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Intrauterine hormone effects on tooth dimensions.
D C Ribeiro1, A H Brook, T E Hughes
1School of Dentistry, The University of Adelaide, Adelaide, Australia, 5005.
Journal of Dental Research
|April 4, 2013
Summary
Females in opposite-sex twin pairs had larger teeth, supporting the Twin Testosterone Transfer (TTT) hypothesis. This suggests intrauterine male hormones influence dental development and human tooth sexual dimorphism.
Area of Science:
- Human biology
- Dental anthropology
- Genetics
Background:
- Human dentition exhibits sexual dimorphism influenced by genetic, epigenetic, and environmental factors.
- The role of intrauterine male hormones in dental sexual dimorphism remains unclear.
Purpose of the Study:
- To investigate the influence of intrauterine male hormones on dental development.
- To test the Twin Testosterone Transfer (TTT) hypothesis by comparing tooth sizes in different twin types.
Main Methods:
- Examined dental models of 134 females from opposite-sex dizygotic (DZOS), same-sex dizygotic (DZSS), and monozygotic (MZ) twin pairs.
- Measured mesiodistal, buccolingual, crown height, and intercuspal dimensions of primary and permanent teeth using image analysis.
Main Results:
- Females from DZOS twin pairs exhibited statistically significantly larger tooth crown size in both primary and permanent dentitions.
- Crown height dimensions showed the most substantial increase in size in DZOS females.
- Findings support the Twin Testosterone Transfer (TTT) hypothesis.
Conclusions:
- Intrauterine male hormone exposure, including testosterone surges, influences dental development.
- The Y chromosome and intrauterine male hormone levels differentially affect tooth dimensions, contributing to human tooth sexual dimorphism.
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