Dental developmental defects due to mercurial treatment in a child from sixteenth-century Alghero (Sardinia, Italy)

A child aged 3.5 to 4.5 years, exhumed from the cemetery of Alghero that is referable to the plague outbreak of 1582-83, showed remarkable dental anomalies in the permanent dentition. In particular, the central incisors exhibited large hypoplastic pits, and the first molars were characterized by a honeycomb appearance with large areas of missing enamel. Microtomographic analysis revealed very low values of enamel volume, while the dentin volumes of the crowns were mainly preserved; chemical analysis showed very high levels of mercury in the hard tissues. The enamel disturbances observed in the child from Alghero are highly suggestive of the administration of mercurial treatment to the individual during early childhood. Despite the absence of the typical signs of congenital syphilis, such as Hutchinson's incisors, it cannot be excluded that the child was affected by the disease. After the appearance of venereal syphilis in Europe at the end of the fifteenth century, mercury was employed to treat its severe skin manifestations, remaining in use until the nineteenth century despite its well-known negative side effects. However, mercury was also used in the treatment of a number of dermatological conditions and to eliminate head lice and fleas. Regardless of the disease the child was treated for, the case presented provides evidence of some of the highest levels of mercury recorded in osteoarcheological remains so far, making the individual the youngest patient documented in the paleopathological literature to exhibit signs of mercurial treatment.