Validity of demirjian and nolla methods for dental age estimation for Northeastern Turkish children aged 5-16 years old

Comparison of the accuracy and bias of Demirjian's method for East Asian children and development of Japanese population-specific age estimation formulae

Despite the increased global mobility owing to the development of the international community, there remains a need for population-specific methods to estimate children's ages. Therefore, this study aimed to substantiate the necessity for a Japanese-specific age estimation method by contrasting the formerly reported age estimation accuracy and bias using Demirjian's method for Chinese, Taiwanese, South Korean, and Japanese children. We analyzed 1,558 panoramic radiographs from Japanese children (777 boys and 781 girls), assessed the maturity of seven left permanent teeth using Demirjian's criteria, and calculated the estimated age using Demirjian's method. The accuracy of the estimated ages was compared with previous reports of children from other East Asian countries which used the same age estimation method. Chinese, Taiwanese, and South Korean boys and girls were all reported to be older than their chronological ages, with the Eastern and Northern Chinese regions being the only exceptions. The same was true for Japanese children: the estimated ages of both sexes tended to be higher than their chronological age. However, there were significant variations in the values, indicating the differences in tooth growth and development between East Asian countries and sexes. Therefore, new regression equations specific to the Japanese population were formulated, and their accuracy was evaluated as the final result of this study.

Radiological Evaluation of the Accuracy of Demirjian, Nolla, and Willems Methods for Dental Age Estimation in 3-17-Year-Old Iranian Children

Background: The stage of tooth formation is one of the most reliable indicators for predicting a patient's developmental age by radiographs. This study compared the accuracy of three distinct dental age estimation methods (Demirjian, Nolla, and Willems) in children aged 3-17 in the northern Iranian population. Methods: This cross-sectional study examined panoramic radiographs of 434 children aged 3-17 from Mazandaran Province, Iran, who had teeth 31-37 present on the left mandible. This study employed the Demirjian, Nolla, and Willems methods to estimate the dental age of the sample and compare it with the chronological age. The data were analyzed using SPSS v16. A paired t-test was used to compare chronological and dental ages. The Pearson correlation was used to correlate the chronological and dental ages. The errors of different methods were compared using the Wilcoxon test. P values < 0.05 were considered significant for all tests except Wilcoxon. For Wilcoxon, a P value < 0.017 was considered significant. Results: The three methods presented differing mean estimated ages. The Demirjian method delivered the highest mean, and all three methods differed significantly when compared in pairs. The results showed that the Demirjian method overestimated chronological age by 0.25 years (P < 0.001) in girls and 0.09 years (P = 0.28) in boys. The Willems method underestimated chronological age by 0.05 years (P = 0.47) in girls and 0.12 years (P = 0.13) in boys. The Nolla method underestimated chronological age by 0.41 years (P < 0.001) in girls and 0.40 years (P < 0.001) in boys. The accuracy of each method varied with the patient's age. Conclusion: According to the findings, the Willems method outperformed the Demirjian method, and the Demirjian method exceeded the Nolla method for estimating dental age in Iranian children aged 3-17. Overall, the Demirjian method overestimated the age of the study population, whereas the other two underestimated it.

Predicting chronological age of 14 or 18 in adolescents: integrating dental assessments with machine learning

AIM

Age estimation plays a critical role in personal identification, especially when determining compliance with the age of consent for adolescents. The age of consent refers to the minimum age at which an individual is legally considered capable of providing informed consent for sexual activities. The purpose of this study is to determine whether adolescents meet the age of 14 or 18 by using dental development combined with machine learning.

METHODS

This study combines dental assessment and machine learning techniques to predict whether adolescents have reached the consent age of 14 or 18. Factors such as the staging of the third molar, the third molar index, and the visibility of the periodontal ligament of the second molar are evaluated.

RESULTS

Differences in performance metrics indicate that the posterior probabilities achieved by machine learning exceed 93% for the age of 14 and slightly lower for the age of 18.

CONCLUSION

This study provides valuable insights for forensic identification for adolescents in personal identification, emphasizing the potential to improve the accuracy of age determination within this population by combining traditional methods with machine learning. It underscores the importance of protecting and respecting the dignity of all individuals involved.

Validity of nolla's method for age estimation for children in Kurdish Iraqi population - A retrospective study

Context

Radiographs have an essential role in Chronological Age (CA) estimation and are being used for dental age (DA) determination.

Aims

Detecting the validity of Nolla's method (NM) for the age assessment of Kurdish Iraqi children (KIC).

Methods and Material

A retrospective study was performed using orthopantomographs (OPGs) of 354 subjects aged from 4 to 13 years (178 boys and 176 girls) and their recording files. Subjects were divided into nine study groups: 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 years old. The chronological age (CA) was subtracted from the DA to find the validity of NM; the positive results indicated the overestimation of age, whereas the negative results indicated for underestimation. The data were recorded through a digitalised system using Microsoft Excel worksheet and analysed by Statistical Package for the Social Sciences (SPSS, version 25) programme using the dependent T-test and graphical analysis. The level of P value used in this study was set at < 0.05. Results: The DA is underestimated in ages 9 to 13 in boys and girls. The highest difference in DA-CA was at the age of 9 years (-0.146 ± 0.162).

Conclusions

NM for age estimation was slightly overestimated in age groups of 4, 5, 6, 7, and 8 years in boys and girls without statistically significant differences. However, this method underestimated the ages of KIC ranging from 9 to 13 years significantly.

Validity of age estimation methods and reproducibility of bone/dental maturity indices for chronological age estimation: a systematic review and meta-analysis of validation studies

Several approaches have been developed to estimate age, an important aspect of forensics and orthodontics, using different measures and radiological examinations. Here, through meta-analysis, we determined the validity of age estimation methods and reproducibility of bone/dental maturity indices used for age estimation. The PubMed and Google Scholar databases were searched to December 31, 2021 for human cross-sectional studies meeting pre-defined PICOS criteria that simultaneously assessed the reproducibility and validity. Meta-estimates of validity (mean error: estimated age-chronological age) and intra- and inter-observer reproducibility (Cohen's kappa, intraclass correlation coefficient) and their predictive intervals (PI) were calculated using mixed-effect models when heterogeneity was high (I2 > 50%). The literature search identified 433 studies, and 23 met the inclusion criteria. The mean error meta-estimate (mixed effects model) was 0.08 years (95% CI - 0.12; 0.29) in males and 0.09 (95% CI - 0.12; 0.30) in females. The PI of each method spanned zero; of nine reported estimation methods, Cameriere's had the smallest (- 0.82; 0.47) and Haavikko's the largest (- 7.24; 4.57) PI. The reproducibility meta-estimate (fixed effects model) was 0.98 (95% CI 0.97; 1.00) for intra- and 0.99 (95% CI 0.98; 1.00) for inter-observer agreement. All methods were valid but with different levels of precision. The intra- and inter-observer reproducibility was high and homogeneous across studies.

Dental age estimation with two different methods in paediatric patients with hypothyroidism

OBJECTIVE

This case-control study aimed to evaluate dental age estimation in children with hypothyroidism using two different methods in order to contribute to the literature about the most accurate method.

DESIGN

In the study, panoramic radiographs of 80 patients with hypothyroidism aged 5-13 years and 80 randomly selected age and sex-matched healthy patients were examined retrospectively. The Cameriere's and the Nolla's methods were used for the dental age estimation. Dental ages and their differences with chronological ages were compared according to group and sex.

RESULTS

No statistically significant difference in estimated dental age was found between the hypothyroidism and control groups using both methods (p > 0.05). Among all the males and females included in this study, the dental ages of the females calculated by Nolla's method were significantly lower than those of the males according to the chronological ages (p < 0.05). For females, in both the hypothyroidism (p < 0.001) and control (p = 0.001) groups, the dental age estimated by Cameriere's method was significantly closer to the chronological age compared to Nolla's method, although there was no statistically significant difference for males.

CONCLUSION

Although the dental age of children with hypothyroidism showed similar results to that of healthy children, it is concluded that Cameriere's method led to more accurate results than Nolla's method in females for both healthy patients and patients with hypothyroidism.

Applicability of Willems method for age estimation in Brazilian children: performance of multiple linear regression and artificial neural network

Background

Dental age estimation of children may be necessary in the clinical and forensic fields. In the former, it may contribute to the investigation of dental development and biological maturation. In the latter, dental age estimation may support the Court in several circumstances, such as adoption and unidentified bodies of deceased children. This study aimed to apply Willems method for dental age estimation of children from Southeastern Brazil. The second aim of the study was to test the performance of the method modeled with multiple linear regression (MLR) and artificial neural network (ANN). The sample consisted of 1000 panoramic radiographs of female (n = 500) and male (n = 500) Brazilian children. The individuals were evenly distributed through ten age intervals of 1 year from 6 to 15.99 years. Dental development was classified with the 7-teeth technique of Demirjian et al. (1973), followed by age calculation with Willems method (2001). The difference between chronological and estimated ages was quantified for the original Willems model and for the MLR and ANN models.

Results

For females and males, the overall difference found with Willems original model was 0.27 and 0.28, respectively. With MLR and ANN, the overall differences were 0.54 and 0.35, and 0.26 and 0.24, respectively. The ANN was able to reduce half of the mean error of female age predictions up to 100%. The same phenomenon occurred in 1/3 of the males. Despite the improvements of the ANN model to specific age groups, the original Willems model performed similar or better in 40% of the studied age intervals. All the models showed the worse age predictions in the interval between 15 and 15.99 years (p < 0.001).

Conclusions

Willems method remains optimal and applicable after 20 years since original development. The ANN model might be an option for future improvements (depending on sex and age interval).

Dental age estimation of Tibetan children and adolescents: Comparison of Demirjian, Willems methods and a newly modified Demirjian method

Tibetan ethnic group is one of the oldest ethnic groups in China and South Asia. This study set out to analyze the dental development and validate Demirjian method and Willems method in estimating dental age of Tibetan children and adolescents, and to modify Demirjian method based on Tibetan population to provide ethnic-specific reference data and a more reliable method for forensic age assessment in Tibetan ethnic group. In this study, 1951 samples aged between 4 and 15 years were retrospectively collected and analyzed. Multiple linear regression was used to establish relationship between chronological age (CA) and developmental stages of left mandibular permanent teeth. The accuracy of the modified method was tested and compared with that of Demirjian and Willems method. Results showed that dental maturity score (DMS) was significantly greater in girls than in boys in all age groups except for the 4-year age group (p < 0.05). Mean absolute error (MAE) was 0.96 years for both boys and girls by Demirjian method, and 1.06 and 1.16 years for boys and girls respectively by Willems method. Adjusted scores table was established and tested. The age of boys was overestimated by 0.13 years and the age of girls was underestimated by 0.06 years by the adjusted scores table. MAE was lower than that of the other two methods. In conclusion, Demirjian method and Willems method was not sufficiently accurate in estimating dental age of Tibetan population. The modified method was more suitable for dental age estimation of Tibetan population than Demirjian and Willems method.

Accuracy of the London atlas, Willems, and Nolla methods for dental age estimation: a cross-sectional study on Eastern Turkish children

OBJECTIVES

This study aimed to estimate the dental age (DA) using the London Atlas, Willems, and Nolla methods and to compare their accuracies.

METHODS

The DA was estimated using the aforementioned methods on panoramic radiograms of a total of 919 Eastern Turkish patients aged 6-14 years, of whom 459 were female and 460 were male. The overestimation and underestimation values were determined in relation to the chronological age (CA) values. The paired t test was used to compare the mean DA and CA values. Multiple regression analysis was used to derive gender-specific formulations for the three methods.

RESULTS

The most accurate method for estimating the DA was the Willems method (mean prediction error 0.80), followed by the London Atlas (mean prediction error 0.83) and Nolla (mean prediction error 0.89) methods. Statistically significant differences were found only between the Willems and Nolla methods.

CONCLUSION

All three methods can be used for DA estimations of Eastern Turkish children.

CLINICAL RELEVANCE

Willems was the most suitable method for this patient sample. However, the London Atlas method may be preferred due to its practicability and comparable accuracy.

Accuracy of the Demirjian, Willems and Nolla methods for dental age estimation in a northern Chinese population

OBJECTIVE

The objective of the present study was to evaluate the accuracy of the Demirjian, Willems, and Nolla methods for dental age estimation on a sample of the northern Chinese population.

DESIGN

The study consisted of 2000 panoramic radiographs (1000 boys and 1000 girls) with an age range between 5 and 14 years. The mean error and absolute mean error were calculated according to each method, and the accuracy was statistically analysed.

RESULTS

The three methods used for Chinese subjects overestimated the dental age by 1.16, 0.50, and 0.07 years. The absolute mean error was largest in most age groups for the Demirjian method, which was considered inaccurate in age estimation for teenagers, and it was more than 1.00 years for only several age groups for the Willems method and only girls aged 14 years for the Nolla method. The mean error and absolute mean error were lowest for the Nolla method and highest for the Demirjian method.

CONCLUSIONS

Although the Demirjian method is frequently used in Chinese subjects for legal and medical purposes, the Willems and Nolla methods were more reliable than the Demirjian method. Among the three methods, the accuracy in the northern Chinese subjects was highest for the Nolla method. Therefore, it is recommended to evaluate the accuracy of different methods before assessing the age in specific populations.

Accuracy assessment of dental age estimation with the Willems, Demirjian and Nolla methods in Spanish children: Comparative cross-sectional study

Background

The objective of this study was to evaluate and compare the validity and accuracy of the Willems, Demirjian and Nolla methods in predicting chronological age in a Spanish ethnicity population.

Methods

A sample of 604 orthopantomographs of Spanish children aged 4 to 13 years was evaluated by two independent evaluators. Descriptive statistics were applied to calculate the chronological age and dental age, presenting the mean and standard deviation. The difference between dental age and chronological age was calculated for each method. A positive result indicated an overestimation and a negative figure indicated an underestimation. The Wilcoxon test for paired data and Spearman’s correlation coefficient were applied by age groups and sex to compare the chronological age and dental age of each method (that of Willems, Demirjian and Nolla). Statistical tests were performed at a 95% confidence level.

Results

The interexaminer agreement was 0.98 (p = 0.00), and the intraexaminer agreement was 0.99 (p = 0.00). The Willems method significantly overestimated the age of boys (0.35 years (0.93)) and girls (0.17 years (0.88)). The Demirjian method significantly overestimated the age of boys (0.68 years (0.95)) and girls (0.73 years (0.94)). The Nolla method significantly underestimated age in boys (0.44 years (0.93)) and girls (0.82 years (0.98)).

Conclusions

In the Spanish population, the use of the Demirjian method for legal and medical purposes is frequent. This study reveals that the Willems method is more appropriate due to its greater precision in estimating dental age.

Comparative assessment of chronological, dental, and skeletal age in children

Background

Age of a child can be assessed from various parameters such as chronological age, height, weight, secondary sexual characteristics, skeletal age, or dental age. The present study was planned to assess and compare chronological age with dental age (Demirjian's method and Willem's method) and skeletal age (Fishman's method).

Materials and Methods

The present study was done on a sample of 100 children in the age group of 9-14 years. The chronological age was computed through the birth certificates and dental age was calculated from their orthopantomograms (OPGs) using Demirjian's and Willem's methods. Hand-wrist radiograph of the left hand was used to compute skeletal age using Fishman's method. Paired t-test and Pearson's correlation coefficients were calculated as a part of statistical analysis at a significance level of P < 0.01.

Results

The mean chronological age among the group was 12.37 ± 1.34 years, the mean dental age by Demirjian's method was 12.36 ± 1.72 years, the mean dental age by Willem's method was 12.36 ± 1.51, and the mean skeletal age by Fishman's method was 13.03 ± 1.34 years. Out of the all methods evaluated in the study, Fishman's method of age estimation showed the least value of correlation coefficient (r = 0.728) with the chronological age, whereas Willem's method showed the maximum correlation with the chronological age (r = 0.885).

Conclusion

It can be concluded from the present study that the dental age estimation evaluated by the digital OPG by both the methods, that is, Demirjian's method and Willem's method, has shown high accuracy when applied to the children of Faridabad. Skeletal maturation evaluated by Fishman's method using hand-wrist radiographs was found to overestimate the age when compared to chronological age in both the sexes.

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.

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

Age estimation is an important procedure in forensic medicine and is carried out for a number of reasons. For living persons, age estimation is performed in order to assess whether a child has attained the age of criminal responsibility, in scenarios involving rape, kidnapping or marriage, in premature births, adoption procedures, illegal immigration, pediatric endocrine diseases and orthodontic malocclusion, as well as in circumstances in which the birth certificate is not available or the records are suspect. According to data from the UNHCR (United Nations High Commissioner for Refugees), the number of people seeking refugee status continued to increase in the last years, driven by the wars in Syria and Iraq, as well as by conflict and instability in Afghanistan, Eritrea and elsewhere. The objective of this study is to compare the accuracy of estimating dental age versus chronological age using the Nolla and Demirjian methods in a Spanish population. A final sample of 2641 panoramic X-rays corresponding to Spanish patients (1322 males and 1319 females) between 7-21 years of age was analyzed. Dental age was assessed using the Nolla and Demirjian methods, establishing comparisons with mean chronological age based on the Student t-test for paired samples, followed by the generation of a linear regression model. Both methods showed slight discrepancy between dental and chronological age. On examining the reproducibility of the Nolla and Demirjian methods, technical errors of 0.84% and 0.62%, respectively, were observed. On average, the Nolla method was found to estimate an age 0.213years younger than the chronological age, while the Demirjian method estimated an age 0.853years older than the chronological age. Linear combination of the mean Nolla and Demirjian estimates increased the predictive capacity to 99.2%. In conclusion the Nolla and Demirjian methods were found to be accurate in estimating chronological age from dental age in a Spanish population. The error was found to be greater in males than in females, and involved an over-estimation of age with the Demirjian method and under-estimation of age with the Nolla method. Combination of the Nolla and Demirjian methods for estimating chronological age from dental age affords a predictive capacity of over 99%, and is fast and easy to perform, and inexpensive.

Using Dental Age to Estimate Chronological Age in Czech Children Aged 3-18 Years

The Demirjian methods to determine dental age are based on analysis of orthopantograms. The dental age estimation is based on establishing the tooth development stages. The purpose of this study was to assess the accuracy of estimation of dental age by Demirjian in the use of all of his four methods. 505 Czech healthy boys and girls aged 3 to 18 years were examined radiographically at the Department of Stomatology, Second Faculty of Medicine, Charles University in Prague. It was mentioned the factors of underlying diseases influence the accuracy of the dental age estimation. For statistical evaluation, descriptive statistics was used to compare deviations of the mean values of chronological and dental age in each age group. The resulting difference between dental age and chronological age is not significant in both genders only when using both Demirjian 7-teeth methods of 1973 and 1976. Therefore these may be most appropriately used for forensic age estimation. There are shown standard deviation differences in different countries. Demirjian's original 7-teeth method from 1973 and Demirjian's revised 4-teeth method from 1976 appear to be the best methods for calculating the dental age of healthy Czech children of both genders.

A Comparison of the Accuracy of Four Age Estimation Methods Based on Panoramic Radiography of Developing Teeth

Background and aims. Tooth development is widely used in determining age and state of maturity. Dental age is of high importance in forensic and pediatric dentistry and also orthodontic treatment planning .The aim of this study was to compare the accuracy of four radiographic age estimation methods. Materials and methods. Orthopantomographic images of 537 healthy children (age: 3.9-14.5 years old) were evaluated. Dental age of the subjects was determined through Demirjian's, Willem's, Cameriere's, and Smith's methods. Differences and correlations between chronological and dental ages were assessed by paired t-tests and Pearson's correlation analysis, respectively. Results. The mean chronological age of the subjects was 8.93 ± 2.04 years. Overestimations of age were observed following the use of Demirjian's method (0.87 ± 1.00 years), Willem's method (0.36 ± 0.87 years), and Smith's method (0.06 ± 0.63 years). However, Cameriere's method underestimated age by 0.19 ± 0.86 years. While paired t-tests revealed significant differences between the mean chronological age and ages determined by Demirjian's, Willem's, and Cameriere's methods (P < 0.001), such a significant difference was absent between chronological age and dental age based on Smith's method (P = 0.079). Pearson's correlation analysis suggested linear correlations between chronological age and dental age determined by all four methods. Conclusion. Our findings indicated Smith's method to have the highest accuracy among the four assessed methods. How-ever, all four methods can be used with acceptable accuracy.

The reliability of Cameriere's method in Turkish children: a preliminary report

Dental age estimation in children is an important issue both legally and medically. Currently, however, there is a lack of contemporary dental age estimation standards for a Turkish population. This study assessed the accuracy of Cameriere's method by examining the panoramic radiographs of 573 healthy Turkish children between the ages of 8 and 15 years. Radiographs of the left permanent developing mandibular teeth, except wisdom teeth, were evaluated. All subjects were divided into 7 groups according to their chronological age. The Intra-class Correlation Coefficient was used to determine the intra- and inter-observer agreement error. A comparison of the distributions of estimation errors among age groups was performed using the Nemenyi test. There were no significant differences between inter-observer (p=0.352), and intra-observer readings after 2 weeks (p=0.275 and p=0.273, respectively). The dental age was underestimated when using Cameriere's method with a mean difference of -0.35 years (-0.24 years for girls and -0.47 years for boys). The median values of the differences between dental and chronological age were -0.44 years in boys (range: -3.70, 4.06) and -0.21 years in girls (range: -2.74, 3.29). In addition, the differences between dental and chronological ages in the different age groups decreased with increasing chronological age. Results from the Nemenyi test implied that Cameriere's method is more accurate for girls than for boys in this cohort of a Turkish population.

Applicability of the Demirjian method for dental age estimation in western Turkish children

OBJECTIVE

The aim of this study was to examine whether the Demirjian method would be appropriate for estimation of the dental age of western Turkish children.

MATERIALS AND METHODS

This study comprised 635 Turkish children (age = 7-16 years) from the western Aegean region who were chosen on the basis of radiological evidence from digital orthopantomograms. Their dental maturity was evaluated according to the stages proposed by Demirjian. A paired t-test was used for statistical analysis.

RESULTS

The mean difference between the chronological and dental ages ranged from 0.10-0.76 years for males and from 0.28-0.87 years for females.

CONCLUSION

The applicability of the Demirjian method is not suitable for western Turkish children and western Turkish children have a lower degree of dental maturity than that observed in the eastern, northeastern and northern Turkish subjects.

Accuracy of four dental age estimation methods in southern Indian children

INTRODUCTION

For various forensic investigations of both living and dead individuals, the knowledge of the actual age or date of birth of the subject is of utmost importance. In recent years, age estimation has gained importance for a variety of reasons, including identifying criminal and legal responsibility, and for many other social events such as birth certificate, marriage, beginning a job, joining the army and retirement. Developing teeth are used to assess maturity and estimate age in number of disciplines; however the accuracy of different methods has not been assessed systematically. The aim of this study was to determine the accuracy of four dental age estimation methods.

MATERIALS AND METHODS

Digital Orthopantomographs (OPGS) of South Indian children between the ages of 6 and 16 y who visited the department of Department of Oral medicine and Radiology of GITAM Dental College, Visakhapatnam, Andhra Pradesh, India with similar ethnic origin were assessed. Dental age was calculated using Demirjian, Willems, Nolla, and adopted Haavikko methods and the difference between estimated dental age and chronological age were compared with paired t-test and Wilcoxon signed rank test.

RESULTS

An overestimation of the dental age was observed by using Demirjian and Nolla methods (0.1±1.63, 0.47±0.83 years in total sample respectively) and an underestimation of dental age was observed by using Willems and Haavikko methods (-0.4±1.53, -2.9±1.41 years respectively in total sample).

CONCLUSION

Nolla's method was more accurate in estimating dental age compared to other methods. Moreover, all the four methods were found to be reliable in estimating age of individuals of unknown chronological age in South Indian children.

Three-dimensional evaluation of the mandibular third molars' development in unilateral crossbite patients: A cone beam computed tomography study

Objectives:

The aim was to investigate mandibular third molar (3M)'s maturation in the crossbite and normal sides by two- and three-dimensional analyses using cone beam computed tomography (CBCT).

Materials and Methods:

A retrospective study was performed using CBCT of 25 patients (16 females and 9 males; mean age: 16.8 ± 2.9 years) with unilateral posterior crossbite. The formation stages and the volume of the mandibular 3Ms were evaluated by means of CBCT data of the patients without knowing the crossbite side of the patients.

Results:

Statistically no significant differences were found in the development of the 3Ms between the crossbite and the control sides, whereas the volume of 3M was found to be less in the crossbite side than in the normal side (P = 0.021).

Conclusions:

A volume of 3M was found to be less in the crossbite side than in the normal side.

Assessment of dental age of children aged 3.5 to 16.9 years using Demirjian's method: a meta-analysis based on 26 studies

Background A method for assessing dental maturity in different populations was first developed in 1973 by Demirjian and has been widely used and accepted since then. While the accuracy for evaluating dental age using Demirjian’s method compared to children’s chronological age has been extensively studied in recent years, the results currently available remain controversial and ambiguous.

Methods A literature search of PubMed, Embase, Web of Science, CNKI and CBM databases was conducted to identify all eligible studies published before July 12th, 2013. Weighted mean difference (WMD) with corresponding 95% confidence interval (95% CI) was used to evaluate the applicability of Demirjian’s method for estimating chronological age in children.

Results: A meta-analysis was conducted on 26 studies with a total of 11,499 children (5,301 boys and 6,198 girls) aged 3.5 to 16.9 years. Overall, we found that Demirjian’s method overestimated dental age by 0.35 (4.2 months) and 0.39 (4.68 months) years in males and females, respectively. A subgroup analysis by age revealed that boys and girls between the ages of 5 to 14 were given a dental age estimate that was significantly more advanced than their chronological age. Differences between underestimated dental ages and actual chronological ages were lower for male and female 15- and 16-year-old subgroups, though a significant difference was found in the 16-year-old subgroup.

Conclusions Demirjian’s method’s overestimation of actual chronological tooth age reveals the need for population-specific standards to better estimate the rate of human dental maturation.

Assessment of dental maturity of children aged 7-15 years using demirjian method in a selected Iranian population

STATEMENT OF PROBLEMS

Dental age can be estimated on the basis of the tooth mineralization level during the developmental process of the teeth. Among various radiological methods reported for the dental age determination in children, Demirjian method is widely used.

PURPOSE

To evaluate the applicability of Demirjian method in age estimation of the children aged 7-15 years in Babol, a northern city of Iran.

MATERIALS AND METHOD

A cross sectional study was performed on the panoramic radiographs of 168 individuals with 7-15 years old. Maturation of the seven permanent teeth on the left side of the mandible was determined according to the crown and root development stages; described by Demirjian method. The mean of the dental age (DA) according to the Demirjian was compared to the mean of chronological age (CA). Data were collected and analyzed using SPSS, V18. P-values<0.05 were considered significance.

RESULTS

The mean and the SD of CA was 11.06±2.29 (boys: 11.08±2.31, girls: 11.03±2.28). The mean and the SD of DA was 11.44±2.85 (boys: 11.81±2.93, girls: 11.08±2.73) and the mean and the SD of DA minus CA for all of the children were 0.38±1.24 (boys: 0.72±1.2, girls: 0.05±1.21). Also, t-Test analysis showed the differences of the mean value of the estimated - chronological age difference was statistically significant between the boys and the girls group (p< 0.001).

CONCLUSION

Considering the determined differences between estimated dental age and chronological age in this study; Demirjian method can be applicable for estimation of dental age in girls and boys before their puberty in northern of Iran.

Permanent first molar extraction in adolescents and young adults and its effect on the development of third molar

OBJECTIVES

The aim of the present study was to determine the prevalence of permanent first molar (P1M) extraction among Turkish adolescents and young adult subpopulation, and to investigate the effects of P1M extraction on development of the third molars (3Ms) in the same quadrant.

MATERIALS AND METHODS

A retrospective study including 2,925 panoramic radiographs (PRs) taken from patients (aged 13-20 years) who were examined to identify cases of had at least one maxillary or mandibular P1Ms extracted was performed. Additionally, 294 PRs with the maxillary or mandibular unilateral loss of a P1M were used to assess the developmental grades of the 3Ms. Statistical analyses were performed by means of parametric tests after performing a Shapiro-Wilks normality test to the data.

RESULT

A total of 945 patients (32.3 %) presented with at least one P1M extraction with no gender difference (P = 0.297). There were more cases of mandibular P1Ms extracted (784 patients, 1,066 teeth) than maxillary P1Ms extracted (441 patients, 549 teeth) (P < 0.001). The development of the 3Ms on the extraction side, in the both maxilla and mandible, was significantly accelerated when compared with the contralateral teeth (P = 0.000, P = 0.000, respectively). No statistically significant differences were found in the differences in the developmental of the 3Ms between the maxilla and mandible (P = 0.718).

CONCLUSIONS

High prevalence of P1Ms extraction among Turkish adolescents and young adults shows a need for targeted dental actions, including prevention and treatment. The development of the 3Ms on the extraction side, in the both maxilla and mandible, was significantly accelerated.

CLINICAL RELEVANCE

To date, no information about prevalence of P1Ms extraction among Turkish adolescents and young adults is documented. In addition, the present study has a larger population and complementary information about 3Ms development than previous studies.