What are cavities? Causes, symptoms and prevention

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_{This article is intended for information purposes only and does not constitute or replace advice from a medical professional.}

The term “cavity” is another name for tooth decay. Tooth decay is heavily influenced by many factors, including your lifestyle, what you eat, how well you take care of your teeth, if your drinking water is fluoridated and if you use fluoride toothpaste. Genetics also play a role in how susceptible your teeth may be to decay.

Cavities can be very serious. If left untreated, decay can destroy your tooth and kill the delicate nerves at its centre, which may result in an abscess, an area of infection inside your tooth. Once an abscess forms, it can only be treated with a root canal, surgery or by extracting the tooth. Read on to find out more about what causes cavities, signs of a cavity and how to prevent cavities.

What are the signs of a cavity?

Some cavities look and feel like a very obvious hole in your tooth, whereas others develop below the tooth's surface, where you can't see them. If you’re experiencing any unusual tooth pain or cavity symptoms, your dentist will be able to confirm if there’s underlying tooth decay. When you eat foods that contain carbohydrates (sugars and starches), these carbohydrates are eaten by the bacteria in plaque and produce acids that eat into the tooth. Over time, your tooth enamel begins to break down beneath the surface while the surface remains intact. When enough of the sub-surface enamel is eaten away, the surface collapses, forming a cavity.

Cavities are most likely to develop in pits on the chewing surfaces of the back teeth, in between teeth, and near the gumline. But regardless of where they occur, the best way to spot and treat them before they become serious is by visiting your dentist regularly for checkups.

What causes cavities?

So, what causes cavities? Cavities are common and can be caused by several factors, including:

Eating lots of carbohydrates and sugary foods and drinks.
Snacking a lot throughout the day.
Poor oral hygiene or not brushing your teeth thoroughly.
Not getting enough fluoride from your toothpaste or water supply.
Medical conditions like dry mouth or GERD.
Age.
Older fillings that need to be replaced.

Stages of tooth decay

Tooth decay is a process that occurs over time. Here are the 3 stages of a cavity developing:

Plaque forms – when you eat a lot of carbohydrates and sugary foods, plaque can form on and between your teeth if you don’t clean them properly. Bacteria start feeding on the plaque and can harden into tartar. Tartar acts as a shield for the bacteria and can only be removed by your dentist.
Plaque attacks – the bacteria demineralise your tooth enamel and cause tiny openings or holes. These are called caries and are the early signs of a cavity. Once the enamel is weakened, the bacteria can eat deeper into your tooth, reaching the dentine underneath. Dentine is soft and sensitive, and when decay reaches this stage, you may feel pain or sensitivity.
Damage continues – if left untreated, the bacteria will eventually reach your tooth pulp, which contains nerves and blood vessels. The pulp becomes infected and can cause a lot of pain and possible swelling. Damage can even spread outside the tooth to the bone, resulting in tooth loss.

Types of cavities

While cavities are usually more common among children, adults are also at risk. The types of cavities include:

Pit and fissure cavities – the most common type of cavity that occurs in both children and adults, pit and fissure cavities usually are located on the chewing surfaces or between your teeth.
Smooth surface cavities – these cavities can occur on the smooth sides of your teeth.
Root cavities – as we age, gums can recede, leaving parts of the tooth root exposed. Since there is no enamel covering tooth roots, these exposed areas can easily decay.

How are cavities treated?

The sooner cavities are identified and treated, the better. If you’ve ever wondered what dentists do to cavities, we’ve outlined a few treatment options depending on how advanced your tooth decay is.

Fluoride treatment – If you have the early signs of a cavity, a fluoride treatment can be applied to your teeth in the form of a paste or gel to help restore the minerals in your tooth enamel. This is a quick and painless treatment that will only help very early signs of a cavity.
Fillings – Fillings are the most common treatment for tooth decay. Your dentist will remove the area of decay, clean your tooth and fill the hole with either a tooth-coloured composite resin, dental amalgam or porcelain.
Crowns – If your tooth is heavily decayed or weakened, your dentist may suggest a crown instead. This involves removing the decayed area and fitting a crown over your tooth to make sure the inside of your tooth stays protected.
Root canal – If the cavity has progressed and has reached your tooth pulp, you may need a root canal to save your tooth. This involves going deeper into your tooth, removing the infected tooth pulp, cleaning the tooth out and filling the hole.
Extraction – If your tooth decay has progressed to a stage where your tooth can’t be restored, your dentist may suggest a tooth extraction to prevent the bacteria from spreading further.

When to see a dentist

Make an appointment with your dentist if you suspect you have tooth decay and are experiencing any of these cavity symptoms:

Bleeding gums
Trouble eating or chewing
Swollen face
Signs of infection, like a bad/metallic taste in your mouth
Toothache

What can you do until your appointment?

While you’re waiting for your appointment, there are some things you can try that may help alleviate cavity symptoms like pain or discomfort.

Take painkillers like paracetamol or an anti-inflammatory like ibuprofen*.
Brush your teeth with warm water instead of cold.
Use a toothpaste designed for sensitive teeth.
Try to keep your mouth as clean as possible, even around the area of discomfort.
Avoid foods and drinks that are very hot, cold or sweet.

How to prevent cavities

If you’re wondering how to prevent cavities or how to prevent a small cavity from getting bigger, there are a few changes you can make to your oral care routine and lifestyle changes that can help.

Brush at least twice a day using a soft-bristled toothbrush and fluoride toothpaste, especially after eating. Using a fluoride mouthwash can also help with freshening your mouth during the day.
Floss every night to remove any food particles stuck between your teeth.
Have regular dental checkups. Preventative care can help stop problems from occurring and keep minor problems from becoming major ones.
Eat a well-balanced diet that limits starchy or sugary foods. When you do eat these foods, try to eat them with your meal instead of as a snack to minimise the number of times that your teeth are exposed to acid.
Visit your dentist every 6 months for checkups and professional cleaning.
Check if your children's drinking water is fluoridated. If your water supply does not contain fluoride, your dentist or paediatrician may prescribe daily fluoride supplements.

FAQs

Here are the answers to some commonly asked questions about cavity symptoms:

A cavity can be a visible hole in your tooth, but sometimes they are not visible to your eye. Instead, you may notice common cavity symptoms like a dark spot or discolouration, persistent bad breath, sensitivity or a toothache. Make an appointment to see your dentist if you’re having ongoing trouble with these symptoms.

If a cavity hurts, it doesn’t mean your tooth can’t be saved; however, it does mean you should make an appointment to see your dentist for treatment as soon as possible.

You may be able to see or feel a hole in your tooth that is very clearly a cavity. However, sometimes the decay can lie beneath the surface of the tooth and is not always visible to you. Instead, you may notice a white, brown or discoloured spot, or even a crack on the surface of your tooth. Make an appointment to see your dentist if you suspect you may have a cavity.