Dental Age Estimation (DAE): Data management for tooth development stages including the third molar. Appropriate censoring of Stage H, the final stage of tooth development.
BACKGROUND
The final stage of dental development of third molars is usually helpful to indicate whether or not a subject is aged over 18 years. A complexity is that the final stage of development is unlimited in its upper border. Investigators usually select an inappropriate upper age limit or censor point for this tooth development stage.


METHODS
The literature was searched for appropriate data sets for dental age estimation and those that provided the count (n), the mean (x¯), and the standard deviation (sd) for each of the tooth development stages. The Demirjian G and Demirjian H were used for this study. Upper and lower limits of the Stage G and Stage H data were calculated limiting the data to plus or minus three standard deviations from the mean. The upper border of Stage H was limited by appropriate censoring at the maximum value for Stage G.


RESULTS
The maximum age at attainment from published data, for Stage H, ranged from 22.60 years to 34.50 years. These data were explored to demonstrate how censoring provides an estimate for the correct maximum age for the final stage of Stage H as 21.64 years for UK Caucasians.


CONCLUSIONS
This study shows that confining the data array of individual tooth developments stages to ± 3sd provides a reliable and logical way of censoring the data for tooth development stages with a Normal distribution of data. For Stage H this is inappropriate as it is unbounded in its upper limit. The use of a censored data array for Stage H using Percentile values is appropriate. This increases the reliability of using third molar Stage H alone to determine whether or not an individual is over 18 years old. For Stage H, individual ancestral groups should be censored using the same technique.
Department of Orthodontics, King's College London Dental Institute, Floor 25, Tower Wing, Guy's Campus, London SE1 9RT, UK. Electronic address: graham.j.roberts@kcl.ac.uk.
Graham J
GJ
Roberts
Department of Orthodontics, King's College London Dental Institute, Floor 25, Tower Wing, Guy's Campus, London SE1 9RT, UK. Electronic address: fraser.mcdonald@kcl.ac.uk.
Fraser
F
McDonald
Biostatistics and Research Methods Centre, Division of Patient and Population Health, Denmark Hill Campus, King's College London Dental Institute, Denmark Hill, London SE5 9RW, UK. Electronic address: manoharan.1.andiappan@kcl.ac.uk.
Manoharan
M
Andiappan
Department of Orthodontics, King's College London Dental Institute, Floor 25, Tower Wing, Guy's Campus, London SE1 9RT, UK. Electronic address: victoria.s.lucas@kcl.ac.uk.
Victoria S
VS
Lucas
D000328:Adult; D000366:Age Determination by Teeth; D066264:Datasets as Topic; D006801:Humans; D008297:Male; D015233:Models, Statistical; D008964:Molar, Third / Q000254:growth & development*; D011336:Probability; D012016:Reference Values; D014070:Tooth / Q000254:growth & development*; D014074:Tooth Calcification / Q000502:physiology; D055815:Young Adult
Censored data; Dental age estimation; Third molars; Three standard deviations