The real, natural colour of teeth is not pure, brilliant white. It is a range of off-white shades that can include hints of light yellow, grey, or brown. The exact shade of a person’s teeth is determined by the combination of the colour of the two outermost layers of the tooth: the enamel and the dentin.
The Anatomy of Tooth Colour: Enamel and Dentin
To understand tooth colour, you need to understand the basic structure of a tooth.
- Dentin: This is the inner layer of the tooth, lying just beneath the enamel. Dentin is a bone-like tissue that makes up the bulk of the tooth. Its natural colour is a pale yellow. The colour of the dentin is the primary determinant of your overall tooth colour.
- Enamel: This is the hard, protective outer layer that covers the dentin. The enamel is naturally a bluish-white and is translucent, meaning it is semi-transparent.
The colour you see when you look at your teeth is the yellow of the dentin showing through the translucent bluish-white enamel. The thickness and translucency of your enamel will determine how much of the yellow dentin is visible.
Thicker, more opaque enamel will block more of the dentin’s color, making the teeth appear whiter. Thinner, more translucent enamel will allow more of the yellow dentin to show through, making the teeth appear more yellow.
Factors That Determine Your Natural Tooth Colour
Your natural tooth shade is not something you can control. It is influenced by several factors.
| Factor | How it Affects Tooth Colour |
|---|---|
| Genetics | This is the most important factor. Your genes determine the natural shade of your dentin and the thickness and translucency of your enamel. Some people are just born with naturally whiter or more yellow teeth than others. |
| Age | As we age, the enamel layer on our teeth naturally wears down and becomes thinner. This thinning allows more of the yellowish dentin to show through, making the teeth appear more yellow over time. |
| Dentin Thickness | The thickness of the dentin layer itself can also affect the shade. Thicker dentin can result in a more yellowish appearance. |
Why Do Teeth Get Stained? (Extrinsic Staining)
While your natural shade is determined by genetics, your teeth can become darker or more yellow over time due to external stains that accumulate on the enamel. This is called extrinsic staining.
Common causes include:
- Foods and Drinks: Frequent consumption of dark-colored foods and drinks like tea, coffee, red wine, and colas can stain the enamel.
- Tobacco: Smoking or chewing tobacco is a major cause of yellow and brown stains on the teeth.
- Poor Dental Hygiene: Not brushing and flossing regularly allows plaque and stain-producing substances to build up on the teeth.
These extrinsic stains can often be removed by professional cleaning at a dental clinic or managed with whitening toothpastes. For deeper, intrinsic stains or to change the natural shade of the teeth, cosmetic procedures like professional teeth whitening (bleaching) are required.
Understanding that a range of off-white shades is normal can help set realistic expectations for dental health and cosmetic treatments. It is a different kind of knowledge about the body than understanding the causes of acne-prone skin or what a CBP test result means, but all contribute to a better understanding of our health.
Frequently Asked Questions (FAQs)
What is the real natural colour of teeth?
The real, natural colour of teeth is not paper white. It is a range of off-white shades, often with a slightly yellowish, grayish, or brownish hue. This colour is determined by the combination of the yellow inner dentin layer showing through the translucent outer enamel layer.
Why are my teeth yellow even though I brush them?
If you have good dental hygiene, your yellow teeth are likely due to your genetics. You may have naturally more yellow-toned dentin or thinner enamel, which allows more of the dentin colour to be visible. Additionally, as you age, the enamel thins, naturally making teeth appear more yellow.
Are yellow teeth stronger than white teeth?
There is a common belief that slightly yellow teeth are stronger, and there is some truth to it. A yellowish tint can indicate that you have thick, healthy dentin and the enamel is naturally translucent. Artificially whitened, chalky-white teeth can sometimes be a sign of weakened enamel.
How can I make my teeth whiter?
For surface stains, you can use whitening toothpastes and maintain good oral hygiene. For changing the natural shade of your teeth, you will need professional teeth whitening (bleaching) done by a dentist. This procedure uses a bleaching agent to lighten the colour of your dentin.
What foods cause teeth to turn yellow?
Foods and drinks that are dark in color and high in tannins are the main culprits. These include coffee, black tea, red wine, colas, berries, and soy sauce. Limiting your consumption of these and rinsing your mouth with water after having them can help reduce staining.