Diachronic patterns of dental hypoplasias and vault porosities during the predynastic in the Naqada region, Upper Egypt

The diachronic pattern of the frequencies of linear enamel hypoplasias and porotic hyperostosis was studied in temporally separated samples of adult p redynastic Egyptian remains from the Naqada region, Upper Egypt. The sample s covered a period of increasing population density and social complexity a s well as decreasing Nile flooding in Egypt. First and second molars were e valuated for hypoplasias in material from the Naqada I, II. and III periods ; sample sizes were 13, 30, and 25, respectively, for the first molar, and 11, 28, and 24 for the second molar. Cranial vaults were examined for porot ic hyperostosis using several approaches; sample sizes were 26, 66, and 51 for Naqada I, II and III, respectively. Linear regression showed a decreasi ng trend for several variables: for the individual frequency of first molar hypoplasias (rho = 0.025), the vault porosity score, which indicates the s everity of the lesions (rho < 0.001), and the extent score, which indicates the number of superior vault bones having porosities (rho < 0.001). Logist ic regression showed a temporal decline in the percentage of crania per sam ple having any vault porosities and only higher grade lesions (rho < 0.012 and rho < 0.003, respectively). Lesions of the second molar showed no direc tional trend. The results contrast with the common observation that these s keletal markers usually increase in contexts of increasing population densi ty and social complexity. (C) 2001 Wiley-Liss, Inc.