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On deflecting wrinkles and the Dryopithecus pattern in human mandibular molars
Author(s) -
Morris Donald H.
Publication year - 1970
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.1330320112
Subject(s) - molar , cusp (singularity) , mandibular first molar , orthodontics , dentistry , mandibular second molar , mandible (arthropod mouthpart) , mandibular molar , occlusion , biology , medicine , mathematics , genus , geometry , zoology , cardiology
The utility of the traditional Dryopithecus pattern observations on mandibular molars in hominid dental analysis has been challenged recently from several points of view. Both fossil and contemporary evidence suggest the independence of cusp number and groove pattern on mandibular molars and the quality of dentitions which are normally available for study make it difficult to determine both aspects of pattern (cusp number, groove pattern) equally. Now this paper shows that one of the polymorphisms on the occlusal surface of mandibular molars, the “deflecting wrinkle,” may be responsible for the spurious appearance of a Y molar pattern. It presence serves to insure a “2–3 contact” and hence the identification of the Y molar pattern. While seldom reported in traditional dental data, the wrinkle varies in frequency from 7% in South African white first permanent molars to 78.5% in Bushmen. Elsewhere, Hanihara has proposed that it be considered part of the “Mongoloid dental complex”.