290 Forensic dentistrywidth of periodontal ligament (Stage H), there is a high probability that an
individual is at least eighteen years old. The probability that an individual
with complete root formation of the mandibular third molars is eighteen or
older is 90.1% for white males and 92.2% for white females.
Subsequent to this ABFO study, several investigations of the relation-
ship of third molar development to chronological age have been performed
using similar methods and parameters with other specific population
groups.153–157 In virtually every instance a wide range of ages associated with
each stage of tooth development was confirmed. In a large multinational
study carried out on three samples, it was found that at each stage of third
molar development Japanese subjects were on average one to two years older
than corresponding German subjects, and South Africans were on average
one to two years younger.^156
As for the probability that an individual with third molars showing com-
plete root formation is at least eighteen years old, results among the com-
parative studies have also differed somewhat with the ethnic group studied
(Table 13.13). This indicates that if an odontologist uses this technique to
assess legal adulthood of an individual, he should consider ethnicity of the
subject and refer to appropriate studies for data.Table 13.13 Comparison of Empirical Probabilities (%) of Individuals with
Complete Third Molar Root Formation (Grade H) from Different Population
Groups Being at Least 18 Years of Age
Study Ye a r Subjects Number Results
Mincer et al. 1993 U.S. and Canadian whites 657 Max F 89.6%
Max M 85.3%
Mand F 92.2%
Mand M 90.1%
Solari and Abramovitch 2002 Hispanics (Houston, TX) 679 Max F 79–84%a
Max M 75–76%
Mand F 91–92%
Mand M 85–89%
Gunst et al. 2003 Belgian whites 2,513 Max F 88.2%
Max M 82.7%
Mand F 94.0%
Mand M 96.6%
Arany et al. 2004 Japanese 1,282 Max F 99%
Max M 97%
Mand F 99%
Mand M 98%
a Contralateral third molar values.
Max = Maxilla
Mand = Mandible
M = Male
F = Female