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Quantitative investigation on irregular cusps in lower permanent molars.
Nichidai Koku Kagaku = Nihon University Journal of Oral Science
|December 1, 1989
Summary
Australian Aboriginals exhibit higher frequencies of anomalous molar tubercles, including the 6th cusp and deflecting wrinkle, compared to Japanese and Dutch populations. These findings suggest a more primitive lower molar morphology in Australian Aboriginals.
Area of Science:
- Anthropology
- Dental Morphology
- Human Evolution
Background:
- Anomalous cusps and tubercles on human molars can provide insights into population genetics and evolutionary history.
- Previous studies have noted variations in dental traits across different human populations.
Purpose of the Study:
- To investigate the frequency of specific anomalous cusps and tubercles on human lower first molars across Japanese, Australian Aboriginal, and Dutch white populations.
- To compare the prevalence of the 6th cusp, 7th cusp, deflecting wrinkle, and transverse ridge among these groups.
Main Methods:
- Utilized moiré contourography for precise three-dimensional measurement of minute dental cusps.
- Examined four specific traits: 6th cusp, 7th cusp, deflecting wrinkle, and transverse ridge on lower first molars.
Main Results:
- Australian Aboriginals displayed the highest frequencies for all four investigated traits, with significantly greater occurrences of the 6th cusp and deflecting wrinkle.
- Japanese and Dutch populations showed lower frequencies, though the 6th cusp was more prevalent in Japanese individuals than in Dutch.
- No significant sex-based differences were observed in the frequency of these traits across any population.
Conclusions:
- The elevated frequency of these anomalous traits in Australian Aboriginals suggests a retention of primitive lower molar morphology.
- These findings contribute to understanding human dental variation and evolutionary patterns.