-B4, DenseNet-201, and MobileNet V3 models underwent cross-validation on a dataset of 3896 orthopantomograms (OPGs) with batch sizes escalating from 10 to 160 in a doubling progression, as well as random subsets of this training dataset. Results demonstrate the EfficientNet-B4 model, trained on the complete dataset with a batch size of 160, as the top performer with a mean absolute error of 0.562 years on the test set, notably surpassing the MAE of 1.01 at a batch size of 10. Increasing batch size consistently improved performance for EfficientNet-B4 and DenseNet-201, whereas MobileNet V3 performance peaked at batch size 40. Similar trends emerged in training with reduced sample sizes, though they were outperformed by the complete models. This underscores the critical role of hyperparameter optimization in adopting deep learning for age estimation from complete OPGs. The findings not only highlight the nuanced interplay of hyperparameters and performance but also underscore the potential for accurate age estimation models through optimization. This study contributes to advancing the application of deep learning in forensic age estimation, emphasizing the significance of tailored training methodologies for optimal outcomes.

Comparison of Demirjian's comprehensive chart with the London atlas of tooth development in children and adolescents: a pilot study

Dental age estimation has its application in various subdisciplines of medicine and dentistry. New methods of dental age (DA) estimation are emerging and it is important that we compare different methods to determine which one is more closely related to the chronological age. Demirjian's method is one of the most widely used techniques and has been tested in various ethnic populations globally. In 2016, another approach to DA estimation is the London atlas of human tooth development and eruption. No study has compared Demirjian's comprehensive chart and London atlas method in the Indian population. Hence, in the current study, we estimated DA using Demirjian's comprehensive chart and London atlas method for association with the known chronologic age in children and adolescent population. The study also attempted to determine if sexual dimorphism existed in DA estimated by the two methods. Estimation was performed for both methods on 100 orthopantomogram records (50 males and 50 females, aged 6-16 years) of orthodontic patients. The data were compared and analysed using paired t-tests. There was an overestimation of DA by Demirjian's comprehensive chart on an average of +1.3 years in males and +0.5 years in females, whereas using London atlas, it was +1.4 years in males and +0.5 years in females. The mean of underestimation was -0.6 years in males and -0.8 years in females using Demirjian's comprehensive chart, whereas it was -0.8 years in males and -0.5 years in females. A statistically significant difference (P < 0.0001) was found when mean chronological age (11.6 ± 2.6) years of the participants was compared with DA estimated using either Demirjian's comprehensive chart (12.3 ± 2.8) years or London atlas (11.8 ± 2.9) years. The trends in this pilot study point towards more accuracy of London atlas over Demirjian's method when done using comprehensive chart for estimating DA. In summary, the results of the current pilot study indicates greater accuracy of London atlas method over Demirjian's comprehensive chart method for estimating DA in Indian population. This finding should be validated by conducting similar studies using larger sample, on diverse Indian ethnic populations, for applicability in pedodontic, orthodontic, and forensic domains.

Key points

No study has compared Demirjian's comprehensive chart and London atlas method in the Indian population.The dental age estimated by London method was closer to chronological age as compared to Demirjian's method in our study sample.Significant difference was found in chronological age and estimated age using London atlas method in both males and females.

The effect of reference sample composition and size on dental age interval estimates

OBJECTIVES

Validation studies in juvenile dental age estimation primarily focus on point estimates while interval performance for reference samples of different ancestry group compositions has received minimal attention. We tested the effect of reference sample size and composition by sex and ancestry group on age interval estimates.

MATERIALS AND METHODS

The dataset consisted of Moorrees et al. dental scores from panoramic radiographs of 3334 London children of Bangladeshi and European ancestry and 2-23 years of age. Model stability was assessed using standard error of mean age-at-transition for univariate cumulative probit and sample size, group mixing (sex or ancestry), and staging system as factors. Age estimation performance was tested using molar reference samples of four sizes, stratified by year of age, sex, and ancestry. Age estimates were performed using Bayesian multivariate cumulative probit with 5-fold cross-validation.

RESULTS

Standard error increased with decreasing sample size but showed no effect from mixing by sex or ancestry. Estimating ages using a reference and target sample of different sex reduced success rate significantly. The same test by ancestry groups had a lesser effect. Small sample size (n < 20/year of age) negatively affected most performance metrics.

DISCUSSION

We found that reference sample size, followed by sex, primarily drove age estimation performance. Combining reference samples by ancestry produced equivalent or better estimates of age by all metrics than using a single-demographic reference of smaller size. We further proposed that population specificity is an alternative hypothesis of intergroup difference that has been erroneously treated as a null.

Forensic Age Estimation: A Multifactorial Approach in a Retrospective Population Study

Objectives: The objective of this study was to evaluate the accuracy of forensic age estimation in a German population by combining clavicle and wisdom teeth assessments based on cone beam computed tomography (CT) data. The study aimed to determine the reliability of this approach in predicting biological age. Material and Methods: A total of 161 CT data sets from 120 males and 41 females with known exact ages were evaluated by three raters. The clavicle was assessed according to stages 1-5 (including substages 2a-c and 3a-c), and the Demirjian stage's classification method was used for the wisdom teeth. Inter-class correlation (ICC) was calculated to assess the agreement among the three raters. Additionally, ordinary least square regressions were performed to predict chronological age using the clavicle or one of the four teeth. Finally, age prediction models using multiple indicators were developed. Results: The ICCs ranged from 0.82 for the clavicle to 0.86 and 0.88 for the wisdom teeth. Linear estimation tended to overestimate chronological age, especially in subjects over 18 years old. The clavicle showed the strongest overestimation. Combining age estimation from the clavicle with the upper and lower wisdom teeth improved the predictive power, resulting in a 14% and 15% increase in R² for the upper and lower wisdom teeth, respectively. Adding more than one tooth to the prediction did not improve the predictive power (all ΔR² < 1%). Conclusions: Age estimation using CT can be significantly improved by combining information from the analysis of wisdom teeth with age estimation based on the clavicle.

Age Group Classification of Dental Radiography without Precise Age Information Using Convolutional Neural Networks

Automatic age estimation using panoramic dental radiographic images is an important procedure for forensics and personal oral healthcare. The accuracies of the age estimation have increased recently with the advances in deep neural networks (DNN), but DNN requires large sizes of the labeled dataset which is not always available. This study examined whether a deep neural network is able to estimate tooth ages when precise age information is not given. A deep neural network model was developed and applied to age estimation using an image augmentation technique. A total of 10,023 original images were classified according to age groups (in decades, from the 10s to the 70s). The proposed model was validated using a 10-fold cross-validation technique for precise evaluation, and the accuracies of the predicted tooth ages were calculated by varying the tolerance. The accuracies were 53.846% with a tolerance of ±5 years, 95.121% with ±15 years, and 99.581% with ±25 years, which means the probability for the estimation error to be larger than one age group is 0.419%. The results indicate that artificial intelligence has potential not only in the forensic aspect but also in the clinical aspect of oral care.

Comparing the accuracy of Demirjian and Nolla methods and establishing a new method for dental age estimation in northeastern Chinese children

Dental age estimation plays an important role in the field of clinic medicine and forensic medicine. The Demirjian and Nolla methods are common scoring methods for dental age estimation but there was no research about the comparison of accuracy of these two methods in northeastern Chinese children. Hence, in this study, we compared the accuracy of these two methods to explore more suitable method for our studied population. We collected 535 orthopantomograms from northern Chinese children aged from 6 to 15 years and divided them into training dataset and testing dataset according to the ratio of 7:3. The dental age of training dataset were estimated using Demirjian and Nolla methods, respectively. The results suggested that the mean differences of these two methods were 0.24 and -0.40 years, and mean absolute difference were 0.65 and 0.59 years. Then to further improve the accuracy of dental age assessment, the new improved formulas and dental age conversion tables were established after analyzing the relationship between the sum scores based on Nolla method and chronology age in training dataset. According to the new method used in testing dataset, the minimum value of mean difference (0.00) and mean absolute difference (0.49) were obtained, which are largely smaller than that of Demirjian and Nolla methods. The new developed method and dental age conversion scales may be more suitable dental age estimation method for northeastern Chinese children.

Mandibular Teeth as Predictors in Forensic Age Estimation: A Cone-Beam Computed Tomography-Based Pulp Volume Regression Study

Background

Age estimation is integral to science of forensic odontology and plays an important role in human identification. Pulp volume estimation using cone-beam computed tomography (CBCT) to derive age can be very useful as it is noninvasive and can be applied on individuals of all ages.

Aims and Objectives

The study aimed to estimate the chronological age-based pulp and tooth volume (PTV) ratios in adults from Uttar Pradesh, India, using CBCT and voxel counting dental software.

Materials and Methods

Thirty-six CBCT scans were allocated into three Groups, I, II, and III (12 in each group) randomly to study the pulp volume of lateral incisor, canine, and first premolar, respectively. PTV was calculated by image segmentation method using Xelis Dental software. A correlation between chronological age with PTV was established using derived regression equations.

Statistical Analysis

All the data were subjected to statistical analysis using Statistical Package for Social Sciences version 16.0.

Results

Estimated age and standard error were determined. Standard errors of estimates were 11.24 years (LI), 7.78 years (C), 9.89 years (PM) group, lowest being for canines. The estimated age was compared with the chronological age. The difference between the chronological age and the estimated age by the derived equation for the present study was statistically nonsignificant (P = 1.00).

Conclusions

The results of the study show the feasibility of calculation of PTV ratios on CBCT to estimate the age for the set population with canine as the best predictor of age for the present study population.

[Forensic medical diagnostics of age by the Cameriere method]

THE AIM OF THE STUDY

Was to conduct the comparative analysis of the age groups' separation accuracy (<18 years old; ≥18 years old) by orthopantomogram depending on the examination's side in Russian population sample. The number of orthopantomograms equal 600 (190 of male and 410 of female) aged from 14 to 23 were investigated. Index value of third molar (Im³) was calculated by the R. Cameriere method, in female and male, on the right and left sides. Index of third molar on the right and left sides shows a high correlation. In the male sample the result specificity was 0.97 on the left and 1.0 on the right, the sensitivity was 0.96 on the left and 0.94 on the right. In the female sample the values were as follows: the specificity was 0.96 on the left and 0.98 on the right, the sensitivity was 0.92 on the left and 0.94 on the right. The results showed the possibility of Im³ (0.08) use to determine the target age group for Russian citizens of both sexes regardless of examination side.

Adapting Demirjian Standards for Portuguese and Spanish Children and Adolescents

Estimation of children's chronological age is highly important in human and forensic sciences. The Demirjian method has been reported as accurate for this purpose. The literature review shows some evidence that the accuracy of estimating chronological age via the Demirjian standards is not a straightforward process. The objective of this research is to analyze the reliability of the Demirjian standards in Portuguese and Spanish children and adolescents and adapt it to include sex and group age as contingent factors.

METHODS

Orthopantomographs of 574 Portuguese and Spanish male and female children and adolescents were employed to test the reliability of the Demirjian method. After testing for inter-rater consistency and age estimation using the Demirjian standards, multiple regression analysis was performed controlling for sex and age group.

RESULTS

The Demirjian standards overestimated chronological age for both sexes, mainly for females. Through the development of regression functions, more detailed dental age estimation was performed. The predictive capacities of the Demirjian method and the significant teeth varied as a function of children's age. The Demirjian global standard predicted over 65% of the variance of the chronological age. Taking a tooth-by-tooth approach, the predictive ability increased by over 70%.

CONCLUSIONS

The accuracy of estimating chronological age via the Demirjian method is not as reliable as it might appear, judging from the results found according to age group and according to sex crossed with age group.

Forensic Dental Age Estimation: Development of New Algorithm Based on the Minimal Necessary Databases

Objectives Dental age determination relies on the presence of wisdom teeth, which can be assigned to specific age ranges according to their stage of development. The purpose of this study is to highlight the applicability of the Demirjian staging of layman compared to expert, as well as the inclusion of all four wisdom teeth in the overall assessment, in order to emphasize and critically highlight a precise age estimation in clinical practice, especially in the case of agenesis or the presence of less than all four wisdom teeth. Material and Methods: In this study, dental age determination is performed and compared by a trained layperson and an expert using 385 orthopantomograms. The radiographs of known chronological age from male patients in the age range of 11−22 years were acquired from the University Medical Center Mainz. All four wisdom teeth were radiologically viewed if present. Demirjian staging with stages A−H was applied, and regression analysis was performed. Results: The relationship between mineralization of wisdom teeth (18, 28, 38 and 48) and age was linear for all teeth (p < 0.01), except for tooth 18 (p = 0.02). Comparing the prediction of the four teeth individually revealed that the lower teeth gave better predictions than the upper ones (R2 ≥ 0.50 vs. R2 < 0.50). Conclusions: For clinical use, the mandibular wisdom teeth should be preferred when performing dental age estimation using the Demirjian staging method. As a result of the present analysis, two ways of determining dental age by wisdom teeth can be suggested. One is to take only tooth 38, with the formula: age = 3.3 + 0.73 × mineralization of tooth_38. The second recommendation would be to take tooth_48. If both are unavailable, the formula would be age = −0.5 + 0.94 × mineralization tooth_28. Utilizing tooth 18 would not lead to more precise results.

Regressive changes of crown-root morphology and their volumetric segmentation for adult dental age estimation

Cone‐beam computed tomography (CBCT) enables the assessment of regressive morphological changes in teeth, which can be used to predict chronological age (CA) in adults. As each tooth region is known to have different correlations with CA, this study aimed to segment and quantify the sectional volumes of the tooth crown and root from CBCT scans to test their correlations with the chronological age (CA). Seventy‐five CBCT scans from individuals with age between 20 and 60 years were collected retrospectively from an existing database. A total of 192 intact maxillary anterior teeth fulfilled the eligibility criteria. The upper tooth volume ratio (UTVR), lower tooth volume ratio (LTVR), and sex were used as predictor variables. The UTVR and LTVR parameters were both found to be differently correlated to CA and independent from each other. Regression models were derived from each tooth, with the highest R² being the maxillary lateral incisor (R² = 0.67). Additional single predictor models using each ratio were capable of reliably predicting the CA. The segmentation approach in volumetric adult dental age estimation proved to be beneficial in enhancing the reliability of the regression model.

Demirjian method and Willems method to study the dental age of adolescents in Shanghai before and after 10 years

BACKGROUND

The aim of this study is to assess the validity of whether the difference in dental age between 2009 to 2011 and 2021 is affected by environmental factors such as environmental pollution, floating population, and dietary habits. Demirjian and Willems dental age estimation methods were conducted for a Han population of children aged 8 to 14 in Shanghai, China. A total of 1,259 digital panorama radiographs of children aged 8.00-14.99 was estimated. All digital panorama radiographs were estimated using the Demirjian and Willems methods.

MATERIALS AND METHODS

Both 2009 to 2011 and 2021 were statistically analyzed by paired t-tests. The results show that the Demirjian method overestimates 2009 to 2011 and underestimates 2021 than children's chronological age. According to the Willms method, males are overestimated and females are underestimated from 2009 to 2011, and both genders were underestimated in 2021.

CONCLUSIONS

In conclusion, the difference in dental age between 2009 to 2011 and 2021 was statistically significant. Factors such as environment and dietary habits have been found to be affected by dental development. However, there are disputes among some researchers about the exact factors, so it is suggested to further study the effects of environmental factors on tooth development.

Reliability of dentin translucency and incremental cemental lines in age estimation using light and stereomicroscopes: A comparative study

Age estimation of the dead and human remains has been challenging in forensic medicine, both in mass disasters and criminal investigations. There are several approaches to accurately evaluate age, each with its own benefits and drawbacks. Dentine translucency (DT) and incremental cemental lines (ICL) have often been used for age estimation in living adults and unknown skeletal remains. We attempted to estimate age using both these parameters and compare accuracy of age estimated using these parameters in a larger sample. A total of 300 extracted single-rooted permanent teeth were collected from the patients aged between 15 and 75 years. Longitudinal ground sections in the buccolingual direction of 250 μm thickness were prepared, and the images obtained were subsequently analyzed to measure the length of DT using the ImageJ software program. In addition, the number of ICL were also counted in each tooth section. The age of the individuals was estimated using both methods individually, and the results have shown that both parameters have shown reliable age estimates in the middle age groups. However, there was overestimation of age up to 10.6 years in the younger age group using DT and an underestimation of age up to 13.4 years in the older age group with ICL. Pearson's correlation statistics revealed a strong positive and statistically significant correlation of both the parameters with the chronological age (0.973 and 0.917). To conclude, the method using the ICL should be preferred due to the relatively higher number of errors (<±3 years) which were considered excellent.

Dental maturation in a Chinese sample using Demirjian method

BACKGROUND

Dental calcification information is relevant for clinical, archaeological, and forensic applications. However, dental maturity measurements in current cohorts of Chinese children are insufficient.

AIM

This study aimed to establish the mandibular dental maturity table and determine the accuracy of dental age estimation using the Demirjian method in a Chinese sample.

SUBJECTS AND METHODS

Permanent mandibular teeth, excluding the third molar, in 2091 panoramic radiographs of 1008 males and 1083 females aged 3-15 were graded, and dental age was estimated according to Demirjian's criteria. Age-of-attainment was calculated with probit regression for each stage by sex, and sex differences were analysed using the Mann-Whitney U test. Dental age was compared with chronological age using paired t-tests.

RESULTS

Although females showed earlier age-of-attainment than males, significant sex differences were only found in stages D-G (p < 0.05). The Demirjian method overestimated the dental age in both males (0.68 ± 1.05 years) and females (0.59 ± 0.97 years).

CONCLUSIONS

The relationship between mineralisation stage and chronological age in this study can be applied as a reference for mandibular dental maturity of Chinese children and adolescents. The Demirjian method overestimated the chronological ages of this sample.

Third molar development in a London population of White British and Black British or other Black ethnicity

Population differences in dental development between Black and White ethnic groups have been debated but not previously studied in the UK. Using inappropriate data for dental age estimation (DAE) could lead to erroneous results and injustice. Data were collected from dental panoramic radiographs of 5590 subjects aged 6-24 years in a teaching hospital archive. Demirjian stages were determined for left-sided teeth and third molars and data collected regarding hypodontia and third molar agenesis. Third molar development in self-assigned Black British, including other self-assigned Black ethnicity, was compared with that of self-assigned White British subjects. Data were compared for males and females in the two ethnic groups using T-tests for Demirjian Stages A-G of third molar development and Mann-Whitney tests for Stage H once a cut-off age at the maximum age for Stage G had been imposed. Third molar development occurred earlier in subjects of Black ancestry compared to those of White ancestry. While both ethnic groups showed large age ranges for every third molar stage, in female subjects these generally occurred at least 1.5 years earlier, and in males at least one year earlier. Hypodontia and third molar agenesis were more prevalent in White British, but the ethnic difference in third molar development persisted in subjects with complete dentitions. This is a large study that confirms ethnic differences in a London population, emphasises the difficulties of establishing the 18-year-old threshold using DAE, and confirms the risk of overestimating the age of individuals of Black ethnicity using White ethnic reference data.

Evaluating the accuracy of two different age estimation methods in growing children in Navi Mumbai using Orthopantomograph: A radiographic study

BACKGROUND

Age estimation through dental maturity indicators is relatively more accurate, reliable, and valid for living as well as dead individuals. It acts as an important tool in diagnosis and treatment planning in clinical as well as in forensic dentistry. There are various methods to estimate the dental age. Out of which, Demirjian's method has been widely used in various populations. However, there is a dearth of literature on Indian population comparing Demirjian's method to Cameriere's method.

AIM

The purpose of this study was to evaluate the accuracy of Demirjian's and Cameriere's age estimation methods to chronological age in growing children using orthopantomograph (OPG).

SETTING AND DESIGN

The sample consisted of digital OPGs of 280 children in Navi Mumbai aged 5-16 years.

MATERIALS AND METHODS

Digital OPGs were used to assess the dental maturity of seven mandibular left teeth using Demirjian and Cameriere's method and were compared to the chronological age.

STATISTICAL ANALYSIS USED

Data were analyzed using Student's t tests.

RESULT

Irrespective of gender, dental age estimated by Cameriere's method (mean 10.23 ± 2.79 years), underestimated the chronological age (mean 11.74 ± 2.86 years) for overall population which showed statistically significant difference. Demirjian's method overestimated (mean 12.24 ± 3.06 years) the chronological age for the overall population but was statistically insignificant.

CONCLUSION

Demirjian's method is more closely in correlation with the chronological age of growing children as compared to the Cameriere method when applied to children of age 5-16 years in Navi Mumbai.

Validating dental age estimation in Kenyan black children and adolescents using the Willems method

PURPOSE

This study aimed to validate the Willems Belgian Caucasian (Willems BC) age estimation model in a Kenyan sample, to develop and validate a Kenyan-specific (Willems KB) age estimation model and to compare the age prediction performances of both models.

METHODS

Panoramic radiographs of 1038 (523 female, 515 male) Kenyan children without missing permanent teeth and without all permanent teeth fully developed (except third molars) were retrospectively selected. Tooth development of the seven lower-left permanent teeth was staged according to Demirjian et al. The Willems BC model, performed on a Belgian Caucasian sample and a constructed Kenyan-specific model (Willems KB) were validated on the Kenyan sample. Their age prediction performances were quantified and compared using the mean error (ME), mean absolute error (MAE) and root-mean-square error (RMSE).

RESULTS

The ME with Willems BC method equalled zero. Hence, there was no systematic under- or overestimation of the age. For males and females separately, the ME with Willems BC was significantly different from zero, but negligible in magnitude (-0.04 and 0.04, respectively). Willems KB was found not to outperform Willems BC, since the MAE and RMSE were comparable (0.98 vs 0.97 and 1.31 vs 1.29, respectively). Although Willems BC resulted in a higher percentage of subjects with predicted age within a one-year difference of the true age (63.3% vs 60.4%, p=0.018), this cannot be considered as clinically relevant.

CONCLUSION

There is no reason to use a country-specific (Willems KB) model in children from Kenya instead of the original Willems (BC) model.

A novel report of dental development pattern in a 3-year-old girl with three congenitally missing primary canines: A review of the literature and a case study

Dentists may encounter patients with numerical dental anomalies in clinical practice and understanding of these conditions would allow early detection as well as intervention. The absence of one or more teeth congenitally is referred as hypodontia. This dental anomaly is rarely reported in primary dentition and the most commonly affected teeth in the primary dentition are mandibular lateral incisors and primary canines are remarkably very rare and this entity has not been often reported. This case study was aimed to report a 3-year-old Indian girl with the absence of three canines primary dentition and also evaluate the overall dental development pattern of developing permanent teeth. Furthermore, a new finding for pediatric dentists that the development of permanent canines in case of missing primary canines.

Application of Cameriere's method for dental age estimation in children in South China

The aim of this study was to evaluate the applicability of Cameriere’s European formula for age estimation in children in South China and to adapt the formula to establish a more suitable formula for these children. Moreover, the performance of dental age estimation based on Cameriere’s method combining the developmental information of permanent teeth (PT) and third molar (TM) was also analysed. Orthopantomographs of 720 healthy children in Group A, and orthopantomographs of 320 children and 280 subadults in Group B were assessed. The samples of Group A were divided into training dataset 1 and test dataset 1, and the samples of Group B were also divided into training dataset 2 and test dataset 2. A South China-specific formula was established based on the training dataset 1, and the comparison of accuracy between the Cameriere’s European formula and the South China-specific formula was conducted with the test dataset 1. Additionally, a PT regression model, a TM regression model, and a combined regression model (PT + TM) were established based on the training dataset 2, and the performance of these three models were validated on the test dataset 2. The Cameriere’s European formula underestimated chronological age with a mean difference (ME) of −0.47 ± 1.11 years in males and −0.69 ± 1.19 years in females. However, the South China-specific formula underestimated chronological age, with a mean difference (ME) of −0.02 ± 0.71 years in males and −0.14 ± 0.73 years in females. Compared with PT model and TM model, the PT and TM combined model obtained the smallest root mean square error (RMSE) of 1.29 years in males and 0.93 years in females. In conclusion, the South China-specific formula was more suitable for assessing the dental age of children in South China, and the PT and TM combined model can improve the accuracy of dental age estimation in children.

Key points

Orthopantomographs of 720 healthy children in Group A, and orthopantomographs of 320 children and 280 subadults in Group B were assessed.

A South China-specific formula was established based on the training dataset 1, and the comparison of accuracy between the Cameriere’s European formula and the South China-specific formula was conducted with the test dataset 1.

A PT regression model, a TM regression model, and a combined regression model (PT + TM) were established based on the training dataset 2, and the performance of these three models were validated on the test dataset 2.

The South China-specific formula was more suitable for assessing the dental age of children in South China, and the PT and TM combined model can improve the accuracy of dental age estimation in children.

Age determination in children by orthopantomograph and lateral cephalogram: A comparative digital study

BACKGROUND AND AIMS

The assessment of age is useful in forensic medicine and forensic odontology and in treatment planning in various branch of dentistry. The aim of study is comparative evaluation and assessment of applicability of Demirjian's method, Willem's method of dental age (DA) estimation, and Maria de Paula Caldas's method of skeletal age estimation for children aged 9-16 years.

MATERIALS AND METHODS

A total of 140 individuals (70 females and 70 males) between the age group of 9-16 years were enrolled. These individuals were grouped by a difference of 1 year into 7 groups (each group comprising of 20 individuals: 10 males and 10 females). Dental age estimation was performed from orthopantomograph images of mandibular teeth of left quadrant by both Demirjian's and Willem's methods. Skeletal age estimation was done from Lateral Cephalogram by Caldas Digital Method. The differences between the chronological age and the estimated dental and skeletal ages were statistically tested using paired t-test.

RESULTS

Demirjian's DA estimation overestimated males (0.4040 years) and females (0.1316 years). Willem's DA estimation method underestimated males (0.1386 years) and females (0.4210 years) and Caldas skeletal age estimation overestimated males (0.2982 years) and females (0.4259 years).

CONCLUSION

The study concluded Willem's DA estimation method was the most accurate for male and Demirjian's method for female for Gujarati Population. Caldas's new computer-assisted method for skeletal age estimation used in the present study is easy to perform and less time-consuming and objective method and can be applied for Gujarati population.

Expressing Uncertainty in Dental Age Estimation: A Comparison between Two Methods of Calculating the "Average" Standard Deviation

The expression of uncertainty is defined by the standard deviation and is usually expressed in multiples of the standard deviation (±1sd, ±2sd, and ±3sd). The objective was to use weighting of the sd calculation by the number or count of subjects for each tooth development stage. A comparison shows the difference between the range of uncertainty using the unweighted sd and the weighted sd. The range of uncertainty related to Dental Age Estimation is statistically significantly greater (p < 0.001) for the weighted sd compared to the unweighted sd. It is concluded that the number of subjects for each Tooth Development Stage in the Reference Data set should be included in the calculation for a single Dental Age Estimation using the Simple Average Method when presenting the uncertainty associated with the point estimate of the "mean" for Dental Age Estimation of a single subject of unknown age.

Expressing Uncertainty in Dental Age Estimation: A Comparison between Two Methods of Calculating the "Average" Standard Deviation

The expression of uncertainty is defined by the standard deviation and is usually expressed in multiples of the standard deviation (±1sd, ±2sd, and ±3sd). The objective was to use weighting of the sd calculation by the number or count of subjects for each tooth development stage. A comparison shows the difference between the range of uncertainty using the unweighted sd and the weighted sd. The range of uncertainty related to Dental Age Estimation is statistically significantly greater (p < 0.001) for the weighted sd compared to the unweighted sd. It is concluded that the number of subjects for each Tooth Development Stage in the Reference Data set should be included in the calculation for a single Dental Age Estimation using the Simple Average Method when presenting the uncertainty associated with the point estimate of the "mean" for Dental Age Estimation of a single subject of unknown age.

Accuracy of age estimation in 6-21 year old South Indian population - A comparative analysis of clinical and radiographic methods

Unavailability of chronological age brings to the forefront the importance of age estimation for human identification. Dental age is routinely assessed based on the calcification stages and/or the eruption of teeth, which exhibit wide variations amongst different ethnic groups. The current study aimed at estimating the dental ages in 384 South Indian subjects aged 6-21 years, using clinical and radiographic methods and comparing the predictive accuracy of these two dental age estimation methods. For the estimation of age by clinical method, Foti and co-workers' mathematical Model 2 was employed and for the radiographic method, Chaillet and Demirjian's method with Acharya's Indian formula was used. The clinical method yielded a mean error in the range of -3.16 to 4.07 years and -1.83 to 4.32 years among male and female subjects respectively whereas the radiographic method yielded an error of -9.52 to 1.96 years among males and an error of -10.72 to 2.66 years in females. The mean absolute error for the entire sample obtained by clinical method was 0.80 years and by radiographic method was 0.89 years. We found that the clinical method had a better accuracy in estimating dental age of children and adolescents when compared to the radiographic method in South Indian (Karnataka) population. However, the difference between the two is negligible implying that either of the methods can be employed in clinical practice.

Periodontal Ligament Visibility (PLV): validation of PLV to determine adult status

BACKGROUND

Gradual obliteration of the Periodontal Ligament Visibility (PLV) of lower third molars indicates increasing age. This is used to help determine whether or not an age disputed subject is above or below the 18 year threshold.

AIM

The main focus was to determine, in test subjects of known age, whether the PLV system used 'blind' is able to reliably indicate whether the subject was a child (age < 18 years) or adult (age > 18).

MATERIALS AND METHODS

A total of 250 normal subjects in the age range 16 to 26 years, from the archives of Guy's Hospital in London, UK, were used to validate the system of PLV. The radiographic assessment of PLV1 was used to categorize four grades of PLV.

RESULTS

It was found that for both females and males PLV-C and PLV-D gave very high probabilities (p = 1.000) of the test subjects being of adult status.

CONCLUSION

Periodontal Ligament Visibility has the potential to play an important part in the assessment of age disputed asylum seekers who look adult and claim to be children.

The applicability of dental wear in age estimation for a modern American population

OBJECTIVES

Though applied in bioarchaeology, dental wear is an underexplored age indicator in the biological anthropology of contemporary populations, although research has been conducted on dental attrition in forensic contexts (Kim et al., , Journal of Forensic Sciences, 45, 303; Prince et al., , Journal of Forensic Sciences, 53, 588; Yun et al., , Journal of Forensic Sciences, 52, 678). The purpose of this study is to apply and adapt existing techniques for age estimation based on dental wear to a modern American population, with the aim of producing accurate age range estimates for individuals from an industrialized context.

MATERIALS AND METHODS

Methodologies following Yun and Prince were applied to a random sample from the University of New Mexico (n = 583) and Universidade de Coimbra (n = 50) cast and skeletal collections. Analysis of variance (ANOVA) and linear regression analyses were conducted to examine the relationship between tooth wear scores and age.

RESULTS

Application of both Yun et al. () and Prince et al. () methodologies resulted in inaccurate age estimates. Recalibrated sectioning points correctly classified individuals as over or under 50 years for 88% of the sample. Linear regression demonstrated 60% of age estimates fell within ±10 years of the actual age, and accuracy improved for individuals under 45 years, with 74% of predictions within ±10 years.

DISCUSSION

This study demonstrates age estimation from dental wear is possible for modern populations, with comparable age intervals to other established methods. It provides a quantifiable method of seriation into "older" and "younger" adult categories, and provides more reliable age interval estimates than cranial sutures in instances where only the skull is available.

Orthodontic Treatment: Real Risk for Dental Age Estimation in Adults?

Dental age estimation becomes a challenge once the root formation is concluded. In living adults, one dental age indicator is the formation of secondary dentine, also associated with orthodontic treatment as well as root shortening. The aim of this study was to establish whether these secondary effects of orthodontic treatment could generate a statistically significant difference in dental age estimations when using Kvaal's method. The study sample included 34 pairs of pre- and postorthodontic panoramic radiographs, from different individuals with exactly the same age and sex distribution. Females 65%, median age 17.5 years, and males 35%, median age 22.5 years, were included. After data collection, dental age was estimated per tooth using formulae previously published. The risk of obtaining over-estimation of age was calculated. (RR = 1.007). The changes caused by orthodontic treatment do not have any significant effect on age estimation when Kvaal et al.'s method is applied on panoramic radiographs.

Demirjian approach of dental age estimation: Abridged for operator ease

Background:

Present times have seen an alarming increase in incidence of crimes by juveniles and of mass destruction that Highlight the preponderance of individual age estimation. Of the numerous techniques employed for age assessment, dental age estimation (DAE) and its correlation with chronological age (CA) have been of great significance in the recent past. Demirjian system, considered as gold standard in DAE is a simple and convenient method for DAE, though,, although, referring to multiple tables make it cumbersome and less eco friendly due to excessive paper load.

Aim:

The present study was aimed to develop a comprehensive chart (DAEcc) inclusive of all Demirjian tables and developmental stages of teeth and also to as well as to test the operator ease of 50 undergraduate dental students in performing DAE using this chart.

Materials and Methods:

The study was performed in two stages, wherein the first stage was aimed at formulation of the comprehensive chart (DAE_CC) which included pictorial representation of calcification stages, the Federation Dentaire Internationale notation of the teeth, and the corresponding scores for each stage with a concluding column at the end to enter the total score. The second stage assessed the applicability of the ease of DAE by DAE_CC, whereby fifty 2^nd year BDS students were asked to trace the calcification stages of the seven permanent left mandibular teeth on a panorex, identify the correct stage, assign the corresponding score, and to calculate the total score for subsequent dental age assessment.

Results and Conclusions:

showed that average time taken by the students for tracing seven mandibular teeth was 5 min and for assessment of dental age was 7 min. The total time taken for DAE was approximately 12 min, thus making the procedure less time consuming. Hence, this study proposes the use of DAEcc for age estimation due to ease in comprehension and execution of Demirjian system.

A Novel Mandibular Maturity Marker at the 18-Year Threshold

The final stage of third molar development is used to assign a subject to above the 18-year threshold. Some subjects exhibiting this final stage are less than 18 years. Radiographs from 1000 females and 1000 males age 16.00-25.99 years were examined. Each half-year age band comprised 50 females and 50 males. Three categories of root canal widths (RCW) of the LL6, LL7, and LL8 [FDI 36, 37, and 38] were defined. Reproducibility was achieved by re-assessing the same subjects 12 months apart. For females, the minimum value for RCW-A was 16.33 years, RCW-B 17.23 years, and RCW-C 18.45 years. For males, the minimum values were RCW-A 17.16 years, RCW-B 18.29 years, and RCW-C 18.16 years. The presence of RCW-C in a female, and the presence of RCW-B or RCW-C in a male is compelling evidence that the subject is above the 18-year threshold.

Dental Age Estimation: A Test of the Reliability of Correctly Identifying a Subject Over 18 Years of Age Using the Gold Standard of Chronological Age as the Comparator

This study was designed to test the reliability of using the third molars to demarcate between child and adult status. A total of 2000 dental panoramic tomographs were used for assessment of the calculated age using the 8-stage system of tooth development and applied to all four third molars. The LL8 was also assessed using this 8-stage system. For each tooth development stage, the Normal distribution and percentile summary data were estimated. The calculated dental age compared with the chronological age was statistically significantly different (p < 0.001) for both females and males giving underestimates of the true age. Comparison of single tooth dental age and chronological age was only slightly different. The most important finding is that the assignment to above or below the 18-year threshold, in the age range 17 years to 19 years, could be wrong on up to 50% of occasions.

Comparison of the diagnostic accuracy, sensitivity and specificity of four odontological methods for age evaluation in Italian children at the age threshold of 14 years using ROC curves

The age threshold of 14 years is relevant in Italy as the minimum age for criminal responsibility. It is of utmost importance to evaluate the diagnostic accuracy of every odontological method for age evaluation considering the sensitivity, or the ability to estimate the true positive cases, and the specificity, or the ability to estimate the true negative cases. The research aims to compare the specificity and sensitivity of four commonly adopted methods of dental age estimation - Demirjian, Haavikko, Willems and Cameriere - in a sample of Italian children aged between 11 and 16 years, with an age threshold of 14 years, using receiver operating characteristic curves and the area under the curve (AUC). In addition, new decision criteria are developed to increase the accuracy of the methods. Among the four odontological methods for age estimation adopted in the research, the Cameriere method showed the highest AUC in both female and male cohorts. The Cameriere method shows a high degree of accuracy at the age threshold of 14 years. To adopt the Cameriere method to estimate the 14-year age threshold more accurately, however, it is suggested - according to the Youden index - that the decision criterion be set at the lower value of 12.928 for females and 13.258 years for males, obtaining a sensitivity of 85% and specificity of 88% in females, and a sensitivity of 77% and specificity of 92% in males. If a specificity level >90% is needed, the cut-off point should be set at 12.959 years (82% sensitivity) for females.

Controversies in age estimation from developing teeth

BACKGROUND

Numerous dental reference data exist to estimate age from developing permanent teeth.

AIM

To compare the performance of reference data that provide a point estimate using the developing second molar.

METHODS

Performance of several methods estimating age using mandibular second molar formation was compared using the Maber test sample (age = 3-16) of 946 dental radiographs. Mean difference and mean absolute difference between dental and chronological ages were calculated. The percentage of individuals with mean absolute difference <1 year was counted across age group and tooth stage. Results for the choice of Demirjian or Moorrees tooth staging, pooled-sex, opposite sex reference data, selected stages (initial cusp tips, crown complete, root half and root complete) and statistical approaches were compared.

RESULTS

Tooth reference data conditioning on age, particularly probit mean age (age-at-transition) adapted for age prediction performed best. Results using sex-specific reference data, Moorrees stages and selected Moorrees stages were marginally better than other methods. No method performed well for ages 15 and 16 years.

CONCLUSION

Adapted maturity data L9a and N25a reference data for this tooth performed best across age categories and tooth stages, with a mean absolute difference of 0.8 year.

Age estimation using development of third molars in South Indian population: A radiological study

AIM

To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A-H) method of Demirjian et al. in Chennai population of South India.

MATERIALS AND METHODS

A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P < 0.05 was considered as the level of significance.

RESULTS

The results showed that the mean age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P < 0.05).

CONCLUSION

There are differences indicating that maxillary and mandibular third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization.

Dental age assessment in children: a comparison of four methods in a recent French population

The aim of this study was to analyze the accuracy and the reliability of four methods of dental age estimation (Demirjian, Willems I, Willems II, and Chaillet standards) in a French population. Orthopantomograms of 743 children aged between 4 and 15 years were used. The Demirjian standards gave a consistent overestimation of dental age compared with chronological age (+0.45 and +0.46 years for girls and boys, respectively). We found that three modified methods were more accurate for both sexes than Demirjian's method: the Willems I method appeared to be more suitable when the sex and ethnicity are both known (-0.09 and +0.14 years for girls and boys, respectively); the Willems II method was more accurate for children of unknown sex (mean difference = 0.00 years), and the Chaillet method was found to be more accurate than the Demirjian method, but less accurate than the Willems I method (-0.59 and -0.18 years for girls and boys, respectively).

Age estimation using third molar teeth: A study on southern Saudi population

OBJECTIVE

To estimate the age of an individual between 13 and 23 years, using Demirjian method in Saudi male patients in the southern region of the Kingdom of Saudi Arabia.

MATERIALS AND METHODS

A total of 360 male patient's digital panoramic radiographs were used to evaluate the morphology of mandibular 3rd molar teeth roots according to the Demirjian method. Using descriptive statistical method, age was calculated.

RESULTS

Result showed a strong relation of age with stages of root development of 3rd molar teeth. The standard deviation of mean of root development stages is 1.47 years of age.

CONCLUSION

This study suggests that age can be predicted with a statistical significant result for ages between 13 and 23. Further studies with large population are needed for better statistical results and for female age assessment.

Comparison of the applicability of four odontological methods for age estimation of the 14 years legal threshold in a sample of Italian adolescents

The 14-years age threshold is especially important in Italy for criminal, civil and administrative laws. Several methods relying on dental calcification of the teeth, up to the second molar, are used for the evaluation of age in childhood. The objective of the research was to compare the inter-rater agreement and accuracy of four common methods for the dental age estimation - Demirjian (D), Willems (W), Cameriere (C) and Haavikko (H) - in a sample of Italian adolescents between 11 and 16 years. The sensitivity and specificity, and the different level of probability, according to the peculiarities of Italian criminal and civil law, were compared for the methods examined, considering the threshold of 14 years. The sample was composed of 501 digital OPGs of Italian children (257 females and 244 males), aged from 11 years and 0 days to 15 years and 364 days. The maturation stage of the teeth was evaluated according to D, W, H and C methods by three independent examiners. Mixed statistical models were applied to compare the accuracy and the errors of each method. The inter-rater agreement was high for the four methods and the intraclass correlation coefficients were all ≥ 0.81. Methods H and C showed a general tendency to underestimate the age in the considered sample while the methods D and W tended to overestimate the child's age. In females, D and W were more accurate than C, which is more accurate than H. In the males, W is the most accurate method even though it over-estimated age. Considering the 14-years threshold, the sensitivity of D and W methods is quite high (range 0.80; 0.95) and specificity is low (range 0.61; 0.86). The principal findings of the research are: the W and D methods are much more accurate than C and H, but they tend to overestimate the age. The C method largely underestimates the age (by ~1 year) for both genders and for all operators. H is unsuitable for dental age estimation in the Italian population, while W and D yielded high sensitivity but low specificity, thus producing high rates of false positive results. The choice of method to estimate if an Italian child has reached the 14-years legal threshold should mainly be chosen according to the different legal milieu (if civil or criminal) and the gender of the examined individual. The age assessment in criminal case must be prudently managed.

Forensic odontological examination of a 1500 year-old human remain in ancient Korea (Gaya)

Forensic odontological examination was performed on one of the 1500-year old human remains of ancient Korea (Gaya) excavated from a burial site at Songhyeon-dong, Changnyeong, South Korea in April, 2008. The main purpose of the examination was to age estimate the remains and record any dental characteristics to aid full-body reconstruction and life history data collection. Oral and radiographic examinations and metric data collection were conducted. During the oral examination, the following observations were made: dental caries, semi-circular abrasion on the maxillary right lateral incisor and enamel hypoplasia on the left and right canines and first premolars in the mandible. The metric data was similar to that of average metric data of modern Koreans. Age estimation was initially conducted using the degree of dental attrition with methods of Takei and Yun, and was estimated to be approximately 40 years. However, it was observed in the radiographic examination, that the maxillary right second molar, together with the mandibular left and right second and third molars had incompletely developed root apices. The age estimation was then performed using the developmental status of the lower second and third molars. The age was estimated to be approximately 16 years using Lee's method which was consistent with the estimation using forensic anthropology. This case study highlights that the degree of attrition should not be used as a sole indicator for age estimation.