For Decay/caries to occur it requires multiple factors
(bacteria, diet, host, and time), diet is one of these main
contributing factors. (Learn more about the other factors
here) Fermentable carbohydrates are consumed by the bacteria
to begin the decay/caries process which can eventually
destroy teeth. These include the usually well-known sugary
foods such as lollies, cookies, soft drinks, and cakes. But
surprising to most it also includes foods like bananas,
crackers, breakfast cereals (Frosties, Fruit loops,
Nutri-grain) and bread.
When the bacteria use these fermentable carbohydrates, they
release acidic waste. This has two problems. First it
changes the environment which can cause the change in the
composition of plaque encouraging more acidic bacteria to
thrive and survive (ecological plaque hypothesis). With more
acidic bacteria and more fermentable carbohydrates this
encourages more grow, quicker release, and longer exposure
to acid. The second problem is that more acid in the mouth
lowers the pH. When the pH of the tooth surface falls below
the critical pH (5.5 in enamel and 6.5 in dentine),
demineralisation (loss of mineral) occurs. Decay/Caries
occurs when net demineralisation (Loss of mineral) exceeds
net remineralisation (gain of mineral).
Although not all sugars are equally cariogenic/decay at
causing the same extent of tooth destruction. Complex
carbohydrates such as starch are not completely digested in
the mouth and have a low cariogenicity (decay causing).
Simple carbohydrates such as glucose and fructose easily
diffuse into plaque, are transported into bacterial cells,
and have a high cariogenicity (causing).
Acid is one of the main reasons your teeth break down. It
requires the right bacteria and their sugary food source
to produce the acid. Therefore, after eating something
sugary the bacteria utilizes these sugars produce acid,
this can lower the pH of the environment which can result
in tooth decay. Some soda/fizzy drinks have both acid and
sugar which is like a double hit at lowering the pH. The
pH is a scale used to specify acidity or basicity of an
aqueous solution. With lower pH being more acidic.
The Stephan curve was a graph designed to model how plaque
reacts with fermentable carbohydrates particularly sucrose
over time.
Normally the mouth sits at around 7 which is a neutral pH.
When the mouth is exposed to acidic drinks or sugary food
that the bacteria can utilize and turn into acid this
results in a drop in the pH into the red section. It is in
the red section when the tooth is prone to decay. The
outer white layer (enamel) can usually withstand pH values
greater than 5.5 before decay occurs whereas the second
yellow layer (Dentine) can only withstand pH values
greater than 6.5. As a result when you have gum disease or
the yellow dentine layer becomes exposed to the oral
environment it is more prone to decay as 6.5 is close to
7.0 and small changes drop this if you are not careful.
However, the body has mechanisms to bring the pH back to
normal levels. It uses saliva that has protective
buffering superpowers to re-establish the balance.
Unfortunately, this can take time to kick in. There are
ways you can help the body. That can be rinsing with water
or milk which help to reestablish the pH. Chewing sugar
free gum helps more saliva be produced from the parotid
glands and limiting snacking.
When you frequently snack, you do not give your body a chance to get back to a neutral level. It is like trying to use your phone every second instead of letting it fully charge. Eventually the battery will wear down. Instead when you let you mouth return to a neutral pH with less acid insults. It is like letting your battery fully recharge in each hit. This way the phone battery lasts longer, and you get better use out of the phone.
If you have finished reading all the information on this page, get a certificate for your hard work.
This page provides general information about dental topics. It does not contain all the known facts of this subject and is not intended to replace personal advice from your dentist. If your not sure about anything on this site, contact us or speak to your local oral health practitioner. Make sure you give your local oral health practitioner your complete medical history and dental history.
References:
Rugg-Gunn, A. J., & Murray, J. J. (1983). The role of sugar in the
aetiology of dental caries. Journal of Dentistry, 11(3), 190–199.
doi:10.1016/0300-5712(83)90183-5
Gustafsson, B. E., Quensel, C.-E., Lanke, L. S., Lundqvist, C.,
Grahnén, H., Bonow, B. E., & Krasse, B. (1953). The Effect of
Different Levels of Carbohydrate Intake on Caries Activity in 436
Individuals Observed for Five Years. Acta Odontologica
Scandinavica, 11(3-4), 232–364.
Krasse, B. (2001). The Vipeholm Dental Caries Study: Recollections
and Reflections 50 Years Later. Journal of Dental Research, 80(9),
1785–1788. doi:10.1177/00220345010800090201
Edgar, W. M., & Higham, S. M. (1995). Role of Saliva in Caries
Models. Advances in Dental Research, 9(3), 235–238.
doi:10.1177/08959374950090030701
Bowen, W. H. (2012). The Stephan Curve revisited. Odontology,
101(1), 2–8. doi:10.1007/s10266-012-0092-z
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