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Genealogical samples that couple dental data and documented relatedness information provide unique opportunities to examine the biological foundations of tooth variation. Over the past century, these resources have been critical for examining the various factors that influence dental phenotypes—the same traits that anthropologists regularly apply to reconstructions of past phenomena. Genealogical samples are uniquely suited to test long‐standing assumptions underlying bioanthropological practice, for example, biodistance and phylogenetic analysis, which commonly reference aspects of tooth size and form as proxies for latent genetic information. This article provides an overview of published genealogical research, with a focus on the practical implications of quantitative genetic and environmental studies of (non)human primate dentitions. To highlight the utility of genealogical samples for understanding the influence of specific non‐genetic factors on dental characters, we also present novel data on gestational hormone effects in opposite‐sex dizygotic twin pairs as a test of the twin testosterone transfer (TTT) hypothesis. This article discusses fruitful next steps in genealogical dental research, as well as important ethical considerations surrounding the use of associated datasets, which are sensitive in nature. As we forge ahead in an age of phenomics, genealogical samples are likely to play a key role in generating comprehensive genotype–phenotype maps of the dentition and in refining bioanthropological methods. [ABSTRACT FROM AUTHOR]

Archaeological investigation of the dentoalveolar complex in situ within a human skull requires detailed measurements using non‐invasive techniques. Standard macroscopic and radiographic methods have limitations but large volume micro‐computed tomography (LV micro‐CT) scanning has the potential to acquire data at high resolution in microns. In this study, archaeological specimens are analyzed using three‐dimensional data visualization software from LV micro‐CT scans with the aims of (1) determining whether LV micro‐CT can act as a single technique to provide detailed analysis of the dentoalveolar complex and (2) how findings from the LV micro‐CT technique compare with standard methods. These aims are explored by measuring a range of human skull specimens from a rare archaeological sample requiring non‐invasive methods, for multiple dental and alveolar bone health categories. The LV micro‐CT technique was the only method to provide a full range of detailed measurements across all categories studied. A combination of macroscopic and radiographic techniques covered a number of categories, but the use of multiple methods was more time consuming, did not provide the same level of accuracy, and did not include all measurements. There were high levels of reproducibility for intra‐operator scoring and good inter‐operator agreement from four operators with one operator whose results were outliers. As a further investigation of the potential of the LV micro‐CT technique, an additional individual, a fragile, fragmented skull of an infant was studied. This investigation confirms the value of LV micro‐CT scanning as a non‐invasive, accurate, single technique for the extensive analysis of the dentoalveolar complex within archaeological skulls, which also allows the relationship of different tissues to be studied in situ. [ABSTRACT FROM AUTHOR]

This study aims to expand our understanding of the genetic architecture of crown morphology in the human diphyodont dentition. Here, we present bivariate genetic correlation estimates for deciduous and permanent molar traits and evaluate the patterns of pleiotropy within (e.g., m1–m2) and between (e.g., m2–M1) dentitions. Morphology was observed and scored from dental models representing participants of an Australian twin and family study (deciduous n = 290, permanent n = 339). Data collection followed Arizona State University Dental Anthropology System standards. Genetic correlation estimates were generated using maximum likelihood variance components analysis in SOLAR v.8.1.1. Approximately 23% of deciduous variance components models and 30% of permanent variance components models yielded significant genetic correlation estimates. By comparison, over half (56%) of deciduous–permanent homologues (e.g., m2 hypocone–M1 hypocone) were significantly genetically correlated. It is generally assumed that the deciduous and permanent molars represent members of a meristic molar field emerging from the primary dental lamina. However, stronger genetic integration among m2–M1/M2 homologues than among paired deciduous traits suggests the m2 represents the anterior-most member of a "true" molar field. The results indicate genetic factors act at distinct points throughout development to generate homologous molar form, starting with the m2, which is later replaced by a permanent premolariform crown. [ABSTRACT FROM AUTHOR]

The associations seen clinically between variations in tooth number, size and shape reflect the repetitive genetic interactions occurring between the epithelium and mesenchyme during the initiation and morphogenetic stages of dental development. The aim of this study was to investigate this relationship further by comparing multiple crown parameters, including cusp numbers, between patients with mild hypodontia and controls. Digital images of dental casts of the permanent dentition from 28 Romanian subjects with mild hypodontia and 28 controls were used. Measurements of the vestibular and occlusal surfaces were performed using a 2D image analysis method. Seven dimensions were measured (mesio-distal, occluso-gingival, bucco-lingual, vestibular perimeter, vestibular area, occlusal perimeter and occlusal area) and cusps on premolars and first molars were counted. Multivariate analysis of variance was performed using SPSS V17 software. The results showed teeth in the hypodontia group were smaller than those of controls, with many measurements being significantly different (significance values varied from p=0.048 to p=0.0001). Lower first incisors and upper first premolar teeth presented the most reduced dimensions. Mesio-distal, bucco-lingual and occlusal area and perimeter dimensions were the most affected. Upper first molars presented the Carabelli trait in significantly less subjects in the hypodontia group than in controls. This variation was accompanied by a difference in tooth height. Lower premolars showed reduced cusp numbers in hypodontia subjects, accompanied by variation in tooth width or depth. In conclusion, this study demonstrated differences in multiple parameters of crown size and shape in patients with mild hypodontia compared to controls. The degree of these differences varied between different tooth types and dimensions. [ABSTRACT FROM AUTHOR]