Benoit Bertrand

Approaches to co-occurrence: Scurvy and rickets in infants and young children of 16–18th century Douai, France☆

Disease co-occurrence is defined as the presence and interaction of multiple diseases in a single individual. The phenomenon occurred in the past, but detailed analyses of individuals affected by co-occurrence seldom appear. This paper presents 12 possible cases of scurvy and rickets co-occurrence from the Saint-Amé skeletal collection in Douai, France, dated to the 16-18th century. Each individual was evaluated for evidence of both diseases using macroscopic and radiographic techniques. Additional backscatter scanning electron microscopy evaluation for evidence of rickets was completed on a sub-sample of seven co-occurrence cases. Co-occurrence detection increased with the use of multiple techniques. No unique features identifying scurvy and rickets co-occurrence were observed; instead features associated with both diseases were present. Following clinical expectations, scurvy features were clearly developed while rickets features were subtle. Possible disease sequence and socio-cultural implications are suggested. The studys findings are important to further research on disease co-occurrence as information on cases enhances our ability to understand site context.

Cementochronology, to cut or not to cut?

One of the continuing problems in paleopathology and paleoepidemiology is an inability to accurately age adult skeletons. Accurate age estimations are critical to the proper evaluation of population health and are necessary in circumventing certain aspects of the osteological paradox. Cementochronology is most likely the only age indicator in anthropology that directly considers a continuously growing tissue and does not require either complex statistical manipulations or the use of a reference population. The major issues and recent advances linked to this technique are reviewed for its successful implementation. This review is a partial outcome of an international research program initiated in 2010 to develop and expand cementochronology. Because cementochronology is a reasonably straightforward histological protocol, it can be implemented in less than 24h for one tooth at a relatively low cost. The only aspect of cementochronology that requires extensive previous experience is the counting of increments. These unique aspects largely justify the regular implementation of cementochronology in paleoepidemiology and paleopathology in the confident exploration of population health issues and demographic inferences.

New Insights on the Composition and the Structure of the Acellular Extrinsic Fiber Cementum by Raman Analysis

Acellular extrinsic fiber cementum is a mineralized tissue that covers the cervical half of the tooth root surface. It contains mainly extrinsic or Sharpey’s fibers that run perpendicular to the root surface to anchor the tooth via the periodontal ligament. Acellular cementum is continuously and slowly produced throughout life and exhibits an alternating bright and dark pattern under light microscopy. However, although a better understanding of the structural background of acellular cementum is relevant to many fields, such as cementochronology, periodontology and tissue engineering, acellular cementum remains rarely studied and poorly understood. In this work, we studied the acellular cementum at the incremental line scale of five human mandibular canines using polarized Raman spectroscopy. We provided Raman imaging analysis and polarized acquisitions as a function of the angular orientation of the sample. The results showed that mineral crystals were always parallel to collagen fibrils, and at a larger scale, we proposed an organizational model in which we found radial collagen fibers, “orthogonal” to the cementum surface, and “non-orthogonal” fibers, which consist of branching and bending radial fibers. Concerning the alternating pattern, we observed that the dark lines corresponded to smaller, more mineralized and probably more organized bands, which is consistent with the zoological assumption that incremental lines are produced during a winter rest period of acellular cementum growth.

Ancient Vitamin D Deficiency: Long-Term Trends

Vitamin D deficiency is now widely recognized as one of the most common health conditions in the world, with important consequences for overall health. Levels of deficiency appear to be rising, but the extent to which past humans were affected by vitamin D deficiency and the roles of this hormone in past human health are currently unknown. The discovery that mineralization defects in tooth dentin reflect periods of deficiency and are preserved in our earliest ancestors offers a unique opportunity to provide information on past social and cultural organization and, with further work, to contribute to ongoing debates on change in skin pigmentation. Here we show that humans from some of the earliest Middle Eastern and European communities were affected by deficiency, but levels and severity appear to have increased notably through time. On a simple comparative scale, severity of deficiency was four times as high in Greek communities in 1948 CE as in early farming communities from ca. 3000 BCE; some individuals in the later periods would have had rickets. Research using interglobular dentin in humans and nonhuman primates has the potential to fill in many important gaps in understanding past and present aspects of vitamin D deficiency.

The rachitic tooth: The use of radiographs as a screening technique

This study investigates morphological changes in pulp chambers of living and archaeological individuals with past vitamin D deficiency. Living individuals (n=29), four with detailed medical and dental records and three groups of archaeological individuals (n=25) were radiographed; selected individuals were further evaluated histologically for the presence of incremental interglobular dentin (IIGD), indicative of deficiency (28 living; 17 archaeological). Measurements of pulp horns/chambers from radiographs were conducted to quantify morphological observations. One group had clear skeletal evidence of rickets from St. Matthew, Quebec (n=1) and St. Jacques, France (n=4); a second group had slight skeletal indicators from Bastion des Ursulines, Quebec (n=6); and a third group lacked both skeletal and radiological evidence of deficiency from St. Antoine (n=6) and Pointe-aux-Trembles (n=4). Results showed archaeological individuals with clear and slight skeletal evidence of past deficiency displayed constricted or chair shaped pulp horns. Living individuals with deficiency exhibited similar pulp chamber morphology. Radiographic pulp horn/chamber measurements corroborated morphological findings and significant differences were found in pulp horn/chamber measurements between those with and without deficiency. Results suggest that radiograph assessment of teeth can be used as a screening technique to elucidate patterns of deficiency and select individuals for microCT or histological assessment.