The differential diagnosis of dental wear lesions affects their clinical management. We hypothesized that surface texture parameters can differentiate simulated erosion, abrasion, and erosion-abrasion lesions on human enamel and dentin. This in vitro study comprised 2 parts (both factorial 4 × 2), with 4 lesion types (erosion, abrasion, erosion-abrasion, and sound [no lesion; control]) and 2 substrates (enamel and dentin). Flattened/polished dental specimens were used in part 1, whereas natural dental surfaces were used in part 2. Testing surfaces were evaluated in blind conditions, using average surface roughness (Sa) and the following scale-sensitive fractal analysis parameters: area-scale fractal complexity (Asfc), exact proportion length-scale anisotropy of relief (eplsar), scale of maximum complexity (Smc), and textural fill volume (Tfv). Two-way analyses of variance, followed by Fisher's protected least significant difference tests (α = 0.05), were used to evaluate the effects of lesion and substrate. Classification trees were constructed to verify the strength of potential associations of the tested parameters. In part 1,Asfc, Sa, and Tfv were able to differentiate erosion and erosion-abrasion lesions from the sound (no lesion) control in both substrates; only Asfc differentiated erosion and erosion-abrasion enamel lesions (allP< 0.05). The best association of parameters correctly classified up to 84% and 94% of the lesions on enamel and dentin, respectively. In part 2, only Asfc differentiated erosion and erosion-abrasion lesions from the sound (no lesion) control in both substrates, whereas eplsar was able to differentiate erosion from erosion-abrasion (allP< 0.05). The association of parameters correctly classified up to 81% and 91% of the lesions in enamel and dentin, respectively.Asfc, Sa, and Tfv were able to differentiate erosion and erosion-abrasion lesions, despite their complicated surface textures. The association of parameters improved the differentiation of lesions for both enamel and dentin in polished or natural surfaces.
Surface morphometry comprises a relevant set of techniques that provide objective tools to identify, map, and understand use wear patterns in stone tools. Thus far, these techniques have been applied mainly to 2D or 2.5D data, but their application to 3D 360º data is promising and still underdeveloped. Here, we apply new 3D techniques to calculate morphometric variables and to analyse surficial features and changes in pounding stone tools used for baobab processing among Hadza foragers of Tanzania. Baobab pounding stones were collected after use by Hadza foragers for processing the plant food and then 3D point clouds were acquired from laser scanners and SfM photogrammetry. Morphometry was conducted directly on 3D point clouds to avoid time-consuming and surface modifications related to more complex 3D data, such as meshing. Several morphometric variables were computed for the complete pieces (360º sphere) providing fast and accurate data to identify the detailed morphometric features of the artefacts. Additionally, stone surface changes due to baobab processing were measured by comparing the stone surface before and after use, thus enabling calculation of spatial abrasion patterns. Data were interpreted using multivariate exploratory statistical analysis. Differences in the effect of processing on surface morphology are likely explained by variations in raw source material and use. Results suggest that the traces produced by baobab processing on stone tools should be detectable in the archaeological record.
Objectives: Studies of dental microwear of bioarchaeological assemblages and extant mammals from museum collections show that surface texture can provide a valuable proxy for reconstructing diets of past peoples and extinct species. However, no study to date has focused on occlusal surface microwear textures of living hunter-gatherers. Here we present the first such study of the Hadza foragers of Tanzania. Methods:We took high-resolution dental impressions of occlusal surfaces for a total of 43 molds representing 25 men and women, 1-3 samples each, at different times during the rainy and dry seasons. Dental replicas were prepared and scanned by confocal profilometry and standard microwear texture parameters were calculated. Central tendencies and dispersions of variable scores were compared by season and by sex.Results: We found no differences between sexes or seasons in texture attribute central tendency, but some for dispersion. Females had notably low microwear texture dispersion in the dry season while males had higher dispersion in some attributes, particularly in the dry season. These differences seem to be driven primarily by low variance among females in the dry season.Conclusions: This study demonstrates microwear texture data can be generated for living foragers. Given caveats of small samples available and consideration of foraging groups in transition, this study hints at variation in microwear texture dispersion between sexes and seasons for the Hadza, suggesting that such analyses might be of value for assessing hunter-gatherer diet. K E Y W O R D Sdiet, hunter-gatherers, tooth wear
This study investigates two key variables-residential context and subsistence-among sacrificial victims dating to the Late Horizon (A.D. 1450-1532) in the Huaca de los Sacrificios at the Chotuna-Chornancap Archaeological Complex in north coastal Peru. We investigate whether aspects of sacrifice in this distant coastal province mirrored that found in Inca heartland contexts such as the capacocha, or remained more typical of coastal sacrificial traditions. Stable carbon, nitrogen, and oxygen isotope values were characterized in bone carbonate, bone collagen, and hair keratin to estimate geographic residence during the decade before death and diet in the decade, versus months, before death. Bone δ18 Ocarbonate values have a mean (±SD) of 26.8 ± 1.1%, bone δ13 Ccarbonate values -6.7 ± 1.7%, and bone δ(13) Ccollagen values 11.8 ± 1.3%; bone δ15 Ncollagen values have a mean of 11.5 ± 1.3%. Combined hair δ13 Ckeratin values have a mean of -12.8 ± 1.6%, and hair δ15 Nkeratin values 10.8 ± 1.3%. In contrast to contemporaneous coastal and highland contexts, we are unable to identify immigrants among the sacrificed individuals or changes in diet that indicate provisioning with a standardized diet leading up to death. Instead, results suggest that victims were local to the area, but consumed moderately variable diets consistent with local subsistence patterns. These findings suggest a distinct pattern of human sacrifice in the Late Horizon and underscore the regional and temporal variation in sacrificial practices in the central Andes.
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