What Causes Teeth Discolouration and How Can You Treat It?
Teeth discolouration means your teeth have moved away from their natural shade. They can look yellow, brown, grey or even black. Some people see white spots or dark patches instead. The change can show on one tooth, a few teeth or your whole smile. Many Australians notice it after years of coffee, tea and red wine, but diet is only one of several causes.
The cause decides how well a treatment works. A stain from a daily flat white behaves differently from a grey tooth after a knock to the mouth. Once you know what is behind your stains, you can choose a whitening treatment with the right expectations.
What Is Teeth Discolouration?
Everyone has a natural tooth colour, and it can vary from person to person. Slightly yellow teeth may be completely normal for some people. Discolouration occurs when teeth change from their usual shade or develop uneven colouring.
Tooth stains generally fall into two categories: extrinsic and intrinsic. Extrinsic stains develop on the enamel, the hard outer layer of the teeth. They are often caused by foods, drinks, tobacco and plaque build-up. Intrinsic stains develop inside the tooth, in the dentin beneath the enamel. These stains may result from ageing, dental injuries, certain medicines or other health conditions. Some people have both types of stains at the same time.
Common signs of discolouration include:
Yellow or brown tones across your teeth
Grey or dark patches on one tooth
White spots on the enamel
An uneven shade between neighbouring teeth
Everyday Causes of Stained Teeth
Coffee, black tea, red wine and cola are the top causes of stained teeth. These drinks hold dark pigments called tannins that cling to enamel. Curry, soy sauce, tomato sauce, beetroot and berries do the same. Enamel has tiny pores, so colour builds up slowly with each cup or meal. Acidic drinks make it worse because acid softens enamel for a short time and lets more pigment in.
Smoking and vaping leave tar and nicotine on your teeth, which turn them yellow and then brown. Plaque adds to the problem. It is a sticky film of bacteria that holds colour against the tooth. If you skip brushing or flossing, plaque hardens into tartar, and tartar stains very easily.
Main sources of surface stains:
Coffee and black tea: dark tannins stick to enamel with every cup.
Red wine and cola: strong pigments plus acid that softens enamel and lets colour in.
Curry, soy sauce, beetroot and berries: deep-coloured foods that leave pigment on the tooth surface.
Smoking and vaping: tar and nicotine turn teeth yellow, then brown.
Causes Inside the Tooth
Age is one of the biggest causes of yellow teeth. Enamel wears thin over the years, and the dentin underneath is naturally yellow. As the enamel thins, more of that yellow shows through. This is why teeth often look darker after 40, even when you brush well.
Injury can darken a tooth from the inside. A knock to the mouth can damage the nerve, and the tooth may turn grey or dark over the following weeks. Medicines can also leave marks. Tetracycline and doxycycline antibiotics taken before about age eight can cause grey or brown bands. Too much fluoride while teeth are forming can cause white or brown spots, called fluorosis. Decay, old silver fillings, root canal treatment and some medical treatments such as chemotherapy can change tooth colour as well.
What Your Tooth Colour Can Tell You
Tooth colour can help you understand what may be causing the discolouration. The table below lists some common tooth shades and their possible causes.
Colour | Common causes |
Yellow | Thinning enamel, ageing, plaque build-up |
Brown | Coffee, tea, tobacco, tooth decay |
Purple tinge | Red wine |
White spots | Fluorosis, early enamel changes |
Grey or black | Dead nerve, deep decay, old fillings, injury |
Blue-grey bands | Tetracycline taken in childhood |
The Treatment That Works for Most Stains
Professional teeth whitening can help reduce discolouration caused by coffee, tea, red wine and tobacco. The whitening gel works by breaking down stain molecules, making them less noticeable and helping teeth appear lighter. It can also improve yellowing that develops naturally with age.
However, whitening may not work equally well on every type of stain. Grey marks caused by certain antibiotics during childhood and teeth that darken after an injury may respond less to treatment. Before starting, a specialist can assess your tooth shade, check the cause of the discolouration and explain the results you may expect.
How Professional Teeth Whitening Works
Professional in-chair whitening uses a 6% hydrogen peroxide gel. A cold blue LED light activates the gel and speeds up the process. A 60-minute session lifts teeth to 6 shades. A 90-minute session lifts teeth to 10 shades and suits coffee, tea and wine drinkers and smokers. People who want a bigger change can have two 90-minute sessions four weeks apart, which lifts teeth to 14 shades.
Your appointment begins with a check-in, a tooth shade assessment and a before photo. The specialist then applies the whitening gel and uses LED lights as part of the treatment while you relax. Once the session is complete, they check your new tooth shade and take an after photo so you can compare the results. Let your specialist know about any crowns, veneers or fillings before treatment, as these may not change colour with whitening.
Step 1: Check-In
The team welcomes you into a private, comfortable treatment space and explains the process. Inform the specialist about any crowns, veneers, fillings or previous dental treatments.
Step 2: Initial Shade Check
The specialist checks your current tooth colour and records your starting shade. A before photo is also taken to help compare your smile before and after treatment.
Step 3: Gel Application
The specialist carefully applies whitening gel across your teeth to ensure even coverage. This helps the treatment target visible stains caused by coffee, tea, wine and other factors.
Step 4: LED Light Activation
A cold blue LED light is used alongside the whitening gel while you relax. The light supports the whitening process, helping reduce discolouration and improve your tooth shade.
Step 5: Final Shade Check
After treatment, the specialist checks your new tooth shade and takes an after photo. Comparing both photos helps you see the colour change achieved during your session.
What to Expect During and After Treatment
Most people feel little or no discomfort during whitening. Mild sensitivity can happen in rare cases, and it usually fades within 24 to 48 hours. A lower gel strength helps keep sensitivity down.
Your teeth take up colour more easily right after treatment. That is why the studio asks you to wait one hour before eating. It also asks you to follow a white diet for 48 hours. This means avoiding curry, red sauces and other dark foods. If you want a coffee or glass of wine in that window, drink it through a straw.
How Long Do Whitening Results Last?
Results depend on your habits, your genetics and the starting colour of your teeth. Many clients keep a noticeably whiter smile for up to six months or longer. Coffee, tea, red wine, dark soft drinks and smoking bring the stains back faster. People who drink these daily may see colour return sooner than people who drink them once in a while.
A top-up session can refresh your shade when it starts to fade. A 60-minute session suits a top-up well.
Factors that affect how long results last:
Daily habits: dark drinks and smoking fade results faster.
Genetics: some people hold their shade longer than others.
When Should You See a Dentist First?
Most discolouration is cosmetic, but some changes are a warning. See a dentist if one tooth turns dark after an injury or darkens on its own. The same applies if a tooth looks grey or bluish, if the colour is patchy, or if the change comes with pain or sensitivity. These signs can point to nerve damage or decay, and they need a dental exam before any whitening.
If you have tooth decay or gum problems, visit your dentist before starting whitening. If you are pregnant, speak with your dentist about whether whitening should be postponed until after pregnancy.
Who Gets the Best Results From Teeth Whitening?
People with yellow or brown stains from coffee, tea, red wine, smoking or age tend to see the biggest change. Healthy natural teeth with no decay give the gel an even surface to work on. A darker starting shade also leaves more room for the teeth to lighten.
Results are more modest on teeth with grey bands or injury marks, and on teeth with a lot of dental work. A shade check before treatment shows where your teeth sit and how many shades you can expect. The 90-minute session suits heavier stains, and the 60-minute session suits a light refresh.
Quick guide to results:
Best results: yellow or brown stains from food, drink and age.
Good fit: healthy natural teeth with no decay.
Modest results: grey bands or injury marks.
Session choice: 90 minutes for heavier stains, 60 minutes for a light refresh.
Final Thoughts
Teeth discolouration can develop for several reasons, including coffee, tea, smoking, ageing and dental injuries. The right treatment depends on what is causing the colour change. Professional teeth whitening can help lighten many yellow and brown stains,
although some types of discolouration may need a different approach. A shade check before treatment helps you understand the results you may expect and whether whitening is suitable for your teeth.
If you are considering a brighter smile, you can book a session online at White And Bright. For questions about the available treatments, call 1800 978 638 or email smile@whiteandbright.com.au before your appointment.
Frequently Asked Questions About Teeth Discolouration
What are the most common causes of teeth discolouration?
The most common causes include coffee, tea, red wine, smoking, plaque build-up and ageing. Dental injuries, certain medications and tooth decay can also change tooth colour. Identifying the cause helps determine the most suitable treatment.
Can yellow teeth become white again?
Yes, professional teeth whitening can help lighten yellow teeth caused by food, drinks and ageing. However, results depend on the type of discolouration. Grey stains caused by dental injuries or certain medications may be more difficult to treat.
How can I remove stains from my teeth?
Brushing twice daily with fluoride toothpaste, flossing regularly and limiting stain-causing foods and drinks can help reduce surface stains. Professional teeth whitening may help with persistent discolouration, while a dental cleaning can remove plaque and tartar build-up.
How long do professional teeth whitening results last?
Professional teeth whitening results can last six months or longer, depending on your diet, oral hygiene and lifestyle habits. Limiting coffee, tea, red wine and smoking can help maintain your brighter smile. A top-up session may help refresh your results when stains return.
When should I see a dentist about teeth discolouration?
You should see a dentist if one tooth suddenly turns grey, brown or black, or if discolouration occurs alongside pain or sensitivity. These changes may indicate tooth decay, nerve damage or an injury. A dental examination can identify the cause and help determine whether whitening is appropriate.
