PLAQUE CONTROL
Plaque Control
Research has indicated that dental caries does not develop in
experimental animals fed their entire diet by stomach tube. However, Bowen (1969a) has shown that plaque still forms on tooth
surfaces of monkeys in spite of receiving their diet in this manner.
Bowen (1969a) further showed that the capacity of plaque to
produce acid was influenced by the experimental regimen. When a
normal cariogenic diet was fed by stomach tube for two weeks,
almost no acid was formed in the plaque. Plaque formed in the
presence of glucose had a "much less acidogenic capacity than that
formed from sucrose. Plaque formed three months after the animals had been returned to their normal diet had approximately the
same acidogenic potential as that formed before the experiment.
Periodontal disease is the major cause oftooth loss after 35 years
of age. In common with dental caries, periodontal disease is widespread. In one study 99 per cent of secondary schoolchildren were
found to have some form of the disease and, by 17 years of age, 36
per cent had one or more true periodontal pocket (Sheiham 1969).
From 35 to 39 years of age, 46 per cent of adults in the UK exhibit
the terminal stages of periodontal disease and are about to lose
teeth because of the disease. In those between 55 and 59 years of
age, the percentage has increased to 95 per cent (Sheiham 1971). It
has been shown (Loe et al. 1965) that clinical gingival inflammation can be eliminated by thorough toothbrushing. In addition,
most periodontal disease can be controlled or prevented by oral
hygiene practice aimed at the removal of plaque (Greene and
Vermillion 1971).
It is now well accepted that dental plaque is a major aetiological
factor in the two main dental diseases-caries and periodontal
disease. Plaque consists essentially of microcolonies of bacteria
held in a gel-like matrix. The matrix is derived from the bacteria
themselves, from saliva and, in areas adjacent to gingival tissue,
from gingival fluid and inflammatory exudate. The mechanism of
plaque formation has been mentioned in Chapter 1. Shortly after a
polished tooth surface is exposed to saliva, a structure less organic
pellicle forms. The first micro-organisms start to colonize it and a
thin layer of bacterial plaque is formed within hours. After 24
hours without tooth cleansing, a clinically observable soft deposit is
seen at the tooth-gingival margin interface. Plaque formation at
the cervical margins is relatively independent of the passage of
food orally. Hence, the concept of 'self-cleansing' on an ordinary
diet does not exist in man. Tube-feeding is associated with as much
plaque formation as chewing and swallowing. Excessive chewing of
fibrous foods between meals cannot prevent the formation of
plaque. Even if the bacteria which cause caries and periodontal
disease are present in the mouth, they cannot initiate either disease
process until they are able to attach themselves to the teeth in the
L. M. Silverstone, Preventive Dentistry
© Update Books Ltd and Leon M. Silverstone 197
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