1.Foods and  drinks

Acidic foods can erode the enamel of your teeth, which might expose the yellow-hued of your dentin, leavining you with yellow teeth.

2. Coffee

The enamel of your teeth contains microscopic pits and ridges that can hold particles of food and drink.

Pigments from dark-coloured drinks such as coffee, tea, and red wine can become embedded in those cracks and ridges and cause permanent, yellow stains on your teeth.

3.Smoking 

The nicotine and tar in tobacco can make your teeth yellow in a very short period of time.

4. Medications

Certain antibiotics for example tetracycline and doxycycline are known to discolour teeth when given to children younger than 8 years because their teeth are still developing

5.Mouthwash

Mouthwash (Corsodyl Original) containing chlorhexidine can also stain teeth and should not be used for a prolong time. Corsodyl Daily will not stain your teeth.

6.Age

As you get older, the outer layer of enamel on your teeth gets worn away, revealing the natural yellow colour of dentin.

7.Trauma.

If you had trauma that affected a tooth when you were a young child you may have damaged your developing permanent tooth.

Trauma to a permanent tooth, can cause internal bleeding or cause the nerve to die that will cause the tooth to discolour.

Teeth whitening is ideal for patients who have healthy teeth and gums who would like a brighter smile. Patients with yellow tones to their teeth respond best.

If you want whiter, brighter teeth ask your dentist about Teeth whitening.