A refined method of measuring basal crown and Cusp areas by use of a three-dimensional digitizing system

Gen Suwa, Reiko Kono

Research output: Contribution to journalArticle

7 Citations (Scopus)


In measuring basal crown and cusp areas of molars, one must determine a standard reference plane on which the projected measurements are made. In this paper, we present a new three-dimensionally based system which enables an objective determination of crown orientation. This is done by combining five laser scanned images of a molar taken occlusally and from four oblique angles to form a composite three-dimensional representation of the entire molar crown surface. Using this digitized data set, we derive a standard occlusal orientation that maximizes projected occlusal surface area. We can also choose other orientations for projection, such as those defined by the cervical line or cusp apices. Crown and cusp areas were measured in each of these orientations and compared for discrepancies on a mandibular first molar of Australopithecus afarensis. We found that orientations differ by more than 10 degrees, resulting in large discrepancies in cusp area values. It is concluded that, to enable reliable interpretation of cusp area data, whatever orientation methods used should be carefully chosen and rigidly followed.

Original languageEnglish
Pages (from-to)95-105
Number of pages11
JournalAnthropological Science
Issue numberSUPPL.
Publication statusPublished - 1998
Externally publishedYes



  • Australopithecus afarensis
  • Cusp area
  • Orientation
  • Three-dimensional metrics

ASJC Scopus subject areas

  • Anthropology

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