Why do teeth stain and how to prevent it

how to prevent stained teeth

Many feel having bright, white teeth boosts confidence and self-esteem, however, teeth don’t always stay as white as we would like them to.

What causes teeth to stain?

There are many reasons why teeth discolour, including health, oral hygiene, lifestyle, ageing, diet, genetics and previous dental history. It’s important to discover the reason behind why your teeth are discoloured as this is a factor in how to treat them.

Did you know teeth can stain from the inside or the outside?

Intrinsic stains are caused by tooth decay, dental injury, developmental problems or medication. These types of stains are formed within the tooth and are more difficult to whiten. Intrinsic teeth stains that are caused by severe decay or trauma can be treated with internal bleaching, but this means the tooth needs to be root canal treated first. Internal bleaching can only be performed by a dentist. It is important to note that sometimes the darkness may relapse over the years after the internal bleaching.

Extrinsic tooth enamel stains can be caused by tobacco, or chemicals in food and drinks called chromogens like coffee, dark tea, red wine, grape juice, cranberry juice, blueberries, blackberries, cherries, pomegranates and some sauces to name a few. These stains are on the outside of the tooth enamel and are easier to remove during professional scale and clean procedures. Chemical bleaching can also be used to improve the shade of your teeth even further.

The good news is with good oral hygiene and regular maintenance by your dentist, therapist or hygienist extrinsic tooth stains can easily be managed.

Other causes of teeth discolouration


Teeth have their own natural colour, and some people may have darker teeth than others. There are two layers making up a tooth. 

  1. Dentine, which is a creamy, yellow colour, and 
  2. Enamel, which is whiter and translucent, making it look a lot like frosted glass. 

A young person would have thicker enamel layers with less surface damage to absorb stains, so they appear lighter. As you age, the outer white layer of enamel thins down with wear and tear, becoming more translucent so that the yellow dentine underneath shows through or becomes exposed. Furthermore, the cracks and surface defects that develop over a lifetime of use, soak up even more stains as well.


Genetics plays a large part in how susceptible your teeth are to staining. If your teeth have started out with a thicker layer of the whiter enamel, you’re likely to have naturally whiter teeth which stay that way for longer.

Childhood illness

The adult dentition is already well and truly being formed from the time we are born and throughout childhood. Even though we don’t see the adult teeth emerge until the ages of 6-13 years old, your teeth have been maturing inside the jaws for many years prior. This is why when children have severe fevers, ear infections or other medical problems in their early childhood, these events can impact the quality of the enamel that is being formed. The result is – brown or bright white patches or defective enamel, which can become more attractive to food stains and decay later in life.

Plaque and tartar

Bacteria, saliva and food mix to form plaque attaching to teeth, which hardens up with the calcium from our saliva to form tartar. This plaque bacteria then produce acids that weaken tooth enamel, making it very easy for stains to soak in. The longer plaque stays stuck to your teeth, the more tartar accumulates if not adequately brushed or flossed. Of course, decay also sets in when plaque acid levels are too high.


When dental decay is severe, the dentine and enamel turn brown and black. That’s pretty much what we expect to see of anything else that rots, right? Even if the decay is drilled out and the cavity filled, often the discolouration is too intense to completely remove or mask the darkness of the tooth.

Dental Work

Unfortunately, previous dental work can also be a source of discolouration. Older metal fillings that contained mercury can transfer their colour into the tooth the longer they are there. These days, we have some amazing tooth-coloured filling materials that can make teeth look very natural at the time it is repaired. However, these fillings can become roughened by the wear and tear over the years and noticeable stains get attached readily. If that filling is kept past its use-by-date long enough, the adhesive that sticks fillings to teeth gets worn out, allowing stains to seep in and around the outline of the old filling material.

How do I prevent teeth discolouration?

As much as we would like them to, teeth do not renew themselves. The best way to avoid your teeth from staining is to prevent the staining as much as possible in the first place. Assess your lifestyle, food and beverage choices and oral hygiene habits. Avoid things that will wear down or damage your enamel surface. Do everything you can to prevent decay from developing in the first place so that the fillings that follow are not required. Tooth erosion and staining are a part of life, however, improving your oral hygiene, food habits and lifestyle choices can make a significant difference in how white your teeth remain.

Lifestyle and Dental habits to keep teeth whiter for longer:

  • Use an electric toothbrush
  • Brush teeth for two minutes
  • Brush teeth at least twice a day
  • Floss between your teeth daily
  • Avoid vigorous brushing
  • Use a non-abrasive fluoride toothpaste
  • Limit acidic food and drinks
  • Limit foods and drinks that stain
  • Use a straw to sip liquids that stain teeth
  • Avoid tobacco products
  • Eat a healthy diet

Most importantly, have your teeth cleaned by a dental therapist or hygienist every 6 months. Don’t forget to attend regular checkups with your dentist for early detection and early prevention measures to keep decay and leaking fillings under control. It will keep your mouth healthy and help your teeth stay white and bright.

Article by Brenda Loh

Brenda has a heart of gold – and patients like you love her for it. Wanting to look after people stems way back to when she was a child and now it still shines through everything she does. Born in Malaysia, of Chinese heritage, and raised in the inner suburbs of Melbourne, Brenda has been a mainstay at the clinic since 2003 and has grown to love Geelong and the people around her.