Teeth Whitening – Myths vs Facts

After returning to the city for the past three years, we have decided to treat our patients to a discounted whitening treatment.  We are offering patients $150 off a take home whitening kit redeemable at your next check up and clean. We have been inundated with calls about this offer and what exactly the procedure involves, so we would like to take the time to answer some of your burning questions about teeth whitening.

teeth whitening

What makes your teeth yellow? 

There are two main reasons your teeth may appear darker. These are intrinsic or extrinsic factors. Intrinsic tooth discolouration is a result of the natural colour of the inside of your tooth.  Extrinsic tooth discolouration occurs due to staining on the outside layer of your tooth from consuming foods, drinks and smoking. 


Your teeth have a layer on the surface called film protein which protects the tooth enamel and under this layer of enamel there is a yellowish core called dentin. Some people naturally have darker dentin than others. Enamel can wear down and make the teeth appear darker. When the tooth enamel wears down or becomes thinner, the layer of dentin gets closer to the surface which can make the teeth appear more yellow. 

Intrinsic discolouration may be due to a number of factors including: 

  • Genetics 
  • Tetracycline – an antibiotic given to children under 8 years of age 
  • Trauma to a permanent tooth 
  • Age related factors – enamel thins as we age allowing the dentin to show through 
  • Grinding/bruxism – teeth grinding can wear down the enamel exposing the dentin
  • Acid erosion – an acidic diet can lead to acid wear, causing enamel to thin 

Intrinsic tooth discolouration unfortunately can-not be treated with tooth whitening products.  Whiter teeth can be achieved with more invasive treatment options such as veneers and crowns. Preventative measures should be used to avoid invasive treatments. 


Teeth can become darker/yellow as a result of staining to the outside layer of the tooth enamel. This type of discolouration is generally easy to treat with good oral hygiene and regular dental hygiene appointments with your dentist. Extrinsic discolouration generally responds well to whitening treatments. 

Common extrinsic factors include: 

  • Coffee/tea
  • Acidic foods eg. Lemon
  • Soft drinks
  • Red wine 
  • Smoking
  • Beetroot
  • Turmeric 

Teeth whitening. Healthy white teeth are smiling and yellow from cigarettes and sad coffee on green mint background with toothbrush

What is in whitening products that make your teeth white? 

Teeth whitening products contain hydrogen peroxide or a similar chemical agent which removed extrinsic staining for your enamel. In Australia, there are regulations ensuring these products contain no more than 6% hydrogen peroxide. 

What are the options that are being advertised? 

Whitening toothpaste 

Whilst toothpastes that claim to be “teeth whitening” can be useful for removing extrinsic staining, it will not whiten your enamel.  Most dentists will not recommend a whitening tooth paste as they often contain abrasive substances. Prolonged use of an abrasive tooth paste can lead to thinning of the enamel and sensitivity. 


Charcoal has recently made its way into the mainstream media as a popular alternative for whitening teeth.  Recent studies into this method have not yet been successful in proving the effectiveness of charcoal as a teeth whitening option.

LED Lights

Some dentists believe LED lights can speed up the process of teeth whitening by accelerating chemical reactions. It is important to make sure that if you do choose a method of whitening with an LED light that proper UV protection is used.  The evidence to support the effectiveness of LED lights is inconclusive and some dentist prefers not to use them. 

In-Chair Whitening

Whilst this method is the quickest, it is also the most expensive and often painful method. This method has become less popular for this reason.  Results often appear to be successful at first, although it is possible that teeth can appear whiter immediately after this treatment as a result of dehydration to the tooth. 

Whitening Trays

This is our recommended method for achieving a whiter smile. It is minimally invasive and can produce great results at your own pace. We take an impression of your teeth and make custom fit trays.  You manually fill these trays with gel and wear for 30minutes per day for 1-2 weeks to achieve optimum results. Results may vary. This method is recommended for long term results as the trays can be kept and re-used for future whitening treatments. Simply purchase more gel and repeat the process.  1 x Tube of Gel = $35 (approximately 10 x 30minutes sessions worth of gel). 

Hands working on a teeth whitening tray

Preventative Measures

Some tips for avoiding extrinsic staining: 

  • Brush and floss your teeth after meals where possible
  • Rinse your mouth with water after eating or drinking high staining  and acidic foods/drinks such as: red wine, coffee, lemon, turmeric 
  • Keep up to date with your regular dental hygiene appointments
  • Children under 6 years of age should avoid fluoride toothpastes 

If you are interested in teeth whitening and would like to find out more information about our teeth whitening discount please click here. The purpose of this page is to provide insight into the teeth whitening options. Information for this blog has been sourced from Colgate and Crest. Please consult your dentist for further recommendations and advice for the most suitable teeth whitening method for you.