Teeth are said to be the hardest substances in the human body—so hard, in fact, that only specialised tools can cut through them. Despite their sheer strength, however, teeth are still prone to damage.

It may come as a surprise to some but tooth decay is actually quite a common problem in the general population. As a matter of fact, tooth decay is second only to the common cold in terms of frequency of incidence.

There are many reasons why teeth may become decayed or go bad, but chief among all these is improper mouth care and oral hygiene. This is because inadequate tooth brushing leaves food and bacteria in the mouth, which can form a sticky layer on the surface of teeth called plaque. Bacteria in the mouth consume the sugars and leftover food, and in the process, they release acids which then dissolve the minerals of the tooth. With prolonged exposure to the acids and bacteria, teeth can eventually rot and change colour. Rotted areas turn into those familiar dark spots commonly known as cavities, or what dentists call dental caries.
Dental caries may not present any signs and symptoms in the beginning, save for the change in colour of affected areas.

Over time, however, as the infection spreads deeper into the layers of the tooth, dental caries can lead to pain. This occurs when the infection breaches the enamel and dentin layer and invades the root pulp which contains the nerves of the tooth. Pain secondary to tooth decay can present in many ways: some sufferers experience sharp pains that shoot downwards along the neck while others feel a dull constant pain that may be throbbing in nature or not.

In addition to pain, bad teeth can also present with concurrent illnesses in the chest or sinus regions. This is because the infection can spread into these adjacent areas, causing patients to experience frequent chest colds, sinus infections, gum infections or headaches. Tooth decay, when left untreated, can lead to formation of abscesses. Dangerous consequences of extensive tooth decay are heart and brain infections—the bacteria can spread to these areas by way of blood vessels.

Treatment for tooth decay depends on the extent of the infection. For minor surface cavities, removal of infected parts by drilling and placement of fillings may be the only treatment needed. For deeper infections, however, root canal therapy, extraction, and replacement of teeth may be necessary.
The best way to prevent tooth decay is to practice good dental hygiene. This means regular brushing and flossing, and prompt consultation with a dentist whenever issues with the teeth arise.