Human teeth consist of four types of tissues: dentin, pulp, enamel and cementum. The pulp is the innermost layer of the tooth followed by dentin and the outer layer which is enamel. The cementum portion of the tooth is located at the base of the tooth, which holds the tooth in place along the jaw line. According to KidsHealth.org, humans develop 20 baby teeth which are later replaced by 32 permanent teeth.
Dental Enamel Erosion
Dental enamel coats each tooth and acts as a protective shield. When the enamel erodes, it causes yellowing to occur. According to the Centers for Disease Control, too much acidic exposure can lead to erosion of dental enamel. The CDC states that questionnaires were mailed to competitive swimmers who all swam in the same swimming pool after a Virginia dentist reported treating two patients with enamel erosion. Water samples were obtained from water in the pool and were tested by Virginia's Consolidated State Laboratories. The results concluded that the pool water was 100,000 more times acidic than what a normal pool should be and believes the acidity in the water contributed to enamel erosion which caused yellowing of the teeth.
Dentin
Dentin, which is the middle layer of the tooth, naturally gives teeth a yellowish color. Dentin makes up most of the tooth and is a hard, yellow substance. The composition of dentin is so hard that it resembles a bone, which makes your teeth feel similar to that of a bone. Dentin plays a vital role in oral health because it helps protect the innermost layer of our teeth, the pulp which contains the blood supply and nerve endings. When you have a toothache, it's the pulp that sends out pain signals letting your body know there is a cavity, injury or a nerve is exposed.
Considerations
Certain factors will cause teeth to yellow such as different medications, smoking and age. Even some antibiotics such as doxycycline and tetracycline will cause teeth to become yellow or gray, permanently. Smoking not only yellows teeth but it can do the same to fingernails. Age can factor into teeth yellowing because over time, our enamel wears off, exposing dentin. Excessive tarter buildup can lead to yellowing of the teeth. Eating habits can also contribute to discolored teeth when foods such as dark beverages are consumed or very acidic foods that cause the enamel to wear down, making the outer layer of the tooth transparent exposing more dentin.
Prevention/Solution
Dentists may whiten teeth using different procedures that vary in price. According to YourDentistryGuide.com, the nationwide cost of tooth whitening averages around $650 per visit. A less expensive alternative to in-office whitening is professionally dispensed take-home kits. The cost of professional take-home kits ranges from $100 to $400. Over-the-counter kits are another option to consider, they are less expensive-- ranging from $20 to $100. With over-the-counter kits, users may not experience a full-mouth whitening effect since the trays are not individually custom made as opposed to professional kits which will whiten all teeth, not just the front teeth. Whitening toothpaste is available, by prescription and over-the-counter, which my help combat tooth discoloration.
Misconceptions
In-office and over-the-counter tooth whitening is not permanent and may need to be repeated over a period of time or several times. No tooth whitening is permanent. Whitening toothpaste can be abrasive, especially if excessively used, and can cause tooth enamel to wear down over time.
References
- KidsHealth.org: Mouth and Teeth: Basic Anatomy of the Mouth and Teeth
- KidsHealth.org: Mouth and Teeth: Normal Development of the Mouth and Teeth
- Centers for Disease Control: Erosion of Dental Enamel Among Competitive Swimmers
- KidsHealth.org: Your Teeth: Tooth Tour
- YourDenistryGuide.org: Teeth Whitening: How It Works and What It Costs
