Why Your Teeth Are Yellowing (And What You Can Do About It)

Tooth discolouration is one of the most common cosmetic concerns in dentistry, and one that affects almost everyone to some degree over time. If you have noticed your teeth looking less bright than they once did, or if you have always been bothered by the colour of your teeth, understanding why discolouration occurs is the first step toward knowing what can actually be done about it.

Extrinsic vs Intrinsic Staining

Tooth discolouration falls into two main categories: extrinsic staining, which occurs on the surface of the tooth, and intrinsic staining, which occurs within the tooth structure itself. The distinction matters because the two types respond differently to treatment.

Extrinsic staining is caused by pigmented compounds from food and drink depositing on the tooth surface or in the thin film of protein that coats the enamel. Coffee, tea, red wine, and certain foods are the most common culprits. Tobacco - whether smoked or chewed - is one of the most potent sources of surface staining. Extrinsic staining can often be significantly improved with professional cleaning and polishing, and responds well to whitening treatment.

Intrinsic staining is within the tooth itself. It can be caused by exposure to certain antibiotics (particularly tetracycline) during tooth development in childhood, fluorosis (excess fluoride during tooth development), trauma to a tooth that causes internal bleeding and subsequent darkening, or the natural ageing process in which the enamel gradually thins and the yellower dentine beneath shows through more prominently.

The Ageing Factor

Natural ageing is one of the most significant contributors to tooth discolouration. Over decades, the outer enamel layer is gradually worn away through normal eating, drinking, and tooth contact. As the enamel thins, the dentine beneath - which is naturally yellow - becomes more visible through the surface, giving the teeth a yellower appearance even when there is no specific staining involved. This is why older adults often have noticeably more yellow teeth than younger people regardless of their diet or oral hygiene.

Additionally, the dentine itself adds more mineral over time, becoming denser and darker. This internal darkening compounds the effect of enamel thinning to produce progressively more yellow teeth as the years pass.

Other Contributing Factors

Certain medications can cause tooth discolouration as a side effect - antihistamines, some blood pressure medications, and antipsychotic drugs have been associated with staining. Dry mouth, which reduces saliva production, is another contributing factor: saliva plays a role in washing away staining compounds and maintaining the mineral content of the enamel, and when saliva flow is reduced, staining accumulates more readily.

What Can Be Done

For extrinsic staining, a professional scale and clean followed by polishing can make a noticeable difference, and teeth whitening can produce dramatic improvements. For staining caused by ageing and enamel thinning, whitening remains effective for many patients, though the results vary. For more severe intrinsic discolouration - such as that caused by tetracycline staining - whitening alone may not be sufficient, and veneers or crowns may provide a more predictable cosmetic result.

The first step is always a professional assessment to determine what is causing the discolouration and what treatment options are appropriate. At South Yarra Dental Group, the team can evaluate your specific situation and recommend the most effective approach for the type of staining present.

Want to Brighten Your Smile?

South Yarra Dental Group can identify the cause of your tooth discolouration and recommend the right treatment. Contact the practice to arrange an appointment.

Call 03 9827 3314 or email team@sydg.com.au.