The histopathology of fluorotic dental enamel in wild boar and domestic pigs

Studies into the behavioral ecology of wild boar and domestic pigs are promising, yet largely neglected, areas of archaeozoological research. Changes in both the diet and health of animals may reflect specific details about the possible scale and extent of human impact on hunted wild boar populations and domesticated pigs in the past. Histological and chemical ‘signatures’ of (for example) physiological stress, brought about by possible human influence, can often be recovered in the dental and skeletal tissues of Sus. However, a fuller interpretation of what the significance of these signatures might be can only be achieved if their aetiology is known, and that can only be done by studying these phenomena in modern extant populations. One of the many aspects of the human–Sus relationship is the exposure of wild boar to contaminants from anthropogenic sources. An example of this is the pollution of wild boar habitats by fluoride from power plants and other emission sources, leading to the occurrence of characteristic dental changes, known as dental fluorosis, in the affected individuals of Sus scrofa (Kierdorf et al. 2000). However, dental fluorosis also occurs in wild and domestic mammals (and in humans) living in areas with increased environmental levels of fluoride from natural sources (Shupe et al. 1983; Cronin et al. 2000, 2003; Garrott et al. 2002; WHO 2002). The macroscopic changes of dental fluorosis reflect a disturbance of the processes involved in enamel formation. Once the permanent dentition of an individual is fully formed, exposure to excess levels of fluoride will not lead to fluorotic enamel changes. Dental fluorosis can therefore be used as a highly sensitive indicator of excess fluoride exposure during the period of tooth formation in humans and other mammals (Fejerskov et al. 1988; DenBesten 1994; Boulton et al. 1999; Kierdorf & Kierdorf 1999; Kierdorf et al. 1999). Higher levels of fluoride also exert negative effects on the skeleton throughout the life of an individual, the pathological changes being known as skeletal fluorosis (WHO 2002). This crippling disability is a major human health problem in various regions of Africa, China, and the Indian subcontinent, where millions of people are affected (Finkelman et al. 1999; WHO 2002).