Sinodonty and Sundadonty

Tsunehiko Hanihara (1993) believed that the dental features of Aboriginal Australians have the characteristic of high frequencies of "evolutionarily conservative characteristics," which he called the "proto-sundadont" pattern, as he believed that the dental pattern of Aboriginal Australians was ancestral to that of Southeast Asians.{{cite journal |last1=Hanihara |first1=Tsunehiko |title=Craniofacial Features of Southeast Asians and Jomonese: A Reconsideration of Their Microevolution Since the Late Pleistocene |journal=Anthropological Science |date=1993 |volume=101 |issue=1 |pages=25–46 |doi=10.1537/ase.101.25 }}

C.G Turner II shows with his analysis of 2016 that sundadonty is the proto-East Eurasian dental morphology and is not connected to the Australian dental morphology, rendering the term "proto-sundadont" inaccurate for the Australian dental morphology. He also shows that sinodonty is predominant in Native Americans.{{cite journal |last1=Scott |first1=G. Richard |last2=Schmitz |first2=Kirk |last3=Heim |first3=Kelly N. |last4=Paul |first4=Kathleen S. |last5=Schomberg |first5=Roman |last6=Pilloud |first6=Marin A. |title=Sinodonty, Sundadonty, and the Beringian Standstill model: Issues of timing and migrations into the New World |journal=Quaternary International |date=February 2018 |volume=466 |pages=233–246 |doi=10.1016/j.quaint.2016.04.027 |bibcode=2018QuInt.466..233S }}

Analysis on the Sinodonty and Sundadonty of New world groups by G.R. Sott et al. (2016) shows the distinction among East Asians is not nearly as dramatic as the difference between all Asians and all New World groups. Other researchers like Stojanowski et al., 2013;

Stojanowski and Johnson, (2015) suggest New World groups may be neither Sinodont nor Sundadont and in most regards, could be viewed as super-Sinodont. A clear dental morphology not only ties New World groups to Asians, particularly northeast Asians, but it also exhibits a pattern largely consistent with the Beringian Standstill model (BSM) based on a Sinodont source population.

{{anchor|Mongoloid Dental Complex}}

Turner defined the Sinodont and Sundadont dental complexes in contrast to a broader Mongoloid dental complex. Hanihara defined the Mongoloid dental complex in 1966. In 1984, Turner separated the Mongoloid dental complex into the Sinodont and Sundadont dental complexes.{{cite journal |last1=Díaz |first1=Eider |last2=García |first2=Lorena |last3=Hernández |first3=Michelle |last4=Palacio |first4=Lesly |last5=Ruiz |first5=Diana |last6=Velandia |first6=Nataly |last7=Villavicencio |first7=Judy |last8=Moreno |first8=Freddy |title=Frequency and variability of dental morphology in deciduous and permanent dentition of a Nasa indigenous group in the municipality of Morales, Cauca, Colombia |journal=Colombia Medica |date=2014 |volume=45 |issue=1 |pages=15–24 |doi=10.25100/cm.v45i1.1281 |pmid=24970955 |pmc=4045228 }}

Ryuta Hamada, Shintaro Kondo and Eizo Wakatsuki (1997) said, on the basis of dental traits, that Mongoloids are separated into sinodonts and sundadonts, which is supported by Christy G. Turner II (1989).{{cite journal |last1=Hamada |first1=Ryuta |last2=Kondo |first2=Shintaro |last3=Wakatsuki |first3=Eizo |title=Odontometrical Analysis of Filipino Dentition |journal=昭和歯学会雑誌 |trans-journal=The Journal of Showa University Dental Society |date=1997 |volume=17 |issue=3 |pages=197–207 |doi=10.11516/dentalmedres1981.17.197 |doi-access=free }}{{cite journal |last1=Turner II |first1=Christy G. |title=Teeth and Prehistory in Asia |journal=Scientific American |date=February 1989 |volume=260 |issue=2 |pages=88–96 |doi=10.1038/scientificamerican0289-88 |pmid=2643828 |bibcode=1989SciAm.260b..88T }}

Turner found the Sundadont pattern in the skeletal remains of Jōmon people of Japan, and in living populations of Taiwanese indigenous peoples, Filipinos, Indonesians, Borneans, and Malays.

In 1996, Rebecca Haydenblit of the Hominid Evolutionary Biology Research Group at Cambridge University did a study on the dentition of four Pre-Columbian era Mesoamerican populations and compared their data to other Eastern Eurasian populations. She found that "Tlatilco", "Cuicuilco", "Monte Albán" and "Cholula" populations followed an overall Sundadont dental pattern "characteristic of Southeast Asia" rather than a Sinodont dental pattern "characteristic of Northeast Asia".{{cite journal |last1=Haydenblit |first1=Rebeca |title=Dental variation among four prehispanic Mexican populations |journal=American Journal of Physical Anthropology |date=June 1996 |volume=100 |issue=2 |pages=225–246 |doi=10.1002/(SICI)1096-8644(199606)100:2<225::AID-AJPA5>3.0.CO;2-W|pmid=8771313 }}

According to a 2016 study, Sundadonty is characterized by an early generalized pattern with simple crown and root traits.

Turner found the Sinodont pattern in the Han Chinese, in the inhabitants of Mongolia and eastern Siberia, in the Native Americans, and in the Yayoi people of Japan.

Sinodonty is a particular pattern of teeth characterized by the following features:

• The upper first incisors and upper second incisors are shovel-shaped, and they are "not aligned with the other teeth".{{cite journal |last1=Kimura |first1=Ryosuke |last2=Yamaguchi |first2=Tetsutaro |last3=Takeda |first3=Mayako |last4=Kondo |first4=Osamu |last5=Toma |first5=Takashi |last6=Haneji |first6=Kuniaki |last7=Hanihara |first7=Tsunehiko |last8=Matsukusa |first8=Hirotaka |last9=Kawamura |first9=Shoji |last10=Maki |first10=Koutaro |last11=Osawa |first11=Motoki |last12=Ishida |first12=Hajime |last13=Oota |first13=Hiroki |title=A Common Variation in EDAR Is a Genetic Determinant of Shovel-Shaped Incisors |journal=The American Journal of Human Genetics |date=October 2009 |volume=85 |issue=4 |pages=528–535 |doi=10.1016/j.ajhg.2009.09.006 |pmid=19804850 |pmc=2756549 }}
• The upper first premolar has one root, and the lower first molar in Sinodonts has three roots (3RM1).{{cite book |last1=Scott |first1=G. Richard |chapter=Dental Anthropology |pages=175–190 |editor1-last=Dulbecco |editor1-first=Renato |title=Encyclopedia of Human Biology |volume=3, Con–Fe |edition=2nd |publisher=Academic Press |date=1997 |isbn=978-0-12-226973-8 |oclc=1193402233 |url=https://archive.org/details/encyclopediaofhu0003unse_e2d3_02ed }}

The EDAR gene causes the Sinodont tooth pattern, and also affects hair texture,{{cite journal |last1=Kamberov |first1=Yana G. |last2=Wang |first2=Sijia |last3=Tan |first3=Jingze |last4=Gerbault |first4=Pascale |last5=Wark |first5=Abigail |last6=Tan |first6=Longzhi |last7=Yang |first7=Yajun |last8=Li |first8=Shilin |last9=Tang |first9=Kun |last10=Chen |first10=Hua |last11=Powell |first11=Adam |last12=Itan |first12=Yuval |last13=Fuller |first13=Dorian |last14=Lohmueller |first14=Jason |last15=Mao |first15=Junhao |last16=Schachar |first16=Asa |last17=Paymer |first17=Madeline |last18=Hostetter |first18=Elizabeth |last19=Byrne |first19=Elizabeth |last20=Burnett |first20=Melissa |last21=McMahon |first21=Andrew P. |last22=Thomas |first22=Mark G. |last23=Lieberman |first23=Daniel E. |last24=Jin |first24=Li |last25=Tabin |first25=Clifford J. |last26=Morgan |first26=Bruce A. |last27=Sabeti |first27=Pardis C. |title=Modeling Recent Human Evolution in Mice by Expression of a Selected EDAR Variant |journal=Cell |date=February 2013 |volume=152 |issue=4 |pages=691–702 |doi=10.1016/j.cell.2013.01.016 |pmid=23415220 |pmc=3575602 }} jaw morphology,{{cite journal |last1=Adhikari |first1=Kaustubh |last2=Fuentes-Guajardo |first2=Macarena |last3=Quinto-Sánchez |first3=Mirsha |last4=Mendoza-Revilla |first4=Javier |last5=Camilo Chacón-Duque |first5=Juan |last6=Acuña-Alonzo |first6=Victor |last7=Jaramillo |first7=Claudia |last8=Arias |first8=William |last9=Lozano |first9=Rodrigo Barquera |last10=Pérez |first10=Gastón Macín |last11=Gómez-Valdés |first11=Jorge |last12=Villamil-Ramírez |first12=Hugo |last13=Hunemeier |first13=Tábita |last14=Ramallo |first14=Virginia |last15=Silva de Cerqueira |first15=Caio C. |last16=Hurtado |first16=Malena |last17=Villegas |first17=Valeria |last18=Granja |first18=Vanessa |last19=Gallo |first19=Carla |last20=Poletti |first20=Giovanni |last21=Schuler-Faccini |first21=Lavinia |last22=Salzano |first22=Francisco M. |last23=Bortolini |first23=Maria- Cátira |last24=Canizales-Quinteros |first24=Samuel |last25=Cheeseman |first25=Michael |last26=Rosique |first26=Javier |last27=Bedoya |first27=Gabriel |last28=Rothhammer |first28=Francisco |last29=Headon |first29=Denis |last30=González-José |first30=Rolando |last31=Balding |first31=David |last32=Ruiz-Linares |first32=Andrés |title=A genome-wide association scan implicates DCHS2, RUNX2, GLI3, PAX1 and EDAR in human facial variation |journal=Nature Communications |date=19 May 2016 |volume=7 |issue=1 |article-number=11616 |doi=10.1038/ncomms11616 |pmid=27193062 |pmc=4874031 |bibcode=2016NatCo...711616A }} and perhaps the nutritional profile of breast milk.{{cite press release |title=Did last ice age affect breastfeeding in Native Americans? |url=https://www.sciencedaily.com/releases/2018/04/180423155057.htm |work=ScienceDaily |publisher=University of California - Berkeley |date=23 April 2018 }}

In the 1990s, Turner's dental morphological traits were frequently mentioned as one of three new tools for studying origins and migrations of human populations. The other two were linguistic methods such as Joseph Greenberg's mass comparison of vocabulary or Johanna Nichols's statistical study of language typology and its evolution, and genetic studies pioneered by Cavalli-Sforza.{{original research inline|date=July 2016}}

Today, the largest number of references to Turner's work are from discussions of the origin of Paleo-Amerindians and modern Native Americans, including the Kennewick Man controversy. Turner found that the dental remains of both ancient and modern Amerindians are more similar to each other than they are to dental complexes from other continents, but that the Sinodont patterns of the Paleo-Amerindians identify their ancestral homeland as north-east Asia. Some later studies{{which?|date=July 2025}} have questioned this and found Sundadont features in some American peoples.

A study done by Stojonowski et al in 2015 found a "significant interobserver error" in the earlier studies and their statistical analysis of matched wear and morphology scores suggests trait downgrading for some traits.{{cite journal |last1=Stojanowski |first1=Christopher M. |last2=Johnson |first2=Kent M. |title=Observer error, dental wear, and the inference of new world sundadonty |journal=American Journal of Physical Anthropology |date=March 2015 |volume=156 |issue=3 |pages=349–362 |doi=10.1002/ajpa.22653 |pmid=25363296 |bibcode=2015AJPA..156..349S }}

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• Ainu people
• Austronesian peoples
• Malay race
• Mongoloid
• Odontometrics
• Shovel-shaped incisors

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Category:Pseudoscience

Category:Stereotypes of East Asian people

Category:Dentition types

Category:Human mouth anatomy