INTRODUCTION

The human mouth is heavily colonized with bacteria. There are around 100 million bacteria in every millilitre of saliva, and it is estimated that around 800 bacterial species are present as part of the commensal microflora. Unlike the normal microflora at other body sites that live in harmony with the host, the oral microflora, at this stage of man's evolution, has to be controlled. If plaque accumulations are not removed by brushing or by other mechanical or chemical means, the gums become inflamed, a condition known as gingivitis. Around some teeth in some individuals, a more serious condition arises, known as periodontitis, which is an inflammatory condition leading to loss of attachment between the gums and teeth and destruction of the supporting structures of the teeth, which can eventually lead to their loss. Individuals with high sucrose intake in their diets are also at risk of dental caries where certain species, notably Streptococcus mutans and lactobacilli, ferment the sucrose to produce acids which demineralize the enamel layer. If left untreated, the bacteria invade first the dentine and then the pulp, rendering it non-vital, which in turn can lead to the formation of an abscess around the apex of the tooth. Such abscesses can spread via the tissue planes or the bloodstream to cause serious infections elsewhere in the body, such as abscesses of the liver or brain, which can be fatal.