Teeth Whitening – Tell me about my options

Whitening Toothpastes The concept of whitening toothpastes has been around for over 50 years. However, these original toothpastes were excessively abrasive and worked by removing not only stains but also enamel layers. Modern versions of whitening toothpastes are much more tooth friendly and, if used regularly, can help to maintain whiter teeth. The key word here is MAINTAIN – they rarely whiten to any great degree. 

Whitening toothpastes contain detergents and a very mild abrasive to gently scrub staining from the surface of the enamel. Silica is the most commonly used abrasive, although some products also contain alumina and dicalcium phosphate. Additional chemical or polishing agents such as peroxide, titanium dioxide and baking soda are also used. In the concentrations used, none of these products actually alters the shade of the tooth itself. 

The Science of Professional Teeth Whitening: Hydrogen Peroxide vs. Carbamide Peroxide The active ingredient in Boutique Whitening products is hydrogen peroxide. Some of our products contain carbamide peroxide, which breaks down to hydrogen peroxide. 

A man named Louis Jacques Thenard discovered in 1818 that hydrogen peroxide is a potent oxidizing agent. The whitening action is a result of oxygen free radicals that oxidize larger pigment molecules into smaller, less visible molecules. By the European Directive, dental professionals are only permitted to sell products that contain a maximum of 6% hydrogen peroxide. However, over-the-counter products that do not require the supervision of a dental professional may contain only 0.01% hydrogen peroxide. These products are ineffective in whitening the teeth as the concentration of peroxide is too low. 

Carbamide peroxide is hydrogen peroxide compounded with urea. Urea helps stabilise the formula giving carbamide peroxide a more predictable and longer shelf life than hydrogen peroxide alone. By the European Directive, dental professionals can prescribe up to 16% carbamide peroxide. In the presence of water, carbamide peroxide degrades into urea and hydrogen peroxide. Any given volume of carbamide peroxide will yield 35% volume of hydrogen peroxide when it breaks down. A notable difference between hydrogen peroxide and carbamide peroxide is the rate of breakdown, and therefore, the rate of release of oxygen ions. Carbamide peroxide is a more stable molecule and breaks down more slowly than hydrogen peroxide. Carbamide releases about 50% of its peroxide in the first 2 to 4 hours, then the remainder over the next 2 to 6 hours. 

Hydrogen peroxide breaks down almost immediately, releasing its peroxides entirely within the first hour. It is thought that due to this relatively concentrated bombardment of peroxides on the pulp, hydrogen peroxide produces more sensitivity than carbamide peroxide of a comparable concentration.

In Office Tooth Whitening Whitening lamps or ‘laser’ tooth whitening options are often perceived by the public to be superior to home whitening because they can ‘see’ the procedure being performed.

Is the light necessary and is there any clinical benefit? This raises some controversy and polarises opinion. The theory is that the light ‘activates’ the gel in some way, increasing the rate of free radical release. There are numerous studies showing the lights to be effective, however, these are usually done by the companies that manufacture the lights themselves. These should therefore be approached with an open mind! So although there is questionable evidence to prove the effectiveness of lamps, if your patients are happy with the results, and they enjoy the experience then the choice is up to you. There is however, an overwhelming body of evidence to show that dentist supervised home whitening is very effective, and produces consistently superior results.

Internal Whitening Teeth can darken for a variety of reasons, one of the most common being external trauma

When a tooth experiences trauma, the pulp becomes necrotic. Blood is released as a result of the subsequent inflammation. When the hemoglobin breaks down to iron sulfide, it stains the dentinal tubules black. Non-vital teeth often respond relatively well to external bleaching techniques, however, it is necessary in some cases to whiten the tooth from within the root canal system. 

The protocol for internal whitening:

  1. Internal bleaching is possible only after a root canal has been performed.
  2. The pulp chamber must be cleaned with ultrasonic tips to remove all necrotic tissue, pulp and blood. 
  3. The gutta-percha is removed from the coronal portion of the pulp chamber to just beneath the level of the cemento-enamel junction. This should only be done after the endodontic cement has had a chance to fully set. It is advisable to use non-eugenol based endodontic cements as these inhibit the bonding of composite resins.
  4. Resin-modified glass-ionomer should be used to seal the canal. Studies have shown that internal resorption can occur if bleaching products seep into the root canal space. 
  5. 10% Boutique by Night (Carbamide Peroxide) should be introduced into the pulp chamber via syringe, and changed every 2 hours. 
  6. Alternatively, you can use a 16% carbamide peroxide and the same protocol as described above.
  7. In more extreme cases, you can use the inside/outside technique whereby the above protocol is followed, but supplemented with a single tooth whitening tray, with gel placed buccally and palatally, throughout the process and overnight. 
  8. Most cases will resolve in 2 to 4 days, and you can continue to whiten as normal.

Laboratory made trays versus in-house trays This technique requires the manufacture of custom fabricated trays by a laboratory skilled in the use of thermoplastic materials – they should NEVER be manufactured by the dentist in house. The time taken to manufacture trays in-house negates any cost saving, and the lack of quality will adversely affect the outcome of the treatment. 

The ideal work-flow to manufacture the trays is outlined below. This would be difficult to recreate when manufacturing the trays in-house, hence our recommendation to always have laboratory made trays. 

Supervised Home Whitening Dentist-supervised home-whitening is the safest, most popular, and most well-researched whitening procedure. 

As with all dental procedures, the first step is a thorough assessment and diagnosis, coupled with good quality photographs showing the closest matching shade tab (always ensure you can see the label of the shade tab). 

Trays should ideally be made with a 1.5mm single-skin, semirigid material. Vacuum and pressure forming together will ensure a tray that is a close fit to the model. Vacuum forming alone usually results in a poor fitting tray. The gingival margins should be carved prior to forming. This creates a marginal seal to prevent ingress of saliva, and wash-out of the gel.

There are two schools of thought as to how the margins of the tray should be finished – scalloped or straight. Boutique Whitening trays come with a straight margin. This requires less finishing which results in a closer fitting, more stable tray. If a whitening tray has reservoirs then a scalloped margin is better to ensure excess gel can be removed easily. 

The literature shows that reservoirs are not required. Boutique Whitening trays are manufactured with no reservoir.  However, they do have a ‘dosing dot’, basically a small dimple on the labial surface of each tooth. The patient simply has to fill the dot to ensure the correct volume of gel is dispensed. This means fewer problems with sensitivity owing to over filled trays and gel touching the gingivae. The kits also last longer, which in turn gives better results.

Are your patients ready for a whiter, brighter smile?