Types of Tooth Discolouration
Tooth discolouration can be broadly classified into three categories. The distinction between them is clinically important because different types of staining respond to different treatment approaches.
Extrinsic Stains (Surface Staining)
Surface stains develop on the outside of the enamel and are caused by pigmented substances that come into regular contact with the teeth. Tea, coffee, red wine, and tobacco are among the most common contributors. These stains can often be reduced or removed with professional cleaning and may respond well to whitening treatment.
Intrinsic Discolouration (Internal Changes)
Intrinsic discolouration originates within the tooth structure itself. It may result from previous trauma, certain medications taken during tooth development, excessive fluoride exposure, or nerve damage. Because the colour change is within the dentine or deeper layers, surface cleaning alone is unlikely to improve it — alternative approaches may be needed.
Age-Related Colour Changes
Over time, enamel naturally becomes thinner through everyday wear, allowing the warmer colour of the underlying dentine to show through more prominently. This gradual yellowing is a normal part of ageing and is often compounded by decades of exposure to staining foods and drinks.
Common Causes of Stained or Discoloured Teeth
Tooth discolouration can result from a wide range of factors. In many cases, more than one cause may be contributing to the overall appearance of the teeth.
Tea, Coffee, and Red Wine
These beverages contain chromogens — intensely pigmented compounds that adhere to tooth enamel over time. Tannins in tea and wine further enhance the ability of staining molecules to bind to the tooth surface.
Smoking and Tobacco Use
Tar and nicotine in tobacco products produce stubborn brown and yellow stains that accumulate on the enamel surface. Long-term smoking can cause deep, widespread discolouration that is difficult to remove with brushing alone.
Poor Oral Hygiene
Inadequate brushing and flossing allows plaque and tartar to build up on the teeth. These deposits can become stained by food and drink pigments, contributing to a dull or discoloured appearance.
Ageing Enamel
As enamel gradually thins with age, the naturally yellow dentine beneath becomes more visible. This is a common and expected change, though its extent varies between individuals.
Previous Dental Trauma
A knock or injury to a tooth can damage the nerve or disrupt blood flow, leading to darkening of the affected tooth over time. This may occur months or even years after the original injury.
Certain Medications
Some medications, when taken during tooth development in childhood, can cause intrinsic discolouration. Other medications may contribute to surface staining in adults. Your dentist can discuss whether medication may be a factor in your case.
When Discolouration May Indicate an Underlying Issue
While most tooth discolouration is cosmetic in nature and related to external staining or natural ageing, certain patterns of colour change may suggest an underlying dental issue that warrants professional assessment.
A sudden change in the colour of a single tooth — particularly darkening — may indicate nerve damage from a previous injury, internal decay, or changes following root canal treatment. These colour changes occur within the tooth structure and tend to develop gradually over weeks or months.
Grey, brown, or black discolouration localised to one tooth is worth mentioning to your dentist, even if the tooth is not painful. Early assessment can help identify the cause and determine whether any treatment is needed to protect the tooth or prevent further changes.
Professional Assessment Before Whitening
A dental examination before whitening treatment is important to ensure the treatment is appropriate, safe, and likely to achieve a satisfactory result. Your dentist will consider several factors during this assessment:
Identifying the Type of Staining
Your dentist will determine whether the discolouration is extrinsic (surface-based), intrinsic (within the tooth), or age-related. This distinction is important because it directly influences which treatment options are appropriate.
Checking Oral Health Status
Whitening treatment requires that the teeth and gums are in a stable, healthy condition. Active decay, gum disease, or untreated dental issues should be addressed before any whitening is considered.
Evaluating Existing Restorations
Crowns, veneers, fillings, and other restorations do not respond to whitening agents. Your dentist will assess whether visible restorations may affect the evenness of results and discuss this with you.
Assessing Suitability
Not all types of discolouration respond equally to whitening. Your dentist will advise whether professional home whitening is likely to be effective for your specific pattern of staining, or whether alternative approaches may be more appropriate.
Professional Home Teeth Whitening
Professional home whitening is a dentist-supervised treatment that aims to lighten the natural colour of your teeth gradually. Unlike over-the-counter products, this approach uses custom-made trays and professionally prescribed materials, with your progress monitored by your dental team throughout.
Results vary between individuals and depend on factors such as the type and severity of staining, natural tooth colour, and how consistently the treatment is used. Your dentist will discuss realistic expectations based on your specific situation during the initial assessment.
What home whitening typically involves:
- Custom-made whitening trays designed from dental impressions to fit your teeth precisely
- Dentist-prescribed whitening materials for use at home over a recommended period
- Gradual lightening of natural tooth colour with results developing over the course of treatment
- Professional monitoring throughout to assess progress and manage any sensitivity
- Guidance on maintenance and top-up treatments to help sustain results over time
Home whitening is suitable for appropriate candidates only. Your dentist will confirm suitability during your assessment.
Other Treatment Options
Depending on the type, extent, and cause of discolouration, your dentist may discuss alternative or complementary approaches to improving the appearance of your teeth:
Professional Dental Cleaning
A scale and polish performed by a dental hygienist can effectively remove surface stains from tea, coffee, wine, and tobacco, often noticeably improving the brightness of the teeth without the need for whitening.
Composite Bonding
Tooth-coloured composite material can be applied to the surface of discoloured teeth to mask staining and improve appearance. This may be suitable for localised discolouration or teeth with minor surface irregularities.
Dental Veneers
In selected cases where intrinsic discolouration is significant and does not respond to whitening, porcelain or composite veneers may be considered to provide a uniform, improved appearance.
Internal Whitening
For non-vital teeth (those that have undergone root canal treatment) that have darkened, internal whitening may be an option. A whitening agent is placed inside the tooth to lighten it from within.
Professional Assessment for Tooth Discolouration
A dental assessment helps determine whether staining is surface-based, structural, or related to an underlying condition, and whether professional home whitening or an alternative approach is most appropriate for your situation.
Depending on the findings, your dentist may recommend professional home whitening, composite bonding, dental veneers, or a professional dental cleaning to address surface stains.
Assessment for tooth discolouration and whitening suitability is available at our London clinics. You can attend our South Kensington dental clinic or our City of London clinic near St Paul's for a professional dental review.
Can Tooth Stains Be Prevented?
While some degree of colour change is a natural part of ageing, the following habits can help reduce the accumulation of surface stains and maintain a brighter appearance:
- Maintain good daily oral hygiene with twice-daily brushing and regular flossing to reduce plaque and surface stain build-up
- Attend regular professional dental cleaning appointments to remove tartar and surface deposits that contribute to discolouration
- Moderate consumption of highly pigmented foods and drinks such as coffee, tea, red wine, and dark berries
- Rinse your mouth with water after consuming staining beverages to help reduce pigment adhesion
- If you smoke, consider stopping — tobacco is one of the most significant contributors to dental staining
- Discuss any concerns about tooth colour with your dentist, who can advise on the most appropriate approach for your situation
