Bleaching teeth at home safe for short-term

Tooth-whitening kits for use at home are effective in brightening smiles of people, but may not be safe. There's no evidence that teeth whitening kits are safe to use for longer than two weeks. Bleaching products for teeth generally contain hydrogen peroxide or carbamide peroxide, and may be dispensed by dentists or sold over the counter. These products first became widely available in the 1990s, but to date there has been no critical evaluation of studies supporting their safety and effectiveness. Researchers from the University of Michigan in Arbor reviewed 25 studies of home tooth-whitening products after sorting through 416 published articles on these products. They then examined the studies in detail, analysing the quality of the results and the risk of bias. All studies that compared the kits to placebo found that they were effective for whitening teeth. Side effects included mild to moderate tooth sensitivity and gum irritation. Twenty-one of the studies had a high risk of bias, while four had a moderate bias risk. While products with a higher concentration of bleaching agent worked faster, they also carried a higher risk of side effects. The researchers conclude that the products appear to be safe for short-term use, but urge that independent studies be done to evaluate their long-term safety.