age estimation from oral and dental structures 267(Table 13.3) show the typical two waves of tooth emergence.^40 There is one
group between six and eight years of age, when the first molar and the inci-
sors emerge. Then there is a quiescent interval of about two years, followed
by emergence of the canines, premolars, and second molar between about ten
and twelve years of age. The characteristic female precedence also is evident
in these averages (Figure 13.2), where girls, on average, emerge their teeth
earlier than boys (mandibular M2 is the one exception in these data, where
mean age is 6.3 for both sexes).
Numerous studies have attempted to describe the effect of primary tooth
extraction on the eruption rate of the succedaneous tooth, though most are
Table 13.2 Average Ages at Mandibular Root
Resorption Stages of Three Primary TeethStageFemales Males
Mean SD Mean SD
Deciduous Canine
Resorption 1/4 4.9 0.54 6.1 0.67
Resorption 1/2 7.3 0.78 8.4 0.89
Resorption 3/4 8.7 0.92 9.8 1.02
Exfoliation 9.5 1.00 10.6 1.10
Deciduous First Molar: Mesial Root
Resorption 1/4 4.9 0.54 5.4 0.60
Resorption 1/2 7.2 0.78 7.6 0.82
Resorption 3/4 8.7 0.93 9.4 0.98
Exfoliation 9.5 1.05 10.7 1.12
Distal Root
Resorption 1/4 5.1 0.58 6.4 0.69
Resorption 1/2 7.7 0.82 8.3 0.88
Resorption 3/4 9.3 0.97 10.0 1.04
Exfoliation 10.1 1.05 10.7 1.12
Deciduous Second Molar: Mesial Root
Resorption 1/4 6.1 0.67 6.6 0.72
Resorption 1/2 8.3 0.88 8.5 0.90
Resorption 3/4 10.0 1.05 10.4 1.08
Exfoliation 11.1 1.15 11.6 1.20
Distal Root
Resorption 1/4 6.9 0.74 6.6 0.79
Resorption 1/2 8.6 0.91 8.5 0.99
Resorption 3/4 9.9 1.04 10.4 1.14
Exfoliation 11.1 1.16 11.6 1.20
Source: Data derived from Moorrees et al.^28