ABSTRACT

It is argued that dental structures within the oral environment have evolved with an ability to resist dissolution when exposed to acidic conditions, and to promote remineralisation after damage has occurred. It is hypothesised that dietary acids acted as one of the selective forces in the evolution of the oral environment. It appears that a balance was achieved in hunter-gatherer populations, with the composition and action of saliva, and associated oral biofilms, evolving to protect the teeth against dietary acids. However, in the relatively short period of time since the development of farming and especially with the adoption of modern cultural practices, changes in diet have overwhelmed the oral environment, creating an imbalance. In general, the vast increase in consumption of acidic foods and drinks has decreased the protective mechanisms of saliva. Similarly, the increased consumption of sugar has changed the ecology of oral biofilms, leading to and maintaining a lower oral pH. A combination of these factors has tipped the balance towards demineralisation and increased the risk of oral diseases, such as dental caries and erosive wear, that are so prevalent in many of today's societies.

INTRODUCTION

The Paleolithic, stone age or hunter-gatherer way of life, covers a period of over 2.5 million years of hominin evolution, culminating with the appearance of modern Homo sapiens over 200,000 years ago. This period demonstrates the most basic technological developments including the use of the most primitive stone tools (Toth and Schick, 2007).