Willems Method Research Articles

Dental age estimation methods in children based on radiograph panoramic

Objectives: Age estimation is a key point in forensics, archeology, pediatrics and pediatric dentistry. Analysis using the development of teeth is one of the available methods that are used for physical identification, as well as age, in children. This article reviewed several journals about the methods of age identification, especially in children. The purpose of this review was to briefly inform about the recent researches regarding the application of age identification methods in children by using panoramic radiography as it is the most widely used method, in the years 2020-2021.
 Review: This article was a narrative review. Analyzed articles were searched from the PubMed database which were published between 2020 until 2021. There were 12 journals in accordance with the inclusion criteria of age estimation method in children using panoramic radiography.
 Conclusion: 7 of 12 journals that met the inclusion criteria used Willems method in the researches, 5 journals used Demirjian method, 3 journals used Cameriere method, 2 journals used Nolla method. Willems method was the most used analysis for identifying age and proved to be effective for identification in various populations, such as Belgium, Caucasian, Turkish, Saudi Arabian, Kenyan, Chinese and Taiwanese.

Estimation of Dental Age by Demirjian and Willems Method in a Tertiary Care Hospital of Nepal

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

Age estimation based on Willems method versus country specific model in Saudi Arabia children and adolescents

BackgroundThe aims of this study were to create a method for estimation of dental age in Saudi children and adolescents based on the Willems model developed using the Belgian Caucasian (BC) reference data and to compare the ability of the two models to predict age in Saudi children.MethodsDevelopment of the seven lower left permanent mandibular teeth was staged in 1146 panoramic radiographs from healthy Saudi children (605 male, 541 female) without missing permanent teeth and without all permanent teeth fully developed (except third molars). The data were used to validate the Willems BC model and to construct a Saudi Arabian-specific (Willems SA) model. The mean error, mean absolute error, and root mean square error obtained from both validations were compared to quantify the variance in errors in the sample.ResultsThe overall mean error for the Willems SA method was 0.023 years (standard deviation, ± 0.55), indicating no systematic underestimation or overestimation of age. For girls, the error using the Willems SA method was significantly lower but still negligible at 0.06 years. A small but statistically significant difference in total mean absolute error (11 days) was found between the Willems BC and Willems SA models when the data were compared independent of sex. The overall mean absolute error for girls was slightly lower for the Willems BC method than for the Willems SA method (1.33 years vs. 1.37 years).ConclusionsThe difference in ability to predict dental age between the Willems BC and Willems SA methods is very small, indicating that the data from the BC population can be used as a reference in the Saudi population.

Comparison of Two Methods in Estimating the Relation Between Dental Age and Chronological Age

Introduction: Personal identification is becoming increasingly important not only in legal medicine but also in criminal investigation, identification, and genetic research. Dental age (DA) estimation has gained acceptance because it is less variable when compared to other age indicators. Aim: This study aims to determine DA by radiographic methods in digital orthopantamogram using Willem's method and in intraoral periapical radiograph using Kvaal's method and also to find out the accuracy of two methods in determining the relation between DA and chronological age. Materials and Methods: The study sample consisted of 75 randomly selected subjects who referred to the Oral Medicine and Radiology department for the purpose to undergo orthodontic treatment, were selected. Orthopantmograph and one intraoral periapical radiograph of right mandibular first molar using paralleling cone technique were taken for each patient The DA was determined using orthopantamography by Willem's method and intraoral periapical radiograph by Kvaal's method. Results: The student's t-test was used to analyze the significance between the two different age estimation methods. In Demirjian's method, the overall mean difference between estimated DA and CA for males was 15.10 years, while for females was 11.88 years. Estimated DA assessment by Willem's method appeared to underestimate chronological age both in males and females. Conclusion: In this study, a significant relation was found between estimated DA and CA in the Willem method (p-0.00) and Kvaal's method (p-0.05). Both the methods seem to be applicable in estimating the age of both genders.

Application of Willems Method as an Age Estimator in Early Adolescents of Bangalore Population.

Introduction:Dental age (DA) assessment is a reliable method for chronological age (CA) estimation used for criminal, forensic, and anthropologic purposes. Age estimation also provides valuable information when the birth date is unavailable, as in case of migrants. Furthermore, the CA of living people is important for employment and marriage purpose.Objectives:The aim of the present study is to check the reliability of the Willems method in the population of Bangalore.Materials and Methods:The study was conducted on 205 (109 boys and 96 girls) participants by their radiographic records in the department of forensic odontology using modified Demirjian's method by Willem et al.Results:A total of 205 subjects were selected for the study, among which 109 (53.2%) were boys and 96 (46.8%) were girls. The mean CA was 12.23 ± 1.75 and the mean DA was 12.20 ± 1.99. Willems method seems to be reliable in estimating DA in Bangalore populations.Conclusion:This study showed that the Willems method gave near precise estimation of the CA.

Dental age and skeletal maturity assessment in patients with cerebral palsy.

The aims of this study were to calculate the estimated dental age and the degree of skeletal maturity in patients with cerebral palsy and control patients (i.e., without a diagnosis of cerebral palsy) and to compare the findings with the chronological age of patients in both study groups. In this cross-sectional study, the European formula and the Willems method were used to estimate the dental age of 52 patients with cerebral palsy and 104 control patients, all aged between 7 and 15years. For all patients, their estimated dental age was compared with their chronological age. The degree of skeletal maturity of 35 patients with cerebral palsy and 104 control patients was estimated according to Baccetti's method. There was no statistically significant difference in the deviation of the estimated dental age from the chronological age between patients with cerebral palsy and control patients when the European formula or the Willems method was applied. No difference was found in the frequency of Baccetti's stages between patients with cerebral palsy and control patients in the same age category, for both sexes. To estimate dental age in patients with cerebral palsy, the European formula is preferable for orthodontic purposes and the Willems method is preferable for forensic purposes. Using Baccetti's method it was not possible to detect potential differences in skeletal maturity between patients with cerebral palsy and controls.

Accuracy of the radiographic methods of Willems, Cameriere and Blenkin–Evans on age estimation for Turkish children in the northwest Anatolia region

ABSTRACT The aim of this study is to compare the accuracy of the Willems Method (WM), Cameriere Method (CM) and Blenkin–Evans Method (BM) in the same study sample and determine which one is more suitable for Turkish population. This study included panoramic radiographs of 1024 individuals (619 boys and 585 girls) aged between 6.00 and 15.99 years. Dental age (DA) was calculated using WM, CM and BM for the total study sample, and separately, taking into account age groups and gender. Repeatability statistics evaluated with Cohen’s Kappa test. The differences between chronological age (CA) and the DA were statistically tested using a paired sample t-test and the Wilcoxon signed-rank test. WM overestimated the CA by 0.23 years, while both CM and BM underestimated it by 0.51 and 0.05 years, respectively. In all samples, the DA-CA difference was significant in all methods with one exception BM in boys. Although WM and BM both seem satisfactory in age estimation for children at the northwest Anatolia region of Turkey, BM performs slightly better than CM and it has shown the most accurate results except for the 15 year age group.

Dental Age Estimation According to European Formula and Willems Method: Comparison Between Children With and Without Cleft Lip and Palate.

To assess dental age and deviations of dental from chronological age according to the Willems and Cameriere methods (European formula) in patients with cleft lip and/or cleft palate (CL/P) and compare it with control group. Retrospective cross-sectional study. Clinic of Orthodontics. Sixty-nine patients with CL/P between 6 and 15 years of age (55 with unilateral and 14 with bilateral CL/P) with 148 panoramic radiographs. The same number of radiographs was examined in the age-matched control group. Estimation and comparison of dental age and differences of dental from chronological age in relation to the type of cleft, sex, and age in the group of patients with and without CL/P according to Willems and Cameriere method. No significant intersex and intergroup differences were found in deviations of dental from chronological age according to Cameriere method (P > .05). Significant difference in deviation of dental from chronological age was found between the patients with and without CL/P according to Willems method (P < .001). Cameriere European formula for dental age estimation, which is not influenced by sex and tooth morphology, showed similar dental development of children with and without CL/P. However, Willems method detected that deviation of dental from chronological age significantly differed between children with and without clefts.

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

This study aimed to estimate the dental age (DA) using the London Atlas, Willems, and Nolla methods and to compare their accuracies. The DA was estimated using the aforementioned methods on panoramic radiograms of a total of 919 Eastern Turkish patients aged 6-14years, 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. 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. All three methods can be used for DA estimations of Eastern Turkish children. 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.

Comparación de diversos métodos de estimación de edad dental aplicados por residentes de Postgrado de Odontopediatría

La estimación de la edad dental en los pacientes pediátricos que recibirán tratamiento odontológico es de gran importancia ya que permite evaluar su estado de maduración. Objetivo: Determinar la precisión en la estimación de la edad dental a través de la utilización del método de Nolla, Demirjian y Willems, aplicado por residentes del Postgrado de Odontopediatría en un grupo de niños venezolanos del Distrito Capital. Materiales y métodos: Se seleccionó a conveniencia una muestra estratificada por edad y género incluyendo 71 radiografías panorámicas de alta calidad de niños aparentemente sanos con edades comprendidas entre los 4 y 11 años, evaluando la edad dental según los métodos de Nolla, Demirjian y Willems. Cada radiografía fue evaluada por mínimo dos observadores de forma aleatoria. Resultados: Se obtuvo mayor correlación entre la edad dental y cronológica para los métodos de Demirjian y Willems. Hubo diferencia estadísticamente significativa entre la edad cronológica y la edad dental calculada con Nolla (-0,30 p=0,001) y Demirjian (0,272 p&lt;0,001), no siendo estadísticamente significativa la diferencia para Willems (0,02 p=0,74). Se obtuvieron diferencias en el cálculo de la edad dental entre los tres métodos, siendo el más sensible al efecto del observador el de Nolla. Conclusión: La estimación de la edad dental en pacientes pediátricos puede ser realizada por observadores entrenados. La edad dental siempre dependerá de la variabilidad de cada paciente, de la aplicabilidad del método de estimación para una población determinada y del grado de experiencia del observador.

A modified dental age assessment method for 5- to 16-year-old eastern Chinese children

ObjectivesAge estimation is widely applied in the field of orthodontics, pediatric dentistry, and forensic science. Dental age estimation by the radiological method is frequently used because of its convenience and noninvasiveness. However, there are not enough suitable methods for eastern Chinese children. This study aimed to establish a modified formula for eastern Chinese children according to the Demirjian method and then compared the accuracy of the modified method with the Demirjian method and Willems method.Materials and methodsA total of 2367 dental panoramic radiographs from individuals aged 5–16 years of eastern China were collected as samples. Age estimation was conducted using the Demirjian and Willems methods. The polynomial curve fitting method was used to modify the Demirjian method to improve its application to the eastern Chinese children. The paired t test and accuracy ratio were used to compare the applicability of the modified methods with two commonly used methods.ResultsThe mean chronological age (CA) of the subjects was 11.20 ± 3.29 years for boys and 10.99 ± 3.12 years for girls. The mean difference values between the CA and dental age (DA) (CA–DA) using the Demirjian and Willems methods were 0.73 and 0.7 for boys, respectively, and both 0.79 for girls. The modified method using the polynomial curve fitting presented a smaller underestimation compared with CA for both boys (0.04 years) and girls (0.09 years), which showed a high suitability to Chinese children to some extent.ConclusionsThe Willems method was more accurate in estimating DA compared with the Demirjian method. However, the modified method was more accurate than the two methods; therefore, it can be used in eastern Chinese children.Clinical relevanceIt was thought to be a non-invasive, convenient, and efficient method to connect DA and CA. By estimating dental age, pediatrist, and orthodontists can better understand the development of permanent teeth and provide a more accurate orthodontic treatment time and treatment plan to children patients.

Validity of Willems age estimation method in children’s & adolescents’ of Dakshina Kannada Region, India

Willems gender-specific and non-specific maturity scores derive the age of the individual with acceptable error margins in the Belgian Population. This needs to be validated in various subpopulations to enable its use in age estimation. Our aim was to test the validity of both Willems’s I & II maturity scores to estimate dental age in children and adolescents (aged 5–20 yrs) in Dakshina Kannada population in India. Seven teeth of mandibular left quadrant from 800 Orthopantomograms (Male:Female::372:428) of individuals aged 5–20 years were staged using Demirjian’s method and substituted by the Willems maturity scores to derive the age. The chronological and the predicted age of the individuals were correlated to derive the mean absolute error of age estimation in male, female and total. The mean absolute error of estimation of age in males, females, and total of Willems I and II techniques were 1.11, 1.04, 1.07, 1.15, 1.04 and 1.09 years respectively. The gender nonspecific scores predominantly underestimated the age. The Willems I technique showed an underestimation of age in females and over-estimation of age in males (p < 0.001). The present study validates Willems method of age estimation in Dakshina Kannada population, showing a low error rate of ∼1 year.

Uporedna analiza pristupa muzičkom obrazovanju u metodama Edgara Bilemsa i Morisa Martenoa

The paper presents a comparative analysis of the Willems method and the Martenot method, bearing in mind their attitude towards music education. The richness of each method, especially when it comes to gaining practical experiences in music education, can be a very important basis for improving general music education today, as well as learning in the field of music. These methods are characterized by specific characteristics and approaches related to aspects of rhythm, melody, harmony and body movement, but also the integration of contents of other arts. Therefore, the aim of the paper is to present the specifics and advantages of both methods, based on the analysis of the way in which each of the methods is conceived - starting points, understandings of music education, theoretical foundations of both methods, phases of work and used materials, and the role and importance of teachers.

Applicability of Willems method of dental age estimation to the population of Raichur city of Karnataka

Introduction: Dental age is one of the parameter for the growth assessment and tooth calcification provides a better measure of dental age in comparison to tooth eruption. There are numerous methods available in literature to determine dental age based on tooth calcification. Nowadays Willem’s method is gaining wider recognition because many studies have proved its accuracy in various populations in Western countries but very few studies are available about its applicability to Karnataka State population (South Indian Population). Hence this study has been carried out to test the applicability of Willem’s method to the population (children) of Raichur city of Karnataka state (south Indian population). Materials and Methods: Sample size of 250 south Indian children in 6-13 years age group participated in the study out of which there were 111 females and 139 were males. Dental age was calculated using Willems method and chronological age was determined using date of birth. Pearson’s correlation coefficient and students” t” test was applied for statistical analysis of the data. Results: There was positive correlation between two ages in both genders. 0.06 years was the mean difference in total male sample and 0.07 years was the mean difference in total female sample. Conclusion: The mean difference between chronological and dental age was very minimal and both ages were positively correlated thus indicating that Willem’s method was accurately applicable to the children of Raichur city of Karnataka state (south India). To support our observations we recommend further studies with larger sample size. Keywords: Chronological age, Dental age, Willem’s method.

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

This study aimed to validate the Willems Belgian Caucasian (Willems BC) age estimation model in a Kenyan sample, to develop and validate a Kenyan-specific (Willems KB) age estimation model and to compare the age prediction performances of both models. Panoramic radiographs of 1038 (523 female, 515 male) Kenyan children without missing permanent teeth and without all permanent teeth fully developed (except third molars) were retrospectively selected. Tooth development of the seven lower-left permanent teeth was staged according to Demirjian etal. The Willems BC model, performed on a Belgian Caucasian sample and a constructed Kenyan-specific model (Willems KB) were validated on the Kenyan sample. Their age prediction performances were quantified and compared using the mean error (ME), mean absolute error (MAE) and root-mean-square error (RMSE). The ME with Willems BC method equalled zero. Hence, there was no systematic under- or overestimation of the age. For males and females separately, the ME with Willems BC was significantly different from zero, but negligible in magnitude (-0.04 and 0.04, respectively). Willems KB was found not to outperform Willems BC, since the MAE and RMSE were comparable (0.98 vs 0.97 and 1.31 vs 1.29, respectively). Although Willems BC resulted in a higher percentage of subjects with predicted age within a one-year difference of the true age (63.3% vs 60.4%, p=0.018), this cannot be considered as clinically relevant. There is no reason to use a country-specific (Willems KB) model in children from Kenya instead of the original Willems (BC) model.

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

ObjectiveThe 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. DesignThe 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. ResultsThe 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. ConclusionsAlthough 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

BackgroundThe 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.MethodsA 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.ResultsThe 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)).ConclusionsIn 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.

Applicability of 2 Dental Age Estimation Methods to Taiwanese Population.

The aim of this study is to assess the accuracy of Demirjian and Willems dental age estimation methods on a population of 8- to 15-year-old Taiwanese children. A total of 799 digital panoramic radiographs (404 boys, 395 girls) of children aged from 8.00 to 15.99 years are evaluated. All panoramic films are assessed by 2 examiners using Demirjian and Willems methods. We randomly select 48 panoramic films to evaluate the reproducibility of dental age measurements. The intraobserver and interobserver Cohen's kappa values are 0.733 and 0.762, respectively.The difference between chronological age and dental age is calculated for each individual using both methods. The result shows that Demirjian method slightly overestimates the chronological age of children. The mean age difference is 0.12 years for boys (standard deviation [SD], 0.80) and 0.21 years for girls (SD, 0.95). Willems method slightly underestimates the chronological age of children. The mean age difference is -0.22 years for boys (SD, 0.80) and -0.12 years for girls (SD, 0.92).In conclusion, Demirjian and Willems methods are both accurate for assessing dental age in the Taiwan region of China. The mean age differences of both methods are within ±1 year, which is acceptable at forensic odontology level. However, although the discrepancy between chronological age and dental age is frequently observed between -0.5 and 0.5 years in both methods, there is no guarantee it will be accurate for any particular individual, further modifications to both methods are suggested.

Evaluation of the Willems and Cameriere’s dental age estimation methods in Turkish children–A modified version of Cameriere’s method

The purpose of this study was to compare the accuracy of dental age estimation results obtained using the Willems and Cameriere methods in a large Turkish sample. A further aim was to adapt Cameriere’s regression equation to the Turkish population and to produce an updated regression model appropriate for Turkish children. Finally, we compare the results of the Cameriere and Willems methods.The study group was obtained from two dental radiology department archives. The total sample consisted of 1878 Turkish children (972 boys, 906 girls) aged between five and 15 years. Willems and Cameriere’s age estimation methods were applied. Cameriere’s method performed almost identically for both sex groups. However, the Willems method performed differently for boys and girls within the age range of 8–14. While the Willems method overestimated the dental age than the chronological age in all age groups, Cameriere's method underestimated the dental age than the chronological age in the 8–14 age group.Both Cameriere’s and Willems methods are applicable to the Turkish population. However, researchers should consider that the Cameriere method unbiasedly estimates an individual's age depending on chronological age, while the Willems method overestimates this in all age groups.

The applicability of Willems dental age estimation method for Indonesian children population in Surabaya

BackgroundThe applicability of dental age estimation has been expanded to meet a variety of medico-legal needs, law enforcement, and disaster victim identification. The objective of this study is to examine the applicability of the Willems method for Indonesian children.Material and methodA total of 110 panoramic radiographs of the patients (6–14 years old) who met the inclusion criteria were obtained from the Department of Forensic Odontology and Department of Radiology, Universitas Airlangga, Indonesia. Estimated dental age (EDA) was assessed using the Willems method by two blinded examiners. The statistical analysis was carried out using IBM® SPSS® Statistics version 23.0 (IBM, Armonk, NY, USA).Results and discussionThe mean of the chronological age (CA) in this study is 11.30 ± 1.43 years (boys) and 11.65 ± 1.55 years (girls). The overall mean difference between CA and EDA for boys and girls is − 0.08 ± 0.76 and − 0.31 ± 0.97, respectively. This study showed that the mean age difference in girls was more significant than in boys. The growth spurt timing between boys and girls might cause a difference in dental maturation, whereas the onset of the pubertal growth spurt in girls is about 2 years earlier than in boys. In general, girls start and finish their dental development earlier than boys end.ConclusionThe present study suggests that the dental age estimation methods proposed by Willems can be considered as an applicable method for the children population in Surabaya, both boys and girls. However, a detailed study may be required while applying this approach to the 11–14-year-old girl population in Surabaya, as a substantial underestimation was observed in this community.