Permanent tooth emergence among Zambian schoolchildren: a standard for the assignment of ages

There is sufficient variation in the timing of permanent tooth emergence to warrant population specific standards. Due to the lack of reliable ages in rural Zambia, a tooth emergence standard is derived from an urban sample of 543 Zambian schoolchildren. The standard allows assignment of an age to a child based on the total number of permanent teeth emerged. As a way to evaluate the ability of the standard to assign correct ages to Zambian children, a randomly chosen test (10%) sample was withheld from the formation of the standard. Accuracy of the standard in assigning ages to children in both the test and main samples was assessed in ±0.5, ±1.0, and ±2.0 year intervals. Both the main and test samples were able to accurately assign correct ages within ±0.5 year ∼40% of the time and within ±1.0 year ∼65% of the time for both males and females. To further facilitate use in field settings, the standard was visually smoothed. Once again the accuracy of the standard was very similar when applied to the main and test samples. The smoothed standard was as accurate as the original standard. The smoothed standard is thus recommended for application to rural Zambian children of unknown or unreliable age. Am. J. Hum. Biol. 10:45-51, 1998. © 1998 Wiley-Liss, Inc.