This is my pet peeve subject. There are many ways to do it, in a dental office, in the mall, at home with professional products and over the counter products. Some ways work better than others, and some hardly work at all and some are just a scam. There are also a couple of inherent problems with the process in general.
Let’s start with how the process works. Basically, a chemical is placed on the teeth for a period of time. These chemicals oxidize and remove stains. It makes sense that the longer the chemicals stay in place, the better the results will be. It also makes sense that the better the mechanism for getting the chemical to actually stay in contact with the teeth, the better the results. The stains come off with the outermost layer first, then progressively inward with further treatments.
Let’s start with OTC products. Do they work? Yes. However, the strengths are not as strong as what is available with a prescription and keeping them in intimate contact with the teeth is difficult. On the plus side is that you can do it for as long as you like. Your supply of chemical is only limited by how much time you want to devote to the process and the costs for the varying products. Crest Whitestrips are one of the higher end products in the OTC category. They attempt to get the chemical on the teeth better, and the chemical comes in a gel that is sticky. The negatives are that they only whiten the front teeth. Those teeth have to be pretty straight or the strips don’t go on or stay on very well. Like all OTC products the strength of the chemical is less than prescription products. The long-term cost is higher than the most effective prescription product.
In office whitening is the next category. Does it work? Yes. However, the results are greatly variable from one patient to the next. The chemicals do maintain intimate contact with the teeth, but only for an hour to an hour and a half, depending on the dental office. The chemicals are the strongest available, but that often leads to greater sensitivity. This is the highest cost category because it is taking the time of the dental office to do it. $500 to $700 is not unusual. Some offices also use a proprietary light like “Zoom” or “Sapphire” to “enhance” or “activate” the chemicals. The lights are for show. They do absolutely nothing. All independent research confirms this. The only literature that supports the use of any light is research provided by or funded by the manufacturers of the lights. The short exposure time of this process is a problem in that the surface stains are removed, but the more deep seeded stains are left behind. It looks good in the beginning but fades more quickly. Some offices overcome this by supplementing the process with take home trays and gel. To me, this is an admission that it doesn’t work that well to begin with. Also, much of the whiter result is a result of tooth dehydration. More on that later.
Next is kiosk/mall whitening. Does it work? Probably not. See In office whitening above, but now it’s done by teenagers with very little training. You might get a retired hygienist who knows what they’re doing, but you’re just as likely to get a high school student who’s more interested in getting a date than taking care of you. One plus is that it is cheaper.
Saving the best for last is take home professional whitening. Does is work? Absolutely. This is by far the method of choice for the best and longest lasting result. Molds are made of your teeth. From those molds a custom set of trays is made to hold the chemical on your teeth. This is the best way to ensure intimate contact of the chemical, and it is prescription strength. In fact, it can come is varying strengths. You place the gel into the tray and do the whitening on your time. The cost is around $350 to $400 for the entire mouth and most of that is for the time to make the trays. One reason the cost is lower is that is does not require much, if any, of the dentist’s time. I recommend wearing the trays between 1 and 1 and 1/2 hours per treatment. Most patients do it once per day, but you can go up to 4 times per day. Each treatment gets deeper and deeper into the teeth, thus making the results last longer than any other option. Touching it up later is very cheap as long as the trays continue to fit. Don’t leave them in a hot car, chew on them, etc. Over time this is the cheapest method if you choose to do the maintenance.
All whitening systems have the potential to cause sensitivity, particularly when there are areas of your teeth exposed that are not covered with enamel. Exposed dentin anywhere greatly increases the chances of sensitivity. The good news is that all sensitivity caused from whitening is completely reversible. Some methods are easier than others. Decreasing the frequency of use is often the first choice. Of course, discontinuation will make sensitivity go away, although the greater the concentration of chemical, the longer it takes. The use of fluoride afterwards helps, too. The fluoride is applied with a toothbrush in all methods except the take home professional method where it can be placed in the trays and used for an extended period of time which gives the quickest relief.
Some stains are easier to remove than others. I recommend a dental cleaning first to remove the superficial plaque, tea, coffee, coke, smoking, etc. Dark liquid stains and other environmental stains come off pretty easily. Age related darkening improves easily as well. Developmental staining such as stain from antibiotics is much more difficult. It takes months of committed usage to remove. Some chalky stains like from high concentration fluoride in the drinking water may actually get worse.
It is irrefutable fact that dehydrated teeth are lighter in color than hydrated teeth. Two of the methods above require isolation of the teeth. The reason for the isolation in the in office method is that the chemical concentration is so high that it will burn the gum tissue. You can’t let this stuff touch the gums. I’m not exactly sure why the kiosk/mall method uses some isolation because the chemicals generally aren’t any stronger than the tray method. Maybe they want you to think that it does something like the light they use. This isolation causes the teeth to become dehydrated. When you leave, they look a lot whiter, but the next day they don’t seem quite as bright as they were the day before. Then you’re thinking you’re just already getting used to it because they were whiter yesterday. Your eyes are not deceiving you, but you were deceived.