Complete guide to teeth whitening

Teeth whitening has become one of the most sought-after dental procedures by the public in recent years. It is a cosmetic oral treatment universally valued by men and women alike, and treatments are available in multiple options to satisfy every budget, time frame, and desired result scale.

The growth in popularity is driven by the public demand for whiter, more perfect smiles. In return consumers have access to more diverse teeth whitening methods than ever before. These include in-office whitening systems carried out by dentists and home-based whitening products such as gels, strips, toothpastes, mouthwashes etc. The effectiveness of these different whitening methods is dependent upon the type of tooth discoloration that is being treated.

The causes of tooth discoloration can be categorized into two groups, extrinsic and intrinsic causes:

  • Extrinsic (external) staining: stains that appears on the outer surface of the tooth called enamel and are caused by factors such as smoking, dark pigments in food and beverages, metals etc. The colouring compounds of these sources are absorbed directly onto the surface of the tooth causing visible stains to appear. These stains can be managed with a good oral hygiene routine and teeth whitening treatments at-home or at the dentist office.

  • Intrinsic (internal) staining: occurs within the tooth itself due to factors such as aging, genetics, overuse of fluoride, medications, and injury. The stains develop within the inner layer of the teeth called the dentin and are more permanent than extrinsic stains. The enamel wears down over time exposing the yellower dentin inside the tooth. These stains are less receptive to professional dental bleaching and will require more permanent tooth whitening treatments. If you think that your stains are intrinsic, it’s best to consult a dentist.  


The chemistry behind teeth whitening

Teeth whitening is a process that change the colour of a tooth by making it lighter. It is done by physically removing stains from the tooth or by using a chemical bleaching agent to lighten the tooth colour. The most common active bleaching ingredient in whitening products is hydrogen peroxide or carbamide peroxide, both subject to strict regulations in Europe and the UK. Carbamide peroxide breaks down in contact with water to release hydrogen peroxide, which bleaches the tooth.    

During the process of dental bleaching the whitening gel works penetrates the pores in the enamel allowing the peroxide within to whiten the dentine of your tooth. During this process, your teeth are likely to become more sensitive when in contact with the gel. If you already suffer from sensitive teeth, your dentist will be able to guide you and advise on the best treatment options before you begin.

Tooth stains are compounds that have chromogens accumulated inside the tooth (intrinsic) or on the tooth (extrinsic) that are of darker colour and shades. They can either be organic compounds or metal containing compounds. The organic compounds can be bleached using hydrogen peroxide or other whitening agents such as PAP.   

Different teeth whitening products are marketed to address the stain type to be removed. These products can include stronger toothpastes with larger amounts of detergents and abrasives for smokers to remove tobacco stains from the tooth surface; bleaching agent to lighten the colour of the tooth; and whitening products that both clean and bleach the teeth. Very complex and severe stains are best treated by dentists while at-home teeth whitening products can be used to effectively and safely remove milder stains.   

The treatment time required for whitening the tooth is dependent on the time of exposure and the concentration of bleaching compound. This in turn is dependent on the type of whitening method employed, usually 1 to 2 shades for cleansers and over the counter (OTC) gels, and more for professionally applied products.

Types of teeth whitening treatments

  • Whitening toothpastes: usually contain higher amounts of abrasives and detergents than standard toothpastes, to remove tougher stains. Whitening toothpastes typically can lighten tooth color by about one or two shades. Watch out for those tooth pastes that contain low concentrations of carbamide peroxide or hydrogen peroxide.

  • Whitening gel and strips: most whitening gels are peroxide-based gels applied with a small brush directly to the surface of the teeth or via syringe and mouthguard, although some brands use PAP gel instead. Treatment instructions are usually twice a day application for 14 days and can usually lighten teeth by 1 or 2 shades for average products, and several shades whiter for premium products. Using whitening gel is a great way to make your smile brighter. To maintain a whiter smile, floss daily and brush twice a day with a whitening toothpaste.

Whitening strips deliver a thin layer of peroxide gel or PAP on plastic strips shaped to fit onto the surfaces of the teeth. There are a variety of white strip products on the market with varying instructions and ingredients (e.g., Charcoal and PAP). A typical set of instructions are to apply the strips twice daily for 30 minutes for 14 days and the teeth can usually be lightened by 1 or 2 shades.

Tooth sensitivity can occur with some teeth whitening products containing hydrogen peroxide, although both irritation and sensitivity usually stop once you’re done treating your teeth. The best way to help avoid and prevent these possible side effects is to whiten under the advisement of your dentist or use products not containing hydrogen peroxide.

  • Tray and mouthguard-based tooth whiteners: these whitening systems are available both professionally and at-home kits. The method involves use of a fitted tray containing bleaching gel (e.g., hydrogen peroxide from the dentist) worn for 2 to 4 hours a day or overnight. Tooth whitening results are generally noticeable in a few days, lightening the teeth by 1 or 2 shades.

  • In-office whitening: generate faster results because the dental products deliver higher concentrations of peroxide than is allowed in at-home kits. Thus, gum tissues are usually protected before the bleaching agent is applied in the tray. Some dentists use laser systems to increase the rate of the chemical reactions. Teeth whitening results are seen after one 30- to 60-minute treatment. More significant results can be obtained with several applications.


In-office whitening

Risks associated with teeth whitening

Commonly reported risks with tooth whitening include increased tooth sensitivity and mild gum irritation. The degree of these side effects is directly related to the concentration of the hydrogen peroxide bleach component, duration of the treatment, and the non-bleach composition of the product used. Tooth sensitivity usually occurs at the time of treatment and can last several days; gum irritation begins within a day of the treatment and can also last several days. This is not exactly true as some very aggressive regimens can damage the tooth through dehydration and demineralization such that the tooth temporarily appears whiter.

It is important to note that these side effects are associated with the use of peroxide and not the use of PAP as active bleaching agent. If you suffer from sensitivity and irradiation after using hydrogen peroxide based products, you may well be better off using a product that contain PAP since tooth sensitivity is not associated with the use of PAP as active ingredient. VOLT London only use PAP in the teeth whitening gel.

How long does the whitening results last?

One of the common questions is How long will the teeth whitening results last?”. It is difficult to predict the persistence of whitening treatments because users may routinely expose their teeth to dark food or beverages, which are known to stain teeth and would experience re-staining within a month after the whitening treatment is concluded. However, if the teeth are not exposed to chromogens such as coffee, red wine, cigarette smoke, dark foods etc. then it would be reasonable to assume that whitened teeth could persist up to a year after completed treatment. Depending on your lifestyle, there will be a few months between top-up treatments and at-home kits can be used for those treatments.

Conclusions about teeth whitening

  • At-home teeth whitening kits results in less tooth sensitivity than in-office bleaching if you follow the manufacturer instructions for safe usage.
  • How long teeth whitening results lasts depends on which method you use to whitening your teeth (in-office vs. at-home) how you maintain them. The dentists will be able to advise you on the best treatment option for you, your lifestyle, and taking tooth sensitivity into account.
  • Ultimately, how long teeth whitening results lasts depends on how well you look after your teeth post treatment. Maintaining good oral hygiene habits and avoiding foods that are known to stain can help to prolong the whiteness of your teeth.
  • If you avoid consuming staining food, drinks, and tobacco as well as practice good oral hygiene, then your bleaching treatment can last between 6-12 months.
  • The optimal method to maintain white teeth after an in-office whitening treatment is to use monthly at-home whitening kits as top-up treatments.


More Posts

Do teeth whitening kits work?

If your teeth are discolored and daily brushing is not taking the stains away, a professional teeth whitening kit can help restore your teeth to

Is teeth whitening safe?

Teeth whitening is a common oral treatment and is considered safe when you follow the user instructions. There are two options to whiten your teeth:

PAP teeth whitening technology

If you are new to teeth whitening it is likely confusing to find a product that you know will generate safe and effective results whilst