Can teeth whitening damage my teeth
The short answer is NO, but care is required. Tooth whitening as performed today has its origins in the 1980s and so now has a 30 year history. In general, most in-office and dentist-prescribed, at-home bleaching techniques have been shown to be effective, although results may vary depending on such factors as type of stain, age of patient, concentration of the active agent, and treatment time and frequency. However, concerns have remained about the long-term safety of unsupervised bleaching procedures, due to abuse and possible undiagnosed or underlying oral health problems.
Allergic sensitivity: There have been no allergic sensitivity reported for carbamide or hydrogen peroxides, or for alternative peroxo-adducts,
Tooth enamel: A detailed review of tooth whitening products in 2010 [Goldberg et al, http://www.ncbi.nlm.nih.gov/pubmed/19543926] reported on an investigation performed with the very high magnification microscope that concluded that most bleaching agents (even those containing 10% (w/v) carbamide peroxide), induce slight to moderate alterations of the enamel surface and a decreased enamel micro hardness, with clear variations between the bleaching agents notable. These micro lesions are of much lesser importance than those arising from enamel etching performed in the dental office as a very frequent part of placing dental fillings, crowns and veneers.
From some reports, it appears that minor defects are also induced in the subsurface. These defects might have an immediate effect of interfering with the adhesive properties of restorative materials.
However After some time, the enamel changes are gradually reduced. As a result of ion re-precipitation controlled by some salivary proteins and/or by the bacterial plaque, calcium-phosphate precipitation occurs inside the porous enamel, a phenomenon that leads eventually to re-hardening and furthermore contributes to a return to the normal situation. [Rodrígues JA et al, Am J Dent. 2001 Apr;14(2):67-71. Effects of 10% carbamide peroxide bleaching materials on enamel microhardness, http://www.ncbi.nlm.nih.gov/pubmed/11507802]
Also regarding tooth enamel and dentine: transient mild to moderate tooth sensitivity can occur in up to two-thirds of users during early stages of bleaching treatment. Sensitivity is generally related to the peroxide concentration of the material and the contact time; it is most likely the result of the easy passage of the peroxide through intact enamel and dentin to the pulp while the bleaching agent is on the tooth surface.
However, there have been no reported long-term adverse affects upon the dental pulp (often referred to as ‘the nerve’) when proper techniques are employed.The incidence and severity of tooth sensitivity may depend on the quality of the bleaching material, the techniques used, and an individual’s response to the bleaching treatment methods and materials. To date, there is little published evidence documenting adverse effects of dentist-monitored, at-home whiteners on enamel, but two clinical cases of significant enamel damage have been reported, apparently associated with the use of over-the-counter whitening products This damage may be related to the low pH of the products and/or overuse.
Sensitivity can be prevented or decreased by treating the teeth 30 min prior to whitening by desensitising agents containing 3% potassium nitrate and 0.11% per weight fluoride.
Gum and soft tissues: gum irritation is sometimes reported.peroxide is caustic in higher concentrations.
When the dental surgeon at the chair-side applies H2O2 or alternative peroxo-adducts, there is a clinical control of the risk factor for developing gingival irritation. This is not always the case with nightguard, i.e., dentist-prescribed home-applied bleaching methods. The situation may be even worse when patients without any control of a dental surgeon are using whitening methods. Carefully adapted trays are mandatory if the dental practitioner wishes to prevent or suppress gingival irritations. H2O2, together with lauroyl and benzoyl peroxides, all represent compounds with the potential to generate free radical species. They are not carcinogenic when applied topically to the mouse skin, but they are potent skin irritants. Notable modifications induced by peroxides in skin are epidermal hyperplasia and the induction of dark keratinocytes: 15% or 30% (w/v)H2O2 gave rise to an extensive epidermolysis, inflammation, and vascular injury in rodents. This was found to be followed by a rapid regeneration and epidermal hyperplasia. After topical application of 10% (w/v) carbamide peroxide, an increase in the quantity of cells located in the basal layer of the oral mucosa revealed by proliferating cell nuclear antigen(PCNA) staining was noted. However, by immunode-tection of cyclin D and p16 (representing a proliferation marker and a negative regulator of cell proliferation, respectively, the alteration of which are considered as markers of an initial cancer formation), studies carried outon the oral mucosa failed to indicate any significant alteration. In contrast, using the PCNA as a marker, the same researchers have shown a transient proliferation after topical application of carbamide peroxide to the basal and suprabasal epithelial oral border. Therefore, the controversy is not yet solved.
In fact, temporary burnings of the tissue arising from H2O2 have been reported. In the hamster pouch, severe inflammatory processes are now well identified. During the treatment of periodontal diseases, the bacteriostatic properties of H2O2 have been widely used, and in this context, cell lysis has been reported at a concentration s slow as 1%.
Carefully adapted plastic trays or night-guards may reduce the amount of whitening agent that is expelled onto the oral mucosa when the patient overfills the tray. Strips and painted lacquers reduce the risk. The ingestion of bleaching gel may produce gastric pain, although the repeated ingestion of peroxide-containing gels does not seem to have severe consequences.
- MALCOLM J. GRENNESS
B.D.Sc., L.D.S., M.Med.Sc., PhD, F.R.A.C.D.S
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