**1. Introduction**

Bioanthropological1 researches carried out in the last few decades have given special emphasis to the study of the relation between disease, as well as social and environmental phenomena, enhancing the already strong connection between lifestyle and health conditions during history of humankind (Cohen & Armelagos, 1984; Katzenberg & Saunders, 2008; Larsen, 1997). Because infectious diseases result from the interaction between host and agent, modulated by ecological and cultural environments, the comparative study of the historic prevalence of diseases in past populations worldwide can provide important data about their related factors and etiology.

The study of dental diseases (such as caries) has been given special attention from Paleopathology2. The tooth, for its physical features tends to resist destruction and taphonomic conditions better than any other body tissue and therefore, is a valuable element for the study on individual's diet, and social and cultural factors related to it, from a population perspective.

Caries is one of the infectious diseases more easily observable in human remains retrieved from archaeological excavations. For their long time of development and non-lethal nature the lesions presented at the time of the death remain recognizable indefinitely, allowing to infer, along with other archaeological and ecological data, the types of food that a specific population consumed, the cooking technology they used, the relative frequency of consumption, and the way the food was shared among the group (Hillson, 2001 2008; Larsen, 1997; Rodríguez, 2003).

<sup>1</sup> Formerly called Physical Anthropology, Bioanthropology is a discipline that provides integrated information about the lifestyle of past populations and their associations with the environment through the study of human remains. The North American school denominates it Bioarchaeology (Buikstra & Beck, 2006; Larsen, 1997; Roberts & Manchester, 2005).

<sup>2</sup> In general, diseases, signs and determining factors have been studied by Bioanthropology under the label of Paleopathology (the study of diseases in past societies through ancient texts, art and human remains). The specific study of the oral diseases during ancient times is named Oral or Dental paleopathology (Campillo, 2001; Waldron, 2009).

Caries Through Time: An Anthropological Overview 5

diet entirely based on raw meat and vegetables, the patterns of chewing, digestion and nutrition changed accordingly. The process of cooking using fire turned the food safer, juicer, and easier to digest, promoting a higher intake of energy that, in evolutionary terms, had a sequence of favorable physiological effects. The easy digestion of cooked food would have favored the reduction of the digestive system, facilitating metabolic energy savings that were used to develop the brain (Aiello & Wheeler, 1995; Cartmill, 1993; Wrangham, 2009). Nevertheless, it is supposed that *H. erectus,* a hunter-gatherer, obtained approximately 50% of its calories from carbohydrates (Wrangham, 2009) and under the hypothesis of cooking (that obviously included meat and vegetables), caries should have been present much earlier in the fossil record. However, caries appears clearly much later. So, the data on oral does not support the idea of a cariogenic diet based on cooked vegetables from the earliest periods. Maybe, in

The unquestionable oldest evidence of caries comes from a fossil found in 1921 in Broken Hill, Northern Rhodesia (Zambia) during the exploration of a zinc mine. The specimen denominated Broken Hill 1, a *Homo rhodesiensis* cranium (African version of the *Homo heidelberguensis*  650,000-160,000 BP) shows extensive dental caries and coronal destruction. Except for five teeth, all the rest is affected by rampant caries and several crowns are almost completely destroyed. Caries seems to have its origin in the interdental spaces. Besides, Broken Hill man experienced alveolar recession and dental abscesses in many teeth (Fig. 1). Although lesions have been attributed to a diet rich in vegetables and/or poisoning by the existing metals in the region (Bartsiokas & Day, 1993), it seems that, given the interdental origin of the caries and the absence of tooth picks evidence, the Broken Hill 1 developed his lesions due to his ignorance in

Fig. 1. **The unquestionable oldest evidence of caries in the human paleontological record.** 

Pictures of *H. rhodesiensis* skull cast. Map modified from Google Maps 2010.

the use of tooth picks, which was known by other earlier hominines (Puech, 1978).

the beginning, fire was employed only for cooking meat.

Considering the available data, we know that the highest caries rates3, their distribution and severity profiles observed nowadays are the result of a complex process of slow dietary changes, directly linked to the development of Western civilization. Consequently, the current caries patterns are not observed in past populations, on the opposite, they show a high variability along time and space that corresponds to a wide range of subsistence strategies, specific cultural regulations, and particular historical processes.
