Shortly after compound microscopes became readily available, about the middle of the nineteenth century, useful investigations began to be made into the nature of the various deposits occurring on teeth. These gained considerable impetus with the growth of the sciences of microbiology and pathology. In the late nineteenth century the work of W.D. Miller was most noteworthy in this field, and shortly after the publication in 1883, of his chemico-parasitic theory of dental decay, the plaque hypothesis was established. According to this concept, as developed largely by G.V. Black in the closing years of the nineteenth century, the plaque formed the immediate environment of the tooth surface and the production of acid within the dental plaque was necessary for the development of caries.
This led to a great deal of investigation into the biochemical activities of the dental plaque, but most of these early investigations were undertaken with the object of elucidating the aetiology of digital caries. A smaller number were concerned with basic nature of the dental plaques and their methods of formation and attachment. Later it became clearer that all plaques cariogenic, that calculus formation occurred within the matrix of the bacterial plaque and that plaques, due to their buffering capacity, may play a useful role in protecting tooth surfaces from decalcification by acid foodstuffs. …………………………