My offices often ask me, “What is the difference between carbamide peroxide and hydrogen peroxide, and which one works better for teeth whitening or tooth bleaching?” I've found that the Whiter Image products are unique becuse they add Carbamide Peroxide to Hydrogen Peroxide in most of their products, to give your patients the added benefits of both fast whitening action and anti-sensitivity.
Carbamide peroxide (CH6N2O3), also called urea peroxide, urea hydrogen peroxide (UHP), and percarbamide, is an adduct of hydrogen peroxide and urea.
Carbamide peroxide is mainly used as a disinfecting and bleaching agent in cosmetics and pharmaceuticals. As a drug, this compound is used in some preparations for the whitening of the teeth.
In tooth bleaching, the hydrogen peroxide produced acts to oxidise extrinsic staining within tooth enamel. There are several methods of applying the peroxide gel to the tooth ranging from night-guard application at home or in-office application. The bleaching obtained is proportional to the length of time the peroxide is applied to the tooth, and the concentration used. Concentrations used for tooth whitening purposes range between 10% and 36%. Higher concentrations may carry a higher risk of side effects such as chemical burns of the gingiva and lips.
The actual teeth bleaching procedure is still accomplished by placing a peroxide-based (either hydrogen or carbamide) bleaching gel, via various methods, into direct contact with the teeth. This contact of bleach to teeth is made either by painting the gel directly onto the teeth or using the custom tray method. It has been shown that these two techniques will result in noticeable whitening of the teeth. The finished degree of whitening ultimately achieved is predicated on the relative type, the strength or concentration of the peroxide-based gel that is used, as well as the amount of time that the active gel is left in contact with the surface of the teeth.
If the concentration is low, a longer amount of contact time against the teeth with the active bleach is needed to achieve a satisfactory result. This meant that for the patient a number of daily treatments were needed either in the dental office or at the patient’s home for the teeth to become satisfactorily white.
Making the teeth bleaching gel concentration stronger, on the other hand, would speed the color change, but would often lead to increasingly painful tooth sensitivity, which was a very non-desirable result for both the patient and practitioner. So, industry experience has been that a good result could be obtained at home if the patient used either a medium peroxide concentration of bleaching gel coupled with a regimen of spacing the treatments into an hour or less per day for a number days to a week.
When you get your teeth whitened, the hydrogen peroxide component is what actually whitens them. Tooth bleaching today is based upon hydrogen peroxide (HP) as the active bleaching agent. Hydrogen peroxide is a relatively unstable molecule by itself, and will quickly disassociate into highly reactive, strong oxidizing agents through the formation of three types of free radicals (hydroxyl radicals, per-hydroxyl radicals, and superoxide anions), reactive oxygen molecules, and hydrogen peroxide anions. In all of these free radicals, it is the highly unstable free oxygen component in each that reacts with, oxidizes, or if you will, attacks the long-chained, dark-colored chromophore molecules, the atoms or groups in a molecule that cause discoloration, in the patient’s teeth enamel. This attack splits the chromophore molecules into smaller, less colored, and more dissolvable molecules, which results in whitening of the teeth. It doesn’t really remove any stain, but it actually changes the nature and composition of the stains on the teeth. The final results of the bleaching treatment depends mostly on the concentration of the Hydrogen Peroxide available to produce the free radicals, on the amount of time the produced radicals are in contact with the teeth, and the ease in which the radicals can reach the chromophore molecules
Hydrogen Peroxide, in a gel substrate, may be applied directly to the teeth, or it can be produced in another chemical reaction from the more stable Carbamide Peroxide (CP) in the presence of water. Carbamide peroxide has two portions, the Carbamide portion and the Hydrogen portion.
Even if you are using carbamide peroxide, what actually whitens your teeth is hydrogen peroxide. Something that many people don’t know is that carbamide peroxide is made from hyrdrogen peroxide. To create carbamide peroxide, a urea molecule is added to the hydrogen peroxide molecule and the result is carbamide peroxide. Please note that there is a 3:1 relationship between carbamide and hydrogen. For example, 12% hydrogen peroxide is theoretically equivalent to 36% carbamide peroxide. However, this doesn’t mean that you’ll get the same results with 36% carbamide and 12% hydrogen peroxide. Carbamide Peroxide takes more time, but Carbamide Peroxide is much more stable than Hydrogen Peroxide and also has a much longer shelf life.
In order for carbamide peroxide to whiten your teeth, it must first break down into hydrogen peroxide. The problem in using carbamide in chair-side treatments that are 15 to 20 minutes is that it takes at least 15 minutes for carbamide peroxide to begin to break down into hydrogen peroxide (and longer to completely break down). Only when the carbamide peroxide has broken down into hydrogen peroxide can it begin to whiten your teeth. So if you use carbamide peroxide for teeth whitening during a 20-minute treatment, your customer will only have a little hydrogen peroxide on his/her teeth for 5 minutes. That’s why most people that use carbamide peroxide are using it for take-home whitening or to prevent sensitivity. Carbamide peroxide has been used traditionally for patient's with difficult stains and sensitivity such as tetracycline-stained teeth, because the patients needs a much higher level of hydrogen peroxide but doesn't want sensitivity.
Most teeth whitening suppliers choose to use carbamide peroxide because it causes less gum irritation than hydrogen peroxide. When a fast single-treatment in one-hour-or-less is not being done, and one wants to design a take home teeth bleaching kit that is safe and very forgiving of consumer mishandling, Carbamide Peroxide is the better choice. It is much more stable and takes longer to react than Hydrogen Peroxide. It has a longer shelf life since it needs to come into contact with water before it starts to react, whereas Hydrogen Peroxide can start to react by being over-exposed to the in-office light energy.
The last factor involved in the Carbamide Peroxide versus Hydrogen Peroxide debate is that of using a very bright, blue light, in the visible spectrum, to accelerate the reaction. Does one form of peroxide or the other work better with an accelerator light? It has been shown that using a light can aid in the bleaching process that results in whiter teeth in less time. Also, it is also seen in the literature, that by examining the studies of the light being used in teeth bleaching, it is always used with hydrogen peroxide instead of carbamide peroxide. It appears that the added light energy of visible light at 480-520 nanometers (visible spectrum blue light) helps increase the energy of activation of the peroxide molecule to form its free radicals. Carbamide Peroxide first has to break down into carbamide and hydrogen peroxide, so it takes longer for the chemical combination to become ready to accept the light’s extra energy input to help activate or catalyze the breakdown of the Hyrdrogen Peroxide into its bleaching-capable free radicals.
Looking for products with COMBINED hydrogen peroxide and carbamide peroxide for both strength and quick uptake of whitening and for anti-sensitivity? Check out the Whiter Image whitening line through Dental Girl (www.dgdentalgirl.com) or call or email your Dental Girl representatives at email@example.com for more info.