Tooth Decay : Sensible Advice On Prevention

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Tooth Decay : Sensible Advice On Prevention

by Dental Design, on 10th July 2014 | Comments Off on Tooth Decay : Sensible Advice On Prevention

When you eat sugar-containing food or drink something that contains sugar, (natural or added), something happens in your mouth.

The bugs in plaque use this sugar for fuel. They create acid from the sugars through fermentation, and this causes the environment of your mouth to become acidic. In technical terms, the pH of your mouth drops.


This is important, because when the pH of your mouth drops, and your plaque is making acid, that acid has the ability to dissolve the minerals, such as calcium, out of the tooth surface, a process known as DEMINERALISATION.


The critical pH level in your mouth is 5.5, as it is when the pH drops below this point, that your teeth start to dissolve. This process is the first step in dental decay.


Stephan Curve

The Stephan Curve shows the effect of eating and drinking sugar-containing food in a graphical form.

It uses the pH scale; pH is simply a measure of how acidic an environment is.

7 is the netural point, anything underneath that, is acidic and anything above it, is alkali (or basic) The further away from neutral you get the stronger the acid or alkali environment.


Diet Blog Curve 1

Let’s look at a typical Stephan Curve of a person with little tooth decay.

This person ate 5 times:

Diet Blog Curve 2


Morning snack


Afternoon snack


Now, let’s suppose that this person changes their habits – perhaps they have a new baby and are drinking coffee throughout the day to keep awake.

Let’s see what happens if this person were to drink 3 coffees with sugar during the day (or if you are not a coffee drinker let’s pretend it’s juice or fizzy pop). Let’s also give them a packet of sweets or biscuits to pick at while watching TV in theevening- just before bed. We have marked this line in green.


Can you see how the time spent with dissolving teeth is greatly increased?

Diet Blog Curve 3

If this was your regular routine, over time you would find yourself with quite a few cavities.

Some interesting things to note. You can see:

1: Pretty much every time you eat something, the pH drops below the critical point of 5.5.

(This will not happen if you never eat sugar-containing food. Unlikely but not impossible.)

2: It takes 30-40 minutes for your saliva to get you back to the safe zone.

3: The longer you snack for, the longer you are at risk and the longer it takes for your mouth to recover.

4: If you have something else sugary to eat before your saliva has done its job- Boom! Your curve heads straight back down into acid territory; the danger zone where your teeth dissolve in acid.


Now we have seen what happens- how does this translate into the practical advice your dentist and hygienist give you?

Let’s see how the diet advice from the dentist will correct the dangerous elements of the graph.


1: Avoid sugary snacks between meals. Snacking often is not necessary in a sensible diet.  Eating more at meal times will help reduce snacking. If you must snack, choose a savoury food such as whole nuts, cheese or plain crackers.

2: Group sugary things with your meals, particularly drinks. This includes any squash or fruit juice, sweet hot drinks such as hot chocolate, sweetened tea, sweetened coffee and smoothies.

3: Stop adding sugar to hot drinks, i.e., coffee, tea and chocolate.  Either replace with a non-sugar alternative or sweetener, or better still, give up sweetened hot drinks.

4: Drink water when you’re thirsty in between meals.

5: Keep sugar clear of night time: nothing sugary before bed and nothing sugary during the night. Atnight your saliva flow rate drops- saliva is natural protection so anything left in your mouth during this time does a lot more damage.



Your dentist and hygienist are not on a campaign to remove all pleasurable food from your diet, we just want to give you the evidence based advice that we follow ourselves.

Dentists, dental nurses and hygienists generally get very little tooth decay. This is because we are taught the Stephan Curve and understand its implications. I hope this article will encourage you to think about what your are eating and drinking in between meals and help you to make informed, healthy choices for your teeth.

Written By Aoife O’Donoghue – Dentist

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