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

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

Estimating ages by third molars: Stages of development in Brazilian young adults

The purpose of this study was to estimate age through the analysis of third molar stages of development in Brazilian young adults. A cross-sectional study was conducted by analyzing 659 panoramic X-rays. Two techniques were used to establish the stages: Modified Scoring (MST) and Demirjian (DT). Regression formulas were calculated. Statistical analyses were conducted by t, Kappa tests, and simple and multiple linear regressions (5% level of significance). Out of the participants, 40.7% were female and 59.3% were male, with ages from 15–22 years. The Kappa test showed good results for intra-observer (0.84 for MST and 0.95 for DT) and inter-observer examination (0.81 for MST and 0.92 for DT). Differences were found in the stages of tooth formation between male and female, but differences were not observed between the left and right sides. We found that both DT and MST underestimated the ages in about 6 months, depending on the used classification and number of teeth. These methods are appropriate for assessing the ages of young Brazilians, although the DT showed better reproducibility.     

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.     

Human dental age estimation using third molar developmental stages: does a Bayesian approach outperform regression models to discriminate between juveniles and adults?

Dental age estimation methods based on the radiologically detected third molar developmental stages are implemented in forensic age assessments to discriminate between juveniles and adults considering the judgment of young unaccompanied asylum seekers. Accurate and unbiased age estimates combined with appropriate quantified uncertainties are the required properties for accurate forensic reporting. In this study, a subset of 910 individuals uniformly distributed in age between 16 and 22 years was selected from an existing dataset collected by Gunst et al. containing 2,513 panoramic radiographs with known third molar developmental stages of Belgian Caucasian men and women. This subset was randomly split in a training set to develop a classical regression analysis and a Bayesian model for the multivariate distribution of the third molar developmental stages conditional on age and in a test set to assess the performance of both models. The aim of this study was to verify if the Bayesian approach differentiates the age of maturity more precisely and removes the bias, which disadvantages the systematically overestimated young individuals. The Bayesian model offers the discrimination of subjects being older than 18 years more appropriate and produces more meaningful prediction intervals but does not strongly outperform the classical approaches.     

Accuracy of scanography using storage phosphor plate systems and film for assessment of mandibular third molars

Objectives

The aim of this study was to compare the diagnostic accuracy of two digital photostimulable storage phosphor (PSP) systems and film for assessment of mandibular third molars before surgery.

Methods

110 patients were referred to have both their mandibular third molars removed. Each patient underwent a radiographic examination with scanography using either Digora (Soredex, Helsinki, Finland) and film or VistaScan (Dürr Dental, Beitigheim-Bissingen, Germany) and film in a randomized paired design. Two observers examined the following variables on the scanograms: bone coverage, angulation of the tooth in the bone, number of roots, root morphology and the relationship to the mandibular canal. In 75 of the pairs (Digora/film pair = 38 and Vista/film pair = 37) both third molars were eventually removed. During and after surgery the same variables were assessed, which served as reference standard for the radiographic assessments. The Wilcoxon signed-rank test tested differences in accuracy (radiographic compared with surgical findings) between Digora/film and between Vista/film.

Results

There was no statistically significant difference between the diagnostic accuracy of film and either of the two digital receptors for assessment of mandibular third molars before surgery (P > 0.05), although Digora obtained a higher accuracy than film.

Conclusions

Scanography is a valuable method for examination of mandibular third molars before removal and the PSP digital receptors in this study were equal to film for this purpose.     

A study of sports-related mandibular angle fracture: relation to the position of the third molars

Mandibular angle fractures have been considered attributable to the presence of unerupted third molars. We examined the relationship between the incidence of sports-related mandibular angle fractures and the presence of a mandibular third molar with emphasis on the position of the third molar. The incidence of angle fracture was significantly higher in the sports-related injury group than in the group with fracture due to other causes ( P <0.05). The incidence of angle fracture in the athletes with higher impaction scores was significantly higher than that in the subjects with higher scores who did not have sports-related fractures ( P <0.05). The percentage of rugby athletes with third molars was significantly higher than that of those without third molars ( P <0.001), and a high proportion of young athletes (89.5%) was considered to belong to a potential high-risk group for angle fractures. Our findings suggest that mandibular angle fractures are influenced by the presence and characteristics of the third molar in sports-related injuries.     

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.     

Application of age assessment based on the radiographic visibility of the root pulp of lower third molars in a northern Chinese population

International Journal of Legal Medicine - The purpose of the present study was to explore the potential application of radiographic visibility of the root pulp in lower third molars in a northern...     

Earwax: an innovative tool for assessment of tobacco use or exposure. A pilot study in young adults

The present work represents a novel approach using earwax (cerumen) for the evaluation of the smoking status with regards to tobacco use/exposure. The method utilizes the difference in the concentration profiles of nicotine and its related compounds in earwax to discriminate among non-, passive, and active smokers. Earwax samples were collected from three study groups (non-, passive, and active smokers) and subjected to analysis by headspace gas chromatography–mass spectrometry. The nicotine levels in earwax were much lower than cotinine levels, even for active smokers; however, it was reported that the nicotine levels in scalp hair were much higher than the cotinine levels. Therefore, it is obviously correct that earwax is protected from external contamination to a larger extent than expected. The concentration profiles of nicotine and its related compounds (o-nicotine, cotinine, and anabasine) in the analyzed earwax samples were treated by data mining techniques. It was possible to discriminate the studied groups using the evolutionary tree (evtree) algorithm and support vector machine discriminant analysis as the statistical models with the best discrimination accuracies of 96.7 and 95.0%, respectively. The analytical method applied requires no sample pretreatment which makes it easy, fast, and a low-cost alternative method to those employing other biological matrices, such as blood, urine, and hair. The earwax, which is considered a neglected body secretion, is a useful tool to determine the exposure to tobacco smoke noninvasively and without the influence of external contamination.     

Dental age assessment (DAA): a study of a Caucasian population at the 13 year threshold

The purpose of this study was to develop a Reference Data Set for Dental Age Assessment at the 13 year old threshold in Caucasian children.

Patients, Materials and Methods

The Reference Data Set comprised 5187 re-used Dental Panoramic Tomographs (DPTs) between the ages of 11-15 years, from both the Eastman Dental Hospital and King’s College Dental Hospital archives. Tooth Development Stages were recorded for the left maxillary and mandibular teeth and all four permanent third molars (Demirjian et al., 1973, Demirjian 1978). A separate Study Sample of DPTs, comprising 50 males and 50 females aged between 10 and 16 years was collected to test the accuracy of the method. Summary Data was generated for the individual Tooth Development Stages which consisted of the number (n-tds), mean (x), standard deviation (sd) and the standard error (se). By using the mathematical techniques of meta-analysis, this data was used to estimate the age of each subject in the Study Sample. The estimated Dental Age derived was compared to the gold standard of Chronological Age.

Results

The mean difference between the Chronological Age and Dental Age was determined to be −0.1 years (−1.2 months) for males and 0.05 years (−0.6 months) for females.

Conclusion

Dental Age was reliably estimated at the 13 year threshold.     

The diagnostic value of anthropometric indices of maxillary sinuses for sex determination using CT-scan images in Iranian adults: A cross-sectional study

BackgroundThe identification of human remains is an essential part of forensic science. Studying paranasal sinuses is very useful in identification of mutilated or burnt bodies from accidents such as plane crashes. We aimed to assess the diagnostic value of anthropometric indices of maxillary sinuses for sex determination using CT-scan images in Iranian adults.MethodsCT-scan slices of 228 maxillary sinuses (from 144 men and 144 women) were studied. The maximum height, maximum anterior-posterior diameter, maximum width, and maximum distance between the sinuses were measured in both sexes. Our participants were divided into three age groups of 20–34, 35–49, and over 50 to compare the recorded measurements in different age groups.ResultsWe found a significant difference between men and women regarding the maximum height, maximum width, maximum A-P diameter of sinuses and the maximum distance between the right and left maxillary sinuses in all of our participants. We also found that the highest accuracy for sex determination was related to the maximum distance between the sinuses (65.6%) and the lowest to the maximum width of the right sinus (56.2%). The most accurate identification resulted from assessing the maximum distance between the sinuses in the 20–34 age group (74.3%), the maximum anterior-posterior diameter of the sinuses in the 35–49 age group (62.8%) and the maximum height of the left sinus in the over 50 age group (65.7%).ConclusionRegardless of age, according to our study the parameters of height, width, anterior-posterior diameter of sinuses and the maximum distance between the right and left maxillary sinuses are partially valuable for sex determination. The most accurate sex identification was examined in the 20–34 age group from studying the maximum distance between the sinuses. Especially in the over 50 age group, it is not enough to consider the sinus parameter for sex identification.     

Skeletal age assessment in children and young adults: comparison between a newly developed sonographic method and conventional methods

Objective. To compare the performance of a new sonographic (US) method of bone age estimation with other methods currently in use. Design and patients. One hundred and fifteen subjects underwent left hand/wrist radiography and US examination of the hip for bone age assessment. For each patient, measurements of skeletal age were available based on Greulich-Pyle and Tanner and Whitehouse, the latter being presented in three subtypes (RUS, carpals, and B20) in addition to the US values. To assess agreement between methods, each method was compared with every other method. Differences between calculated skeletal age and chronological age were assessed, and the sensitivity, specificity, and predictive values of each method computed. Results. Coupled B20/RUS values showed the best agreement, with 95% of observations within 2.45 years of each other, followed by carpals/B20, B20/GP, and GP/RUS. The US method agreed the least (difference of 4.19–5.13 years) with the other methods. The US method provided 85.8% (US vs RUS) to 91.3% (US vs GP) concordant results in recognizing differences between skeletal and chronological age, and showed a 72.5% sensitivity and a 56.8% specificity. Conclusion. Although the US method promises to permit a safe and cost-effective assessment of skeletal age, its low accuracy makes it currently unsuitable for clinical use.     

Dental age estimation in Malaysian adults based on volumetric analysis of pulp/tooth ratio using CBCT data

Forensic odontology plays an important role in human identification and dental age estimation is an integral part of this process. The aim of the study was to investigate the association between chronological age and pulp/tooth volume ratio in a Malaysian population (Malays and Chinese) from cone-beam computed tomography (CBCT) scans, enhanced with Mimics software. Three hundred CBCT scans of 153 males and 147 females, aged between 16 and 65 years were divided into 5 age groups. Volumetric analysis of the pulp/tooth ratio was performed in maxillary left canines, maxillary right canines and maxillary right central incisors. Simple linear regression and Pearson correlation analysis indicated the strongest coefficient of correlation (R) values for maxillary right central incisors (0.83) followed by maxillary right canines (0.74) and maxillary left canines (0.73). Fisher’s Z test indicated that dental age estimation is gender independent. The derived regression equations were further validated on an independent group of 126 teeth. The results indicated mean absolute error (MAE) values of 6.48 and 8.58 years for maxillary right central incisors and maxillary canines respectively. It was also noticed that MAE values were higher among the age groups ranging from 46 to 65 years. This study showed that a volumetric change in the pulp cavity with age is a valuable assessment method for dental age estimation among Malaysian population.     

Non-adult dental age assessment: correspondence analysis and linear regression versus Bayesian predictions

This study focuses on the evaluation of factors influencing the quality (accuracy and reliability) of non-adult dental age assessment from radiographic stages of permanent teeth (excluding the third molar). We used four distinct cross-sectional samples of 1,528 healthy children: 3 of known geographic origin (Ivory Coast, Iran and France) and 1 additional sample of children whose grandparents originated from a different continent. Two different methods of calculations are compared: the correspondence analysis combined with linear regression (CAR) and Bayesian predictions (with no independence assumption). Our results indicate that the quality of age assessment does not seem to depend predominantly on the use of geographic-specific standards. In the case of Bayesian predictions, we observed a clear trend in favour of significantly higher accuracy and reliability levels when using non-geographic-specific standards. One of the main advantage of Bayesian predictions over maximum likelihood methods of estimation is an overall increase in accuracy with high levels of reliability on a fraction of the test sample and, importantly, across all age categories (contrary to methods based on regression analysis). Importantly, in the case of Bayesian non-adult predictions, and contrary to age estimation techniques based on regression, a better quality does not depend on age.Funded by the French Ministry of Research (Action Concertée Incitative).     

Audit of a 5-year radiographic protocol for assessment of mandibular third molars before surgical intervention

Objectives:

To perform an audit of a three-step protocol for radiographic examination of mandibular third molars before surgery.

Methods:

1769 teeth underwent surgery. A standardized three-step radiographic protocol was followed: (1) panoramic imaging (PAN), (2) stereoscanography (SCAN) and (3) CBCT. If there was overprojection between the tooth and the canal in PAN, SCAN was performed. If the tooth was determined to be in close contact with the canal in SCAN, CBCT was performed. Close contact between the tooth and the canal was assessed in all images, and patient-reported sensory disturbances from the alveolar inferior nerve were recorded after surgery. The relation between the final radiographic examination and sensory disturbances was determined. Logistic regression analysis tested whether signs for a close contact in PAN/SCAN could predict no bony separation between the tooth and canal in CBCT.

Results:

46% of teeth underwent PAN, 31% underwent SCAN and 23% underwent CBCT as the final examination. 21% underwent all three radiographic examinations. 53/76% of teeth with close relation to the canal in PAN/SCAN showed no bony separation in CBCT; if there was close relation in PAN/SCAN, there was 1.6/4.3 times higher probability that no bony separation existed in CBCT. 16 cases of sensory disturbances were recorded: 4 operations were based on PAN, 8 on SCAN and 4 on CBCT.

Conclusions:

The radiographic protocol was in general followed. SCAN was superior to PAN in predicting no bony separation between the tooth and the canal in CBCT, and there was no relation between sensory disturbances and radiographic method.     

Automatic bone age assessment for young children from newborn to 7-year-old using carpal bones.

A computer-aided-diagnosis (CAD) method has been previously developed based on features extracted from phalangeal regions of interest (ROI) in a digital hand atlas, which can assess bone age of children from ages 7 to 18 accurately. Therefore, in order to assess the bone age of children in younger ages, the inclusion of carpal bones is necessary. However, due to various factors including the uncertain number of bones appearing, non-uniformity of soft tissue, low contrast between the bony structure and soft tissue, automatic segmentation and identification of carpal bone boundaries is an extremely challenging task. Past research works on carpal bone segmentation were performed utilizing dynamic thresholding. However, due to the limitation of the segmentation algorithm, carpal bones have not been taken into consideration in the bone age assessment procedure. In this paper, we developed and implemented a knowledge-based method for fully automatic carpal bone segmentation and morphological feature analysis. Fuzzy classification was then used to assess the bone age based on the selected features. This method has been successfully applied on all cases in which carpal bones have not overlapped. CAD results of total about 205 cases from the digital hand atlas were evaluated against subject chronological age as well as readings of two radiologists. It was found that the carpal ROI provides reliable information in determining the bone age for young children from newborn to 7-year-old.     

A third party assessment of work capabilities

The "Third Party Assessment of Work Capabilities" is a timely method for evaluating an individual's pre-hospitalization work behavior. It was developed by Griffiths in 1973 to monitor progress of hospitalized psychiatric patients on work therapy assignments. This survey form has been adapted to evaluate acute/short-term hospitalized soldiers and to assist in their rapid return to duty status. The "Third Party Assessment of Work Capabilities" worksheet, completed by the soldier's work supervisor, identifies five factors that summarize work behavior: task competence, response to authority and supervision, social relationship with others, work enthusiasm and motivation, and confidence and initiative. Once scored and results interpreted, an Occupational Therapy treatment can be implemented and early discharge planning with the soldier's unit initiated. A case study is presented for illustration.     

Magnetic resonance imaging of third molars in forensic age estimation: comparison of the Ghent and Graz protocols focusing on apical closure

International Journal of Legal Medicine - To compare the Ghent and Graz magnetic resonance imaging (MRI) protocols for third molars, focusing on the assessment of apical closure. To study the...