At-Home Whitening with Custom Trays

How the dentist-supervised at-home whitening protocol works, and why it takes longer but causes less sensitivity than the in-office technique.

Professional at-home whitening, not to be confused with over-the-counter kits available without a prescription, involves fabricating custom trays for the patient, made in the dental lab from an impression or scan of the arches. These trays, thin and transparent, are designed to hold the whitening gel in close contact with the tooth surface, while minimizing contact with the surrounding gingival tissue.

The active agent used in this protocol is typically carbamide peroxide, at concentrations generally between 10% and 22% for at-home use — significantly lower than concentrations used in-office. Carbamide peroxide, in contact with oral fluids, partially breaks down into hydrogen peroxide (the actual whitening active ingredient) and urea, the latter with a mild additional antibacterial action.

The patient applies the gel inside the tray and wears it for a period of time indicated by the dentist, typically overnight or for a few hours during the day, repeating the application for a number of sessions generally ranging from 7 to 14 applications per arch, depending on product concentration and desired outcome. The final result is therefore more gradual than with the in-office technique, but this gradualness carries a real clinical benefit: generally lower incidence of dentinal sensitivity, because the enamel is exposed to lower peroxide concentrations spread over a longer period, rather than a single concentrated application.

A direct comparison between the two methods, published in the Rivista Italiana di Igiene Dentale, measured a color result (expressed as ΔE variation) of 1.70 for the in-office technique versus 3.21 for the at-home technique in the study considered — a finding that should be contextualized case by case, but which suggests that at-home whitening, if followed consistently through the entire prescribed course of applications, can achieve color results at least comparable to, if not better than, a single in-office session.

On Oralzon you'll find carbamide peroxide-based gels at various concentrations for professional at-home whitening, along with the materials for making custom trays in the lab.