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Teeth Whitening

Written by Dr. Tyler Tay

Teeth discolorations are inevitable. They may be a result of

  • ageing,
  • continual tobacco usage, or
  • the consumption of certain food and beverages.

If you feel that your smile is lacking some sparkle, you may want to consider teeth whitening.

Table of contents

There are 3 main types of tooth discolouration, each caused by different reasons. They are namely extrinsic, intrinsic and age-related stains.

Extrinsic Stains

Extrinsic teeth stains are staining on the surface of your teeth. They occur when stain particles accumulate in the protein film covering your teeth enamel.

This is usually a result of poor dental hygiene, tobacco use and frequent consumption of coloured food or drinks.

How to remove:
Practising good oral hygiene can help to reduce the occurrence of extrinsic teeth stains. Additionally, these stains respond well to regular dental cleaning.

Intrinsic Stains

Unlike extrinsic stains, intrinsic teeth stains occur below the surface of your teeth. This happens when stain particles work through the exterior of your teeth and accumulate within your teeth enamel, staining the inner layer (known as the dentine).

Intrinsic stains can be caused by:

  • Trauma to the tooth
  • Congenital issues such as cystic fibrosis
  • Consumption of certain antibiotics (e.g. tetracycline*)
  • Excessive consumption of fluoride during the first 8 years of childhood (fluorosis)
  • Genes

How to remove:
Intrinsic stains cannot be removed by cleaning or using abrasives. They may require bleaching by a professional dentist or a chemical teeth-whitening product.

Genetic causes, especially those causing weak and brittle teeth, may require restorative dental procedures such as dental crowns or veneers. These procedures can help to address the discolouration and protect and improve the stability of teeth.

*When a pregnant woman consumes tetracycline, the baby’s teeth can become stained.

Age-Related Stains

Our tooth enamel, which is the outer layer, is translucent. The dentine, on the other hand, is pale yellow. Hence, the thickness of the enamel affects how white our teeth look.

As our tooth enamel erodes due to age, the pale yellow dentine becomes exposed. Moreover, the dentine may become more yellow over time, contributing to the discoloured appearance.

How to remove:
Age-related stains can typically be addressed with teeth whitening. If stains are caused by the discolouration of dental fillings over time, it can be resolved by replacing them with new fillings.

Teeth whitening is not suitable for everyone. You may not be suitable for this procedure if you have/are:

  • Cavities or tooth decay
  • Fractures or trauma to the teeth causing dentine to be exposed
  • On-going orthodontic treatment* like Invisalign or braces
  • Completed restorative dental procedures like dental fillings, crowns and veneers
  • Severe gum disease
  • Pregnant
  • Hypersensitive teeth

Thus, prior to this procedure, it is best to first go for a dental check-up to ensure that you are suitable to undergo this treatment.

*You may be suitable for teeth whitening after your orthodontic treatment is complete.

If you are suitable for teeth whitening, there are 2 options available – chairside (in-office) treatment and take-home whitening kits. Your dentist will advise you on the options.

Chairside (In-Office) Treatment

Our chairside treatments are carried out in the clinic by our professional dentists.

In most cases, a brighter smile can be achieved in one treatment, offering convenience to busy individuals who are looking for results in a short amount of time.

At i.Dental, we offer 2 types of teeth whitening systems:

  • ZOOM® Advance Power Professional Teeth Whitening System: Available at i.Dental @ Yishun
  • Natura+ Whitening System: Available at i.Dental Invisalign Dedicated Clinic, i.Dental Surgeons, i.Dental @ Ubi

How it works:
The dentist will begin by scaling and polishing your teeth to remove any dirt, particles or stains. Next, a cheek retractor will be used to retract your cheeks and protect your tongue and lips. A protective gum barrier will also be applied to protect your gums during the procedure.

After which, a whitening gel will be applied and activated using the ZOOM® or LED light. Depending on your sensitivity level, the number of times the gel is applied and the usage duration of the light may vary.

Once the activation process is complete, the gel will be removed and your teeth will be cleaned and polished. Finally, a fluoride gel will be applied to your teeth to reduce tooth sensitivity.

Take-Home Whitening Kit

This treatment option involves creating custom-made trays for your teeth so you can undergo treatment from the comfort of your home.

It is a cheaper and more convenient alternative to in-office treatment and is gentler on your teeth. However, the treatment time is generally longer.

How it works:
To create custom-made trays, your dentist will take an impression or 3D iTero Scan of your teeth.

On your next appointment, your dentist will share the instructions on how to administer the whitening gel. This differs from case to case depending on your teeth condition and the concentration of the gel.

On average, you will be required to apply the gel for 30 to 45 minutes per day.

  • Whitening (Custom Trays)


    (Inclusive of GST)

  • Whitening (In-Office)

    $1076.92 - 1,294.92

    (Inclusive of GST)

As teeth whitening treatment is a cosmetic procedure, there are no subsidies available and MediSave cannot be used to subsidise a portion of the treatment.

  • Professional Dental Care Services

    We ensure that your needs are met every step of the way; from the initial consultation to post-treatment, our team guarantees that you are provided with high-quality care.

    You can take comfort in knowing that all your dental needs will be handled by our experienced and passionate team of experts.

  • Comfortable Treatment Experience

    At i.Dental, we are equipped with dental technology that can help you achieve your desired smile.

    These technologies serve to complement our dentists’ expertise and allow you to enjoy a better and more comfortable treatment experience.


Teeth whitening is generally safe if performed or administered by a professional dentist. However, you may experience certain side effects like tooth sensitivity and irritation to the gums, lips and tongue.

You are recommended to consult a dentist before proceeding with teeth whitening treatment to ensure that you are suitable for the procedure.

Over-the-counter teeth whitening products like teeth whitening strips and toothpaste are generally ineffective. This is due to 2 reasons:

  • Low concentration of hydrogen peroxide

Hydrogen peroxide is the chemical ingredient that whitens teeth. It opens highly pigmented carbon rings and converts them into chains, which are lighter in colour.

As dictated by the prevailing regulations from the Health Sciences Authority (HSA), teeth whitening products containing more than 0.1% hydrogen peroxide are only available via dentists (as an overly high concentration may also result in problems to the teeth). Thus, over-the-counter products have a low concentration of this chemical, making them ineffective in whitening teeth.

  • Use of sodium perborate

Often, non-peroxide whitening gels use sodium perborate to ‘whiten’ teeth.

Sodium perborate, which is a salt made from hydrogen peroxide, causes dehydration of the teeth, resulting in a brighter colour. However, this effect is short-lived as our teeth are re-hydrated through saliva. Thus, sodium perborate temporarily lightens teeth, rather than whitens them.

You can typically see the results of chairside (in-office) treatment immediately after the procedure. Do note that it may take 2 to 3 days for the shade to stabilise.

On the other hand, take-home whitening kits require a longer time to take effect. You are likely to see results within 1 week of using the kit, though it may require 3 to 4 weeks for you to enjoy the maximum results.

Whitening treatment is not a permanent solution to having white teeth; the duration of whitening effects will vary among different people. As such, it is impossible to know exactly how long the effects of your treatment might last.

Generally, the effects of whitening last for about 1 to 1.5 years, depending on your dietary and lifestyle habits. Those who smoke and consume alcohol may experience teeth staining more easily.

  • Maintain good oral hygiene

To prolong the whitening effects, stick to a dental routine of daily brushing and regular flossing to remove plaque buildup. This is important because plaque can make your teeth appear darker than it is.

Patients who have undergone chairside treatment can maintain and prolong the whitening effect by purchasing the take-home whitening kit.

  • See your dentist regularly

Visiting your dentist for regular checkups can help to maintain your smile. Additionally, scaling and polishing can effectively remove surface stains.

  • Avoid acidic food

As acidic food can cause tooth sensitivity, you are recommended to avoid consuming such food after your chairside treatment or during your take-home treatment duration of 7 to 10 days.

  • Avoid food that will stain your teeth

For at least two weeks following your whitening session, you should avoid coffee, red wine and tea. If you are unsure of what food and drinks to steer clear of, a good rule of thumb is to avoid any food or drink that would stain a white cloth.

Some people may find it impossible to give up their daily coffee or tea. If you belong to that category, consider using a straw! Straws help to prevent staining. Alternatively, rinse with water after consumption of these teeth-staining food and beverages.

If you have intrinsic or age-related stains, you may consider veneers or teeth bonding as an alternative to teeth whitening.

On the other hand, if you have extrinsic stains, you can opt for scaling and polishing before making a decision on whether to whiten your teeth. Practising good dental hygiene and changing your lifestyle can also help with reducing the occurrence of stains.

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