Forensic Dentistry, Second Edition

age estimation from oral and dental structures 287

of most of or the entire crown, leaving just the root stumps functioning at
the gum line.^94
In the broad view, tooth wear can be useful in interpreting three topics:
cultural modifications (such as caused by crafts and food preparation),
dietary reconstruction (for instance, hunter-gatherers wore their teeth
slower than prehistoric agriculturalists), and of course, age estimation (see
Rose and Ungar14 4 for an in-depth review of attrition studies). In addition,
there is a growing body of research using microscopic wear patterns to
disclose dietary adaptations.14 4,145
Grading schemes as in Figure 13.5 are of little use in contemporary pop-
ulations where the rates of wear are slower, so attrition is only moderate even
in old age. In modern, Westernized countries there have been important
demographic and oral health shifts. With people living longer—and retain-
ing more of their teeth—the occlusal wear in the older age grades has been
increasing (because teeth are less often extracted or decayed), and this trend
is expected to continue. Moreover, and especially when abrasion and ero-
sion are included in wear, it becomes relevant to consider all tooth surfaces,
not just the occlusal.14 6 Smith and Knight^147 developed the tooth wear index
(TWI) as an epidemiological tool (Table 13.10), and various other indexes
also are available.148,149 Donachi and Walls provide a critical review of tooth
wear indexes, and make helpful suggestions for extending the TWI to more
situations encountered in the elderly.^150
Table 13.10 Tooth Wear Index (TWI) Scoring Criteria

Score

Surface

Buccal, Lingual, and

Occlusal Incisal Cervical

0 No loss of enamel

surface characteristics

No loss of enamel surface

characteristics

No change in contour

1 Loss of enamel surface

characteristics

Loss of enamel surface

characteristics

Minimal loss of contour

2 Loss of enamel exposing

dentine for less than

1/3 of the surface

Loss of enamel just

exposing dentine

Defect <1 mm deep

3 Loss of enamel exposing

dentine for more than

1/3 of the surface

Loss of enamel and

substantial loss of dentine,

but not exposing pulp or

secondary dentine

Defect 1–2 mm deep

4 Complete loss of enamel,

or pulp exposure or

exposure of secondary

dentine

Pulp exposure or exposure

of secondary dentine

Defect >2 mm deep,

or pulp exposure or

exposure of secondary

dentine

Source: Adapted from Donachi and Walls.^150