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Age estimation using developing teeth in 946 children

Age estimation using developing teeth in 946 children. Helen Liversidge 1 , Holly Smith 2 , Melissa Maber 1 1. 2. Anthropology, The University of Michigan, Ann Arbor. lakareivarlden.org. rcahms.gov.uk. Measuring maturity. maturity events. Measuring maturity

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Age estimation using developing teeth in 946 children

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  1. Age estimation using developing teeth in 946 children Helen Liversidge1, Holly Smith2, Melissa Maber1 1. 2. Anthropology, The University of Michigan, Ann Arbor

  2. lakareivarlden.org rcahms.gov.uk

  3. Measuring maturity maturity events

  4. Measuring maturity • Count number of children by age group • (reached or passed that maturity event) • Plot % of children for each age group • vs. age

  5. 100% of age group youngest child (advanced)

  6. Measuring maturity: mean age of entering a stage . average age of entering the stage age

  7. average age of entering the stage Test sample should include this range

  8. Worldwide study on tooth formation

  9. Variation increases with ageM1 Cc,Apex 1/2 of M1, M2, M3 solid line white UK dotted line Bangladeshi UK

  10. Questions: Which reference/method is best?How to measure best? Estimating age using tooth formation

  11. Test sample • Panoramic radiographs of 491 girls and 455 boys • similar numbers white/Bangladeshi for each year of age

  12. Left mandibular teeth staged by 3rd author Reproducibility 10/100 radiographs Kappa 0.78 to 0.90

  13. Qualitative methods of age estimation using developing teeth 1. Dental maturity scale 2. Data for individual teeth

  14. Qualitative methods of age estimation using developing teeth 1. Dental maturity scale 2. Data for individual teeth a. Maturity of individual teeth – mean age entering a stage b. adapted for estimation c. Descriptives – mean age midstage/ 'within a stage'

  15. Dental age methods tested • Demirjian et al. 1973 • Willems et al. 2001 • Chaillet et al. 2005 • Nolla 1960 • Haavikko 1970 • Moorrees et al. 1963 • Anderson et al. 1973 Liversidge et al. 2006 • Nystrom et al. 2007 • Maturity scales • Maturity - individual teeth (mean age entering a stage) 3. Adapted by addition of half interval 4. Average age midstage Liversidge et al. 2006 Liversidge et al. 2006 flat age distribution Nystrom et al. 2007

  16. Seven teeth >> dental age

  17. Seven teeth >> dental age Dental age - known age = difference

  18. Does a method over/under estimate age? +1 over estimate 0 -1 under estimate difference Bias - direction

  19. How close is estimated age to known age?median |difference| method 1 method 2 absolute difference 0 distance

  20. Dental maturity scalesbias |median|average difference absolute difference D W C N

  21. Results - bias andmedian |difference| • Best is Willems' maturity scale 0.52y • Worst Nolla' maturity scale

  22. Adapting maturational datafor age estimation Holly Smith 1991

  23. mean age of entering a stage . average age of entering the stage age

  24. average age of entering stage 1 and stage 2interval between stages . age

  25. Molar, root cleft

  26. adaption of mean age entering a stage . assume child is half way age

  27. Maturity of individual teethadaption of mean age entering bias |median|average difference absolute difference H M A L N

  28. Results - bias andmedian |difference|individual teeth Mean age of entering stage doesnot accurately estimate age Haavikko 1970 Moorrees et al. 1963 Anderson et al. 1973 Liversidge et al. 2006 Nystrom et al. 2007 Adapting maturity improves bias and median |difference|

  29. Individual tooth data average age of children 'within a stage' age

  30. Maturity of individual teethmidstage/average age ‘in a stage’ L Lflat Lflat Ny M2

  31. Bias of all methods tested

  32. median |difference| all methods w

  33. Bias - best methods • Willems et al. 2001 • Haavikko 1970 adapted • Liversidge et al. 2006 midstage • Liversidge et al. 2006 M2 midstage flat distribution

  34. Cut off age 14/ M2 stage F/G Probability of a child being < 14 years of age with M2 stage up to and including 'R1/2' is p=0.990 9500 children (Chaillet et al. 2005 ) up to and including stage F p=0.999

  35. Best 4 methods - cut off at M2 stage F/G ~ 14 years <17y <G

  36. Best method overall Dental maturity scale of Willems et al. (2001) • low bias, underestimates age by 0.12 y • lowest absolute difference 0.52 y • 48% of children aged to within half a year • 74% of children aged to 10% of age

  37. Willems et al. 2001 -0.13 y 0.52 y 95% c.i. -1.51 to 1.78 95th % 1.69

  38. 2nd best method (single tooth) Midstage M2 from Liversidge flat distribution • low bias, underestimates age by 0.03 y • low absolute difference 0.69 y • 38% of children aged to within half a year • 61% of children aged to 10% of age

  39. Liversidge M2 flat midstage -0.03 y 0.69 y 95% c.i. -2.05 to 2.11 95th % 2.11

  40. Conclusions • Accuracy should be expressed in more than one way bias (average difference) median absolute difference • Variability of M2 apex compromises accuracy • .......up to and including M2 stage R1/2 or F

  41. Conclusions • best dental maturity scale is Willems et al. 2001 • best single tooth is M2 using Liversidge midstage flat distribution

  42. Acknowledgements Melissa Maber Holly Smith

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