Introduction

Dental caries is one of the most commonly recognized diseases in archaeological collections of human remains. Several decades of intensive clinical research have elucidated the mechanisms that underlie it, and its common pattern of occurrence in living people. After two centuries of high caries rates, it seems that the disease is now on the decline. It is less often appreciated that the high rates of the twentieth century were, in any case, an anomaly in archaeological terms. Not only were caries rates much lower throughout the great bulk of human existence, but the nature of the disease was different as well. The present chapter presents an overview of this pervasive and important dental disease – from cause and effect, to variation through time and among populations – and provides context for the remaining papers in this section.

The nature of dental caries

Dental caries is a progressive demineralization of dental enamel, cement, and dentin. It is the cumulative effect of changes in the pH environment of dental plaque deposits on the surface of the teeth. The pH varies during the day. It is lowered by the production of organic acids (especially lactic acid) through the fermentation of carbohydrates by the plaque bacteria, and raised again toward neutral pH by the clearance of fermentable carbohydrates from the mouth and through the buffering effect of saliva.