Tooth dehydration is a common side effect with all teeth bleaching treatments. Once dehydrated, the teeth can look whiter. When rehydration happens (usually a few days), the dehydrated teeth relapse to a darker color. Knowing that teeth dehydrate during bleaching, one may wonder what the actual effects are of
quick in-office laser teeth whitening. Could it be that there is no actual bleaching happening and that it is just dehydrating teeth?
To better understand how a light source can dehydrate teeth its theory must be explained. When undergoing a laser teeth whitening procedure, the light hits the tooth at a very high intensity. The bleach on the surface of the tooth boils off into the air, which is the path of least resistance. Some bleach will infuse into the teeth and allow for some actual bleaching. As the light illuminates the tooth, darker colored parts of the tooth absorb the light rather than reflect it. This absorbed light is converted into heat energy. Areas of the tooth like the pulp chamber and dentin are the darkest so they heat up the most. This causes the tooth to heat up from the inside. As the tooth builds this uncontrollable internal heat, fluids in the pulp and dentin expand. This expansion pushes water out of the tooth through the protein matrix surrounding the enamel rods.
Teeth are porous, so for the same reason they will allow bleach penetration, they will allow fluids out of the tooth. This dehydration as well as the overheating of the tooth is what causes the extreme pain that often is reported following light assisted bleaching procedures. This whole phenomenon is what makes using a light to bleach teeth ambiguous. The idea is to move bleach into the teeth for bleaching to occur. With the lights, all the "teeth fluids" could be moving out of the teeth. So bleach may have to go against the flow to get into the teeth. This could make for a very inefficient technique, as the bleach is always fighting against the current. The final result of this may be that the teeth lose water or dehydrate and appear whiter for a temporary time, usually around 72 hours. After that they began to recover and absorb water from the saliva, much like a sponge, and in so doing they turn dark again.
The “
Rod’s Deep Bleach” method acknowledges this theory as fact and in so doing, the method employs techniques to keep fluids in the teeth. The
MetaTray product also does this.
-TeethWhiteningReviews.com
In the past ,literature has suggested that much of the bleaching effect when multiple in-office bleaching sessions were used ,(before the advent of tray/nightguard bleaching), occurred during the first bleaching session. This is because many of the "easy" surface stains are eliminated on the first bleach exposure. So this again works to the advantage of the light manufacturers. There is no doubt some immediate bleaching occurs that could be determined as permanent whitening when lights are used to bleach teeth. The problem is that the dehydration bleaching effect so overshadows the "real" first visit, bleaching effect, that when the teeth re-hydrate 72 hours later, the patient is left with virtually the degree of whiteness they started with. So this is the state of light enhanced teeth bleaching. Impressive immediate result and poor long term result.
The view that catalysing bleach is the answer to teeth bleaching in-office is reasonable only to a small extent. Just because you make the bleach boil away the ions ,does nothing for making the teeth accept the ions. In other words even if you were to SUPER catalyse a 10% hydrogen peroxide bleach all the way up until it released bleaching ions like a 25% hydrogen peroxide, what makes the teeth take up the bleach any more than if you just used an un-catalysed 25% bleach? Why not use a 25% hydrogen peroxide to start with? It's certainly much less expensive. There can be no doubt that it is possible to make bleach "fizz away" at a faster rate than an un-catalysed bleach. In theory there is probably no limit the the rate of reaction chemically obtainable, the problem is that the changing of the bleach reaction rate does not make the teeth more susecptable to the bleaching ions. The teeth ,apparently, can only use a limited number of bleaching ions. If this were not true we would see the teeth get whiter and whiter with a more highly catalysed reaction speed, and manufacturers would have us changing the bleach every 5 minutes or so as the super catalysed bleach exhausted itself. This would certainly not be unreasonable if the bleaching effect was really enhanced by catalysing the bleach. If this worked to whiten teeth to any significant degree we would all know about it from the CRA evaluations of Zoom and the other manufacturers catalysed products that have been used for several years.
Something must be done to the teeth themselves to improve the actual bleaching result on a permanent basis. And the bleach must produce enough bleaching ions to saturate whatever level of bleach the teeth are capable of absorbing. So there have to be enough bleaching ions available AND the tooth must be effected in some way to make it take up more of those ions. This is the theory that has evolved the METATRAY. If you assume that all regular methods of altering the bleach have been explored. (short of obtaining a NEW DRUG designation). Then the only alternative is working with the TEETH themselves, to MAKE them bleach more effectively. How can you change teeth to force them to bleach? YOU HEAT THEM. AND YOU APPLY THE BLEACH UNDER PRESSURE. The critical part of this equation is CONTROL. The teeth must not be overheated. Just the right amount of heat can be applied to create linear expansion of the teeth to allow more bleaching ions to penetrate the tooth structure without harming the teeth. This controlled heat IN ADDITION to PRESSURE created by (for example, the Metatray In-Office system) a firm tray, preferably sealed at the gingival margin produces the only known alterations to uptake of bleaching ions by the teeth. For these reasons, the Metatray represents the best new alternative to conventional teeth bleaching techniques or products available anywhere. Though in it's infancy, the Metatray is the future of teeth bleaching. Certainly the device can be improved. It can be made more comfortable, more streamlined, ect.... But the primary criteria of applying the correct, safe , amount of heat and pressure are realized already with the current Metatray. For those not convinced, just use the other bleach products in the Metatray, it can only improve their effect by adding the heat and pressure(and light if you will) to those other processes. Additionally, the Metatray is priced so low that it is often less expensive to buy a Metatray than the bleach alone for some In-Office systems.
My teeth had a glow for a few days then went back to normal. Complete waste of money. Now I know why. Thanks.
Also do you know if it damages your teeth permanently because mine were never sensitive before and since the whitening they have been (over 2 years later) ridiculously sensitive.