At-home teeth whitening kits make promises that often can't be kept. Sure, if your teeth aren't misaligned in any way, and aren't particularly discoloured to begin with, then you might experience the whitening results hinted at by the manufacturer. For many other people, the results will be less than satisfying. This is why most people should involve their dentist in their teeth whitening, even if the treatment is to largely be performed at home.
Give Yourself a Head Start
A dental checkup usually involves scaling and polishing. This removes plaque and tartar and the extrinsic staining that is affecting your dental enamel. This should take place before any whitening treatment begins, as this extrinsic staining can be too big a hurdle for many whitening treatments to overcome. It's like giving yourself a head start with your treatment.
Treating Dental Problems
As a part of your checkup, your dentist will also note any problems that might be developing, such as the beginning of any dental cavities. These issues will need to be treated before teeth whitening. The decay associated with a cavity will not whiten, and it's essentially a breach in the tooth's outer surface. You certainly don't want to introduce any of the whitening agent's active ingredients (generally hydrogen peroxide) into your tooth's internal structure. This can be uncomfortable at best, and rather painful at worst. This is yet another reason why your dentist should assess your teeth before whitening can begin.
A Custom Made Approach
Another thing your dentist will do is fabricate a whitening tray just for you. Your dentist will take an impression of your upper and lower dental arches, and can then make a tray that is designed to reflect the contours of your specific teeth, ensuring an even distribution of the whitening agent. This is not possible with the one-size-fits-all approach of the tray that is included in most home whitening kits. They will also give you the whitening agent to be added to the tray, along with precise instructions about how to apply it, including the frequency of application and how long the agent should be in contact with your teeth. These instructions will be tailored to your individual needs, which, again, is not the case with an entirely at-home whitening kit.
A home whitening kit can often lead to disappointment, and this is due to the fact that they need teeth to already be in an acceptable condition to give the results that they suggest are possible. Since this isn't the case for many people, it's best to see your dentist for assistance with teeth whitening.