Dentaltown June 2018 - 84

the pH of the whitening gel when choosing the right whitening system for your patient's
enamel health and sensitivity.
Choosing a whitening gel that falls into the basic (alkaline) category will help prevent
enamel demineralization and tooth sensitivity.6 An alkaline pH environment also optimizes
the hydrogen peroxide whitening gel and its oxidation effect; an alkaline environment
produces a 50 percent greater whitening result in the same amount of time as a lower pH
environment.10
Open versus closed environments. Bleaching can occur via two methods of delivery:
an open-system environment or a closed-system environment.
* An open-system environment occurs during chairside whitening and is completed
using a heat lamp outside of the mouth. The lamp's high temperature compensates
for the hydrogen peroxide that escapes into the atmosphere. In closed-system environments, such as bleaching trays or mouthpieces, the seal keeps the active ingredient in
hydrogen peroxide concentrated, which results in superior whitening results.
It's important to be mindful that the main differences between take-home and chairside
whitening are contact time and the concentration of hydrogen peroxide gel. Understand
that each patient's teeth lighten differently and that some require a combination of both
in-office and take-home whitening to achieve their smile goal.
Temperature. Hydrogen peroxide has innate oxidizing
and antiseptic effects, exemplified by at-home
whitening systems that remove tooth stain. However,
this process has a long wear time and should be
recommended for qualified patients and patients
who have a darker baseline shade. Adding heat
via modern whitening delivery systems decreases
exposure time and increases efficacy. LED light and
heat mouthpieces can be found in many modern
whitening systems; however, heat is the true catalyst.11
LED light has not been shown to have a significant
effect on whitening results. When the temperature
is increased (within a safe range), the reaction rate
accelerates, leading to a quicker, more efficient
whitening session.

Why does whitening cause tooth
dehydration and sensitivity?
We often hear of whitening procedures that
dehydrate teeth, resulting in teeth that look whiter
initially but darken just a few days later once the
teeth rehydrate. Dehydration is a common side effect
The primary factors of whitening are the concentration of the peroxide and the
amount of time it is on the teeth for absorption and breaking down the stain.
of almost all chairside teeth bleaching treatments
The secondary factors increase the efficacy of the whitening oxygen with pH,
that use a light.12
temperature increase, and preventing the escape of the whitening oxygen with a
During chairside whitening, light enters the tooth
closed environment.
at a high intensity and has the effect of dissipating
the bleach through the tooth. The light energy is
absorbed by the dark areas of the teeth, dentin and
pulp. These areas warm up, causing the fluids in the tooth
to expand. The fluids are subsequently forced out of the tooth through the dental tubules,
causing dehydration and sensitivity during the procedure.11
Throughout the chairside whitening procedure, a gingival barrier and cheek/lip retractor
are placed to prevent the highly concentrated hydrogen peroxide from burning or traumatizing

JUNE 2018 // dentaltown.com

http://www.dentaltown.com

Table of Contents for the Digital Edition of Dentaltown June 2018