materials used for bleaching and its reactions on tooth

3. The bleaching agents is that
which aids in restoration of normal color to
tooth by decolorizing the stain with powerful
oxidizing agent ….
There are four agents which
are used commonly in daily dental practice

4. 1. HYDROGEN PEROXIDE
2. SODIUM PERABORATE
3. CARBAMIDE PEROXIDE
4. OVER THE COUNTER
(OTR)

5. Hydrogen peroxide ………
at home or during cleaning a
Wound it is used at a
concentration of 3% to 7.5%
In dentistry it is used at
5% to 35% as a teeth whitening
agent

6. 1.35% food grade undiluted –
removing skin tags , warts and moles .
2.3 % and 6 % grades –
mouthwash , disinfectent , teeth whitening.

7. Peroxides are classified into two as
1.orgonic
2.In organic
When hydrogen atoms substitutes
with metals they are inorganic peroxide .
When hydrogen atoms substitutes
with organic radicals they are organic peroxides .
These two are the strong oxidizers.

8. Hydrogen peroxide (H2O2) has
low molecular weight and hence can
penetrate in to dentin and release oxygen
that breaks down the double bond of organic
and inorganic compounds inside the dentinal
tubule.
2H2o2 2H2O O2

9. It is a clear ; odorless ; colorless liquid
that can be stored in a clear amber bottle.
It is unstable and should be kept away
from heat which could cause it to explode .
It should be carefully handled because of
it’s ischemic effects on skin and mucosa.
It is painful if it comes in contact with
nail beds .

11. Sodium perborate (NaBo3) is
available as powder form or granular form or
different commercial forms.
When fresh it contains about
95% perborate corresponding to 9.9% of the
available oxygen .
When it is in dry form it is
stable.
In the presence of acid warm
however it decomposes to form sodium
metaborate ; H2o2 and nascent oxygen.

12. There are three types of
sodium perborate preparations are available .
a, Monohydrate
b, Tri hydrate
c, Tetra hydratet
Commonly sodium perborate
preparations are alkaline.

13. The powder is water soluble . When
mixed into a paste with superoxol ,this paste
decomposes into sodium metaborate , water
,and oxygen.
Sodium perborate sodium metaborate
Hydrogen
peroxide
O2

14. When sodium perborate
sealed into the pulp chamber ,sodium
perborate oxidizes and discolors the
stain slowly , continuing its activity over
a long period of time . This procedure
is called the walking bleach technique…

15. It is also known as urea
hydrogen peroxide .
It exists in the form of white
crystals or as a crystallized powder
containing approximately 35% H2O2.
Mostly used in home use
bleaching materials with concentrations
ranging from 10 to 30% (equivalent to
approximately 3.5% to 8.6% H2O2)

16. Bleaching preparations containing
carbamide peroxide usually also include glycerin
or propylene glycol , sodium stannate ,
phosphoric or citric acid , and flavor additives.
In some preparations , carbopol
,a water soluble polyacrylic acid polymer is
added as a thickening agent.
Carbopol also prolongs the
release of active peroxide and improves
shelf life.

17. Carbamide peroxide Urea
Ammonia
Carbon dioxide
3.5%Hydrogen peroxide

18. Over- the -counter bleaching
agents that begin marketed include tray
systems , chewing gums tooth pastes ,
bleaching strips and paint on products .
The scientific rationales
behind such systems are not justified.
These products
primarily work by removing
extrinsic surface stain only.

19. One of the most known controversies about
bleaching is the availability of OTC bleaching kit .
Such products ,solid as cosmetics ,have
escaped rigorous legislation in US,UK and
EUROPE. They are freely available ….. This has
caused many problems for patients, and also
dentist .

20. OTC kit contains the following
1. Acid rinse:
This is usually citric or
phosphoric acid which may be harmful to the
dentition ,as continued rinsing may cause tooth
erosion.
The pH of this acid rinse is
between 1- 2

21. 2. Bleaching gel :
This gel is applied for two
minutes .
3. Post-Bleaching ‘ polishing cream’:
This is a tooth –paste containing
titanium dioxide which may give a temporary
painted –white appearance.

22. The principle mechanism involved
in bleaching is that the oxidizing agent reaches
the sites with in enamel and dentin to allow a
chemical reaction to occur between the
discolored segment and the active ingredient .

23. REDOX REACTION
TOOTH BLEACHING AGENT
(reducing agents (oxidizing agent gives free
takes up electrons) electrons)
Free reactive radicles react with the unsaturated bonds
Large stain molecules are converted into smaller ones
Simpler molecules are formed
Reflects less light or becomes colorless

25. Whitening tooth (dentifrices ) in the ADA
seal of Acceptance Program contain polishing or
chemical agents that are designed to improve
tooth appearance by removing surface stains .
They do this through gentle polishing ,chemical
chelation , or some other non bleaching actions
. Several whitening toothpastes that are available
in the market …..which are accepted by ADA.

26. It is 22% carbamide peroxide .
It is available in the form of
syringes and tubes .

29. 1. SURFACE DEBRIDEMENT:
Thorough scaling and polishing should be
performed in order to eliminate all superficial
debris.
2.HYDROGEN PEROXIDE CONCENTRATION:
The higher concentration ,the greater the effect
of oxidation process .the highest concentration
generally used is 35% hydrogen peroxide .

30. 3. TEMPERATURE:
An increase in 10 degrees centigrade
doubles the rate of chemical reaction .
generally , if the temperature is elevated to a
point at which the patient does not feel
discomfort , then the procedure is taking
place at a safe range of temperature.

31. 4. pH:
When hydrogen peroxide is stored and
shipped , an acidic ph must be maintained to
extend shelf life . The optimum pH of
hydrogen peroxide to have it’s oxidation effect
is pH 9.5 to pH 10.8 . This produces a 50%
greater result in the same amount of time as
a lower pH .

32. 5.TIME:
The effect of the bleach is directly related to
the time of exposure . The longer the
exposure , the greater the color change .
6.SEALED ENVIRONMENT:
Placing the hydrogen peroxide into a sealed
environment has been shown to increase its
bleaching efficiency.