The company claims improved stability of peroxide in the gum compositions.
“Peroxides are known to provide tooth whitening effect to users. Due to its interaction with certain carriers, however, peroxides have typically been used as additives in gel compositions. There has been difficulty in providing peroxides to users in other forms that may be desirable for the user,” Kraft said.
It noted that chewing gums had not typically been used to deliver peroxides as the ingredients reacts with gum base and degrades quickly leading to “very short shelf-life stability”.
Kraft has developed a gum where solid peroxide is encapsulated and contained in the inner region of a number of particles within the gum base.
“Solid peroxide compositions are useful in the present invention due to their ability to be encapsulated easily and incorporated into a chewing gum base with relative ease,” it said.
Kraft recommended carbamide or urea peroxide as the “most preferred” compositions, but said others including sodium percarbonate, peroxydone, calcium peroxide and perbenzoic acid could also be used.
In some examples, the compositions provide a foaming effect to the user, enabling the tooth whitening agent to remain in contact with the tooth surface for a desirable period of time, it said.
The firm said the ratios of the formulation were explicitly important to the function and shelf-life of the product. “The gum needs enough encapsulating material to provide an effective barrier between the peroxide and gum base, but not too much as to reduce the whitening effectiveness or mouth feel.”
One factor extremely important to function is that the solid peroxide is fully encapsulated, as “even a slight exposure to water or water-based materials may react with the peroxide and render it ineffective”, Kraft said. The encapsulation material must therefore be water-insoluble and free of any water-based components.
The company claims it has discovered the “optimal balance”.
Testing against the market
Kraft tested four sample gums, with different compositions, against Trident White on product ability to remove extrinsic tooth stain.
The double-blind parallel, controlled clinical study tested 243 individuals at 0 days, three weeks, eight weeks and twelve weeks.
Findings showed, only one sample composition reached a two-fold share increase; it had a combination of 4% carbamide peroxide and 4% sodium tripolyphosphate. “Reaching a two-fold whitening increase is important as it allows the manufacturer of a product to legally and justifiably claim that it results in two shades whiter teeth to the user,” Kraft said.
Kraft noted that the technology could be extended to use in chewing gum-confectionery blends too, that use a gum portion within a confectionery product or also mouthwashes, toothpastes, lozenges and mouth sprays.
However, “particularly preferred compositions are those than can be chewed by the user, such as chewing gums and soft or chewy candies”, it said.
It said the gum or candy could be coated or uncoated, flavored and sweetened, and in a broad range of forms, including slabs, sticks, pellets and balls, but said the preferred application was a slab gum due to the softer formulation.
Whatever product selected – it is important to promote an action that breaks the encapsulated peroxide, like chewing or brushing, it said.
Kraft added that the composition may need to differ in each application in terms of ingredients ratio.
Kraft Foods filed its patent under The Patent Cooperation Treaty (PCT), an international patent law treaty that allows a uniform patent to be considered by signatory national or regional authorities.
The full filing can be found here.