Age estimation in 5-16-year-old children by measurement of open apices: North German formula.

The aims of this study were to test the accuracy of Cameriere et al.'s European formula on a sample of North German children based on dental age (DA) for chronological age (CA) assessment and to adapt the formula used, in case of regional peculiarities of this group of children. Orthopantomograms of 1000 children (444 males and 556 females) aged 5-16years were used. The roots of seven left mandibular teeth were evaluated. The number of teeth with complete root development (N zero (0)) was counted. Teeth with incomplete root development were examined and the distance between the inner sides of the open apex was measured and normalized by dividing it by the tooth length to avoid error due to magnification. Cameriere et al.'s European formula underestimated the mean CA of boys by 0.56+/-1.04years and of girls by -0.32+/-0.96. The results of the regression analysis showed that sex (g), the sum of normalized open apices (s), number of teeth with closed apices (N0) and the first-order interaction between the normalized apex width of the canine (x3) and N0 contributed significantly to the fit. All previously mentioned factors were included in the regression model, yielding to the following formula: DA=9.829+0.632 N0-1.037s+0.686g-1.582N0xx3, where g is a variable: 1 for males and 0 for females. The adapted formula explained 84.1% of the total deviance, with a median age of 0.070 years and 1.185 years interquartile range, (IQR).