By Dr Yao Xu DDS (Minnesota) General Dental Surgeon
Are you troubled by yellow and stained teeth? Are you considering whitening your teeth? Do you have concerns regarding the safety of products on the market? Read on to find out about the Singapore Dental Association’s (SDA) recommendation to the public, and tips on how to safely carry out tooth whitening!
Why your teeth turn yellow
There are many reasons why your teeth can turn yellow. Broadly categorized:
- Superficial stains: daily habits and routines such as smoking and drinking coffee, wine or tea. These stains affect the enamel (outer layer) of your teeth and can be removed through mechanical polishing or whitening / bleaching.
- Intrinsic stains: the other main reason why your teeth become yellow is because the dentin (inner layer of your teeth) undergoes a natural process whereby it “ages” with time and yellows. Certain drug exposure during tooth development or previously root-canal treated teeth may also appear gray. Naturally, since the enamel is translucent, the yellowish color of the dentin makes the whole tooth appear yellow. For intrinsic stains, whitening / bleaching is more effective.
Whitening is achieved either by bleaching with peroxide—which works on stains caused by both genetics and lifestyle choices like diet—or by a polishing/chemical agent that removes surface stains only. With so many different kinds of teeth whitening products that are available in the market right now, it’s hard to choose exactly which way is the best. This all boils down to identifying the key root of your problem, whether it is the enamel or the dentin of your teeth that gives it that yellow glow.
Types of teeth whitening methods
The Singapore Dental Association recommends consumers choose a whitening product only after consulting with their dentist. This is to minimize undesirable side effects such as tooth hypersensitivity, gum damage, as well as to treat the underlying causes of tooth discoloration by a professional.
Extrinsic / surface stains may be removed by abrasive whitening toothpaste, such as those containing baking soda, or with the higher frequency vibration of an electric toothbrush. Simply put, these act to scrub your teeth.
Intrinsic stains, however, requires the inner dentin layer to be whitened. Whitening / bleaching gel/paste actually targets the dentin of your tooth. As the dentin becomes more white, the whole appearance of the tooth does as well.
The sources of tooth whitening treatment can be broadly classified into 4 categories:
- Professionally applied (In-Office) by a dentist
- Dentist-Prescribed/Dispensed for patient home use
- Consumer-Purchased/over the counter (OTC)
- Non-Dental Options
Making a choice
Bleaching material consists of a variety of peroxide compounds, including carbamide peroxide, hydrogen peroxide, sodium perborate and calcium peroxide. Choosing the best teeth whitening method can be a scary and daunting process. Up to two-third of users experience hard tissues, transient mild to moderate tooth sensitivity during the early stages of bleaching treatment. This is because the sensitivity is closely related to the peroxide concentration of the material and the contact time. However, under the help of proper techniques, there is no record on long-term adverse pulpal sequellae.
In summary, whitening / bleaching treatment done in the dental office or at home may results short-term tooth sensitivity and/or gingival irritation. Higher the hydrogen peroxide concentration, more severe the mucosal damage is possible. As such the use of home bleaching materials and unsupervised whitening procedures by non-dental professionals at higher hydrogen peroxide concentrations should be prohibited. It is in the interest of patient safety that Singapore Dental Association recommends that tooth whitening products containing concentrations up to 6% hydrogen peroxide be prescribed by a registered dentist for home use by the patient, and only after consultation with their dentist.
More information can be found on the Singapore Dental Association website, written by Vice President Dr Chye Chuan Hee Kelvin, in consultation with the Health Science Authority. http://sda.org.sg/public-interest/tooth-whitening-bleaching/