Review says tooth-whiteners are effective, but only in short-term
tooth-whitening products do what they claim, but that the effects
are only short-term, with the effects of longer-term use still
remaining unknown.
The review, which was published in the New Scientist this week, was headed by Dr. Hana Hasson and considered 25 of the highest quality studies from over 400 that have been carried out on tooth-whitening products.
It focused on whitening strips, gum guards filled with gel and placed over the teeth and paint-on films currently available in the US, either by prescription or over-the-counter.
The review points out the fact that all of the studies were sponsored by oral care companies to determine the products' effectiveness over a two-week period, which is said to have led to varying degrees of bias.
"All the products seem to work," said Dr. Hasson. "They were dependable in term of effects and safety."
However, the analysis of the studies led Dr. Hasson and her team to conclude that they were not entirely rock-solid, indicating in particular that there is no evidency to suggest that the products are beneficial for anything other than short-term use.
Indeed, of the 25 studies, only 13 considered the effectiveness of the product after three weeks, and only six looked at the effects after one month or longer.
"All the products seem to work," said Dr. Hasson. "They were dependable in term of effects and safety."
Although tooth-whitening products have grown enormously in popularity since the late 1990s, many dental experts have expressed concerned over the fact that their effects are merely cosmetic, rather than leading to better oral hygiene.
The main area of concern is that this kind of product relies on the bleaching of the tooth enamel to make it appear whiter, rather than actually cleaning it.
"They all work, no matter what type or how they're applied," Hasson said.
However, it was also pointed out that products with lower concentrations of active ingredients - including hydrogen peroxide or carbamide peroxide - took longer to work.
In the past there have been a number of scares linking tooth-whitening products to oral cancer, which have subsequently been discounted by scientific evidence, however such products have been linked to increased tooth sensitivity, particularly those with high levels of hydrogen peroxide.
Compounding these problems is the fact that most manufacturers only recommend that the products are used for two-week periods at a time. However, dental experts have pointed out that many consumers are using the products for more prolonged periods and that the effects for this kind of use are not yet known.
Indeed, currently the American Dental Association says it has only approved three tooth-whitening treatments - NiteWhite Whitening Gel by Discus Dental, Colgate Platinum Daytime Professional Whitening System and Opalescence Whitening gel - both of which are available directly from dental practices.