A new comprehensive quantitative approach for the objective identification and analysis of linear enamel hypoplasia (LEH) in worn archaeological dental assemblages

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Objectives The Osteological Paradox posits that skeletal lesions may differentially be interpreted as representing resilience or frailty. However, specific consideration of the etiologies and demographic distributions of individual skeletal indicators can inform the criteria on which to differentiate stress, frailty, and resilience. Adopting a life history approach and adaptive plasticity model, this study proposes a framework for the analysis and interpretation of a commonly reported skeletal lesion, cribra orbitalia, which considers the underlying mechanisms of the condition, the clinical and epidemiological literature relating to anemia and malnutrition, and the bioarcheological evidence. Materials and methods Data were extracted from the European (n = 33 populations) and American (n = 19 populations) modules of the Global History of Health Project. Kaplan–Meier and Cox regression analyses were applied, where time was the age‐at‐death, and the factor or covariate was presence or absence of cribra orbitalia. Results Of 37 samples that produced significant results, 21 demonstrated a change in relationship when the subadults were excluded from analysis. When subadults were included, individuals with cribra orbitalia present had statistically significant lower survival time. With subadults excluded, the relationship either became nonsignificant or was reversed. Discussion We demonstrate that in many cases the inclusion of subadults in analysis impacts upon the apparent mortality associated with cribra orbitalia. Examining cribra orbitalia in children and adults has two separate goals: in children, to determine the prevalence and risk of death associated with active lesions and stress; and in adults, to determine whether childhood health assaults that cause cribra orbitalia are associated with frailty or resilience.

Section: Discussionmentioning

confidence: 99%

A paleoepidemiological approach to the osteological paradox: Investigating stress, frailty and resilience through cribra orbitalia

McFadden

Oxenham

2020

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“…Perikymata on the external surface of teeth reflect the same time interval as RP, and as such are used to estimate the pace of lateral enamel formation as well as to assess inter population and species variation in perikymata counts (Bocaege & Humphrey, 2016; Dean et al, 2001; Dean and Reid, 2001; Guatelli‐Steinberg et al, 2005, 2009, 2014, 2018; Guatelli‐Steinberg et al, 2007; Guatelli‐Steinberg et al, 2012; Guatelli‐Steinberg & Reid, 2010; Mann et al, 1991; McFarlane et al, 2014; Modesto‐Mata et al, 2017, 2020; Ramirez Rozzi, 1993; Ramirez Rozzi & Bermudez de Castro, 2004). Furthermore, perikymata are used in the identification and timing of stress episodes evident as linear enamel hypoplasia (Bocaege et al, 2010; Cares Henriquez & Oxenham, 2020; Cunha et al, 2004; Guatelli‐Steinberg et al, 2004; Guatelli‐Steinberg et al, 2014; Hassett, 2014; Hillson, 1992; King et al, 2002; King et al, 2005; Nava, Frayer, and Bondioli, 2019; Temple, 2016; Temple et al, 2012). These studies of perikymata often assume that RP remains constant within the jaw of a single individual.…”

Section: Introductionmentioning

confidence: 99%

An inconstant biorhythm: The changing pace of Retzius periodicity in human permanent teeth

McFarlane

Guatelli‐Steinberg

Loch

et al. 2020

Objectives Human tooth enamel retains evidence of growth in the form of Retzius lines. The number of daily growth increments between the regularly occurring lines defines their repeat interval, or periodicity. Retzius periodicity is often incorporated into enamel formation times, age‐at‐death reconstructions, or used to provide a basis from which to explore an underlying biorhythm. Biological anthropologists typically assume that RP remains constant within an individual and does not vary along the tooth‐row. Here, we test that assumption. Materials and methods RP was calculated from n = 223 thin sections of human permanent teeth from individuals of British and southern African origin. Forty individuals provided multiple teeth (n = 102 teeth) and a further 121 individuals each provided a single tooth. Results We report first evidence that RP of permanent teeth does not always remain constant within an individual. Of those individuals that provided multiple teeth, 42% (n = 17/40) demonstrated a decrease in RP along the tooth row, with most shifting by two or more days (n = 11). Across the entire sample, mean RP of anterior teeth was significantly higher than molars. Mean premolar RP tended to be intermediate between anterior teeth and molars. Discussion Our data do not support the assumption that RP invariably remains constant within the permanent teeth of an individual. Transferring RP from molars to incisors within an individual can result in a miscalculation of formation time and age‐at‐death by up to 1 year. Implications for biological anthropologists and the source of the underlying long period biorhythm are discussed.

“…Further work might consider the addition of photomontages of tooth surfaces viewed from a lateral perspective, to provide a record of changes in enamel depth. This information might be coupled with WPS data to develop further insights (Cares Henriquez & Oxenham, 2020). Factors limiting the study of perikymata are numerous, including most especially preservation of the features.…”

Section: Discussionmentioning

confidence: 99%

Conventional microscopy makes perikymata count and spacing data feasible for large samples

Edgar

Moes

Willermet

et al. 2021

Objectives: Current methods of quantifying defects of dental enamel (DDE) include either gross or low-level examination for linear enamel hypoplasia, histological analysis of striae of Retzius, or scanning electron microscopy (SEM) of a tooth or a tooth cast. Gross examination has been shown to miss many defects. Other methods can be destructive, require transporting samples, and are expensive. Here, we show that digital light microscopy (DLM) can be used for the analysis of DDE as indicated by widened perikymata spacing (WPS). This method takes advantage of high-power (100Â) microscopy, but is non-destructive, can be implemented almost anywhere, and is inexpensive.Materials and Methods: As proof of concept, we created photomontages of labial surfaces of five human canines from images made using DLM and SEM. We counted and measured the widths of all visible perikymata for each imaging modality and fit measurements to a negative curve representing the expected values for each tooth.We calculated residuals for each measurement. WPS were defined when R 2 was in the 90th percentile, and were considered matched in DLM and SEM images when observed within the same decile of the tooth surface.Results: There were more WPS detected in the images derived from DLM than from SEM. Overall, the data derived from the two imaging modalities provided similar information about the frequency and timing of stress during dental development. Conclusions:The method described here allows for DDE data acquisition as WPS from large samples, making feasible population-level studies that reflect sophisticated understanding of dental development.