| COSMETIC DENTISTRY | OPINION materials, to enhance the whitening
effect. For example, the Lumibrite system can be used in conjunction with DenMatÕs Sapphire Plus, which shortens treatment time to 30 minutes or less. Other systems, such as the Opalescence Boost, use a chemical activator. Sometimes dentists recommend
patients to continue treatment at home using so-called dentist-dispensed take-home kits. These contain a higher concentration of peroxide than OTC kits, although lower than in-office kits. They normally consist of a flexible plastic application tray that helps retain the whitening agent in contact with the teeth and minimises the leakage of whitening agent onto the gums; some are preloaded with whitening agent, while with others the whitening agent is stored in a syringe and applied just before use. An example of such a system is DiscusÕ
(PhilipsÕ) Zoom system, which includes the NiteWhite and DayWhite products. As its name suggests, NiteWhite can be used during sleep, while DayWhite is used in short, daytime sessions.
Ultradent
produces a range of professional home-use products under the brand name Tr’ swhite. Whitening kiosks in places like
shopping malls use similar products to those used by dentists. Many would argue that there the similarity ends, notwithstanding the fact that the operatives in such facilities wear white coats and use surgical gloves. Frequently, they receive little ® if any ® training, and in many places, kiosks have been closed down on the grounds that they were practising dentistry without a licence.
The professional view Unsurprisingly, professional dental organisations recommend consumers to consult a dentist rather than choosing an OTC product or visiting a whitening kiosk. As the American Dental Association (ADA) says, the best place to start is with a healthy mouth, and a dentist can evaluate, diagnose and treat any oral health conditions such as tooth decay, sensitive or cracked teeth, infections or periodontal disease before starting the whitening process. Not only might the whitening process cause unnecessary discomfort if the oral cavity is not perfectly healthy, but it may even aggravate an existing pathologic condition. In addition, a dentist can determine which whitening process is best for an
individual patient, based on the cause of the discoloration and other factors. Some individuals are not suitable for tooth whitening, and the dentist can identify these individuals and help them avoid needless expense. There is also concern about the safety
of tooth-whitening chemicals and procedures that are performed without the supervision of a suitably qualified and licensed dentist. The American Dental Association, for example, recommends that persons should only have their teeth whitened or use a bleaching product after consulting a dentist, arguing that if the chemicals used to whiten the teeth are not applied properly, they could cause damage to both the soft and hard tissues in the oral cavity. There is one other type of tooth
bleaching that has not already been mentioned ® internal bleaching. This procedure is used where an individual tooth has become discoloured by blood or other material that has leaked into the interior of a devitalised tooth, such as one that has been subject to root canal work. In this case the dentist drills a hole into the pulp cavity of the tooth, introduces the bleaching material, and then temporarily seals it up again for a number of days. After this time the tooth contents are removed, and the whitening agent reintroduced. This may be repeated for a number of cycles.
all been raised as safety issues, as has the potential for systemic ingestion. As previously mentioned, hydrogen
peroxide normally breaks down in the body to form water and oxygen, a process that is catalysed by an enzyme called catalase. However, in the presence of certain metal ions, such as ferrous (Fe2+
)
ions, the decomposition may follow a different pathway that involves the formation of free radicals such as HOÐ HOOÐ
and . Free radicals are highly reactive
and may react with macromolecules in the tissues, such as proteins or nucleic acids. The ability of free radicals to react with nucleic acids raises concerns about carcinogenicity, although to date there is no evidence of any link between tooth whitening agents and oral cancer. Nevertheless, concern about the
While peroxide-based
tooth whitening systems are regarded as generally
effective, there have been, and remain, concerns about the safety of bleaching agents.
possible long-term effects of hydrogen peroxide on the various structures in the mouth continues, particularly as patients may be unaware of how to report suspected adverse events, and non-professional teeth whiteners may also fail to report such events. Furthermore, in vitro
studies have suggested that certain dental restorative
materials may be affected by peroxides. There is some evidence that bleaching agents may induce chemical and/or physical changes in restorative materials, such as the development of cracks,
Industry concerns While peroxide-based tooth whitening systems are regarded as generally effective, there have been, and remain, concerns about the safety of bleaching agents, and not just in the hands of unqualified practitioners. For example, the possible effects of bleaching agents on the tooth structure, pulp tissues and the mucosal tissues of the mouth have
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