Teeth Whitening

Nowadays, teeth whitening is considered one of the most popular cosmetic dentistry treatments available. This is not surprising as teeth whitening is a quick, affordable, and non-invasive way to enhance a smile.

In essence, teeth whitening involves bleaching the teeth in order to lighten them. While it can’t make the teeth extremely white, it can lighten the teeth’s existing colour by several shades.

Typically, the teeth’s natural colour is within the range of light greyish to yellow. However, teeth naturally darkens with age. In addition, accumulation of surface stains from consumption of certain foods or drinks as well as use of tobacco products can also affect the teeth’s appearance.

Below are some of the most prevalent reasons for teeth staining.

  • While unknown to many, there is a direct correlation between age and tooth colour. Over the years, teeth can darken as a result of stain accumulation and wear and tear. In most cases, teenagers can experience instant and more dramatic results from teeth whitening. When the teeth start to manifest a yellow cast, dental whitening may entail more effort. For individuals in their forties, the yellow colour of the teeth might turn to brown and might require more dental maintenance. The teeth of people in their fifties may have absorbed more stubborn stains which can be difficult to remove through dental whitening procedures.
  • Thinness and translucency. Both genetic traits can become more pronounced as one grows older. While all teeth can exhibit translucency, those who have thick and opaque teeth have an advantage—they look lighter, have more sparkle, and is more responsive to dental bleaching. On the other hand, teeth that are more transparent and thinner have less of the pigment that’s needed for bleaching, making whitening effect less obvious.
  • Eating habits. Habitual consumption of tea, cola, coffee, red wine, oranges, carrots, and other deeply-coloured foods and beverages may result in considerable staining overtime. In addition, acidic food like vinegar and other citrus fruits contributes to the erosion of the enamel. As a result, the surface of the teeth can become more transparent and the yellow-coloured dentin will become more apparent.
  • Chemicals / drugs. Use of tetracycline during tooth formation can produce a brown or dark grey ribbon stains that can be very difficult to remove. Excessive fluoride consumption can also lead to fluorosis or discolouration marked by faint white marks on the teeth.
  • Falls, alongside other injuries can result in sizeable teeth cracks that can collect a huge amount of debris and stains.
  • Often attributed to stress, teeth grinding (bruxing, gnashing, etc.) can result in micro- cracking of the teeth and can result in the darkening of the biting edges.
  • Smoking habits. Nicotine can leave brownish deposits that can slowly soak into the tooth structure and result in intrinsic discolouration.
  • Starting colour. Everyone is born with an inborn teeth colour than can range from yellow brown down to greenish-grey and is not caused by any dental procedure, which can intensify overtime. Generally, yellow brown is more responsive to bleaching compared to green grey.

There are two staining categories that relate to the teeth: intrinsic and extrinsic.

  • Intrinsic stains. As the name implies, these stains are formed on the teeth’s interior. Intrinsic stains can be attributed to a host of causes including ageing, trauma, excessive fluoride ingestion, and exposure to minerals like tetracycline among many others. In the past, it was believed dental bleaching to whiten the teeth is not powerful enough to correct intrinsic stains. Fortunately, nowadays, even deep-set intrinsic stains can be removed through dental whitening procedures. If all other dental options fail however, there are other effective cosmetic alternatives that do not require whitening but can treat intrinsic staining like dental veneers.
  • Extrinsic stains. This type of stains appears on the teeth’s surface as is often the result of exposure to tobacco and other dark-coloured foods and beverages, which will require dental whitening procedures to remove. In some cases, extrinsic stains can also be the result of routine wear and tear. Extrinsic stains that are superficial can be easily removed through prophylactic dental cleaning and brushing. Stubborn extrinsic stains on the other hand will require more dental effort before it can be removed, often requiring more complex whitening procedures. If not dealt with early and properly, persistent extrinsic stains can penetrate the dentin and can become ingrained there, making teeth whitening difficult.

In addition to the risks, a few dental caveats should also be considered before undergoing teeth whitening treatment.

  • Whitening results won’t be evident until around two weeks after the dental procedure. This should be an important consideration for those patients who will get ceramic restorations and would like to be sure the colour will match that of their newly bleached teeth.
  • If porcelain dental veneers, cosmetic bonding, and other dental restorations are part of the treatment plan, they should not be placed until two weeks has passed after whitening. This is to ensure function, proper adhesive bonding, and shade matching is achieved for an effective whitening of teeth.
  • To prevent the technicolour effect, tooth-coloured restorations might require replacement after bleaching.
  • Teeth whitening is not recommended for nursing or pregnant women as the likely impact of swallowed bleach on the fetus is still unknown.

A number of bleaching products and techniques are now available to patients. However, dentists often use the following methods to whiten the teeth:

  • Vital bleaching. This type is often done on the “living” teeth and is typically the option for teeth stained by food or tobacco. It is also often the alternative for teeth that has darkened with age.
  • Non-vital bleaching. This type of bleaching is done on teeth that are not “alive.” For instance, for teeth that has been discoloured because of root canal, non-vital bleaching is recommended to lighten the teeth from the inside out.
Frequently Asked Questions

Several visits to the dentist are required for teeth whitening. An impression of the teeth will be taken in order to create a mouthguard. Bleaching gel will be applied for a period of 2 to 4 weeks. Some whitening gels can be left for as long as 8 hours at a time, shortening the whitening treatment period to just a week.

Power whitening, also known as laser whitening is yet another teeth whitening system dentists can provide. A bleaching product is painted onto the teeth and a laser or light is shone on the teeth to activate whitening. Laser whitening will take just an hour.

Don’t think twice about asking your dentist any questions you may have related to the procedure. Make sure you know the answers to the basics like the results you can expect, the risks involved, how the procedure will be done, the cost, etc. As a general rule of thumb, make sure all your questions are answered before going ahead with the procedure.

Teeth whitening is not permanent. While it can vary from one person to another, generally, it can last from a few months to up to 3 years. You also need to also remember that the whitening effect won’t last as long if you drink coffee or red wine, or smoke.

Teeth whitening won’t work on crowns, fillings, dentures, or veneers.

While dental cleaning can whiten the teeth, it is only temporary as only the superficial stains are removed. If you want to make your teeth a few shades lighter, you should not consider dental cleaning as a substitute for the whitening procedure.

Not all teeth stains can be whitened by bleaching. To play safe, visit your dentist for proper guidance and recommendations. If you have a worn enamel, gum disease, or sensitive teeth, tooth whitening will most likely be discouraged.

No, teeth whitening is not for everyone. For starters, teeth whitening procedures are not recommended for children and breastfeeding and pregnant women. For individuals with extremely stain teeth, other procedures might be recommended first to determine the cause of the discolouration and correct it. Generally, the condition of the teeth is assessed first before any whitening treatment is performed.

Teeth whitening procedures won’t cause any damage to the enamel as long as it is performed by a dental professional. In other words, teeth whitening should only be performed by your dentist, dental hygienist, or dental therapist.

Overall, teeth whitening should not hurt. However, if you experience any burning, stinging, or irritation in your mouth, make sure you inform your dentist right away. People experiencing teeth sensitivity after teeth whitening is not uncommon. Fortunately, your dentist can provide remedies to manage the sensitivity.

Teeth Whitening Risks

As long as done by a dentist, teeth whitening treatments are considered safe. However, the procedure also comes with certain risks like:

  • Bleaching can cause short-term sensitivity to pressure, touch, and temperature. Sensitivity is most likely to occur when a higher concentration of bleach is used. Some patients may also experience zingers or spontaneous shooting pains in the middle of the front teeth. Individuals who are at greater risk for whitening sensitivity are those with significant cracks in their teeth, gum recession, or those with leakage secondary to faulty restorations. Fortunately, sensitivity due to teeth bleaching won’t last longer than a day or two.
  • Technicolour teeth. Restorations like dental crowns, veneers, or bonding won’t be affected by bleach and therefore will maintain their default colour white the rest will be whitened. The result is what is referred to by many as technicolour teeth.
  • Gum irritation. At least half of those who use peroxide whiteners experience a degree of gum irritation from contact with the trays or from the bleach concentration. Once the bleach has dissipated or the peroxide concentration has lowered, the irritation will eventually disappear.
Teeth Bleaching Methods

Generally, there are three methods available when bleaching teeth. The method that will be used will depend on a few key factors like the number of teeth that needs bleaching and how badly they are discoloured or stained.

Depending on what’s best for the patient, the dentist may recommend the following:

  • Using and putting a special bleach on the stained teeth and using light or heat to begin the bleaching action.
  • Wearing a mouthguard that is custom-made and filled with a special bleach.
  • Brushing the teeth using a special bleach mixed with the toothpaste.

Shade guides

Before and after teeth colour is usually measured using shade guides. Shade guides are hand-held displays of teeth colours. They are also used when choosing crowns as well as other restoration shades.

The standard-setter among the shade guides is the Vitapan Classic Shade Guide. This guide incorporates 16 shades, arranged systematically from light to dark and is divided into four colour groups. It also comes with a universal tooth-colour terminology.

While whitening can lighten the colour of the teeth by nine (or more) shades, those who have their teeth bleached can expect to see a change of two to seven shades.

Teeth Whitening Options

While teeth is not meant to be completely white, many people still want a brighter smile. In line with this, a vast range of teeth whitening options has become available to consumers. These products however fall into two primary categories: bleaches and surface whiteners.

  • Surface whiteners. These kind of products make use of special abrasives to enhance the product’s ability to get rid of surface stains. Majority of the products that fall in this category are either chewing gums or toothpastes. Since the special abrasives in these type of whitening products are usually finer versions of those used in regular toothpastes, it is very unlikely for them to cause excessive tooth wear. However, the product’s effectiveness is generally limited to the removal of surface stains.
  • Most of the bleaching products available are peroxide-based and can effectively alter the colours of the teeth. However, not all teeth discolourations will respond to teeth-bleaching treatments. It is recommended that those who are contemplating having their teeth bleached should consult with a dentist so cause of the teeth discolouration is determined. It is also needed so that dentist can gauge if teeth bleaching is indeed the best option. This is especially important for patients with root canal treatments, crowns, fillings, or those with really dark stains on the anterior teeth.

Dr Clarice Yeoh

B.D.S. (Singapore)

For an appointment please call:
1728 Ang Mo Kio: +65 9631 1728
1728 Tampines: +65 9725 1728
1728 Jurong East: +65 9770 1728
1728 Bedok Central: +65 8764 1728

Dr Clarice Yeoh obtained her Bachelor of Dental Surgery from the National University of Singapore. Following graduation, she has served at various public healthcare institutions, including Singhealth Polyclinics, Health Promotion Board (HPB), National Dental Centre. Notably, she was appointed Dental-Officer-In-Charge within Singapore Armed Forces (SAF).

Dr Clarice strongly believes in providing honest and high-quality care for her patients. She is committed to restoring her patient’s aesthetics, function, and comfort. Additionally, she is known for her cheerful demeanour, creating a warm and welcoming atmosphere in her dental practice.

After clinic hours, Dr Clarice enjoys staying active through yoga and playing tennis. At home, she loves to try out new recipes and hang out with her feline companion, Louie.


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Dr Denise Deng

B.D.S. (Singapore)
For an appointment please call:
1728 Ang Mo Kio: +65 9631 1728
1728 Tampines: +65 9725 1728
1728 Jurong East: +65 9770 1728
1728 Bedok Central: +65 8764 1728

Dr Denise Deng graduated with a Bachelor of Dental Surgery from the National University of Singapore. She has worked in the private sector and public institutions such as National Healthcare Group Polyclinics, HPB School Dental Centre and Khoo Teck Puat Hospital, where she worked alongside specialists and treated patients ranging from preschoolers to elderly, with diverse treatment needs from basic to advanced and emergency dentistry.

Dr Deng is a strong advocate of providing a stress-free dental visit and holistic treatment. She firmly believes in engaging patients in coming up with a unique treatment plan according to their individual needs and concerns. To ensure her patients receive the best care, she is committed to upgrading her skills through various professional development courses and is an active member of the Oral Health Awareness Committee of Singapore Dental Association and the College of General Dental Practitioners. She is also a volunteer dentist with the Ling Kwang Home for Senior Citizens.


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