July 1st, 2009 by admin

PREVENTION OF CARIES BY PLAQUE CONTROL
4.2.1 The individual site
Strong evidence suppor ting the effect of oral hygiene on caries comes from
experimental studies carried out
in vivo
. For instance, it was reported in
1970
that when dental students stopped brushing for 23 days white spots
2
developed along gingival margins of teeth. Students who were in a group
rinsing frequently with sucrose in the test period developed more lesions
than those who did not rinse. But
all
lesions were reversible after 30 days of
careful oral hygiene and daily  uoride mouth rinses (0.2% sodium  uoride).
In other studies plaque formation has been encouraged by placing bands
onto teeth to encourage plaque stagnation beneath the band. White spot
lesions developed over 4 weeks but when the bands were removed and tooth-
brushing restarted, these lesions were no longer so obvious, apparently
because of surface wear (see page 24).
A number of experiments on the role of plaque removal in caries control
are carried out
in situ
. Here subjects carry slices of enamel or dentine, often
on dentures. Sometimes the specimens contain carious lesions and the
experiment monitors how they change with brushing. In other studies,
lesions are created and then brushed or not brushed, to measure how they
progress. The advantage of the
in situ
design is that the tooth slices can be
examined histologically at no detriment to the patient.
Collectively these studies show it is possible to control the development
and progression of carious lesions by meticulous oral hygiene with a  uoride
toothpaste. This is very important information because it means that pa-
tients should be shown how to remove plaque over specific lesions. At a com-
munity level there may not be a strong association between plaque and
caries. But to argue from this that plaque control is not important in caries
management is biologically illogical and  ies in the face of this individual site
evidence.
4.2.2 The individual patient
Children whose dental cleanliness is consistently good may get less caries
than those whose cleanliness is consistently bad. Several studies show par-
ticipants brushing twice daily develop fewer lesions than those brushing less
frequently. It is thus sensible to recommend that patients should brush twice
daily with a  uoride toothpaste.
In most studies it is not possible to separate the effect of the brushing from
the effect of the  uoride in the toothpaste. It would not now be considered
ethical to have a group of volunteers brushing with a  uoride-free tooth-
paste. However, it is possible to look back to clinical studies comparing
uoride and non- uoride toothpastes conducted in the 1960s and 1970s.
These studies usually lasted 2–3 years, and in this rather short time period
the  uoridated pastes showed a reduction in caries of about 24%.
Thus the effect of  uoride in the paste is very important.
The most simple and effective way to control the development and pro-
gression of caries at the individual level is to brush away plaque with a
uoride toothpaste.
4.2.3 The community
There is no clear-cut association between oral hygiene and caries in population
studies but, as discussed in the introduction to this chapter, this is not surprising
because caries is a multifactorial process. Another rather intriguing explanation
may relate to the way plaque was measured in these studies. The indices used
were developed for periodontal purposes and concentrate on gingival plaque
which may be a poor predictor of caries because carious lesions form on occlusal
and approximal surfaces and not only adjacent to gingival margins.
It is a mistake to look on toothbrushing as only a vehicle for  uoride appli-
cation. The quality of plaque removal is also important at the individual site
where a lesion is developing and to the individual patient. In addition, there is
likely to be a synergistic effect between plaque and diet. It has been shown
that the risk of caries increased with increasing levels of plaque at all levels of
sugar consumption. Thus, when sugar consumption is high, plaque removal
can help control the development and progression of caries.
4.24 Professional tooth cleaning
It is not always possible to get people to clean their teeth as well as they
should. There are two possible difficulties:
• they are not sufficiently dextrous to do it
• they can, but they
will not
!
In an attempt to overcome these difficulties, two Swedish researchers, Axels-
son and Lindhe, developed a professional tooth cleaning programme (the
Karlstad programme).
In addition to the traditional components of a caries-
4
preventive programme (repeated oral hygiene instruction, dietary advice, and
topical  uorides) professional personnel cleaned the teeth at regular intervals.
The idea was based on the study conducted in dental students that showed
where dental plaque was allowed to accumulate on a clean tooth surface, white
spot lesions developed in the enamel in 2–3 weeks. Thus plaque was removed
professionally from all tooth surfaces every 2 weeks, together with a topical
application of  uoride, to control caries. Children in the control group under-
took supervised brushing at school, once every month, with a  uoride solution.
When this programme was carried out in children ever y 2 weeks during
the school term, the results were dramatic, the number of lesions per year
reducing from 3 per child to a single lesion in every 10 children. Later studies
by the Karlstad group showed the caries-controlling effect could be retained
in well-motivated children and adults, despite increasing inter vals between
appointments up to 3 months.
PREVENTION OF CARIES BY PLAQUE CONTROL
Researchers who have applied this method in other populations have not
always obtained such impressive results but it does appear particularly effective
on tooth surfaces that are difficult to clean, such as approximal surfaces and
erupting occlusal surfaces. This is a highly expensive treatment programme, but
it may be justified in the management of some highly caries active patients