Custom teeth whitening trays: What advantages do they offer over stock trays?
The advantage of custom-made bleaching trays is that they offer a fit that benefits both the whitening process and the patient's experience.
The term "custom teeth whitening trays" refers to bleaching trays that are made by a dentist (or a dental laboratory) specifically for the patient that will wear them. A dentist will take an impression of their patient's teeth and surrounding soft tissue and then use these impressions to create plaster casts. The patient's whitening trays will then be fabricated directly on these casts, thus ensuring an accurate and customized fit.
What aspects of the bleaching tray's fit are important?
1) The contour of the edges of the bleaching tray is very important.
The biggest concern about the fit of a whitening tray has to do with the way it should fit over the outline of the patient's teeth. And this type of fit accuracy can only be offered by a custom teeth bleaching tray.
A dentist will make sure that their patient's custom trays are trimmed as shown in our illustration. The goal is that the tray's plastic should fully cover over the surface of each individual tooth, yet not significantly cover over any portion of the patient's gum tissue. The reasoning behind this design is as follows:
A) It's best if the edges of the tray lie short of the gum line.
A design where the edges of the whitening tray end right at the gum line helps to minimize the amount of soft tissue irritation that the patient experiences during their bleaching process. It is possible that the tray's edge might rub against the patient's gums and be a source of irritation. Now days, however, custom bleaching trays are usually made from very flexible plastic, so this is not usually a problem.
More importantly, a whitening tray that is trimmed just short of the gum line helps to minimize the contact of the bleaching gel with this tissue. For some patients, especially those using relatively higher concentration whiteners, this can be an important factor in helping to minimize the amount of gum irritation that the bleaching process creates.
B) The tray must cover the entire surface of each tooth.
A whitening effect can only be predictably produced if the whitener is in contact with a tooth's surface. If the bleaching tray falls significantly short of covering the entire surface of a tooth it's unlikely that it would be able to create a whitening effect to any great extent.
2) The whitening tray should stay in place well.
Advantages of custom bleaching trays over stock trays.
Custom bleaching trays have the above mentioned design characteristics for the specific reasons we have outlined. In comparison, the stock whitening trays contained in store bought kits, even those that are intended to be user modified, cannot usually offer these same features and advantages.
1) The fit of a stock whitening tray over a patient's teeth is seldom ideal.
You may find that the stock bleaching tray that has come with the over-the-counter teeth whitening kit you have purchased does not fully cover over all of the (front side) surfaces of your teeth. If it doesn't, you may experience an effect where the tray-covered portions of your teeth do lighten but the exposed surfaces do not.
2) The edges of stock whitening trays usually extend over a patient's gum tissue.
Essentially all stock whitening trays will cover over the wearer's gum tissue to some extent. If so, this contact with the tray may cause a mechanical irritation of the person's gums. Of course, a simple solution for this problem is to trim back the offending portion of the tray.
Usually the bigger problem associated with overextended whitening trays is that they will create a situation where the bleaching gel is held in direct contact with the wearer's gums. For some people this can be a significant problem. Especially in those situation where a relatively high concentration whitener is being used or the time frame associated with the individual bleaching treatments is comparatively long.
