Cavity. That's the word no one wants to hear at the dentist's office. A cavity (say: kah-vuh-tee) develops when a tooth decays (say: dih-kaze), or breaks down. A cavity is a hole that can grow bigger and deeper over time. Cavities are also called dental caries (say: kar-eez), and if you have a cavity, it's important to get it repaired.

But why would your tooth develop a hole? Blame plaque. That's a sticky, slimy substance made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids so when plaque clings to your teeth, the acids can eat away at the outermost layer of the tooth, called the enamel (say: ih-nah-mul).

If you don't go to the dentist, the acids can continue to make their way through the enamel, and the inside parts of your tooth can begin to decay. If you've ever had a toothache or heard an adult complain about one, it may have been because there was a cavity that reached all the way inside a tooth, where the nerve endings are. Ouch!

Your dentist will carefully examine your teeth and may take X-rays. If your dentist discovers a cavity, he or she can repair it for you by first removing the rotted part of your tooth with a special drill. The dentist then fills the hole in your tooth with a special material. It's called a filling.

Does it hurt? Sometimes it does, but your dentist can give you an anesthestic. That's a kind of medicine that will numb the area around the problem tooth while you're getting your new filling.

Though cavities can be repaired, try to avoid them by taking care of your teeth. Here's how:

Brush your teeth with fluoride toothpaste after each time you eat or at least twice a day. Bedtime is an important time to brush. Brush up and down in a circular motion. Gently brush your gums as well to keep them healthy. Floss your teeth once a day to remove plaque and food that's stuck between your teeth. Limit sweets and sugary drinks, like soda. See your dentist twice a year for regular checkups. We hope you'll hear those two wonderful words: "No cavities!"

Your mouth is a busy place. Bacteria - tiny colonies of living organisms are constantly on the move on your teeth, gums, lips and tongue.

Having bacteria in your mouth is a normal thing. While some of the bacteria can be harmful, most are not and some are even helpful.

Certain types of bacteria, however, can attach themselves to hard surfaces like the enamel that covers your teeth. If they're not removed, they multiply and grow in number until a colony forms. More bacteria of different types attach to the colony already growing on the tooth enamel. Proteins that are present in your saliva (spit) also mix in and the bacteria colony becomes a whitish film on the tooth. This film is called plaque, and it's what causes

How Cavities Work
Dental cavities, or caries, have plagued mankind for thousands of years. Fossilized remains of men and women from the Iron Age discovered in Warwickshire, England showed a cavity rate of only 8%. When today's Warwickshire inhabitants were compared, a remarkable high cavity rate of 48% was found. A modern diet consisting of highly processed, sugar-containing foods is the most likely culprit. The problem of dental cavities has been steadily increasing for the last four centuries in industrialized nations, and despite a recent dip due to the advent of fluoride, it continues to the present day.

Dental cavities are an infection caused by a combination of carbohydrate-containing foods and bacteria that live in our mouths. The bacteria are contained in a film that continuously forms on and around our teeth. We call this film plaque. Although there are many different types of bacteria in our mouths, only a few are associated with cavities. Some of the most common include Streptococcus mutans, Lactobacillus casei and acidophilus, and Actinomyces naeslundii. When these bacteria find carbohydrates, they eat them and produce acid. The exposure to acid causes the PH on the tooth surface to drop. Before eating, the PH in the mouth is about 6.2 to 7.0, slightly more acidic than water. As "surgery foods" (candy, sugar frosted breakfast cereals, ice cream, soda an kool-aid, etc.) and other carbohydrates are eaten, the PH drops. At a PH of 5.2 to 5.5 of below, the acid begins to dissolve the hard enamel that forms the outer coating of our teeth. Every exposure to these foods allows an acid attack on the teeth for about twenty minutes!

As the cavity progresses, it invades the softer dentin directly beneath the enamel, and encroaches on the nerve and blood supply of the tooth contained within the pulp. (For a more detailed review of how the pulp becomes infected, you can refer to How a Root Canal Works.)

Cavities attack the teeth in two main ways. The first is through the pits and fissures, which are grooves that are visible on the top biting surfaces of the back teeth (molars and premolars). The pits and fissures are thin areas of enamel that contain recesses that can trap food and plaque to form a cavity. The cavity starts from a small point of attack, and spreads widely to invade the underlying dentin.

What the dentists sees when he/she finds a cavity

A cavity detected with an X-ray The second route of acid attack is from a smooth surface, which is between, or on the front or back of teeth. In a smooth surface cavity, the acid must travel through the entire thickness of the enamel. The area of attack is generally wide, and comes to point or converges as it enters the deeper layers of the tooth.

Contact Bay Area Dentists to book an appointment or get more information.