Cosmetic Dentistrywoman with white teeth

Teeth whitening is fast becoming one of the most common cosmetic dental procedures because it is fast, predictable, and relatively inexpensive.  However, our patients often ask us “is tooth whitening safe”?  Well, the answer is yes, teeth whitening is a very safe procedure.

Before we answer that question in further detail, let us first explain how tooth whitening works and how its performed.

Firstly, a mould or impression is taken of your teeth. This can be performed in the traditional way (by taking an alginate impression and casting the moulds up in gypsum). However, the newer way is to take a digital scan of your teeth and then 3D print the model.  The latter option is generally best as its more accurate.

From these models, a whitening tray which is also known as a bleaching tray is made. It basically looks like a smaller, better fitting version of a mouthguard and its main purpose is to hold the bleach up against the teeth.  The most important feature is to ensure a whitening tray is well-fitted with a good seal.  If the seal is poor, saliva will leak into the tray when you are wearing it and wash the bleach away resulting in a poor outcome.

Once the trays are made, they are tried in your mouth by your dentist or possibly even hygienist.  The clinician will check they fit well, that they are comfortable (i.e. no rubbing on the gums or cheeks) and most importantly that the seal is good.  Once this is all checked you will be given detailed instructions on how the bleaching is to be performed. Here are the steps:

  1. Brush your teeth as normal before you go to bed. Some sensitive toothpastes will actually decrease the effectiveness of bleaching, so it is best to avoid them for now.
  2. Rinse your mouth with water and spit the toothpaste out.
  3. Load the bleach in the tray, placing a small blob on each tooth up until the big molar tooth. Each blob should be about the size of a grain of rice and remember to put it on the front part of the tooth.
  4. Put your lips together, suck up all your saliva and swallow. Do this three times and your mouth will become very dry.
  5. Then place the tray into your mouth. Some excess bleach may exude through the periphery of the tray. This can be wiped with a cotton bud. If you swallow some of the excess bleach don’t worry, it is not harmful. If you are getting a lot of bleach coming out of the sides of the tray you are putting far too much in, so next time adjust the quantity.  Please do not rinse your mouth out after the tray is inserted – the water is likely to get inside the tray and wash the bleach away.
  6. Head off to bed for a good nights’ sleep.
  7. When you wake up in the morning remove the tray, rinse your mouth with plenty of water and then brush as normal. The whitening trays can be cleaned with a normal toothbrush and water.
  8. Repeat the process daily.


How long does teeth whitening take?

This really depends on how stained your teeth are to begin with, the concentrate of bleach and how white you want your teeth to be.  On average it takes around two weeks for the teeth to whiten.  If you want them whiter you carry on whitening them – normally 3 weeks is a decent amount of time.

How safe is teeth whitening?

Teeth whitening is a very safe procedure with few reported side effects.  The most common side effect experienced is sensitivity which is temporary and subsides quickly after the bleaching process has stopped. If your teeth start getting very sensitive during the procedure, we advise you to stop for a few days and then start again.  Once you resume the process it is best to only use the whitening trays every other day.  This will ensure the sensitivity is kept at bay.

In terms of safety, dental bleach supplied by a dental healthcare professional is very safe for your teeth.  It has an almost neutral pH which means its non-erosive.  Bleach bought from the internet or non-dental professional does not contain hydrogen peroxide (as only dentists are allowed to prescribe) and often have other harmful ingredients.  A lot of products contain citric acid which can be around 1000 times more erosive than dental bleach and this can cause serious problems, especially if left on your teeth for prolonged periods.

Studies have shown that the entire bleaching process, if done by a dental healthcare professional, has the same effect as drinking a single can of coke.  So, you can be rest assured it is completely safe. However, we would avoid treatment of pregnant women or women who are breastfeeding.

If you want to know more about whitening your teeth, give us a call – we would be happy to help.