The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include:
• Enamel: The hardest, white outer part of the tooth. Enamel is mostly made of calcium phosphate, a rock-hard mineral.
• Dentin: A layer underlying the enamel. It is a hard tissue that contains microscopic tubes. When the enamel is damaged, heat or cold can enter the tooth through these paths and cause sensitivity or pain.
• Pulp: The softer, living inner structure of teeth. Blood vessels and nerves run through the pulp of the teeth.
• Cementum: A layer of connective tissue that binds the roots of the teeth firmly to the gums and jawbone.
• Periodontal ligament: Tissue that helps hold the teeth tightly against the jaw.
A normal adult mouth has 32 teeth, which (except for wisdom teeth) have erupted by about age 13:
• Incisors (8 total): The middlemost four teeth on the upper and lower jaws which are for biting and cutting the food.
• Canines (4 total): The pointed teeth just outside the incisors which are for tearing the food.
• Premolars (8 total): Teeth between the canines and molars.
• Molars (8 total): Flat teeth in the rear of the mouth, best at grinding food.
The root of each tooth descends below the gum line, into the jaw.
- Cavities (caries): Bacteria evade removal by brushing and saliva and damage the enamel and deeper structures of teeth. Most cavities occur on molars and premolars.
- Tooth decay: A general name for disease of the teeth, including cavities.
- Periodontitis: Inflammation of the deeper structures of the teeth (periodontal ligament, jawbone, and cementum). Poor oral hygiene is usually to blame.
- Gingivitis: Inflammation of the surface portion of the gums, around and between the crowns of the teeth. Plaque and tartar buildup can lead to gingivitis.
- Plaque: A sticky, colorless film made of bacteria and the substances they secrete. Plaque develops quickly on teeth after eating sugary food, but can be easily brushed off.
- Tartar: If plaque is not removed, it mixes with minerals to become tartar, a harder substance. Tartar requires professional cleaning for removal.
- Overbite: The upper teeth protrude significantly over the lower teeth.
- Underbite: The lower teeth protrude significantly past the upper teeth.
- Teeth grinding (bruxism): Stress, anxiety, or sleep disorders can cause teeth grinding, usually during sleep. A dull headache or sore jaw can be symptoms.
- Tooth sensitivity: When one or more teeth become sensitive to hot or cold, it may mean the dentin is exposed.
- Brushing teeth: Daily brushing of the teeth removes plaque and helps prevent cavities.
- Flossing teeth: Using floss or an approved dental gum cleaner cleans teeth below the gum line, where brushing cannot reach.
- Rinsing teeth: Rinsing daily with an antiseptic mouthwash kills bacteria that cause bad breath and gum disease.
- Teeth cleaning: Professional teeth cleaning every six months may help prevent teeth and gum disease.
- Tooth filling: Drilling out the diseased part of a tooth and packing the space with a mineral filling can prevent a cavity from destroying the tooth.
- Root canal: The deep pulp of a tooth is drilled out, cleaned, and filled. A root canal is done when damage to the teeth has affected the deep pulp.
- Tooth extraction: If a tooth is too damaged to repair with a filling or root canal, it may be removed. Wisdom teeth are often extracted to prevent displacement of the other teeth.
- Braces: An artificial device or system that places teeth under tension for a long period of time. Eventually, braces can help crooked teeth become realigned.
- Mouth guard: A plastic mouthpiece can provide protection from teeth grinding and injury during sports.
- Dental sealants: A plastic sealant applied to the teeth can help block bacteria from hiding in crevices on teeth surfaces. Sealants can help prevent cavities.
- Teeth whitening: Over-the-counter and professional chemical treatments can bleach teeth to a brighter white. Tooth sensitivity is the most common side effect.