Forensic Dentistry, Second Edition

266 Forensic dentistry

resorption (Figure 13.1) plus age at exfoliation. The degree of tooth resorp-
tion can be scored directly or from radiographs. Obvious evidence of root
tissue destruction (i.e., loss of a quarter of root length) occurs by five years
of age on c and m1 in girls, and a bit later in boys. Given the ages covered by
these events (Table 13.2), they generally can be combined with ongoing tooth
formation in the permanent dentition, depending on the completeness of the
dental remains.
Emergence of the permanent teeth exhibits fairly consistent sexual dimor-
phism across groups, meaning that girls’ teeth typically erupt at earlier chrono-
logical ages than boys—though the degree of sex difference often is greater
for bony than dental events.31–33 There are racial differences in the timing of
tooth emergence, though the studies are too sparse for most non-European
groups to make definitive claims.31, 34 Broadly, it appears that peoples from
Sub-Saharan Africa are developmentally advanced dentally, sometimes to
striking extents.^35 On the other hand, there seems to be no clear-cut differ-
ences between Asians and Caucasians, and little is known about other racial
groups.^36 Maki et al. found that American-Chinese and American-Japanese
children were significantly delayed in their dental development compared to
American whites.^17 Variation within populations, variation among the traits
studied (such as dental vs. bony maturation), as well as the delaying effects
of poor nutrition, low socioeconomic status, and childhood illnesses further
muddy the issue of race differences.
For Americans with Western European backgrounds, emergence of the
permanent teeth (defined as a cusp tip breaking through the gingiva) occurs
in the range of roughly six to twelve years of age.34,37 The most comprehensive
data for the United States are those for blacks and whites from the Ten-State
Nutrition Survey of 1968–1970; unfortunately, the standard deviations for
these averages are not available.^38 Instead, we illustrate the eruption ages
from a large contemporary cohort of London white children.^39 These data

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1

1

2

3

4

resorption

resorption

resorption

Figure 13.1 the three stages of root resorption of primary teeth used by
moorrees et al.^27 a fourth stage is exfoliation of the tooth. a representative
single-rooted tooth is shown on the left, a multirooted tooth on the right.