Third Molar Development Research Articles

Magnetic Resonance Images for the Prediction of Chronological Age Using Maxillary Third Molar Teeth: An Observational Study.

Dental age estimation using third molars is a reliable method for estimating the age of individuals. Recently, magnetic resonance imaging (MRI) of the head and neck has been found to be applicable for age estimation of third molar teeth. In the present study, we aimed to apply the Modified Demirjian method of age estimation to magnetic resonance (MR) image sections for dental age estimation by determining the mineralization patterns of the maxillary third molars. MRI scans of the patients were performed using SIGNA™ 3.0Tesla MRI GE Healthcare (Chicago, USA) with a moving, multifunctional coil. Two expert radiologists with more than three years of experience independently analyzed the image sections using the open-source Digital Imaging and Communications in Medicine (DICOM) viewer software. The age and sex of the patients whose images were included in the study were recorded using a specially designed proforma. The stage of development of the maxillary third molars was determined using the modified Demirjian method. Inter observer agreement was calculated using the intra class correlation coefficient. Simple linear regression analysis was used to predict the actual age at the third molar development stage. There was excellent agreement between observers (ICC =0.99 (95% CI = 0.98-0.99)). There was also a significant association between the maxillary third molar tooth development stage and chronological age of the individual (P=0.001; B=1.54; 95% CI = 0.71-2.37). The findings from the present study establish that the Modified Demirjian method can also be reliably applied for dental age assessment in MR sections.

Dental Age Assessment Based on Developmental Stages and Maturity Index of Third Molars for Medico-Legal Purposes.

As results may vary depending on the method of examination, this paper analyzes methods of age estimation based on the maturation index of third molars (I3M) and Kohler's developmental stages in living individuals. A total of 1475 orthopantomograms were analyzed. The results showed that the development of third molars tended to be more advanced in males than in females. Regression equations that included the value of the developmental stage of the left third molar most accurately predicted chronologic age in males and females. Using the I3M method, there were no statistically significant bilateral differences between the mandibular right and left third molars. Overall, 82.92% of males and only 72.82% of females were correctly classified with the cut-off value (0.08) for the left mandibular third molar index. In addition, 81.97% of individuals were correctly classified as minors and adults using the Kohler method, while only 78.62% of individuals were correctly classified as minors and adults using the I3M method. Based on the misclassification of minors as adults, both methods should be used with caution and overestimation of age should be considered, especially for those close to 18 years of age.

Third molar eruption in dental panoramic radiographs as a feature for forensic age assessment – new reference data from a German population

Forensic age assessment in the living can provide legal certainty when an individual’s chronological age is unknown or when age-related information is questionable. An established method involves assessing the eruption of mandibular third molars through dental panoramic radiographs (PAN). In age assessment procedures, the respective findings are compared to reference data. The objective of this study was to generate new reference data in line with the required standards for mandibular third molar eruption within a German population. For this purpose, 605 PANs from 302 females and 303 males aged 15.04 to 25.99 years were examined. The PANs were acquired between 2013 and 2020, and the development of the mandibular third molars was rated independently by two experienced examiners using the Olze et al. staging scale from 2012. In case of disagreement in the assigned ratings, a consensus was reached through arbitration. While the mean, median and minimum ages were observed to increase with each stage of mandibular third molar eruption according to the Olze method, there was considerable overlap in the distribution of age between the stages. The minimum age for stage D, which corresponds to complete tooth eruption, was 16.1 years for females and 17.1 years for males. Thus, the completion of mandibular third molar eruption was found in both sexes before reaching the age of 18. In all individuals who had at least one tooth with completed eruption and who were younger than 17.4 years of age (n = 10), mineralization of the teeth in question was not complete. Based on our findings, the feature of assessing mandibular third molar eruption in PAN cannot be relied upon for determining age of majority.

Age estimation using the Demirjian method in third molars on cone beam computed tomography images

The study aimed to estimate the chronologic age of individuals and whether they were aged under or over 18 years by using the Demirjian method on cone beam computed tomography (CBCT) images. The developmental stages of the third molars in the maxilla and mandible of 445 individuals aged between 9 and 26 years were evaluated as eight stages from A to H according to the Demirjian method. The association of these eight stages with chronologic age according to the age of 18 years, which is accepted as the threshold value, and the distribution of the stages was statistically analyzed. There was no significant difference in the mean age at which developmental stages (A–H) were seen between the sexes (p > .05). Stage A was observed up to the age of 15 years in females and 14 years in males, and stage H was observed at the age of 16 at the earliest in both sexes. Stages A and B were not seen in individuals aged 18 years and over. The age of individuals and whether they are below or above 18 years can be estimated by evaluating the development of third molars according to the Demirjian method.

Effect of impaction on third molar development and age estimation – A study in a female black South African population

The impact of impaction on the development of third molars remains a subject of debate within the scientific literature, given the lack of consensus. Simultaneously, there has been a call for dental age estimation studies to consider population-specific factors. This research was conducted with the objective of examining the influence of impaction on the formation of third molars in a cohort of female individuals of black South African descent. The study population comprised 428 panoramic radiographs, focusing on females within the age range of 15 to 23.9 years. Within this sample, mandibular third molars were categorized based on their positioning into two groups: non-impacted and impacted. Dental development stages were assessed and classified according to Demirjian’s 8-level staging system. Descriptive statistics were performed. The outcomes of the independent t-test revealed statistically significant differences in developmental stages, specifically stage G for tooth #38 and stage F for tooth #48, suggesting that impaction had an impact on dental development, albeit not consistently across all developmental stages. Nonetheless, it's noteworthy that the minimum and mean ages across all developmental stages were higher among impacted teeth. In summary, our findings support the conclusion that mineralization of impacted mandibular third molars in South African female subjects proceeds at a slower pace compared to their non-impacted counterparts. Consequently, when estimating dental age in the context of South African females, it is advisable to prioritize non-impacted third molars whenever feasible.

Applying artificial intelligence to determination of legal age of majority from radiographic data

Forensic odontologists use biological patterns to estimate chronological age for the judicial system. The age of majority is a legally significant period with a limited set of reliable oral landmarks. Currently, experts rely on the questionable development of third molars to assess whether litigants can be prosecuted as legal adults. Identification of new and novel patterns may illuminate features more dependably indicative of chronological age, which have, until now, remained unseen. Unfortunately, biased perceptions and limited cognitive capacity compromise the ability of researchers to notice new patterns. The present study demonstrates how artificial intelligence can break through identification barriers and generate new estimation modalities. A convolutional neural network was trained with 4003 panoramic-radiographs to sort subjects into 'under-18' and 'over-18' age categories. The resultant architecture identified legal adults with a high predictive accuracy equally balanced between precision, specificity and recall. Moving forward, AI-based methods could improve courtroom efficiency, stand as automated assessment methods and contribute to our understanding of biological ageing.

Using machine learning to determine age over 16 based on development of third molar and periodontal ligament of second molar

BackgroundHaving a reliable and feasible method to estimate whether an individual has reached 16 years of age would greatly benefit forensic analysis. The study of age using dental information has matured recently. In addition, machine learning (ML) is gradually being applied for dental age estimation.AimThe purpose of this study was to evaluate the development of the third molar using the Demirjian method (Demirjian3M), measure the development index of the third molar (I3M) using the method by Cameriere, and assess the periodontal ligament development of the second molar (PL2M). This study aimed to predict whether Chinese adolescents have reached the age of criminal responsibility (16 years) by combining the above measurements with ML techniques.Subjects & methodsA total of 665 Chinese adolescents aged between 12 and 20 years were recruited for this study. The development of the second and third molars was evaluated by taking orthopantomographs. ML algorithms, including random forests (RF), decision trees (DT), support vector machines (SVM), K-nearest neighbours (KNN), Bernoulli Naive Bayes (BNB), and logistic regression (LR), were used for training and testing to determine the dental age. This is the first study to combine ML with an evaluation of periodontal ligament and tooth development to predict whether individuals are over 16 years of age.Results and conclusionsThe study showed that SVM had the highest Bayesian posterior probability at 0.917 and a Youden index of 0.752. This finding provides an important reference for forensic identification, and the combination of traditional methods and ML is expected to improve the accuracy of age determination for this population, which is of substantial significance for criminal litigation.

Comparative Evaluation of Development of Mandibular Second and Third Molars for the Assessment of Skeletal Maturity

Comparative Evaluation of Development of Mandibular Second and Third Molars for the Assessment of Skeletal Maturity

Assessment of the Relation Between Patterns of Third-Molar Impaction and Blood Group: A Retrospective Study.

Background The prevalence of impacted third molars is high in the global general population. The etiology of impacted third molars is not fully understood, but it is thought to result from combined genetic and environmental factors. Some studies have suggesteda link between the blood group and the risk of impacted third molars. This study aimed to investigate the association between the blood group and the presence of impacted third molars and its pattern. Method A total of 856 panoramic radiographs were included in the study. Thethird molars were evaluated for the pattern of third-molar impaction and blood characteristics recorded as ABO group and presence or absence of Rhesus antigen. Results The results showed no significant association between the blood group and the presence of impacted third molars. The prevalence of at least one impacted the third molar was 34.6%. The most common angulation of impacted third molars was vertical (V) (45.1%), followed by mesioangular (MA) (33.7%), distoangular (DA) (13.8%), and horizontal (H) (7.4%). There was no significant association between the blood group and the number of impacted third molars nor between the blood group and the angulation of the impacted third molars. Conclusion This study suggests that the blood group is not a major factor in the development of impacted third molars. However, further studies with larger sample sizes are needed to confirm these findings.

Correlation Between Third Molar Mineralization and Midpalatal Suture Maturity: A Cone Beam Computed Tomography Study.

BACKGROUND Midpalatal suture ossification varies in patients of different ages, which can lead to making inaccurate presumptions when considering effective treatment timing based on chronological age. Chronological age provides only general information, whereas dental development correlates with skeletal growth, which suggests that tooth mineralization could be considered to be a precise criterion for determining the midpalatal suture's maturity. The present study was conducted to investigate the association between third-molar mineralization and midpalatal suture's maturation stages using cone-beam computed tomography (CBCT) images. MATERIAL AND METHODS The study involved 97 CBCT images of patients aged 8-37 years with normal growth and development. Subjects with cleft lip and palate, caries treatment, or present cavities in the third molars were not included in the study. The stages of midpalatal suture ossification were evaluated according to the protocol suggested by Angelieri et al, and the third-molar mineralization degree was measured by the Demirjian index. Statistical analysis was performed to evaluate correlations between the variables. RESULTS Patients with advanced third-molar mineralization stages were found to have greater midpalatal suture maturity. A statistically significant positive correlation was found between the stages of third-molar mineralization and midpalatal suture maturation (R=0.814, P<0.01). Third-molar development was also found to be associated with chronological age (R=0.883, P<0.01). CONCLUSIONS A measure of third-molar mineralization does not allow for accurate determination of the midpalatal suture maturation stage.

Correlation of chronological age with dental age estimated using modified Cameriere’s method and UT-age estimation software — a cross-sectional study

BackgroundEstimating age is essential in both the analysis of human skeletal remains and assessing live persons. The third molar develops over a longer period and is hence used in age estimation for subadults. Since dental age correlates with chronological age better than other growth markers, this study aims to assess the reliability of dental age assessed using the University of Texas (UT) age estimation method and modified Cameriere’s method.MethodsIt is a retrospective cross-sectional study in which the development and maturation of mandibular third molars were examined in 600 orthopantomograms (264 males and 336 females) of South Indian individuals (16–23 years). Dental age was estimated by using an Indian-specific formula based on maturity index value and the UT-age estimation software program. The results were evaluated using the Student’s t-test for both methods and Pearson’s correlation test to compare chronological age with estimated dental age.ResultsPositive correlation was noted between chronological age and estimated dental age for males, females, and the total sample with highly statistically significant differences (p = 0.000). Modified Cameriere’s method underestimated dental age in samples ranging from less than 1 year to more than 2 years. UT-age estimation method underestimated age in samples above 20 years and overestimated age in samples below 20 years. The predictive classification of utilizing the maturity index was 79.17% accurate.ConclusionsDental age was negligibly over and underestimated in UT software method whereas it was overestimated in the modified Cameriere's method. To evaluate the reliability of these two methods, studies with larger sample sizes and population-specific data sets should be performed.Graphical

Age estimation using development of third molars in 14-24 years age group: A radiological study

Age estimation using development of third molars in 14-24 years age group: A radiological study

Determination of age reference standards based on mandibular third molar root development in a Ugandan population aged 10–22 years

BackgroundThis study was aimed at establishing age estimates based on distal root development of the mandibular third molar for Ugandans aged 10–22 years. This was a cross-sectional study using orthopantomograms (OPGs) of 671 patients attending the Mulago Hospital Dental Clinic. The patients’ chronological age and sex were obtained from either their national identity cards or birth certificates (females; n = 326, 48.6%). Third molar root development was assessed using Demirjian, Goldstein, and Tanner (DGT), modified Demirjian by Solari, Moorrees, Fanning, and Hunt (MFH), and Haavikko methods. Age was summarized using means/standard deviation (SD), medians, and lower and upper quartiles. Sex differences were assessed using Student’s t-test.ResultsCrown completion (stage D) and root initiation (stage Ri) were observed at 12.6 years for females and 13.5 years for males (P = 0.02), while complete apex closure occurred at 19.8 for females and 20.1 for males (P = 0.3). There were statistically significant differences in Demirjian root stages E, F, and G and MFH and Haavikko stages Ri, R1/4, and R1/2 between the sexes (P < 0.05). The difference in the mean age of root development between females and males ranged between 0.9 year at DGT/MFH root stages D and Ri (13.5–12.6) and 1.4 years at Solari, MFH, and Haavikko root stages F, R1/4, and R1/2 (16.3–14.9, 17.1–15.7). No differences were observed between the right and left mandibular molars.ConclusionsThis study provides age reference standards based on third molar root development specific to the Ugandan adolescent and young adult population. The findings can be used to formulate contemporary standards and utilized as reference material to assess third molar maturity for forensic purposes.

Fully automated method for dental age estimation using the ACF detector and deep learning

BackgroundDental age estimation plays an important role in identifying an unknown person. In forensic science, estimating age with high accuracy depends on the experience of the practitioner. Previous studies proposed classification of tooth development of the mandibular third molar by following Demirjian’s method, which is useful for dental age estimation. Although stage of tooth growth is very helpful in assessing age estimation, it must be performed manually. The drawback of this procedure is its need for skilled observers to carry out the tasks precisely and reproducibly because it is quite detailed. Therefore, this research aimed to apply computer-aid methods for reducing time and subjectivity in dental age estimation by using dental panoramic images based on Demirjian’s method. Dental panoramic images were collected from persons aged 15 to 23 years old. In accordance with Demirjian’s method, this study focused only on stages D to H of tooth development, which were discovered in the 15- to 23-year age range. The aggregate channel features detector was applied automatically to localize and crop only the lower left mandibular third molar in panoramic images. Then, the convolutional neural network model was applied to classify cropped images into D to H stages. Finally, the classified stages were used to estimate dental age.ResultsExperimental results showed that the proposed method in this study can localize the lower left mandibular third molar automatically with 99.5% accuracy, and training in the convolutional neural network model can achieve 83.25% classification accuracy using the transfer learning strategy with the Resnet50 network.ConclusionIn this work, the aggregate channel features detector and convolutional neural network model were applied to localize a specific tooth in a panoramic image and identify the developmental stages automatically in order to estimate the age of the subjects. The proposed method can be applied in clinical practice as a tool that helps clinicians to reduce the time and subjectivity for dental age estimation.

Türk Toplumunda 5-15 Yaş Grubu Çocuklarında Üçüncü Molar Dişlerin Gelişimlerinin Radyografik Olarak Değerlendirilmesi

Objective: In this study, it was aimed to determine the age of the onset of crown calcification of third molars in children aged 5-15 years in Turkey, and to evaluate the development status of third molars by age.Material and Methods: Panoramic radiographs of the first 1024 patients between the ages of 5 and 15 years were evaluated. The development (calcification) of third molars was classified according to the Demirjian method.Results: When the onset age of the stages for maxillary and mandibular third molars were compared, no statistically significant difference was found (p≥0.05). In addition, although no statistically significant difference was found between genders regarding the age of calcification onset of third molars, it was observed that teeth #28 and #48 developed in boys approximately one year before girls (p≥0.05). When the onset age of the stages for maxillary and mandibular third molars were compared, no statistically significant difference was found (p≥0.05). Concerning stage 5, in which the furcation zone of third molars begins to calcify, although not statistically significant, all the maxillary and mandibular third molars were seen earlier in girls than boys.Conclusion: It was found that the maxillary third molars on the right side developed earlier than mandibular third molars.

Is there any difference in the development of mandibular third molars according to the type of impaction: An orthopantomographic study in south Indian children and adolescents

Development of third molars and their influence on the dental arch is a major concern in clinical dentistry especially, orthodontics and oral surgery. Lately, their position, eruption potential and development has become a subject of interest in forensic practice. The present study was aimed to determine whether if there is any difference in the development of the mandibular third molars according to the impaction type. Orthopantomographs (n = 1112) from 478 males and 634 females between 15 and 22 years old were analysed. In each radiograph, impaction status and the developmental stage of mandibular third molars were determined. Descriptive statistics were performed at developmental stages D to H. For stage G, there was a delay by 0.74 and 0.62 years for mesioangular impaction, 0.89 and 0.33 years for horizontal impaction, 1.43 and 0.9 years for distoangular impaction and 1.74 and 1.1 years for vertical impaction, in males and females. For stage H, delay by 0.17 and 0.74 years, 0.05 and 0.06 years, 0.48 and 1.48 years and 0.62 and 0.62 years, respectively for all impaction variants in both sexes. Mean chronological age of the distoangular and vertically impacted mandibular third molars were higher in certain developmental stages than mesioangular and horizontal impactions. Our findings concluded that distoangular and vertical impaction variants mineralize more slowly than mesioangular and horizontal variants, however these differences were smaller. Therefore, no distinction is required between impaction types for dental age estimation especially in the prediction of the age of majority (18 years).

Correlation of Left Mandibular Third Molar Development and Chronological Age

The aim of this study is to evaluate the development of the left mandibular third-molar development with modified Demirjian method and its relation to chronological age. A total of 1653 digital panoramic radiographs of healthy individuals aged between 7 and 23 years who visited Yonsei University Dental hospital were selected. The developmental status of the left mandibular third molars was assessed using dental maturity scoring proposed by Demirjian et al. The mean age of the first appearance of mineralization, complete crown formation, and complete root formation were around 9, 14, 21 years respectively. Statistically significant differences between males and females in the development stage of D and G were revealed that crown formation and root length completion were attained earlier in males than in females. There was significant positive relationship between age and third molar development in both sexes, and new formula was presented to estimate age of children and adolescents based on their developmental stages of third molars. In this study, the use of left mandibular third molar as a developmental marker is appropriate, and age estimation can be attained with dental maturity stage.

The use of dental radiographs for age estimation of unaccompanied migrant minors: Scientific and ethical concerns.

Unaccompanied migrant minors are increasingly seeking asylum status in the United States (U.S.) where guidelines for age assessment call for the use of multiple forms of evidence. A commonly used approach in the U.S. is dental radiographs to assess the root development of third molars. Not only has research shown this methodology to be unreliable and imprecise, but the evidence has shown significant variability in dental development by chronologic age, race/ethnicity, sex, socioeconomic status, systemic disease, nutritional health, and other environmental factors. Misclassification of minors as adults based upon the imprecise tool of dental age assessment can have serious and harmful consequences. In the U.S., this misclassification has resulted in the housing of minors with adults in Immigrant and Custom Enforcement (ICE) operated jails. In addition, there are significant ethical concerns with regard to the use of radiographs for purposes that are neither diagnostic nor therapeutic and the lack of informed consent. In this commentary we review the (1) inadequacy of dental radiographs as a means of chronologic age assessment for minors, and (2) the ethical implications of implementing this flawed and inappropriate assessment on a highly vulnerable population.

Age estimation from developing third molars.

We investigated the development of third molars among Malaysians (including variations between jaws and genders) using Demirjian's method. Dental panoramic radiographs of 1224 subjects aged 8 to 24 years were examined, and the molars were assigned Demirjian et al.'s development grades (A-H). Results indicated that 18.8% had congenitally missing or extracted third molars. Development of molars begins earlier in females (also in the mandible), but by age 9, male children's molar development speeds up with more advanced grades in their middle teens than females. Grade C indicates the subject is a juvenile, while initiation of root development (Grade E), was observed from 13 years on. Grade H can occur in a child aged 18 years who technically is still a juvenile. We compared the development and growth patterns of the third molar from both the maxilla and the mandible.

Legal age determined by a new threshold value of third molar maturity index in subjects with impacted mandibular third molars: An orthopantomographic study in south Indian adolescents.

Third molars are one of the few biological markers available for age estimation in juveniles, especially for the estimation of the 18-year-age threshold. Literature has indicated that impaction has an influence on the development of third molars, which could possibly result in age misclassifications. The present study is intended to identify an alternative cut-off value of the third molar maturity index (I3M) in impacted mandibular third molars and also to evaluate its applicability in estimating the major (≥ 18years)/minor (< 18years) status. A total of 1330 digital orthopantomograms (OPGs) of 665 male and 665 female south Indian adolescents aged from 15 to 22years were collected and assessed. Eight hundred forty OPGs (63.1%) represented test sample, and 490 OPGs (36.9%) represented validation sample. I3M was measured for the total sample. Logistic regression, receiver operating characteristic (ROC) curve analysis, and Youden's index were used to test the performance of the method in the test sample. An alternative cut-off value of I3M < 0.17 was established for the highest value of the Youden's index of 0.598 for both sexes. When tested in validation sample, it has resulted in sensitivity and specificity values of 0.91 (95% CI; 0.86-0.95) and 0.90 (95% CI; 0.78-0.91) in males and 0.86 (95% CI; 0.80-0.92) and 0.90 (95% CI; 0.83-0.95) in females. In conclusion, cut-off value of I3M < 0.17 could accurately discriminate adults from minors with impacted mandibular third molars. However, more work is needed to be done among a more diverse sample to confirm these findings.