Professional Dental Whitening: A Complete Guide

How in-office whitening works, why a liquid dam is essential, and what to expect in terms of results compared to the at-home technique.

Professional in-office whitening uses hydrogen peroxide at concentrations generally between 25% and 40%, significantly higher than those used in at-home protocols, with the goal of achieving a visible result by the end of a single session. Before applying the whitening agent, a professional hygiene session is always necessary, to remove plaque and calculus that would otherwise interfere with the whitening agent's action on the actual tooth surface.

The most delicate step operationally is protecting the soft tissues: given the high peroxide concentration used, gums and mucosa are isolated with a traditional rubber dam or, more commonly today, a light-cured liquid dam, which adheres to the gingival margin creating a protective barrier against direct contact with the whitening gel. Imprecise application of this barrier is the most common cause of so-called chemical gingival "burns", an unpleasant but generally transient side effect if the protocol is followed correctly.

The whitening gel is then applied to the teeth and left to act for a defined time, sometimes with the help of a light source (laser or LED) to accelerate the reaction — a point on which, as we'll see in a dedicated deep-dive, more recent literature has raised some doubts about real effectiveness. Treatment may require one or more sessions depending on the extent of discoloration and the desired outcome, decided together with the patient before starting.

The main advantage of professional in-office whitening compared to the at-home technique is the speed of the result, achieved under the professional's direct supervision; the corresponding downside is a higher likelihood of post-treatment tooth sensitivity, precisely due to the higher peroxide concentrations used in a concentrated application time. The choice between in-office, at-home, or a combination of the two depends on the patient's individual sensitivity, available time and expected result, and should always be preceded by a clinical assessment ruling out untreated caries, leaking restorations or other contraindications.

On Oralzon you'll find professional whitening gels at various concentrations, light-cured liquid dams and all the instrumentation needed to safely perform chairside whitening.