The TCMT is an important marker in sinodont populations, and with a high frequency in indigenous Colombians between 60% and 100% (9).
The first subdivision, or Sinodont, composed of Northeast Asian populations, is characterized by the addition and enhancement of some TCMTs, such as the shovel-shaped and layered fold incisors, along with the Y6 cusp pattern, the protostylid (cusp forms) and winging.
Edgar (2007) (19) grouped humans into five clusters: the Mongoloid Dental Complex formed by sinodont and sundadont groups; the Caucasoid Dental Complex formed by Western Eurasian groups (Europe, North Africa, Middle East and India); the Saharan African Dental Complex (composed of West African and South African subgroups closer to sundadont populations of the South Pacific), several Pacific groups of Sahul or Oceania and American Paleo-Indians who present frequencies and morphological variations that take them out of the complexes described.
This is affirmed by past and present American indigenous groups having a sinodont dental morphology, and therefore, should be included in the Mongoloid Dental Complex, which is in agreement with the miscegenation with other ethnic groups.
Turner (15) found significant expressions among sinodonts, South American Indians, and Northeast Europeans.
This occurred in such a way that a group of Mestizos in the city of Cali was characterized in a simplification of the dental morphology as having a low frequency of the cusp of Carabelli (this trait was expressed ambiguously in their fossa forms - characteristic of sinodonts - and cuspids of medium size - a characteristic of Caucasoids), a reduced hypocone (a property of Western Caucasoid groups) and the high frequency of the point P of the protostylid (an exclusive feature of Amerindian populations) (4).
It is considered to be an important marker of sinodont populations of Northeast Asia grouped in the Mongoloid dental complex.
We must take into account that, according to Turner, (24) the American continent was initially occupied by sinodont human groups--first subdivision of the Mongoloid dental complex--characterized by shovel-shaped incisors, deflecting wrinkle, Y6 cusp pattern, protostylid, and winging, such as the case of populations of Northern Asia that migrated from Northern China and crossed Beringia.
This CDTM has not been associated to any world dental complex but its highest frequencies are observed in sinodonts, fist subdivision of Mongoloid dental complex.