Tooth Anatomy and Decay

​Tooth Anatomy

What Are the Different Parts of a Tooth?

Parts of Teeth

• Crown - the top part of the tooth and the only part you can normally see. The shape of the crown determines the tooth's function. For example, front teeth are sharp and chisel-shaped for cutting, while molars have flat surfaces for grinding.
• Gumline - where the tooth and the gums meet. Without proper brushing and flossing, plaque and tartar can build up at the gum line, leading to gingivitis and gum disease.
• Root - the part of the tooth that is embedded in bone. The root makes up about two-thirds of the tooth and holds the tooth in place.

• Enamel - the outermost layer of the tooth. Enamel is the hardest, most mineralised tissue in the body - yet it can be damaged by decay if teeth are not cared for properly.
• Dentin - the layer of the tooth under the enamel. If decay is able to progress its way through the enamel, it next attacks the dentin - where millions of tiny tubes lead directly to the dental pulp.
• Pulp - the soft tissue found in the centre of all teeth, where the nerve tissue and blood vessels are. If tooth decay reaches the pulp, you usually feel pain.

What Are the Different Types of Teeth?

Every tooth has a specific job or function

• Incisors—the sharp, chisel-shaped front teeth (four upper, four lower) used for cutting food.
• Canines—sometimes called cuspids, these teeth are shaped like points (cusps) and are used for tearing food.
• Premolars—these teeth have two pointed cusps on their biting surface and are sometimes referred to as bicuspids. The premolars are for crushing and tearing.
• Molars—used for grinding, these teeth have several cusps on the biting surface.

What are Tooth Cavities or Tooth Decay?

"Cavities" is another way of saying tooth decay. Tooth decay is heavily influenced by our lifestyle, what we eat, how well we take care of our teeth, and the presence of fluoride in our water and toothpaste. Heredity also plays a role in how susceptible your teeth may be to decay.

Types of Tooth Cavities

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

• Coronal cavities—the most common type occurring in both children and adults, coronal cavities are usually located on chewing surfaces or between the teeth.
  
• Root cavities—as we age, our gums recede, leaving parts of the tooth root exposed. Since there is no enamel covering tooth roots, these exposed areas easily decay.
  
• Recurrent decay—​decay can form around existing fillings and crowns. This is because these areas tend to accumulate plaque, which can ultimately lead to decay.
  

Risks and Consequences of Tooth Cavities

Adults are especially at risk for cavities or tooth decay if they suffer from dry mouth, a condition due to a lack of saliva. Dry mouth may be caused by illness, medications, radiation therapy and chemotherapy, and may be temporary (days to months) or permanent, depending on its cause.

Cavities are very serious. Left untreated, a tooth cavity can destroy your tooth and kill the delicate nerves at its centre, which may result in an abscess, an area of infection at the root tip. Once an abscess forms, it can only be treated with a root canal, surgery or by extracting the tooth.

How Do I Know if I Have a Tooth Cavity?

Only your dentist can tell for sure whether you have a tooth cavity. That's because cavities develop below the tooth's surface, where you can't see them. When you eat foods that contain carbohydrates (sugars and starches), these carbohydrates are eaten by the bacteria in plaque, producing acids that eat into the tooth. Over time, the 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 them and treat them before they become serious is by visiting your dentist regularly for check-ups.

How Can I Help Prevent Cavities and Tooth Decay

• Brush at least twice a day and floss daily to remove plaque from between teeth and below the gumline.
  
• Have regular dental check-ups. Preventive 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.
  
• Use dental products that contain fluoride, including toothpaste.
  
• Make sure that your children's drinking water is fluoridated. If your water supply does not contain fluoride, your dentist or paediatrician may prescribe daily fluoride supplements.
  

What Is Fluoride?

Fluoride is a natural mineral found throughout the earth's crust and widely distributed in nature. Some foods and water supplies contain fluoride.

Fluoride is often added to drinking water to help reduce tooth decay. In the 1930s, researchers found that people who grew up drinking naturally fluoridated water had up to two-thirds fewer cavities than people living in areas without fluoridated water. 

Studies since then have repeatedly shown that when fluoride is added to a community's water supply, tooth decay decreases. The American Dental Association, the World Health Organization and the American Medical Association, among many other organisations, have endorsed the use of fluoride in water supplies because of its effect on tooth decay.

How Does Fluoride Work?

Fluoride helps prevent cavities in two different ways:

• Fluoride concentrates in the growing bones and developing teeth of children, helping to harden the enamel on baby and adult teeth before they emerge.
• Fluoride helps to harden the enamel on adult teeth that have already emerged.
• Fluoride works during the demineralisation and remineralisation processes that naturally occur in your mouth.
• After you eat, your saliva contains acids that cause demineralisation - a dissolving of the calcium phosphate under the tooth's surface.
• At other times when your saliva is less acidic, it does just the opposite, replenishing the calcium phosphate that keeps your teeth hard. This process is caused remineralisation. When fluoride is present during remineralisation, the minerals deposited are harder than they would otherwise be, helping to strengthen your teeth and prevent dissolution during the next demineralisation phase.

How Do I Know if I'm Getting Enough Fluoride?

If your drinking water is fluoridated, then brushing regularly with fluoride toothpaste is considered sufficient for adults and children with healthy teeth at low risk of decay.

If your community's water is not fluoridated and does not have enough natural fluoride in it (1 part per million is considered optimal), then your dentist or paediatrician may prescribe fluoride tablets or drops for your children to take daily. Your dentist or paediatrician can tell you how much fluoride is right for your family, so be sure to ask for his or her advice.

If your water comes from a public water supply, you can find out if it's fluoridated by calling your local water district. If your water comes from a private well, you can have it analyzed by an independent environmental testing company that provides water-testing services.

Early Childhood Cavities

Sometimes called baby bottle tooth decay, early childhood cavities is a serious disease that can destroy your child's teeth, but it can be prevented.

What Causes Early Childhood Cavities?

• Letting your baby fall asleep with a bottle. When your baby is asleep, the liquids that contain sugar stay around the teeth and can cause decay. Even breast milk and formula contain sugar.
• Prolonged nursing or allowing your baby to fall asleep while nursing.
• Allowing your infant to walk around with a bottle.

Put Your Child To Bed Without a Bottle...

Your child can fall asleep without a bottle! Here are five tips to try:

• Let your child take a "security" blanket, teddy bear, doll, or favourite toy to bed.
• Quietly sing or play restful music.
• Hold or rock your child.
• Give your child a back rub to help him or her to relax.
• Read or tell your child a story.

What Are the Effects of Early Childhood Cavities?

• Tooth loss
• Ear and speech problems
• Crooked permanent teeth
• Severe pain
• Poor self-image
• Tooth decay

How Can I Prevent Early Childhood Tooth Cavities?

• Get into the habit of putting your baby to bed without a bottle.
• Never put the baby to bed with a bottle filled with formula, milk, juice, sugar water, or soda pop. If your baby must have a bottle to go to sleep, fill it with water.
• Do not let your infant walk around with a bottle.
• Start teaching your infant to use a cup between 6-12 months. Trade your baby's bottle for a training cup by age one.
• Check with your doctor or dentist to make sure your child is getting enough fluoride each day.

Your child's healthy teeth and brilliant smile depend on you!

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