• December 7, 2011
  • Dr. Catherine-Anne Walsh

There are many factors that can cause one’s dental health to deteriorate. Here are some of the most basic causes and contributing factors to tooth decay.


Tooth decay and gum disease are bacterial infections. They are infectious diseases. This means that bacteria responsible for tooth decay (aka cariogenic bacteria) are transferred to young, erupting teeth (in toddlers) from people physically closest to them, usually their mothers. Therefore, the old line: “I got my mother’s (father’s) teeth” is not completely untrue. However, as you will soon learn, it is not a good enough excuse for poor dental health.


Once we inherit decay-causing bacteria, we are not necessarily doomed to a lifetime of poor health. Bacteria rely on the sugar in our diet to survive. They break down the sugar and create harmful acids that then dissolve our teeth. Bacteria then get deeper into the little defects in our teeth and continue to burrow into a tooth surface. If they get deep enough into the tooth structure, they are impossible to remove by brushing or rinsing. They are then free to literally consume our teeth. During each meal, our mouth is flushed by acids, aiding the bacteria in their ‘burrowing’ and also changing the environment, so that it promotes more stubborn, ‘nasty’ types of bacteria to multiply. It takes a bit of time for the acids to be neutralized by our saliva, the natural protector of our teeth. If more food is taken in during this period, then the time our teeth are exposed to acids becomes significantly prolonged and the numbers of ‘nasty’ bacteria begin to increase significantly.

Some diet tips:

It’s best to keep meal times 4 hours apart and avoid sweet snacks in between meals. Tooth-friendly snacks are calcium-rich dairy products, nuts and sugar-free gum and you can have these freely.

Avoid acidic drinks such as soft drinks, electrolyte drinks, fruit juice and sparkling mineral water or limit them to one per day, with a meal. Make sure you drink them quickly and wash them down with plenty of water afterwards. 

Chew sugar-free gum or xylitol-containing gum immediately after a meal for up to 10 minutes, to speed up the production of saliva and neutralization of acids. Restrict high-sugar foods to meal times only: your mouth gets acidic no matter what you eat, so chocolate is not forbidden. Drink plenty of water throughout the day, especially before and after meals. This will ensure a good flow of saliva.


Bacteria live in the deposits of plaque on our teeth (the ‘fury’ build-up). They are ‘wrapped up’ between the gums and tooth enamel, covered with remnants of food. If these deposits are not removed, bacteria access the reservoir of food in the plaque and can dissolve teeth for long periods of time. Physical removal of plaque from teeth, gums and the tongue is essential to prevent bacteria from dissolving our teeth. It is not enough to brush. Bacteria and food settle in the hard-to-reach spaces between teeth and can only be removed by flossing, daily.

Brushing your teeth twice per day with a fluoride-containing toothpaste, using a soft toothbrush and flossing daily is the only way to ensure adequate home care for your teeth and gums.


People who suffer a chronic illness or have been exposed to strong medication, radiotherapy or chemotherapy are at higher risk of tooth decay than healthy people. Cancer treatment and most other medication primarily affect salivary glands and their ability to produce ample, good-quality saliva. This dries the mouth and creates a long-term environment which favours ‘nasty’ bacteria, which destroy teeth quickly. It can also be quite uncomfortable and may cause bad breath.

If you have chronic health problems and are on an ongoing medication, talk to your dentist about some strategies and supplements you may be able to use to protect you from tooth decay. These may include higher fluoride toothpaste, calcium moose, mouthwash, dry mouth gel or saliva replacements.



If you are a professional athlete or a keen triathlon and marathon participant, your strenuous training is dehydrating you. If you do not hydrate properly before training and need to catch up during or after the session, you may be using some commercial electrolyte drinks (Powerade, Gatorade, Smart water). These are often sweet and acidic and very damaging to your teeth when your mouth is dry.

Drink plain water before and after each sip of an electrolyte drink. You may also be using glucose pastes, powders or chewable, which sit against your teeth for a prolonged time. Make sure you follow these up with plenty of plain water to wash off residue and neutralise acids.


Recreational drug use is on the rise in Australia. Most recreational drugs, similar to prescribed medication, dry the mouth and leave the user exposed to a higher risk of tooth decay. There are also dietary preferences for sweets and snacks (‘munchies’) that accompany some drug use, which exacerbate the problem. The most damaging dental consequences of drug use come from the drug ‘ice’ (methamphetamine). There is a term in dentistry for the severe destruction of teeth because of ‘ice’ use, called “Meth Mouth”.

If you think you may have a drug addiction, please talk to your GP or contact one of these helplines in Australia:

Family Drug Support 1300 368 186

Kids Help Line1800 551 800

Lifeline13 11 14

Dr. Catherine-Anne Walsh
About The Author

Dr. Catherine-Anne Walsh

Catherine-Anne is a New Zealand-qualified dentist. She holds a Masters Degree in Public Health from Sydney University and she has a broad range of experiences from working in both the public and private sector.


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