Morphological and chemical analysis of hypoplastic defects in the deciduous canines of prehistoric Europeans: The example of the Neolithic population at Chenon (Charente, France)

Deciduous canine hypoplasia is characterized by an area of thin or missing enamel on the labial surface of the crown. This study reports on the prevalence, distribution and expression of this defect in a sample of deciduous canines collected in the Neolithic necropolis of Chenon in south-west France. We know that the most frequent form of this hypoplasia is subcircular, occupying the median area of the crown. What is new is that it is accompanied here by a larger vertical triangular elongated area. These defects first appeared on average 1.7–1.9 months after birth for the large zone, then on average between four and five months after birth for the reduced zone (often considered to be the true hypoplasia) and lasted eight months for the shallow large zone and two to four months for the reduced deep zone. This double phenomenon disappears completely around 10 months after birth (start of weaning?). The measurements of chemical elements content show a higher Ca/P ratio in the deep defect, lower calcium and potassium concentrations and high magnesium and iron contents linked to the mother's diet. These defects could be due to a lack of D vitamin in the first few months and hypocalcaemia and A vitamin hypovitaminosis in the following months, incompletely compensated by the mother's consumption of vegetables and dietary fats.