Teeth Anatomy
This article was originally published on mouthpower.org.
Knowing just a little bit about teeth anatomy can help you maintain good oral health. If you understand how the teeth are structured and what they are made of, it is easier to appreciate how problems like tooth decay, sensitivity, gum disease, teeth staining, and bad breath occur.
TEETH STRUCTURE
The human tooth is a complex structure that is made up of multiple layers of organic and inorganic matter. Organic tooth matter refers to the living parts of the teeth that consist of cells, fibers, proteins, and water. The inorganic matter is mainly composed of calcium salts and provides the strength and substance of the teeth.
Each tooth can be divided into three sections, which are called the crown, neck, and root. The crown is the visible part of the tooth that we see above the gum line
The roots of the teeth are hidden in the gum tissue and bone and are surrounded by cementum. The crown of the tooth and the root come together at the neck.
The four main parts of the teeth are the enamel, dentin, cementum, and pulp cavity. Each part has unique characteristics and a different combination of organic and inorganic matter. The enamel, dentin, and cementum layers are all mineralized to varying degrees, and the pulp cavity is soft tissue that comprises blood vessels, nerves, and connective tissue.
To understand the different layers better, let’s have a look at them individually.
ENAMEL
Enamel is made up of 4% organic and 96% inorganic matter, and it covers and protects the crown of each tooth. The main inorganic material in enamel is hydroxyapatite, which is a crystalline calcium phosphate.
Facts about enamel.
Enamel is:
- The hardest material in the human body.
- Semi-translucent.
- Brittle and can become fractured if the dentine layer becomes decayed and weakened.
- Unresponsive to external stimuli like heat, cold, sweet, and sour.
- Susceptible to staining and discoloration from highly pigmented foods and beverages.
- Subject to a constant demineralization and remineralization process (click here for more information).
- Weakened by acidic conditions. If the pH of the mouth falls to below pH 5.5, then calcium phosphate will be dissolved from the enamel, making it softer and weaker.
ENAMEL WEAR AND DISEASE.
We already know that enamel is the hardest material in the human body, so it might seem surprising that tooth decay and poor oral health affect almost everybody at some point in their life. If enamel is really so tough, why can it wear and decay so easily?
As hard as enamel is, it can still be weakened quickly if it is exposed to unfavorable conditions for extended periods of time
Acids can come into contact with the teeth from several sources, but mostly they come from the following –
- Bacterial plaque: This is a sticky film that forms on the teeth every day. Plaque consists of about 70% bacteria, which, as part of their life cycle, feed on the sugars and carbohydrates that we eat and then excrete organic acid onto the teeth as a byproduct. This acid then begins to dissolve away calcium and phosphate from the enamel surface, making the teeth softer and weaker.
- Dietary acids: Many of the foods and beverages that we consume are acidic in nature and can cause the teeth to become soft and vulnerable to decay. Many of today’s popular foods and drinks, like sweets, cakes, energy drinks, soft drinks, and fruit juices, all have a detrimental effect on our teeth.
- Acid Reflux: Acid reflux occurs when gastric acid travels up the esophagus, ending in the mouth. People who suffer from acid reflux are at a high risk of experiencing oral health problems simply because of the increased acidity levels of their mouths.
HOW TO KEEP YOUR TEETH ENAMEL HEALTHY.
Since acid is known to be the most damaging substance to teeth, it makes sense that to keep our teeth healthy and strong, we need to limit our mouth's exposure to acid. To keep acid attacks to a minimum, follow these steps –
- Brush teeth twice a day for two minutes: It is very important to remove the plaque that has built up throughout the day and night. Any plaque that is allowed to stay in contact with the teeth for extended periods of time will maintain the concentration of acid on the enamel surface. Plaque is soft and relatively easy to remove, provided it is dealt with quickly. If plaque is allowed to sit on the teeth for more than 48 hours, it will begin to harden and calcify to the point where calculus is formed. Unlike plaque, calculus can’t be removed by normal teeth cleaning and will need to be removed by your dentist.
- Floss teeth every day: Since tooth brushing only cleans about 60% of the tooth surfaces, it is important to use dental floss or an interdental brush to clean the areas between the teeth that a toothbrush can’t reach.
- Use a therapeutic toothpaste: Fluoride toothpaste has a proven record of being effective at strengthening enamel and resisting decay. For people who find the use of fluoride to be too controversial, other toothpastes, such as Theodent, use a chocolate extract to harden the enamel crystals
- Limit snacking: Eating sugary snacks or beverages often throughout the day can cause the mouth to become almost permanently acidic. It takes the oral cavity about 30 minutes to recover to normal after eating, so if we continue to snack, the mouth is not able to achieve balance. It is best to eat snacks in one sitting and not spread them out throughout the day.
- Drink plenty of water: Drinking water is a great way to keep the mouth clean and flush away any food debris from the teeth.
- Eat Xylitol: Although xylitol tastes like regular sugar, it has some very different properties that can benefit your oral health. Oral bacteria can’t process and digest xylitol in the same way that they can with regular sugar. Xylitol effectively starves off bacteria and reduces the harmful effects of plaque.
DENTIN
Dentin forms the main bulk of each tooth, and it is comprised of roughly 70% inorganic matter, 20% organic matter, and 10% water. The dentin layer is situated directly underneath the enamel on the crown and the cementum on the root. Because dentin contains less mineral content than enamel, it is not as hard and has more elastic properties. It is the flexibility of the dentin layer that prevents the enamel from becoming too brittle and fracturing. Inside the dentin, millions of microscopic tubes diverge from the pulp cavity to the enamel on the crown and the cementum on the root.
Facts about dentin.
Dentine is:
- Yellowish in color and is visible through the semi-translucent enamel.
- Not as hard as enamel but harder than bone tissue.
- Sensitive to external stimulation such as heat, cold, and sweet substances.
DENTIN DECAY AND DISEASE.
The dentin layer is protected by enamel on the crown and cementum on the root. If this protection is compromised, then the dentin is also susceptible to decay. Dentin will decay quickly than enamel because it is softer and more porous. Once the dentin is infected, there will probably be some level of
CEMENTUM
Cementum covers the root of each tooth, as well as contributing to the supporting structure of the tooth. Cementum comprises about 45% inorganic matter and 55% organic matter and is softer than both enamel and dentin.
Facts about cementum.
Cementum is:
- Similar in hardness to
bone . - Pale yellow in color.
- Responsible for helping to keep the tooth fixed in place.
PULP
The pulp is the organic, living part of the tooth that comprises nerves, blood vessels, fibers and cells. The pulp is situated inside the pulp cavity and root canal and underneath the dentin and enamel layers. The pulp cavity diminishes in size as we get older due to the gradual increase in secondary dentin.
Facts about pulp.
Pulp is:
- Very sensitive to external stimulation, which is manifested as pain.
- A sensory organ that will respond quickly if the dentin is exposed by initiating the formation of extra dentin (called reactionary dentin).
- Susceptible to irritation and inflammation if it is exposed.
PULP DISEASE AND DECAY.
If decay reaches the pulp cavity, the level of