Willems I VS Willems II: A comparative study of accuracy in 5–15 year old Indian children

Comparative assessment of the Willems dental age estimation methods: a Chinese population-based radiographic study

Background

The comparison of the two Willems dental age estimation methods (gender-specific (Willems I) and non-gender-specific (Willems II)) has not been fully investigated. Here we aimed to explore the applicability of the Willems dental age estimation in an Eastern Chinese population, which may cast light on the field of dental age estimation.

Methods

A total of 1211 oral panoramic radiographs (582 boys and 629 girls) of the Chinese Han population aged 11–16 years old were collected. Dental ages (DAs) were calculated using the Willems method. Statistical significance was set at a p-value < 0.05. Age differences between chronological age (CA) and dental age were analyzed by paired t-tests and mean absolute error (MAE).

Results

The differences between CA and DA determined by the Willems I method were + 0.44 and + 0.09 years for boys and girls, respectively. When using the Willems II method, these differences were + 0.57 and − 0.09. The MAEs of the Willems I method between DA and CA were 0.95 and 1.00 years in boys and girls, respectively. For Willems II, MAEs were 1.02 and 1.00 years in boys and girls.

Conclusions

This study showed that the Willems I method was more accurate than the Willems II method in the boys’ group for predicting age from a whole scale. In comparison, Willems II is more competitive in the girls' group. Neither method may be satisfactory for 11-to-16-year-old teenagers in Eastern China.

Age estimation in the living: A scoping review of population data for skeletal and dental methods

Age estimation of living individuals has become a crucial part of the forensic practice, especially due to the global increase in cross-border migration. The low rate of birth registration in many countries, hence of identification documents of migrants, especially in Africa and Asia, highlights the importance of reliable methods for age estimation of living individuals. Despite the fact that a number of skeletal and dental methods for age estimation have been developed, their main limitation is that they are based on specific reference samples and there is still no consensus among researchers on whether these methods can be applied to all populations. Though this issue remains still unsolved, population information at a glance could be useful for forensic practitioners dealing with such issues. This study aims at presenting a scoping review and mapping of the current situation concerning population data for skeletal (hand-wrist and clavicle) and dental methods (teeth eruption and third molar formation) for age estimation in the living. Two hundred studies on the rate of skeletal maturation and four hundred thirty-nine on the rate of dental maturation were found, covering the period from 1952 and 2020 for a total of ninety-eight countries. For most of the western and central African countries there are currently no data on the rate of skeletal and dental maturation. The same applies to the countries of the Middle East, as well as the eastern European countries, especially as regard the skeletal development.

The applicability of the Demirjian, Willems and Chaillet standards to age estimation of 5-15 year old Indian children

BACKGROUND

Demirjian's method of age estimation has been reported to overestimate age and Willems' method to give consistently more accurate results. Not enough, however, is known about the applicability of Chaillet's standards.

AIM

The present study aimed to compare the accuracy of Demirjian's, Willems' and Chaillet's standards in age estimation of 5 to 15 year-old Indian children.

DESIGN

In this cross-sectional observational study, three methods were compared for accuracy in estimating the age of 1200 Indian children aged 5-15 years.

RESULTS

Demirjian's method overestimated age by +0.24 ± 0.80 years, +0.11 ± 0.81years and +0.19 ± 0.80 years in boys, girls and the total sample, respectively. With Willems' method, overestimations of +0.09 ± 0.80 years, +0.08 ± 0.80 years and +0.09 ± 0.80 years were obtained in boys, girls and the total sample, respectively. Chaillet's method underestimated age by -0.12 ± 0.69 years, -0.45 ± 0.88 years and -0.25 ± 0.83 years in boys, girls and the total sample, respectively. Statistically significant differences were observed between dental and chronological ages with all methods (p < 0.001). Significant sex-based differences were observed only with Demirjian's and Chaillet's methods (p < 0.05).

CONCLUSION

Willems' method was the most accurate in age estimation, followed by Demirjian's and Chaillet's methods. While Demirjian's method was more accurate than Chaillet's in females, Chaillet's method better predicted the age of males.

New model for dental age estimation: Willems method applied on fewer than seven mandibular teeth

Willems method measures the developmental stages of the seven left permanent mandibular teeth and is frequently used for dental age estimation. The aim of this study was to test its accuracy on a large sample of the Croatian population and to develop new models for estimation based on one to seven mandibular teeth. The developmental stages were evaluated on the digital, standardized orthopantomograms of 1868 Croatian children aged 5 to 16. Univariate regression was used for age estimation based on one tooth and regression with forward and backward elimination for selection of the best combination on two to six teeth. Tested in parallel with Willems method, the accuracy of the new models was assessed within intervals of ± 0.5, ± 1, ± 1.5 and ± 2 years and shows the percentage of correct estimations. Using Willems method, the average overestimation was 0.41 years for boys and 0.22 years for girls. Newly developed models that use two to seven teeth proved to be significantly more accurate (p < 0.001). The accuracy of age estimation increases significantly with the number of teeth in a model. Predictably, within the interval ± 0.5 years, a model with three teeth has 3% fewer accurate age estimations than a model including seven teeth. In both theory and practice, Willems method has been considered suitable for age estimation among Croatian children. However, these newly developed models significantly surpass its accuracy. Models using two to seven teeth represent a simple, reliable, and accurate method for age estimation, even in cases with missing mandibular teeth.

Dental age estimation using radiographs: Towards the best method for Sri Lankan children

Research supports the need for regionally and ethnically specific validated data as the reference base for age estimation techniques. This retrospective study evaluated the accuracy of three dental age estimation methods; Demirjian et al. (1973), Willems et al. (2001), and Blenkin and Evans (2010), for use in Sri Lanka for medico-legal purposes. Panoramic radiographs of 688 Sri Lankan children ranging in age from 8.00 to 16.99 years were used to determine their appropriateness to a Sri Lankan population. The mean age and standard deviations (±SD) were calculated separately for males and females of each age group. Paired t-test and mean absolute errors (MAE) were calculated to compare the calculated dental age (DA) with the chronological age (CA) across the nine age groups. The results revealed the mean CA of the entire sample was 12.38 ± 2.68 years, while the mean DA calculated using the Blenkin and Evans method was 11.83 ± 2.20 years, using the Demirjian et al. method was 12.57 ± 2.53 years, and using the Willems et al. method was 11.99 ± 2.43 years. The Demirjian et al. method consistently overestimated the age of males except in the 2 groups aged over 15 years, whereas the Blenkin and Evans method consistently underestimated the age except for the 11.00-12.99 age range. The method of Willems et al. produced DA quite close to CA up until 12.99 years of age, and then underestimated the age for all higher age groups. In females, the Demirjian et al. method consistently overestimated the age up until 13.99 years and then underestimated the higher age groups, while the Willems et al. method underestimated the age in all age groups except 10.00-10.99 years. The Blenkin and Evans method also consistently underestimated the age except in the 10.00-10.99 and 12.00-12.99-year age groups. The percentages of either overestimation or underestimation calculated for ±0.5 years of the true age were 41.0% for the Blenkin and Evans method, 42.8% for the Demirjian et al. method and 49.1% for the Willems et al. method. In conclusion, while all three methods could be applicable in the estimation of dental age for medico-legal purposes, the Willems et al. method appears to be more appropriate in overall measures for the Sri Lankan reference sample, up to the age of 12.99 years.

The Demirjian versus the Willems method for dental age estimation in different populations: A meta-analysis of published studies

BACKGROUND

The accuracy of radiographic methods for dental age estimation is important for biological growth research and forensic applications. Accuracy of the two most commonly used systems (Demirjian and Willems) has been evaluated with conflicting results. This study investigates the accuracies of these methods for dental age estimation in different populations.

METHODS

A search of PubMed, Scopus, Ovid, Database of Open Access Journals and Google Scholar was undertaken. Eligible studies published before December 28, 2016 were reviewed and analyzed. Meta-analysis was performed on 28 published articles using the Demirjian and/or Willems methods to estimate chronological age in 14,109 children (6,581 males, 7,528 females) age 3-18 years in studies using Demirjian's method and 10,832 children (5,176 males, 5,656 females) age 4-18 years in studies using Willems' method. The weighted mean difference at 95% confidence interval was used to assess accuracies of the two methods in predicting the chronological age.

RESULTS

The Demirjian method significantly overestimated chronological age (p<0.05) in males age 3-15 and females age 4-16 when studies were pooled by age cohorts and sex. The majority of studies using Willems' method did not report significant overestimation of ages in either sex. Overall, Demirjian's method significantly overestimated chronological age compared to the Willems method (p<0.05). The weighted mean difference for the Demirjian method was 0.62 for males and 0.72 for females, while that of the Willems method was 0.26 for males and 0.29 for females.

CONCLUSION

The Willems method provides more accurate estimation of chronological age in different populations, while Demirjian's method has a broad application in terms of determining maturity scores. However, accuracy of Demirjian age estimations is confounded by population variation when converting maturity scores to dental ages. For highest accuracy of age estimation, population-specific standards, rather than a universal standard or methods developed on other populations, need to be employed.