Studies from the Academy of General Dentistry, (AGD Impact, April 1998, p.23), during the past five years have proven the lab direct teeth whitening process to be safe and effective. A small percentage of people may experience some tooth sensitivity and gum irritation, which disappears once you stop using the Hi-Intensity Whitening Gel or by decreasing the amount of time you use the whitening system.
As with anything, abuse of a product can result in undesirable consequences. In the event that you are unsure of your current oral health, talk with your dentist prior to whitening.
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Risk & safety article