Tooth enamel is the protective and resistant covering or the outer layer of the tooth. This covers the entire surface of the tooth crown (the part of the tooth that is above the gum line and is visible to the eye). Enamel doesn’t have a uniform thickness along the length and width of the tooth crown.
A normal human tooth is made up of three basic structures. Enamel, dentin, and pulp. Enamel is the outer layer, the dentin is the middle one and the innermost layer is called the dental pulp or the tooth pulp.
Unique Properties of Tooth Enamel
Physical Properties of Enamel
As mentioned earlier, the tooth enamel acts as a protective and resistant covering of around 2mm thickness for the tooth. It also makes the tooth structure suitable for mastication (chewing, grinding and eating).
Enamel is the hardest calcified tissue in the human body. It is even harder than human bone. As it is highly mineralized, enamel can withstand both shearing and impact type of forces.
Tooth enamel is thickest at the incisal or cuspal (the biting and chewing surface) parts of the tooth and is thinnest at the cervical part (the part where the tooth meets the gums or gingiva).
The enamel surface of the tooth has high abrasion resistance because of which it wears down slowly. But if it wears down it can’t be replaced or repaired.
The color of enamel in most people is white. The crystals that form the enamel layer reflect light differently in different directions. The color of enamel in young people is white because of low translucency. As the age advances, the color of the tooth enamel turns slightly yellowish because of the increase in the translucency.
Chemical Properties of Enamel
The enamel is mainly made up of hydroxyapatite crystals, calcium hydroxyapatite being the important one. These crystals constitute to about 88-90% of the entire enamel volume and 95-96% of the entire weight of the enamel.
Water constitutes 2% by weight and 5-10% by volume to the enamel. Water is located between the crystals and the organic matrix in the tooth enamel. Water is a very important component of enamel because it is through this, the fluoride travels in the tooth.
The rest of the structure of the enamel is made up of the organic matrix which consists of enamel proteins and lipid materials.
Structure of Tooth Enamel
The basic structure of the enamel is made up of many components. Below are the important ones.
- Enamel Prisms or rods
- Rod sheath.
- Inter-prismatic substances.
- Hunter-Schreger bands.
- Incremental lines.
- Surface structures.
- Enamel lamellae.
- Enamel tufts.
- Dentino-enamel junction.
- Odontoblastic processes and enamel spindles.
Tooth Enamel Loss
Although there are many reasons for the loss of the enamel layer in a tooth, the following are the most important ones.
- Dental Caries
- Congenital conditions
Because of the high mineral content of the enamel, it is highly prone to demineralization. Sadly once the enamel is lost, it can’t be repaired or rebuilt. Teeth decay or dental caries is the most common cause of demineralization of the enamel layer.
Demineralization of enamel can occur for several reasons, but the most important reason that causes a cavity is sugar. When food items containing sugar are stuck on teeth’s surface bacteria attack these areas and produce an acid called ‘lactic acid’. It is this ‘lactic acid’ which causes the demineralization of the enamel. You can read about dental caries from here.
Attrition is the name given to the condition where there is a tooth structure loss which is a result of a tooth to tooth friction. The most common reason for attrition is clenching or grinding of teeth during sleep, which is also called bruxism.
Abrasion is a condition where there is tooth structure loss because of wear and tear caused by physical damage. The most common cause of abrasion is faulty brushing technique and hard bristled brushes.
Tooth erosion is a condition characterized by saucer-shaped depressions on the tooth surface which are caused by acids. The acids destroy the mineralized structure of the enamel and cause demineralization. This can be because of any of the following reasons.
- Acids found in the soft drinks which we consume on a regular basis.
- Dry mouth or low saliva production
- Acid reflux disease
- Certain drugs and medications
- Idiopathic or unknown causes
- Genetic or hereditary reasons
Abfractions are enamel defects which are believed to be results of stress fractures. Here the teeth structure loss isn’t caused by tooth decay. This, however, is a controversial theory and hasn’t been accepted unanimously.
Congenital conditions like Amelogenesis Imperfecta have defective enamel caused due to mutant genes.
Signs and Symptoms of Tooth Enamel Loss
If for some reason your enamel is damaged and if there is a structural loss, you may have one or more of the following signs and symptoms.
- Tooth sensitivity to hot and cold
- Sensitivity in teeth when biting or chewing food
- Teeth discoloration
- Cracks or lines on the tooth surface
- Chipping away of teeth edge
- Irregular and broken edges of teeth
How To Manage Enamel Loss?
As mentioned earlier, once the enamel structure is lost it can’t be repaired or restored. But what you can do instead is build up the lost tooth structure using artificial restorative materials. (Recently there are some researches going on which claim to have developed certain gels which can repair and regrow damaged enamel).
The treatment for enamel loss depends on the cause of the damage.
- If the enamel loss is due to dental caries, in the earlier stages conventional restorative procedures will suffice.
- If there is an extensive enamel loss stainless steel crown or full coverage crowns may be required.
- For a problem like abrasion, brushing and other habits need to be corrected.
- For attrition, use of night guards may be of great help.
- Similarly, depending on the causes treatment will be planned.