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Preventive Dental Information

This article, the second in the series, is written to educate young adults in understanding the effects of sugar on your teeth.

Dietary sugars play a major role in tooth decay

The modern diet sadly consists of significant quantities of refined carbohydrate (sugars).  These can be considered fermentable sugars and suitable food for the near 500 different species of bacteria that live in the human mouth. Carbohydrates are often hidden in foods as preservatives, especially in pre-packaged, processed and tinned foods.  Beware of this and read the labels for these hidden sugars.

BEWARE, if you buy “low fat” versions of foods, the manufacturers will replace the fats that are removed, with sugars. If you compare the sugar content of full-fat and low-fat yogurts, you will see the difference is clear in the total sugar contents in the nutritional information table. This is another example f hidden sugars used in the manufacture of processed foods. These sugars will provide the plaque bacteria with the means to produce acid to cause decay and toxic chemicals that initiate gum inflammation leading to gum disease.

Chemicals produced by bacteria include organic acids that attack the tooth surface causing demineralisation (dissolving of the calcium in the tooth structure) later cavity formation as the surface layer breaks down to reveal a cavity beneath, that results from the demineralisation process.

Measuring the acid-alkaline balance of the mouth can assess the risk of decay. We call this measurement the pH. If we measure the pH over the day, it varies depending on what foods are eaten. After any sugar, the bacteria ferment the sugar into acid. As a result, the pH of the mouth falls from the neutral value of around 7.0 to an acid value of around 3.5. If no more sugar is ingested, the saliva flows, the sugar is cleared from the mouth and over 40 minutes the pH increases, gradually returning to around the neutral value of 7.0.

Snacking or grazing is a problem

A common problem we face in our modern lifestyle is snacking or grazing: the regular intake of small quantities of food/beverage that takes place throughout the day. This is often referred to as “grazing”. Regular intake of sugar in tea, coffee, carbonated drinks, biscuits, candy, cakes and chewing gum are hidden sugars allows the plaque to grow, and to ferment the sugars producing a broad range of chemicals.

However, in patients who are grazing or snacking regularly and ingesting sugars from whatever source through the day, the pH decreases to an acid level but the bacteria of the mouth but never gets the chance to return to neutral, as sugar is repeatedly introduced to the bacteria of the mouth and they constantly ferment the sugar producing acid. This results in an almost constant acid environment for the teeth with no time for re-mineralisation, only ongoing demineralisation and cavity formation.

This is the reason why dentists and hygienists tell patients that they should try to limit sugar intake to mealtimes. This allows the pH of the mouth sufficient time to return to neutral and for re-mineralisation of the early decay lesions to take place every day.

The “demon” fizzy drinks

One of the most popular fizzy drinks(Coke-Cola) is also one of the most damaging constituents of our diet. Other drinks including high energy drinks are also very damaging to teeth. Many of these drinks have three problems;

  • they are full of sugar
  • they are highly acidic
  • they often contain caffeine that promotes the production of urine further dehydrating the person.

Fizzy drinks should not be thought of as a regular dietary component.  They not only contribute to decay by demineralisation but the acidity of the drink itself causes severe destruction to the teeth by dissolving the enamel, a process called erosion.

Caffeine contained in many drinks also causes a further problem.  If caffeine is ingested (in tea, coffee and in some cold drinks) it leads to an increase in urine output.  We refer to this as a diuretic effect. This leads to additional dehydration and as a result, the body tries to prevent the further loss of water.  This is achieved by reducing the production of other body secretions, one of which is the saliva.

A reduction of saliva leaves the teeth less protected from the acids produced by the plaque. It reduces the ability of the mouth to neutralise the acids produced by the plaque and the acids ingested as part of the diet.

The healing power of saliva

The saliva also delivers minerals that repair the demineralised areas of the teeth that have suffered from acid attack (demineralisation) during the day.  The natural mineral content of saliva results in the demineralised zone of the enamel taking up calcium and phosphate which strengthens the damaged enamel surface. This is a process called re-mineralisation.

After having allowed time for neutralisation of the acid and clearance of the acid by salivary flow, then is the best time to brush the teeth with a fluoride toothpaste. Brushing too soon after consuming sugars means you are brushing tooth surface that has been microscopically softened on the surface (due to acid demineralisation) allowing the mechanical abrasion by the toothbrush removing a very small (microscopic) quantity of enamel from the tooth.  This act of brushing softens the enamel repeated many hundreds of times, can damage the teeth leading to enamel wear and sensitivity of the tooth to cold foods and drinks.

The constant flow of saliva assists in keeping the entire mouth healthy.  Without saliva, the mouth feels dry (called Xerostomia) and this can make swallowing difficult and can cause difficulty speaking.  Both these effects arise due to the dryness of the soft tissues.  However, the lack of saliva may also contribute to gum disease.

The benefits of saliva summarised:

  • lubrication of the oral soft tissues
  • helps with speech
  • helps in swallowing food
  • neutralises acids in the mouth
  • washes away sugar residues from the mouth after eating
  • antibacterial effects limiting bacterial growth.

The antibacterial effect of saliva’s natural enzyme systems helps in the control of the bacteria that live in the mouth.  Without this control, the bacterial plaque is able to accumulate leading to the formation of tartar (also known as calculus) on the tooth and root surfaces.  This calculus assists in the development of gum disease.

Dietary sugar control is a must

Limiting the number of times sugar is consumed each day is the best way to prevent tooth decay.  In other words, avoid “drip-feeding” sugar into the mouth with all those small snacks and drinks throughout the day.  When you are thirsty, the best drink is water, pure and simple!

It is best to try to limit the sugar supply to the bacteria in the plaque to no more than three mealtimes each day.   Once a meal is over, it is best to neutralise the acid produced by the bacteria in the mouth before brushing the teeth.  This can be achieved by chewing sugar-free gum or a little cheese, which is alkaline and neutralises the acid.  Chewing cheese or sugar-free chewing gum is also effective at removing sugars by stimulating the flow of saliva that washes away food debris and sugar residues so they are swallowed and do not remain in the mouth as food for the plaque bacteria to convert into acid to attack the teeth.

Fluoride is important

Fluoride toothpaste normally has around 1000 parts per million (ppm) of Fluoride.  This is generally the correct concentration for adults.  However, some patients who suffer from extensive or widespread decay may be wise to add, to this use of Fluoride toothpaste, the daily use of a high concentration fluoride mouthwash each night before going to sleep.  This must take place after all food and drink has been consumed and after tooth brushing is complete.   Fluoride mouthwashes vary in concentration from the routine use level of 500-550 ppm to the high concentration Fluoride mouthwashes containing 1000-5000 ppm Fluoride.  In Australia around 1000ppm would be a high concentration Fluoride mouthwash.

Fluoride toothpaste protects the teeth from decay by reinforcing the enamel and making it more resistant to acid attack.  It can only do this if it is left on the teeth so over night the fluoride can be absorbed onto the tooth enamel and dentine (where it is exposed) and thereby strengthen the tooth surface and repair any areas of acid attack that has take place during the day.

After brushing with fluoride toothpaste or rinsing with a fluoride mouthwash, you should only spit out the excess toothpaste or mouth wash and NOT wash out your mouth with water.  Leaving the fluoride on the teeth is most important to provide an environment suitable for the overnight repair of demineralisation.

Thank you for reading the second part of our “Preventive dental information for young adults” article, we will be posting the fourth and final part soon.

Contact the friendly team at NQ Surgical Dentistry today on (07) 4725 1656 or call in to see us at 183 Kings Rd, Pimlico QLD 4812


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