Tooth whitening (bleaching) is a safe and successful procedure as long as the recommended materials and clinical protocols for use are adhered to. The currently recommended products contain 10% carbamide peroxide which releases 3.5% hydrogen peroxide. The maximum permitted 21% carbamide peroxide releases 7% hydrogen peroxide.
Until a recent EU Directive limiting bleaching to dental professionals, the prescribing of whitening products was completely unregulated with no controls on the agents used or the amount of peroxide they contained (up to 35%).
This resulted in significant problems with tooth hypersensitivity as well as often indifferent results. Some sensitivity may still be experienced with 10% carbamide peroxide but it is usually mild and transient.
There is no evidence that the hardness and abrasion resistance of teeth is affected by peroxide-containing tooth bleaching products. The dental pulp (nerve) does not appear to suffer any irreversible damage and there appear to be no adverse effects on the adjacent gum tissues.
While not causing harm, there is no evidence from any randomized, controlled, double blind, independent clinical trials that the use of bleaching “laser”lights during (in-office, chairside) whitening techniques increases the longevity or effectiveness of bleaching