8. Tetracycline staining:
more susceptible during the second trimester in vitro to roughly 8 years
after birth.
Tetracycline molecules chelate with calcium and gets incorporated into the
hydroxyapatite crystals.
Severity of stains depends on the time and duration of drug administration.
9. 4 Degrees:
1st Degree
- Light yellow, brown stains
- Uniformly distributed
- No banding or localized concentration
- Responds to bleaching in 2 or 3 session
2nd Degree
- Dark gray stains
- Extensive than 1st degree
- Responds to bleaching in 4-6 session
3rd Degree
- Dark gray stains with banding.
- Responds to bleaching best bands will be evident.
4th Degree
- Does not respond to bleaching.
11. High concentration of fluoride in more than 4ppm cause moderate to
severe discoloration.
Prevalence – Premolars, 2nd molars and mandibular and maximum
incisors.
Types
Mild fluorosis - Brown pigmentation on a smooth enamel surface
- Responds well to bleaching
Moderate - Opaque fluorosis appear gray with white flecks on
enamel surfaces.
Severe - With pitting and dark pigmentation with surface
defects.
- Does not respond to bleaching
13. Traumatic Injuries:
Causes rupture of blood vessel in the pulp.Causing diffusion of blood into
dentinal tubules.
Dark pink immediate after trauma and changes to pinkish brown after some
days.
Causes:
Haemoglobin degrades into hemin, hematin, hematoiden and haemosidrin.
Hydrogen sulphide produced by bacteria combines with hemoglobin &
gives dark colour to tooth
14. Erythroblastosis foetalis: (Rh factor incompatibility between
mother and foetus) characterized by – breakdown of
erythrocytes.
Jaundice: Bluish green or brown stains in dentin caused by
bilirubin or biliverdin.
Amelogenesis imperfecta: is a genetic condition which interfere
with the normal enamel matrix formation.
Enamel hypoplasia: caused by deficiency of vitamins i.e.
A, C, D and calcium and phosphorus
15. a] Trauma during pulp extirpation – hemorrhage
b] Failure to removal of all pulpal remnants.
c] Amalgam restoration cause – dark gray.
d] Gold – dark brown when combined with products of decay.
e] Break down of restoration i.e. acrylic, silicate and composite resins can
cause the tooth to look grayer and discolore
f] Silver containing root canal sealers i.e. “Kerr root”, “grossman sealer”.
g] Volatile oils yellowish brown stain.
.
16. Bleaching is a treatment modality involving an
oxidative chemical that alters the light-absorbing
and/or light-reflecting nature of a material
structure, thereby increasing its perception of
whiteness.
17. Discolouration of anterior teeth – after R.C.T.
Tetracycline stains (mild)
Fluorosis
Haemorrhagic discolouration
.
Discolouration due to ageing
Medication discolouration
18. Hypoplastic or severely undermined enamel.
Deep microcracks
Sensitive teeth
Opaque or white spots
Extensive silicate, acrylic or composite restorations.
19. The active ingredient in tooth bleaching materials
is peroxide compounds.
Currently a variety of bleaching materials are
available, the most commonly used peroxide
compounds are:
Hydrogen peroxide
Sodium perborate
Carbamide peroxide
21. Sodium perborate (NaB03 ) is available in powdered form or as various commercial
preparations.
When fresh, it contains about 95% perborate, corresponding to 9.9% of the
available oxygen.
Sodium perborate is stable when dry.
In the presence of acid, warm air, or water, however, it decomposes to form
sodium metaborate, H20 2, and nascent oxygen.
Three types of sodium perborate preparations are avail able:
monohydrate,
trihydrate,
tetrahydrate.
Commonly used sodium perborate preparations are alkaline.
material of choice in most intracoronal bleaching procedures
22. exists in the form of white crystals or as a crystallized powder containing
approximately 35% H20 2.
It forms H20 2 and urea in aqueous solution.
mostly used in home-use bleaching materials with concentrations ranging from
10 to 30% (equivalent to approximately 3.5% to 8.6% H20 2)
Bleaching preparations containing carbamide peroxide usually also include
glycerine 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
23. Bleaching mechanism:
The mechanism is oxidation / reduction process called as “Redox process”.
In this process the oxidizing agent has a free radical with unpaired electrons, which it gives
up, becoming reduced. The reducing agent (i.e. the substance being bleached) accepts the
electrons and becomes oxidized.
Reducing agent Oxidising agent
Tooth Bleaching material
After the process
Tooth is oxidized Bleaching material is reduced
(Organic pigmentation of tooth oxidized)
In addition to the chemical effect other mechanisms include
cleansing of tooth surface
temporary dehydration of enamel during the bleaching process,
change of enamel surface.
24. The methods most commonly employed to
bleach endodontically treated teeth are:
1. "walking bleach"
2. Thermocatalytic techniques.
Walking bleach is preferred
25. coined by Nutting and Poe in 1961
Involves the following steps:
:Familiarize the patient
Radiographically assess the status
Evaluate tooth color with a shade guide
Isolate the tooth with a rubber dam
Remove all restorative materials from the access cavity, expose the dentin, and
refine the access. Remove all materials to a level just below the labial-gingival
margin.
Apply a sufficiently thick layer, at least 2 mm, of a protective white cement
barrier,
Prepare the walking bleach paste pack the pulp chamber with the paste.
Evaluate the patient 2 weeks later
26. This technique involves placement of the oxidizing
chemical, generally 30% to 35% H20 2 (Superoxol), into the
pulp chamber followed by heat application either by electric
heating devices or specially designed lamps
avoid overheating of the teeth and the surrounding
tissues.
Intermittent treatment with cooling breaks preferred.
In addition, the surrounding soft tissues should be protected
with Vaseline, Orabase, or cocoa butter during treatment to
avoid heat damage.
Potential damage - external cervical root resorption
27. This technique applies ultraviolet light to the labial
surface of the tooth to be bleached.
A 30% to 35% H202 solution is placed in the pulp
chamber on a cotton pellet followed by a 2-minute
expoure to ultraviolet light.
28. External Root Resorption
Chemical Burns
Inhibition on Resin Polymerization and
Bonding Strength
29.
30. Restoration with a lightshade, light-
cured, acid-etched composite resin.
Placing white cement beneath the composite.
Waiting for at least 7 days after
bleaching, prior to restoring the tooth with
resin composites, recommended.
31. Extracoronal bleaching may be used for whitening vital or nonvital
teeth as well as a single tooth or whole arch.
It has experienced a dramatic advancement in materials as well as
techniques after at-home extracoronal bleaching was first
introduced
32. Bleaching procedures are performed in the clinic by a
dental professional.
Current commercial in -office bleaching materials are
almost exclusively in the form of a gel, with 25% to
38% H20 2
In-office extracoronal bleaching may be perfomed
using a bleaching gel alone or a gel with a light.
33. The light source can be a laser (e.g., argon, CO2)
, halogen, plasma arc, or light-emitting diodes (LED).
The wavelength may range from high ultraviolet
spectra, low visible blue light spectra, to invisible
infrared spectra such as the CO2 laser.
The light exposure is intended to enhance the bleaching
efficacy by activating the bleaching gel either through a
specific catalyst or heat.
34. The action is to stimulate the catalyst in the chemical. There is no thermal
effect and less dehydration of enamel.
Argon laser of 488 nm wave-length for 30 seconds to evaluate the
activity of bleaching gel. As the laser energy is applied, the gel is left in
place for 3-4 minutes and then removed. This procedure is repeated for 4-6
times.
Another product uses Ion laser technology. Argon laser is used as described
before. Then CO2 laser is employed with another peroxide solution to
provide penetration of the bleaching agent into the tooth to provide
bleaching below the surface.
Argon laser is in the form of blue light and is absorbed by dark colour. It is
an ideal instrument to be used in tooth whitening when used with 50%
H2O2. The affinity to dark colour ensures that the yellow brown colour can
be easily removed.
35. CO2 laser. It is unrelated to the colour of
tooth and energy is emitted in the form of heat.
It is invisible and penetrates only 0.1 mm into
water and H2O2 where it is absorbed.
This energy can enhance the effect of
whitening after the initial argon laser
process.
Diode laser light:
A true laser light produced from a solid-
state source.
It is ultra fast, taking 3-5 seconds to activate
the bleaching of
agent.
• This type of laser produces no heat.
36. Over-the-counter (OTC) tooth bleaching
products
available directly to consumers.
Contains;
Acid-citric or phosphoric acid
Gel-acidic ph;applied for 2min
Post bleach polishing cream- toothpaste containing titanium dioxide
White strips:
Which is a thin flexible polyetheline strips which contains 5.3% hydrogen
peroxide in gel form.
The strips are used for 30 minutes twice daily for 14 days.
37.
38. Commonly observed clinical side effect during or afterextracoronal
bleaching of vital teeth, with an incidence of up to 50%
.
The sensitivity, usually mild to moderate and transient, often occurs
during the early stages of treatment and usually persists for 2 to 3
Days
Enamel Damage
The effect of extracoronal bleaching on enamel has been conducted
mainly using in vitro systems to examine changes in enamel surface
microhardness and morphology.
Most SEM studies showed little or no morphological changes in the
bleached enamel surface.
39. • The amount of mercury release may vary.
• Avoid extracoronal bleaching for teeth with extensive amalgam
restorations.
