Discoloured Teeth

Discoloured Teeth

Article by Dr Angela Ngauw, General Dental Surgeon, BDS (S’pore)

Yellow, discoloured teeth can have a huge impact on one’s confidence, self-esteem, and not to mention, project a less than favourable impression on others. There are many causes of tooth discolouration and the most common of which are stains, plaque and tartar, cavities, dental fillings and worn down enamel.  

Stains on teeth can be classified as either extrinsic or intrinsic. Extrinsic stains are stains which are on the outer enamel layer of the tooth and they are usually caused by foods or drinks such as coffee, tea and red wine, or tobacco smoking. Extrinsic stains can be removed through scaling and polishing.

Intrinsic stains are stains which are in the internal dentine layers of the tooth. These stains could be caused by trauma and bleeding within the tooth, excessive fluoride intake during childhood, use of tetracycline antibiotics during pregnancy and childhood, and certain genetic disorders of tooth development. Depending on the cause of the intrinsic stain, your dentist may suggest treatments ranging from root canals, bleaching (also called teeth whitening) to veneers and crowns.

Poor oral hygiene leads to the build-up of a sticky, yellow substance on the teeth called plaque. If unremoved, plaque would harden into tartar (also called calculus) which adheres to the teeth, especially near the gum line. Tartar can appear yellow, brown or even black. It cannot be removed by brushing or flossing, and only professional cleaning at the dental clinic would be able to remove tartar completely.

Not only does plaque and tartar cause teeth to turn yellow, they also cause tooth decay or cavities. Cavities form when the acids released by bacteria in plaque soften and break down the enamel of the tooth. Tooth decay may appear as brown or black discolouration on the teeth. Hence, it is important to visit a dentist to get the cavities filled up, as they will get larger (more obvious and unpleasing to the eye) with time and could result in pain.

Certain types of dental fillings like amalgam and some root canal materials may also cause teeth to appear darker with time, as they stain the teeth from within.

Teeth also tend to look more yellow when the outer enamel layer is thinned down, allowing the yellow underlying dentine to show through. The thicker the outer enamel layer, the less obvious the inner yellow dentine layer would be. However, this outer enamel layer can be thinned down, due to certain lifestyle habits such as excessive consumption of acidic foods and drinks, over brushing, and also with age. Therefore, it is important to look into your diet and daily habits to ensure you are not unknowingly causing your teeth to appear more yellow than they should.

Due to the myriad of causes of teeth discolouration, it is best to consult a dentist for a thorough examination. Your dentist would then be able to prescribe the most appropriate treatment for your specific condition. In the meantime, the first step to a healthy white smile always starts with the humble toothbrush, so be sure to brush twice a day to keep your pearly whites happy.