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Diet and dental caries
Sucrose
Dietary sugars all diffuse into plaque rapidly and are fermented to
lactic and other acids or can be stored as intracellular polysaccharides by
the bacteria, but sucrose has more cariogenicity than other sugar types. It
has been called the arch - criminal in dental caries.
The epidemiological evidence for sucrose as the cause of dental caries
Low caries prevalence in population with low sucrose intake
The decline in caries prevalence during wartime with sucrose
shortage
The rise in caries prevalence with increasing availability of sucrose
Archeological evidence of low caries prevalence in areas before
sucrose became freely available
Low caries prevalence in disorders of sucrose metabolism
(hereditary fructose intolerance).
Sucrose refined from sugar canes or sugar beets is the most common
dietary sugar and is largely responsible for the effect of sugar which
favor colonization by oral microorganisms and increase the stickiness of
the plaque, allowing it to adhere in large quantities to the teeth.
Starch and dental caries
Starch constitutes a heterogeneous food group, it varies in botanical
origin, it may be highly refined or consumed in its natural state, it may
be consumed raw or in a cooked form. All these factors should be
considered when assessing the cariogenicity of starches.
Preventive Dentistry
Fifth Grade
أ.م. ساهر سامي
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Starch foods such as rice, potatoes and bread are of low carioganicity in
human. Uncooked starch has very low cariogenicity.
The starch granules in plants are only slowly attached by salivary
amylase because the starch is in an insoluble form and protected by
cellulose membranes. Heating at temperatures used in cooking and
backing, however, causes a partial degradation to a soluble form, which
can be further broken down by salivary and bacterial amylase to
maltose, malt triose, dextrin and small amounts of glucose.
Addition of sugar to cooked starch lead to increase of the cariogenicity
of foods, such as sweetened breakfast cereals, sweet biscuits, cakes and
cookies.
1. Physical form of food and clearance time
In addition to the chemical composition of food, physical and
organoleptic properties (particle size, solubility, adhesiveness, texture
and taste) are important for cariogenicity, since they influence eating
pattern
and oral retention of foods. Diet that results in the greater
retention of refined carbohydrate over the longest period are the most
cariogenic.
The carbohydrate in various drinks are eliminated within 5 minutes
while sweets such as sugar containing chewing gum, toffees and
lozenges generally give high oral sucrose concentration and
clearance time from 40 minutes for chewing gum to 15-20 minutes
for other sweets.
The texture of the diet is also important, for both salivary secretion
and elimination of fermentable carbohydrate from the oral cavity.
A diet that require thorough chewing will result in the secretion of
high amount of saliva with a high pH and strong buffering
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capacity, in contrast to finely textured diet that require little
mastication tend to be retained in the oral cavity and eliminated
slowly.
2. Factors in the diet that protect against dental caries
Food and food components that have anticariogenic properties are
sometimes referred to as “cariostatic factors”. Fluoride is the most
effective of these factors. However, dairy products, plants foods, tea and
even chocolate contain factors that protect against caries. Other factors
are:
Phosphate
The possible caries inhibiting effect of various phosphate, which are
found naturally in many foods. The most promising of the organic
phosphate was phytate, identified as the most active substance in
unrefined cereals. The effectiveness of phytate appears to be due to its
ability to adsorb readily and firmly to enamel surfaces and so prevent the
dissolution of enamel by acids. Phosphates are anticariogenic and appear
to be most effective. Phosphate exhibit their anticariogenic action via
local factors like:
Reduction of enamel solubility
Buffering effect in neutralizing salivary plaque
Rendering fats, carbohydrates and proteins which are less
cariogenic
Interference with enzymatic process on enamel surface to increase
host resistance
Decrease in bacterial adhesion
Interference with synthesis of extracellular polysaccharide
formation
Maintenance or increase of plaque calcium and phosphorous level.
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Other inhibitors like pyridoxine, fat, tannic acid, constituents of coca,
butter are believed to have caries protective factors.
Fat
Fat seems to reduce cariogenicity of food through different ways:
They may act merely by replacing carbohydrate in the diet.
Fat may also form a protective barrier on the enamel, or surround
the carbohydrates, making them less available and speeding up
their removal from the mouth.
Bacterial surface properties involved in plaque formation could
also be altered by fats.
Certain fatty acids have antimicrobial effect and have been shown
to inhibit glycolysis in human dental plaque.
Fruit and dental caries
Fruit and vegetable contain more non-starch polysaccharides and plant
cell wall materials that benefit health. It is preferable to consume whole
fresh fruit as opposed to juice, because their mastication provide a good
stimulus to salivary flow. In addition, fresh juices contain non-milk
extrinsic sugars since liquidation release the fruit sugar from the cellular
structure of the fruit. There is little evidence from epidemiological
studies in humans that consumption of fruit is associated with the
development of caries and induced negative correlation between fruit
consumption and dental caries have been reported.
Milk
Human breast milk: which one of the main sources of sugar in the
diet of small children, normal milk consumption does not cause
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dental caries. It contains higher lactose (7%) and lower
phosphorous (15 mg/100 g) and calcium (34 mg/100 g) than cow’s
milk.
Cow’s milk: contain lactose (4-5%), which is less acidogenic than
other sugar, and also contain calcium (125 mg/100 g), phosphorous
(96 mg/ 100 g) and casein, all of which are cariostatic (prevent
enamel demineralization).
Milk rich with calcium and phosphate which act by:
A. Reducing the rate of dissociation of hydroxyl apatite
B. Reducing the fall in pH by buffering acids produced by
fermentation.
C. Enhancing remineralization.
D. Modifying formation and composition of pellicle and plaque.
Cheese
Numerous animal and experimental studies have indicated that cheese is
anticariogenic because it stimulates salivary secretion and increase
plaque calcium concentration which strongly influences the balance
between de- and remineralization of enamel.
Plant foods
It contains organic phosphate, inorganic phosphate and phytate. The
organic phosphate protect the teeth by adsorbing onto the enamel,
forming a protective coat, also inorganic phosphate have been found to
be effective cariostatic and prevent demineralization of enamel. Phytate
is anticariogenic and act by adsorbing onto the enamel surface to form a
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physical barrier that protects against plaque acids. Also plant foods
(fibrous foods) stimulate salivary flow. Saliva not only help to clear food
debris from the mouth, but also buffer plaque acid, and therefore, favor
remineralization of tooth enamel. (on animal studies only but human
studies have not produced convincing results).
Chocolate
It contain theobromide which is able to increase crystal size in enamel,
thus increasing the resistance to demineralizing acids. However, the high
sugar content of chocolate outweighs these potential effects.
Tea and apple
Apples contain polyphenol (which have antibacterial action) and are
good stimulus to salivary flow.
Tea contain polyphenol in addition to fluoride and flavonoid.
Black tea extracts have been shown to inhibit salivary amylase activity
and reduce dental caries.
3. Intake frequency
Greater the intake frequency of cariogenic food, greater the
susceptibility to decay. Frequent snacking in between meals increase the
duration of time for which plaque pH remains below the critical value
(5.2-5.5) and thus greater demineralization attacks on the teeth.
4. Chemical composition
Carbohydrates are classified as monosaccharide, disaccharide and poly
saccharides. Sucrose which is a disaccharide consisting of fructose and
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glucose is more easily fermentable than polysaccharide as starch. Earlier
it was thought that consumption of sugar mainly sucrose was the key
factor in the development of dental caries. But processed cooked starchy
foods, especially when combined with refined sugar (doughnut, pastry,
potato chips) also contribute to dental caries.