Publications by authors named "Helen Liversidge"

26 Publications

  • Page 1 of 1

Status of Mandibular Third Molar Development as Evidence in Legal Age Threshold Cases.

J Forensic Sci 2019 May 8;64(3):680-697. Epub 2018 Oct 8.

Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AD, U.K.

The completion of the third molar roots has played an important role in ascertaining whether individuals may be at or over a legal threshold of age, often taken as 18 years. This study demonstrates that root apex completion in the third molar is relatively uninformative regarding the threshold of age 18 years in a sample of 1184 males, where mean age-of-attainment of root apex completion for third mandibular molars is about 19.4 years. This paper also considers the legal age threshold problem for cases where the third mandibular molar is not completely formed, and outlines the use of parametric models and Bayes' factors to evaluate dental evidence in statistically appropriate ways. It attempts to resolve confusion over age-within-stage versus age-of-attainment, likelihood ratios versus other diagnostic tests, and prior odds for a case versus the prior density for an age distribution.
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http://dx.doi.org/10.1111/1556-4029.13926DOI Listing
May 2019

A Reappraisal of Developing Deciduous Tooth Length as an Estimate of Age in Human Immature Skeletal Remains.

J Forensic Sci 2019 Mar 20;64(2):385-392. Epub 2018 Aug 20.

Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Turner Street, London, E1 2AD, U.K.

This study provides an update on a quantitative method for immature age estimation based on postnatal deciduous mandibular tooth length. Two known sex and age skeletal collections from Western Europe were sampled (n = 97). Linear regression models for age estimated were calculated for each individual tooth, each sex, and sex combined sample using classical calibration. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. The teeth which develop earlier in life, the incisors and the first molar, showed the greatest precision, while the canine showed the least. This method has greater applicability to archeological skeletons or to children in developing countries than for use in North American or European forensic contexts. The method can be applied to incomplete or poorly preserved remains of unknown sex, particularly when dental radiographs are not an option or when teeth have been removed from the alveolus or crypt.
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http://dx.doi.org/10.1111/1556-4029.13892DOI Listing
March 2019

Estimating age using permanent molars and third cervical vertebrae shape with a novel semi-automated method.

J Forensic Leg Med 2018 Aug 27;58:140-144. Epub 2018 Jun 27.

Institute of Dentistry, Queen Mary University of London, UK.

Estimating chronological age accurately in young adults is difficult and additional methods are required to increase the accuracy. This study explored a new semi-automated method to assess shape change of third cervical vertebra (C3) with age in the living; comparing this as a method to determine whether individuals could be categorised into being less than 18 years of age (<18), or at least 18 years of age (≥18) with tooth formation of the second and third mandibular molars (M2 and M3). The sample was panoramic and lateral skull radiographs of 174 dental patients (78 males, 96 females aged 15-22 years). Twelve variables were compared in two age categories: younger than 18 and at least 18 years of age in males and females separately using a t-test. Tooth formation of M2 and M3 was assessed. Mean values of eight variables of C3 in males and one variable in females were significantly different between the two age categories (p < 0.05). Results for males showed that the best age indicator for age ≥18 was the ratio between height and width of C3 and for females, the ratio between diagonals. Results for molars showed that M2 was mature in 69% of males and 83% of females, within the expected age range of 14-16 years. M3 was highly variable ranging from stages 6-14 for both; M3 was missing in 24% of males and 28% of females and mature in 14% of males and 15% of females. The conclusion was that shape change of C3 has potential as an additional method to group individuals <18 and ≥ 18 years of age.
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http://dx.doi.org/10.1016/j.jflm.2018.05.010DOI Listing
August 2018

Response to Comment on "The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain)".

Science 2018 03;359(6380)

Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.

The comment by DeSilva challenges our suggestion that brain growth of the El Sidrón J1 Neandertal was still incomplete at 7.7 years of age. Evidence suggests that endocranial volume is likely to represent less than 90% adult size at El Sidrón as well as Neandertal male plus Krapina samples, in line with further evidence from endocranial surface histology and dural sinus groove size.
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http://dx.doi.org/10.1126/science.aar3820DOI Listing
March 2018

The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain).

Science 2017 09;357(6357):1282-1287

Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.

Ontogenetic studies help us understand the processes of evolutionary change. Previous studies on Neandertals have focused mainly on dental development and inferred an accelerated pace of general growth. We report on a juvenile partial skeleton (El Sidrón J1) preserving cranio-dental and postcranial remains. We used dental histology to estimate the age at death to be 7.7 years. Maturation of most elements fell within the expected range of modern humans at this age. The exceptions were the atlas and mid-thoracic vertebrae, which remained at the 5- to 6-year stage of development. Furthermore, endocranial features suggest that brain growth was not yet completed. The vertebral maturation pattern and extended brain growth most likely reflect Neandertal physiology and ontogenetic energy constraints rather than any fundamental difference in the overall pace of growth in this extinct human.
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http://dx.doi.org/10.1126/science.aan6463DOI Listing
September 2017

Dental age estimation in a group of Kenyan children using Willems' method: a radiographic study.

Ann Hum Biol 2017 Nov 11;44(7):614-621. Epub 2017 Sep 11.

a Department of Human Anatomy, School of Medicine , University of Nairobi , Nairobi , Kenya.

Background: Radiographic study of developing teeth provides a reliable indication of chronological age. In Kenya, dentists are often required to estimate age. However, there is a paucity of publications on the performance of dental age estimation methods.

Aim: To determine the accuracy of Willems' method of dental age estimation.

Subjects And Methods: A cross-sectional study was done at The University of Nairobi Dental Hospital. Panoramic radiographs of children aged 3.00-16.99 years old were studied. Dental age was estimated according to Willems' method and compared to chronological age and the difference compared to zero using a t-test.

Results: Radiographs of 187 (47%) females and 214 (53%) males were analysed. Willems' method significantly over-estimated the mean overall age by -0.24 ± 1.17 years (p < .000). Age was over-estimated in girls by -0.10 ± 1.18 years (p = .254); however, age in boys was significantly over-estimated by -0.37 ± 1.14 years (p < .000).

Conclusions: Willem's model over-estimated dental age slightly and the method performed better in estimating the age of girls compared to boys. The majority of the children had their age estimated within 1 year of their chronological age. This suggests that Willems' method is suitable for estimating the ages of individual children in Kenya.
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http://dx.doi.org/10.1080/03014460.2017.1371794DOI Listing
November 2017

Skeletal maturity of the hand in an East African group from Sudan.

Am J Phys Anthropol 2017 08 15;163(4):816-823. Epub 2017 May 15.

Bart's and The London School of Medicine and Dentistry, Queen Mary University of London, Institute of Dentistry, London, E1 2AT, United Kingdom.

Objectives: Studies of skeletal maturity from Africa indicate a delay, reflected in a negative relative skeletal age (RSA). This study aims to evaluate the influence of age, socioeconomic status (SES) and nutritional status on skeletal maturation in a large sample of children from North Sudan.

Materials: The sample consisted 665 males and 1018 females from 3-25 years from Khartoum. Height, weight, age of menarche and, SES were recorded of patients attending for dental treatment.

Methods: Skeletal age was assigned from hand-wrist radiographs using the Greulich-Pyle (GP) atlas (1952). RSA (difference between skeletal and chronological ages) was compared in groups divided by age, sex, height-for-age and body-mass-index z scores, and SES. Spearman's correlation and student t-test was used to compare groups.

Results: Delayed skeletal age was noted across all age in boys. In girls, a delay was observed between ages 6-10, while advancement occurred between ages 13-18. Maturity was delayed in low height groups (p < .05) and low SES groups. RSA was negatively associated with HAZ in low SES males (R = -0.0.27, p < .001) and low SES females (R = -0.32, p < .001).

Conclusions: There were statistically significant skeletal delays in North Sudanese males and most pre-menarche females, low height and low SES groups. Post-menarche females were advanced relative to males and GP references. Low SES impacts were statistically correlated to skeletal delay.
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http://dx.doi.org/10.1002/ajpa.23247DOI Listing
August 2017

The timing of mandibular tooth formation in two African groups.

Ann Hum Biol 2017 May 22;44(3):261-272. Epub 2016 Aug 22.

a Queen Mary University of London, Institute of Dentistry , Bart's and The London School of Medicine and Dentistry , London , UK.

Background: Ethnic differences in the timing of human tooth development are unclear.

Aim: To describe similarities and differences in the timing of tooth formation in two groups of Sudanese children and young adults.

Subjects And Methods: The sample consisted of healthy individuals from Khartoum, Sudan, aged 2-23 years. The Northern group was of Arab origin (848 males, 802 females) and the Western group was of African origin (846 males, 402 females). Each mandibular left permanent tooth from first incisor to third molar was assessed from dental radiographs into one of 15 development stages. Mean ages at entry for 306 tooth stages were calculated using probit regression in males/females in each group and compared using a t-test.

Results: Mean ages were not significantly different in most tooth stage comparisons between ethnic groups for both males (61/75) and females (56/76), despite a tendency of earlier mean ages in the Western group. Mean ages for most tooth stage comparisons between males and females (137/155) were not significantly different within ethnic groups suggesting low sexual dimorphism.

Conclusion: The mean ages of most mandibular tooth formation stages were generally not significantly different between ethnic groups or between males and females in this study.
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http://dx.doi.org/10.1080/03014460.2016.1213313DOI Listing
May 2017

A Reappraisal of Developing Permanent Tooth Length as an Estimate of Age in Human Immature Skeletal Remains.

J Forensic Sci 2016 09 20;61(5):1180-9. Epub 2016 Jun 20.

Institute of Dentistry, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Turner Street, London, E1 2AD, U.K.

This study expands on existing juvenile age prediction models from tooth length by increasing sample size and using classical calibration. A sample of 178 individuals from two European known sex and age skeletal samples was used to calculate prediction formulae for each tooth for each sex separately and combined. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. An ANCOVA was used to test sex and sample differences. Tooth length for age does not differ between the samples except for the canine and second premolar, and no statistically significant sex differences were detected. The least prediction error was found in the incisors and the first molar, and the highest prediction error was found in the third molar. Age prediction formulae provided here can be easily used in a variety of contexts where tooth length is measured from any isolated tooth.
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http://dx.doi.org/10.1111/1556-4029.13120DOI Listing
September 2016

Predicting Agenesis of the Mandibular Second Premolar from Adjacent Teeth.

PLoS One 2015 16;10(12):e0144180. Epub 2015 Dec 16.

Queen Mary University of London, Barts and the London School of Medicine and Dentistry Institute of Dentistry, London, United Kingdom.

Early diagnosis of agenesis of the mandibular second premolar (P2) enhances management of the dental arch in the growing child. The aim of this study was to explore the relationship in the development of the mandibular first molar (M1) and first premolar (P1) at early stages of P2 (second premolar). Specifically, we ask if the likelihood of P2 agenesis can be predicted from adjacent developing teeth. We selected archived dental panoramic radiographs with P2 at crown formation stages (N = 212) and calculated the likelihood of P2 at initial mineralisation stage 'Ci' given the tooth stage of adjacent teeth. Our results show that the probability of observing mandibular P2 at initial mineralisation stage 'Ci' decreased as both the adjacent P1 and M1 matured. The modal stage at P2 'Ci' was P1 'Coc' (cusp outline complete) and M1 'Crc' (crown complete). Initial mineralisation of P2 was observed up to P1 'Crc' and M1 stage 'R½' (root half). The chance of observing P2 at least 'Coc' (coalescence of cusps) was considerably greater prior to these threshold stages compared to later stages of P1 and M1. These findings suggest that P2 is highly unlikely to develop if P1 is beyond 'Crc' and M1 is beyond 'R½'.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144180PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4682943PMC
June 2016

Optimal trait scoring for age estimation.

Am J Phys Anthropol 2016 Apr 12;159(4):557-76. Epub 2015 Dec 12.

Centre for Oral Growth and Development, Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AD, London, UK.

Objectives: Little attention has been paid to questions about the applicability of parametric models to age estimation data and the related problem of how to adjust trait scoring in light of potential deviations from particular parametric models. This article addresses this deficit.

Methods: A Lagrange multiplier goodness-of-fit test is applied to two datasets to address the question of whether or not attainment ages for stages are log-normally distributed. The first dataset used in this article consists of scores of the Todd ten-phase system for the pubic symphysis obtained from 938 individuals with known ages. The second dataset consists of scores for 15 stages of formation for the second mandibular molar scored in 2,304 individuals of known age.

Results: For the Todd ten-phase system there is a significant departure from log-normally distributed ages of attainment. To obtain an acceptable goodness-of-fit statistic, Todd scores consequently are collapsed into an eight-phase system that maintains scores I through VII as individual scores but combines phases VIII through X into one phase. The 15-stage scoring system for the second mandibular molar has an acceptable fit to the log-normal distribution for ages of attainment.

Conclusions: The results from the analysis of the Todd pubic symphysis scores show that researchers should use goodness-of-fit tests for parametric models before deciding to collapse scores. Further, such goodness-of-fit tests are an essential tool in answering questions concerning the suitability of various parametric models. For the 15-stage scoring of the second mandibular molar, the log-normal model is appropriate for attainment ages.
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http://dx.doi.org/10.1002/ajpa.22914DOI Listing
April 2016

Age estimation.

Ann Hum Biol 2015 ;42(4):299-301

c Cranfield Forensic Institute, Cranfield University, Defence Academy of the United Kingdom , Shrivenham , UK , and.

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http://dx.doi.org/10.3109/03014460.2015.1089627DOI Listing
July 2016

Age estimation in fossil hominins: comparing dental development in early Homo with modern humans.

Ann Hum Biol 2015 26;42(4):415-29. Epub 2015 Aug 26.

b Queen Mary University of London, Institute of Dentistry , London , UK.

Background: Previous studies have used molar tooth eruption as a comparative marker of maturation in early fossil hominins. However, tooth eruption and tooth formation are independent maturational processes.

Aim: To determine whether estimates of age for entering a stage of dental development in three early hominin fossils fell within the distribution of a modern human sample.

Methods: This study used a comparative model of dental development to identify the stages of dental development most likely to provide information about length of the growth period in early fossil hominins. Age estimates for stages of dental development in fossils were superimposed onto a normal distribution of the same radiographically defined stages derived from a sample of 6540 children of diverse geographical origin.

Results: Both within the dentition of S7-37, from Sangiran, Java, but also for stages of two other specimens (KNM-WT 15000 from Kenya and StW 151 from South Africa), all age estimates for later stages of tooth formation fell within the modern sample range.

Conclusions: A pattern appears to exist in early Homo where, both within and between developing dentitions, age estimates for stages of P4, M2 and M3 tooth formation fell consistently among the more advanced individuals of the modern human sample.
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http://dx.doi.org/10.3109/03014460.2015.1046488DOI Listing
July 2016

Controversies in age estimation from developing teeth.

Ann Hum Biol 2015 15;42(4):397-406. Epub 2015 Jun 15.

a Queen Mary University of London, Bart's and The Royal School of Medicine and Dentistry, Institute of Dentistry , Turner Street , London , UK.

Background: Numerous dental reference data exist to estimate age from developing permanent teeth.

Aim: To compare the performance of reference data that provide a point estimate using the developing second molar.

Methods: Performance of several methods estimating age using mandibular second molar formation was compared using the Maber test sample (age = 3-16) of 946 dental radiographs. Mean difference and mean absolute difference between dental and chronological ages were calculated. The percentage of individuals with mean absolute difference <1 year was counted across age group and tooth stage. Results for the choice of Demirjian or Moorrees tooth staging, pooled-sex, opposite sex reference data, selected stages (initial cusp tips, crown complete, root half and root complete) and statistical approaches were compared.

Results: Tooth reference data conditioning on age, particularly probit mean age (age-at-transition) adapted for age prediction performed best. Results using sex-specific reference data, Moorrees stages and selected Moorrees stages were marginally better than other methods. No method performed well for ages 15 and 16 years.

Conclusion: Adapted maturity data L9a and N25a reference data for this tooth performed best across age categories and tooth stages, with a mean absolute difference of 0.8 year.
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http://dx.doi.org/10.3109/03014460.2015.1044468DOI Listing
July 2016

A radiographic study of estimating age by deciduous mandibular canine and molar root resorption.

Ann Anat 2016 Jan 20;203:33-7. Epub 2015 Mar 20.

Queen Mary University of London, Institute of Dentistry, Turner Street, London E1 2AD, United Kingdom. Electronic address:

Background And Aim: Root resorption of deciduous teeth is an important aspect of dental development; however, the accuracy of using root resorption as a method of estimating age has not been reported. The aim of this study was to assess the accuracy of estimating age from fractions of resorbed root in mandibular deciduous canines and molars, using published reference data.

Methods: The sample was 940 dental panoramic radiographs of dental patients aged 3-16. Deciduous mandibular canine and molar roots were staged into levels of resorption (one quarter, one half and three quarters). Reliability of root fractions was assessed using 193 duplicate readings and calculated using Kappa. Age was estimated using Moorrees et al. (1963), Fanning (1961), and O'Meara and Knott (1967), and the difference between dental and chronological ages tested using t-test. Accuracy was defined as a difference not significant to zero (P<0.05).

Results: Results show that assessment of levels of root resorption was excellent (Kappa 0.88-0.94). Some root fractions of molars estimated age accurately; however, the standard deviation was more than 2 years. The average difference between dental and chronological ages ranged from 0.12 to -2.04 years with standard deviation values up to 2 years and the most accurate method was O'Meara and Knott (1967).

Conclusion: Fractions of deciduous root resorption can help to predict age.
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http://dx.doi.org/10.1016/j.aanat.2015.02.010DOI Listing
January 2016

Albert Edwin William (LOMA) Miles (1912-2008) extracts from personal letters on dental matters.

Dent Hist 2015 Jan;60(1):18-24

Professor Miles (1912-2008) was a key player establishing dentistry as an academic subject. In the many letters he wrote to Helen Liversidge and me, he describes his involvement as Hon. Curator of the Odontological Museum, Editor Archives of Oral Biology, Assistant scientific editor of the BDJ. He writes about his association with Robert Maxwell and the Pergamon Press and his interests and friendships.
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January 2015

Obituary Jules Kieser 1950-2014.

Ann Hum Biol 2014 Nov-Dec;41(6):582-4. Epub 2014 Sep 1.

Reader in Dental Anthropology, Queen Mary University of London.

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http://dx.doi.org/10.3109/03014460.2014.954443DOI Listing
June 2015

Combining radiographic and histological data for dental development to compare growth in the past and the present.

Ann Hum Biol 2014 Jul-Aug;41(4):336-47

Department of Cell and Developmental Biology, UCL , London , UK .

Background: Being able to estimate the age at death of fossil hominins enables meaningful comparisons of both dental and general growth, past and present.

Aim: The aim of this study was to use data for modern permanent canine formation derived from separate histological and radiographic studies to estimate the age at death of an early African Homo erectus specimen (KNM-WT 15 000) with a developing permanent maxillary canine.

Methods: Ground sections of 18 sexed modern human canines were used to reconstruct growth in tooth height along the enamel-dentine junction (EDJ) and onwards into root formation along the cement-dentine junction (CDJ). Daily rates of enamel and dentine formation were used to put a time scale to cumulative fractions of tooth height.

Results: Age estimates for KNM-WT 15 000 averaged 7.89-8.8 years of age (range = 6.6-10.3 years) and were close to previous histological estimates for this individual (7.6-8.8 years).

Conclusions: Stages of dental development in KNM-WT 15 000 were easily accommodated within this age distribution of a modern sample. However, body mass and stature estimates for KNM-WT 15 000 fell well beyond those reported for a modern sample of 438 Sudanese children aged between 7.0-10 years.
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http://dx.doi.org/10.3109/03014460.2014.922614DOI Listing
July 2015

Malnutrition has no effect on the timing of human tooth formation.

PLoS One 2013 30;8(8):e72274. Epub 2013 Aug 30.

Queen Mary University of London, Institute of Dentistry, Bart's and The London School of Medicine and Dentistry, London, United Kingdom ; Khartoum Centre for Research and Medical Training, Qasr Street, Khartoum, Sudan ; El Razi Dental School, Elazhari 2, Khartoum, Sudan.

The effect of nutrition on the timing of human tooth formation is poorly understood. Delays and advancements in dental maturation have all been reported as well as no effect. We investigated the effect of severe malnutrition on the timing of human tooth formation in a large representative sample of North Sudanese children. The sample (1102 males, 1013 females) consisted of stratified randomly selected healthy individuals in Khartoum, Sudan, aged 2-22 years using a cross-sectional design following the STROBE statement. Nutritional status was defined using WHO criteria of height and weight. Body mass index Z-scores and height for age Z-scores of ≤-2 (cut-off) were used to identify the malnourished group (N = 474) while the normal was defined by Z-scores of ≥0 (N = 799). Clinical and radiographic examination of individuals, with known ages of birth was performed including height and weight measurements. Mandibular left permanent teeth were assessed using eight crown and seven root established tooth formation stages. Mean age at entry and mean age within tooth stages were calculated for each available tooth stage in each group and compared using a t-test. Results show the mean age at entry and mean age within tooth stages were not significantly different between groups affected by severe malnutrition and normal children (p>0.05). This remarkable finding was evident across the span of dental development. We demonstrate that there is little measurable effect of sustained malnutrition on the average timing of tooth formation. This noteworthy finding supports the notion that teeth have substantial biological stability and are insulated from extreme nutritional conditions compared to other maturing body systems.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0072274PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3758289PMC
April 2014

The assessment and interpretation of Demirjian, Goldstein and Tanner's dental maturity.

Ann Hum Biol 2012 Sep 4;39(5):412-31. Epub 2012 Oct 4.

Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Turner Street, London E1 2AD, UK.

Background: A frequently reported advancement in dental maturity compared with the 50(th) percentile of Demirjian, Goldstein and Tanner (1973, Hum Biol 45:211-27) has been interpreted as a population difference.

Aim: To review the assessment and interpretation of Demirjian et al.'s dental maturity.

Subjects And Methods: Dental maturity of boys from published reports was compared as maturity curves and difference to the 50(th) percentile in terms of chronological age and score. Dental maturity, as well as maturity of individual teeth, was compared in the fastest and slowest maturing groups of boys from the Chaillet database.

Results: Maturity curves from published reports by age category were broadly similar and differences occurred at the steepest part of the curve. These reduced when expressed as score rather than age. Many studies report a higher than expected score for chronological age and the database contained more than expected children with scores>97(th) percentile. Revised scores for chronological age from this database were calculated (4072 males, 3958 females, aged 2.1-17.9).

Conclusion: Most published reports were similar to the database smoothed maturity curve. This method of dental maturity is designed to assess maturity for a single child and is unsuitable to compare groups.
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http://dx.doi.org/10.3109/03014460.2012.716080DOI Listing
September 2012

Similarity in dental maturation in two ethnic groups of London children.

Ann Hum Biol 2011 Nov 24;38(6):702-15. Epub 2011 Aug 24.

Department of Paediatric Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London E1 2AD, UK.

Background: The existence of ethnic differences in dental maturity is uncertain.

Aims: The aims were to assess the impact of ethnic group and sex on tooth formation and report two new dental age estimation methods.

Subjects And Methods: The sample was radiographs of White and Bangladeshi dental patients in London, England (529 males, 521 females) of 2-22 years. Mandibular permanent teeth were staged after Moorrees et al. (1963, J Dent Res 42:1490). Average age entering tooth stages was calculated using logistic regression with ethnic group and sex as explanatory factors. Maturity data were adapted for age prediction (N25a) and mean age within stage (N25b) was calculated.

Results: Mean ages between ethnic groups was not significantly different in 83 of 91 individual tooth stage comparisons in males and 77 of 91 comparisons in females. Variation within each group was greater than variation between groups. For the combined ethnic group comparison of males and females, results show that average age of most canine and premolar root stages in females was significantly earlier than males and third molar root formation was later in females compared to males (p < 0.05).

Conclusion: Dental maturity of permanent teeth was similar in these ethnic groups.
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http://dx.doi.org/10.3109/03014460.2011.609565DOI Listing
November 2011

The usefulness of dental and cervical maturation stages in New Zealand children for Disaster Victim Identification.

Forensic Sci Med Pathol 2012 Jun 11;8(2):101-8. Epub 2011 Jun 11.

Faculty of Dentistry, Sir John Walsh Research Institute, University of Otago, Dunedin 9054, New Zealand.

Age estimation of young victims of natural and un-natural disasters remains a crucial and challenging task during the process of Disaster Victim Identification (DVI). The purpose of this study was to compare dental maturity using the Demirjian and Cameriere methods and to explore the relationship between dental age and cervical vertebral maturity (CVM) using the Hassel and Farman method for a group of New Zealand children. The study used lateral cephalometric and panoramic radiographs of 200 orthodontic patients aged 7-17 years. Dental age was calculated from mandibular tooth formation stages using the Demirjian and Cameriere methods by calculating the ratio of tooth length to apex width for these teeth. CVM was assessed using stages from Hassel and Farman. Reliability of maturity from reassessment of 20 radiographs showed good agreement for the three methods. Chronological and dental ages were compared using a mixed model. Descriptive statistics of dental ages by CVM stage were calculated. The results show that both dental methods were similar in assessing maturity. A disadvantage of using the Cameriere method was that all seven teeth reached maturity at 13.69 and 14.06 years in females and males respectively, compared to age 16 using the Dermijian method. Females reached CVM stages at earlier chronological and dental ages than males. Mean chronological age for CVM stages 2-5 is about 1 year earlier in females than males. The Demirjian and Cameriere methods of dental maturity and CVM are reliable and useful in assessing dental and skeletal maturity. Ideally in a DVI situation, both the methods of Demirjian and Cameriere, together with CVM, should be employed in the ageing of individuals suspected of being between 7 and 16 years.
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http://dx.doi.org/10.1007/s12024-011-9251-8DOI Listing
June 2012

Bias and accuracy of age estimation using developing teeth in 946 children.

Am J Phys Anthropol 2010 Dec;143(4):545-54

Institute of Dentistry, Bart's and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AD, England, UK.

Developing teeth are used to assess maturity and estimate age in several disciplines. The aim of the study was to determine which of the most well known dental age estimation methods was best at estimating age. The target sample of dental radiographs (N = 946, ages 3–16) was described by Maber et al. (Forensic Sci Int 159 (2006) S68–S73). Seven mandibular permanent teeth (I1–M2) were assessed, and dental age was calculated using four dental maturity scales and fifteen methods that use data for individual teeth. The mean difference between dental age and real age was calculated (bias) as well as several other measures of accuracy (mean/median absolute difference, percentage aged to within six months and to within 10% of real age). Most methods estimated age with significant bias and standard deviation of bias ranged from 0.86 to 1.03 years. Analysis by age group showed most methods over-aged younger children, and considerably under-aged older children. The method that performed best was the dental maturity scale of Willems et al. (J Forensic Sci 46 (2001) 893–895) with bias of −0.14 ± 0.86 years (N = 827), mean absolute difference of 0.66 years, 71% aged to 10% or less of age, and 49% aged to within six months. Two individual teeth, P2 and M2, estimated age with bias not significantly different to zero for most formation stages using methods based on a large reference sample (L9a Demirjian stages) and a uniform age distribution (N25a Moorrees stages). Standard deviation of bias was least for early crown stages and most for late root stages. Methods that average ages for individual teeth improve if schedules for ‘mean age entering a stage’ are adjusted for prediction. Methods that directly calculate ‘mean age within stage’ can be improved by drawing from a uniform age distribution.
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http://dx.doi.org/10.1002/ajpa.21349DOI Listing
December 2010

Permanent tooth formation as a method of estimating age.

Front Oral Biol 2009 21;13:153-157. Epub 2009 Sep 21.

Unlabelled: The aims of this study were to describe maturity data of permanent tooth formation from a large sample and to adapt these for estimating age, to compare mean age dental formation stages between ethnic groups and sexes.

Methods: This was a retrospective, cross-sectional study of 1,050 panoramic radiographs of healthy dental patients in London aged 2 to 22. Similar numbers of each sex and ethnic group (White and Bangladeshi) were selected for each year of age. Permanent mandibular teeth were scored using 14 stages described by Moorrees and co-workers in 1963 plus crypt stage. Mean age of each tooth stage (age when 50% of sample had reached/ passed each stage) was calculated using probit regression for males and females by ethnic group for each stage. Data were combined where no significant difference between mean age for groups was observed. Average age 'within a stage' was also calculated for each tooth stage.

Results: No ethnic difference was noted in mean age. Canine root stages and third molar apex stages were significantly different between the sexes. The average age of most stages was considerably later than that given by Moorrees and co-workers. Accuracy of age estimation on a separate test sample of radiographs was considerably more accurate using these new data.

Conclusions: These results provide an accurate method to estimate age from developing permanent mandibular teeth. The lack of ethnic difference in dental maturity of individual teeth, suggest that these findings might be appropriate to accurately estimate age for other groups.
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http://dx.doi.org/10.1159/000242409DOI Listing
March 2010

Estimating age in Maori, Pacific Island, and European children from New Zealand.

J Forensic Sci 2008 Mar 14;53(2):401-4. Epub 2008 Feb 14.

Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.

The islands of New Zealand are populated by persons of European, Maori, and Pacific Island extraction. The purpose of this research is to quantify the levels of dental maturation of each of these three populations, in order to obtain data that will be useful in forensic identification and age estimation. The sample consisted of 1383 orthopantomographs (660 males, 723 females) of 477 Maori, 762 European, and 144 Pacific Island children between the ages of 3 and 14 years. Each radiograph was digitized and the stages of mineralization of the seven left mandibular permanent teeth were assessed using the eight stages described by Demirjian. Values for 1, 3, 5, 50, 95, 97, and 99% confidence intervals are listed for each maturity score. Intra-observer reliability was evaluated using Bland-Altman's method on data from re-scoring one out of every 20 radiographs and standard dental maturation curves were constructed for the three populations by means of a quantile regression method. Despite the fact that quantile regression analysis showed that across the age group investigated there were differences between boys and girls, knowledge of the sex does not increase the accuracy of the age estimate, simply because the magnitude of the error of age estimation is greater than the difference between the sexes. Our analysis also shows that population divergence is most marked after the age of 9 years, with a peak difference seen at age 10.
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http://dx.doi.org/10.1111/j.1556-4029.2007.00643.xDOI Listing
March 2008

Advanced dental maturation in New Zealand Maori and Pacific Island children.

Am J Hum Biol 2008 Jan-Feb;20(1):43-50

Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.

This study employs Demirjian's (1994: CD Rom. Norwood, MA: Silver Platter Education) method for assessing dental maturation to compare the rates of development in children of three ethnic populations living in New Zealand-Maori, Pacific Island, and European. We test the hypothesis that Maori and Pacific Island children will have significantly advanced dental maturation compared with New Zealand children of European extraction. The study population consists of orthopantomographs of 1,343 children (623 females and 660 males) between the ages of 2.5 and 14 years, and involves three ethnic groups-Maori, European, and Pacific Islander. Bland/Altman plots for the mean chronological age against the age difference suggest that dental age as determined by the Demirjian method is consistently lower than the chronological age of the children examined. A mixed model regression analysis shows that this difference between dental and chronological age is significantly greater in Maori than in European children (regression coefficient = 0.414; z = 7.01; P < 0.001) and also significantly greater in Pacific Island children than European children (regression coefficient = 0.574; z = 6.25; P < 0.001). Regression analysis shows that the 50th quantile maturity score of boys and girls differs by 1.49 (t = -6.18, P < 0.01) and the interaction of sex and age is also significantly different (t = -2.44, P < 0.01). Similarly, Maori girls show a difference in maturity score of 1.28 (t = -3.77, P < 0.01). However, the slopes for Maori boys and girls did not differ significantly (age/sex interaction, t = -1.25, P = 0.212). We conclude that Pacific Island children are advanced in dental maturity compared with Maori children who in turn are more advanced than New Zealand children of European origin.
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http://dx.doi.org/10.1002/ajhb.20670DOI Listing
January 2008