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Bleaching
1.
2. • INTRODUCTION
• HISTORY
• CAUSES OF DISCOLORATION
• INDICATIONS AND CONTRAINDICATIONS
• MATERIALS USED IN BLEACHING
• CHEMISTRY AND MECHANISM
• BLEACHING TECHNIQUES
• ADVANTAGES AND DISADVANTAGES
• CONCLUSION
3. The lightening of the color of a tooth through
the application of a chemical agent to oxidize
the organic pigmentation in the tooth is
referred to as bleaching.
Sturdevant
4. • In 1300’s the most requested dental service other than
extraction was tooth whitening.
• In 14th century, Guy De Chauliac cleaned teeth gently with
honey and burnt salt to which some vinegar was added.
• In 18th century, barbers surgeons applied, “Aquafortis” a
solution of nitric acid, after abrading enamel with coarse
metal files to whiten teeth.
• In1864 Truman used chlorine and acetic acid for non vital
tooth bleaching. The commercial derivative of this,
known as Labarrque’s solution.
• The first publication of bleaching was in 1877 by Chapple,
the agent of his choice was oxalic acid.
5. • In 1884, Harlan used hydrogen peroxide for the first time
which he called as hydrogen dioxide.
• In 1961, Spasser described Walking Bleach Technique.
• In the late 1960’s , a successful technique for home
bleaching was introduced by Klusmier, at which time he
discovered that 10% carbamide peroxide loaded in a
mouth guard with the intent to improve the gingival
condition also resulted in a bleaching effect.
• In 1976, Nutting and Poe introduced the walking bleach
technique which uses 35% hydrogen peroxide and sodium
perborate for nonvital bleaching.
• In 1989, Haywood and Heymann introduced “Night guard
vital bleaching” (10% carbamide peroxide).
• In 1996 Reyto introduced Laser tooth whitening.
6. • Extrinsic discoloration
Extrinsic stains are located on the outer surfaces of the
teeth.
• Intrinsic discoloration
Intrinsic stains are those which are internal or present
with in the tooth structures.
• Stain internalization
Those circumstances where extrinsic stain enters the
tooth through defects in the tooth structure .
9. Pulpal necrosis
Bacterial, mechanical, or chemical irritation to the pulp may
result in tissue necrosis and release of disintegration by-
products that may penetrate tubules and discolor the
surrounding dentin.
10. • Dentin hypercalcification
During trauma temporary disruption of blood supply occurs,
followed by destruction of odontoblasts. These are replaced
by undifferentiated mesenchymal cells that rapidly form
irregular dentin on the walls of the pulp lumen. As a result,
the translucency of the crown gradually decreases, giving rise
to a yellowish or yellow-brown discoloration.
• Pre-eruption trauma
• Discoloration of a permanent tooth may occur after trauma
to its primary counterpart.
13. Pulp tissue remnants:
•Tissue remaining in the pulp chamber disintegrates gradually and may
cause discoloration.
•Pulp horns must always be included in the access cavity to ensure
removal of pulpal remnants and to prevent retention of sealer at a later
stage.
• Intracoronal bleaching in these cases is usually successful.
Intra canal medicaments:
Phenolics or iodoform-based medicaments
14. Obturating materials:
Incomplete removal of obturating materials and sealer remnants in
the pulp chamber, mainly those containing metallic components,
often results in dark discoloration.
This is easily prevented by removing all materials to a level just
below the gingival margin.
Silver amalgam:
Silver amalgam produces a stain ranging from slate gray to dark
gray.
Stains from amalgam are likely to occur when dentinal wall is thin
and the filling material almost shimmers through the enamel.
, periapical inflammation of a primary tooth, or other infections in the area of a developing tooth bud.
Discoloration is usually white or yellow-brown
it usually is limited to the facial enamel surface of one or two teeth, usually the maxillary incisors.
15. • First reported in mid-
1950s, less than a
decade after
widespread use of this
antibiotic.
• Most susceptible to
tetracycline
discolouration during
their formation i.e.
during the II trimerster
in utero to roughly 8
years after birth.
16. Severity of the stains depends on the time, duration
and the dosage of the drug and also the type of
tetracycline.
Chlortetracycline (Aureomycin): Gray-brown
Dimethylchlortetracycline (Ledermycin): Yellow
Doxycycline (Vibramycin): Does not cause
staining
Oxytetracycline (Terramycin): Yellow
Under fluorescent light
17. I-Light yellow or gray stain
II-Yellow-brown or deeper gray stain
III-Brownish-yellow or blue-gray stain
with distinctive banding
18. May arise endemically from
naturally occuring water
supplies or from fluoride
delivered in mouth rinses,
tablets or toothpastes as a
supplement.
High concentration of
fluoride in excess of 1ppm is
believed to cause a metabolic
alteration in the ameloblasts
resulting in defective matrix
and improper calcification.
Mild- brown pigmentation
Moderate- flat gray or white flakes
Pitting- dark pigmentation with surface defects
19. Enamel becomes thinner
•Dentin becomes thicker
•More yellow or grayish yellow
Discoloration due to dental caries:
•opaque, white halo or gray
discoloration.
•Bacterial degradation of food debris in
areas of tooth decay or decomposing
filling can cause even deeper brown to
black discolorations.
20. Extrinsic tooth
discoloration has been
classified according to its
origin
•Metallic
•Non-metallic.
Metallic staining of teeth
may be associated with
occupational exposure to
metallic salts and with a
number of medicines
containing metal salts.
Black staining iron supplements
and iron foundry
workers
Violet to black color Potassium
permanganate in
mouth rinses.
Golden brown Stannous fluoride
Grey color silver nitrate salt
21. Non-metallic extrinsic stains are adsorbed onto tooth surface
deposits such as plaque or the acquired pellicle .
Tobacco(smoking) Tea stain Coffee stain
Stain induced by use of
chlorhexidine mouthwash
Stain from use of
antibiotics
Green stain from
chromogenic bacteria
22. Based on chemistry of the discoloration – Nathoo 1997
N1 type dental stain: The chromogens binds to the tooth
surface to cause tooth discoloration.
N2 type dental stain : The chromogen changes color after
binding to the tooth.
N3 type dental stain : The pre-chromogens binds to the
tooth and under goes a chemical reaction to cause a stain.
23. Mild discoloration on surface
• Evenly distributed discolorations without bands
or white spots
• Teeth discolored as their innate colors or ageing
• Hemorrhagic discoloration
• Discoloration of anterior teeth after rct
• Medication discoloration
24. • Sensitive teeth i.e. severe cases of attrition,
abrasion, erosion or abfraction.
• Cracks, hypoplastic or severely undermined
enamel.
• Extensive restorations.
• Discolorations in the gray, blue gray or black
range .
• Discolouration by metallic salts, particularly silver
amalgam,
• Enlargement of the pulp or other disease that
makes the tooth sensitive to bleaching solutions
25. • Generalized dental caries
• Lack of compliance
• Pregnancy and nursing
• Peroxide allergy: A carefully applied rubber dam
can help prevent reactions.
28. •Various concentrations of this agent are available,
but 30 to 35% stabilized aqueous solutions
(Superoxol) are the most common.
•Clear, colorless, odorless liquid, stored in
lightproof amber bottles.
•Unstable and should be kept away from heat,
which could cause it to explode.
• Can alone be used or mixed with sodium
perborate into a paste for use in the ‘Walking
bleach’.
• Caustic and burns tissues on contact.
• Delivery in an alkaline medium improves its
oxidizing efficiency.
29. • Oxidizing agent is available in a 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.
S.P + H2O S.M.Borate + H2O2
S.P + H2O2 S.M.Borate + H20 + O2
•THREE TYPES OF SODIUM PERBORATE PREPARATIONS ARE AVAILABLE:
•Monohydrate
•Trihydrate
•Tetrahydrate
•They differ in oxygen content, which determines their bleaching
efficacy.
30. •THREE TYPES OF SODIUM PERBORATE PREPARATIONS ARE AVAILABLE:
•They differ in oxygen content, which determines their
bleaching efficacy.
Monohydrate
Trihydrate
Tetrahydrate
31. •Also known as urea hydrogen peroxide,
• Is a bi-functional derivative of carbonic acid
• Available in the concentration range of 3 to 45%.
• Popular commercial preparations contain about 10%
carbamide peroxide,
• mean Ph of 5 to 6.5.
32. C.P 3% H2O2 + 7% Urea
H2O2 H2O + 2(O) and Urea NH3 + CO2
H2O2 is the active ingredient whereas urea raises the ph of
the solution
Bleaching preparations containing carbamide peroxide
usually also include Carbopol, urea, glycerine, preservatives
and flavoring agents.
33. CARBOPOL
• A water-soluble polyacrylic acid polymer
• Thickening agent, resulting in better retention in the night
guard
•Increase in length of bleaching-solution strength for
carbamide peroxide
•Slows rate of oxygen release extending duration of
bleaching action.
• Improves shelf life.
Increase in length of bleaching-solution strength for
carbamide peroxide bleaching preparations with carbopol vs
those without carbopol.
34. The bleaching process is based on the oxidation of the
bleaching agent.
Oxidation is the chemical process by which organic
materials are converted into carbon dioxide and water.
The oxidation-reduction reaction that takes place in the
bleaching process is called the REDOX REACTION.
Before the bleaching process, tooth is the reducing agent
and bleaching material is the oxidizing agent.
After bleaching, tooth is oxidized i.e. organic pigment of
tooth is oxidized and the bleaching material is reduced.
35. Low PH
High PH
The free radicals produced by the peroxides are perhydroxyl and nascent oxygen.
Of these, the perhydroxyl is a more potent free radical, which is responsible for a
better bleaching action
The buffering of peroxide to a pH range of 9.5 to 10.8 provides a greater
amount of perhydroxyl free radicals.
37. Oxidation of beta carotene. A free radical acts at
the unsaturated (double) bond (jagged line),
producing two molecules of colorless vitamin A.
38. Prolonged use of a bleaching agent causes the whitening
action to slow down beyond a point during the treatment.
Ideally, this is the point at which whitening should be
terminated.
If the degradation process continues, there is further
decomposition of organic matrix, resulting in a total loss of
enamel matrix protein.
39.
40.
41. 1. Pt education and informed consent
2. Careful diagnosis
a)Visual examination:
Thorough visual examination, which will generally indicate the cause
of dental staining and the extent and depth of discoloration.
b)Behavioral history:
Previous and current use of tobacco, coffee or tea, and highly colored
beverages and foods.
42. c)Medical history:
•Focus on any systemic problems or medications that might have
affected .
• problems begin during critical periods of tooth development
• needs to be investigated through the prenatal period.
d)Determining soundness of individual teeth
vitality
•Periapical or other pathologic condition.
•Caries
•Defective restorations
•Any enlargement of the pulp
43. 3. Record keeping with photographs
and shade selection
Use intra oral video camera or
high quality 35-mm camera.
These photographs will provide
an excellent record of pre-
treatment state.
It also will help the patient to
later recall how he or she
looked before any treatment
and to recognize the cumulative
effect of what may be a gradual
improvement in tooth colour.
Before
After
45. Application of Orabase/Vaseline on labial and lingual tissues
And vaseline on lips
Rubber dam of heavy gauze is used
Punched holes –smaller in size
47. A thorough prophylaxis, using Prophy-Jet 30 (Dentsply), will
enable
visualization of the extent of deep stains
better prepare the teeth for treatment.
may remove enough of extrinsic stain, calculus and plaque
to satisfy some patients without further bleaching.
48. v
Bleaching procedures can be classified depending upon
A. Tooth vitality - into:
a. Vital tooth bleaching procedures
b. Non-vital tooth bleaching procedures
B. Site/Venue of acquiring treatment, into:
a. In - Office / chair-side
b. Home bleaching / out of the office
51. The techniques used for bleaching of vital teeth
IN-OFFICE BLEACHING: Also called as Chairside bleaching.
•Thermo/Photo Bleaching
•Bleaching using Mc Innes solution
•Power Bleaching
DENTIST PRESCRIBED HOME-APPLIED BLEACHING: -
•Matrix bleaching-or night guard vital bleaching
OVER-THE-COUNTER KITS
Whitening strips
Whitening pastes
Tray-based bleaching systems
56. Keep the light about 30 cms (13 inches) from the teeth and
direct the beam to the surface to be bleached temperature
ranges from 115°-140°F.
57. Add new solution at
every 4 to 5mins
Use a timer
Removal of dam, wiping, rinsing and neutralization with Na gel
58. Great heat is generated during bleaching which can
result in tooth sensitivity.
Causes tooth dehydration
Uncomfortable for patient
Slower in action
59. In this technique, high intensity light, which was used as a heat
source, is replaced with conventional halogen units, plasma
arc lamps, LED lights, Xeno halogen lights and lasers.
ADVANTAGES
• Time factor(fast result)
• Avoids problems of home bleaching
DISADVANTAGES
• Caustic nature of 35-50% HP
• Increased in office time
• Dehydration of teeth resulting in false light shade
• Expensive
61. Tungsten-Halogen curing light:
- Curing light provides heat
- Time consuming
process(40-60sec/tooth)
Xenon Plasma arc light
Non laser, high-intensity light
Adv: Very fast 3sec/tooth
Dis adv: Thermal trauma to the pulp
and surrounding soft tissues
62. When the source of activation is laser it is known
as laser bleaching technique.
Types of lasers
1)Carbon dioxide
2)Argon
3)Diode
63. Argon laser:
A true laser is delivered to chemical agent
488nm WL, Blue light, absorbed by dark stains
Action is to stimulate the catalyst in the chemical.
Adv:
-No thermal effect,
-Less dehydration of enamel,
-Less time(10sec/tooth)
64. Carbon dioxide laser:(10,600nm)
• Invisible infrared light, energy is emitted
in the form of heat
• Directly interacts with catalyst/peroxide
• Deeper penetration
Diode laser light:
- 830 and 980 nm
- It is ultra fast 3-5 sec to
activate the bleaching agent
Adv:
Produce no heat
65. Mixing hydrogen peroxide: (a) the powder is introduced to
the liquid by pressing down to the release cap; (b) arrow
shows the broken seat; the powder and liquid can now be
mixed by gentle agitation; (c) the activator is added and
the contents begin to gel; (d) the finished product – a
thick glue that can be placed on to the teeth.
66. Adv of laser bleaching
• Faster
• It may act as a jump start for difficult cases by helping to
remove difficult stains caused by tetracycline and fluorosis
Disadvantages
• Expensive
• Post operative sensitivity can be high.
68. Gel is mixed to get good consistency
A 2-3 mm layer of freshly mixed gel should be
applied to all the labial surfaces of teeth in the
smile zone and lipped over to cover the incisal
edges and extend slightly lingually or palatally
Activation with or without light source depends
on the bleaching system used.
Procedure:
69. The gel is left in place for a length of time
dependent on the system and the cocentration
of HP used, usually about 10mins, but can
range from 3-20 mins at a time.
Gel is suctioned off the teeth using high
volume suction, rinsed , wiped using damp
gauze before being lightly dried
70. • The application and activation procedure is repeated one
more time before final washing and drying of the teeth.
Power bleaching procedures usually involve three 10-minute
passes.
• Surrounding mucosa are examined for blanching or areas of
redness indicating hydrogen peroxide seepage through the
isolation.
• Areas of damage should be thoroughly washed with copious
amounts of water before the application of a neutralizing
agent, such as vitamin E, usually supplied within the bleaching
kits
Antioxidants
71. • Polishing with a diamond polishing paste gives a high lustre.
• Application of a neutral colorless fluoride gel.
• Final shade assessment and postoperative photographs.
• Patients should be given postoperative instructions.
72. NIGHT GUARD BLEACHING/ HOME
BLEACHING TECHENIQUE
• Introduced by Dr. Van Haywood
and Dr. Harald Haymann in
1989.
• Dentist prescribed home bleach
technique.
73. • Home bleaching is a simple technique whereby, after an initial
consultation with the dentist, a mouth guard or tray is made
for the patient to bleach the teeth at home.
• The patient is given the bleaching materials (normally 10%
carbamide peroxide) to take home together with a bleaching
protocol.
• The patient applies the bleaching material into the tray. The
tray with the material is worn for several hours during the day
or at night depending on the patient's schedule, while the teeth
lighten.
74. Various names have been associated with
home bleaching are :
• Nightguard Vital Bleaching
• Matrix bleaching
• Dentist-assisted / prescribed home-applied bleaching
• Dentist-supervised at-home bleaching
• At-home bleaching
75. Advantages
• Simple and fast
• Simple for dentists to monitor without extended
clinical time.
• It is cost effective
• It is not usually a painful procedure.
• Patients can bleach their teeth at their convenience
• Results relatively quick.
76. Disadvantages
• Patients need to participate actively in their treatment.
• The color change is dependent on the amount of time the trays
are worn.
• The system may be open to abuse by using excessive amounts
of bleach for too many hours per day.
• It is difficult for patients who react easily to tolerate the
bleaching trays in their mouth.
77. Clinical examination of all teeth
Pre-existing shade evaluation
Alginate impression of the arch
to be taken.
78. Tray :step by step
Model prepared
Block resin applied on the labial
surface of the teeth to be
bleached to form a small
reservoir for the bleaching agent.
Cast a model
79. BIOSTAR
Fabrication of bleaching tray is
done using BIOSTAR
Place the model on the base
section of the vacuum tray forming
machine. Ensure that the plastic
sheet is properly placed over the
model.
Model and tray material in
position
80. Plastic sheet is now more easily
removed from the press. Scalloping
the tray on the buccal / facial surface
of the model using a heated scalpel
blade. Tray trimmed 1mm above the
gingival margin.
Molded plastic tray
Polishing of the tray is done gently
with a special soft cotton wheel.
Finished tray placed back on the
cast to prevent distortion.
Finished upper tray
82. Gentle finger pressure is applied to the tray to improve retention and suction while
removing the excess material at the same time.
Insufficient material is placed into
the tray. The tray is over extended.
More material is added
84. • Familiarize the patient with the
use of bleaching agent and
wearing the guard, instruct the
patient that this procedure
should be performed 3-4 hours
per day or over night.
• Recall the patient every 2
weeks to monitor stain
lightening.10% carbamide
peroxide is used for this
technique ,this can be later
increased to 16%,or up to 20%
as per the case reqirements.
86. • Active treatment
• Passive treatment
Active treatment
• Fluoride toothpaste
• Neutral sodium fluoride gel
• Potassium nitrate-fluoride gel
87. Passive treatment
The bleaching technique can be modified:
• Excess material is removed.
• Patient can use a bleaching gel with a lower concentration.
• Reduce daily treatment time or bleach every other night.
• Patient should not replenish the bleaching solution more than
once.
• Dentist can ensure that the tray is trimmed back further so that
it is not impinging on the gingiva.
88.
89. Bleachingagent – Old / NewMcInnes solution
Old Mc Innes(Acidic
medium -4.6)
New Mc Innes(Alkaline
medium-9)
Ratio Ratio
Bleaching
enamel
30% H2O2 5 parts 30% H2O2 1 part
Etches
enamel
36% HCl 5 parts
Removes
surface
debris
0.2% ether 1 part
constituent constituent
20% NaOH 1 part
0.2% ether 1 part
90. New Mc Innes solution
• HCL has some deliterious effects such as
Loss of contour
Irritation of gingiva
Sensitivity of teeth
• Chen,Xu and Shing(1993)
• HCL replaced by NaOH 20%
• NaOH is highly alkaline in nature and therefore dissolves calcium at a
slower rate.
• Loss of contour is minimized.(Nagarani et al)
91. Procedure:
The solution should be freshly mixed and applied directly to the enamel
surface for 5min at 1-min interval
On completion of the bleaching, the solution is neutralized with a baking
soda solution and copious irrigation with water.
Bleached surface should be poolished with cuttle disc and a prophylactic
paste.
Procedure may have to be repeated 2 or 3 times before the desired shade is
obtained.
93. ASSISTED BLEACH TECHNIQUE OR WAITING ROOM
BLEACH TECHNIQUE
• This bleaching technique was invented by Den- Mat.
• The dentist applies the 35% carbamide peroxide into a
custom-made bleaching tray. After the excess material is
removed, the patient returns to the waiting room for a
period of about 30 minutes with the bleaching tray in the
mouth.
• After 30 minutes, the bleach is suctioned off the teeth
before rinsing. The procedure can be repeated 2 -3 times
more in one session.
94. COMPRESSIVE BLEACHING TECHNIQUE
• This technique, reported by Miara, suggests that the Power
bleaching technique can be made more effective by
compressing the gel against the teeth. In order to enable the
permeation of oxidizing ions through the enamel, the
nascent oxygen must be guided under pressure.
• The procedure involves the usual isolation and placement
of 35 % hydrogen peroxide gel in custom made tray, which
is put in place and any excess material is removed before
the lingual and buccal edges of the tray are sealed with light
cured resin material to prevent any leakage during
decomposition.
95. • Once edges are sealed , the gel is activated using either a
halogen light or plasma arc.
• After 30 minutes the gel and isolation are removed and teeth
are washed .
Sealing the margin of the tray with
composite resin
97. Why use a varnish system ?• Vivastyle paint on is insoluable in water. Consequently, the
varnish is not prematurely washed off the teeth by saliva.
• Vivastyle paint on contains 6% carbamide peroxide when
applied. This component releases oxygen , which gently
lightens stains. Once it has dried, its concentration is about
five times higher.
101. Vivastyle paint on is applied directly to the teeth with
a brush and allowed to dry for 30 seconds
102. The dried varnish remains on the teeth for 20 minutes
and is subsequently removed with a toothbrush.
APPLICATION OPTIONS
Once daily for 20 min. over a period of 14 days.
Twice daily for 20 min. over a period of 7 days .
104. Advantages
• professional tooth whitening without a tray, as
– Patients find tray application uncomfortable
– Patients are looking for a more cost-effective alternative
• smooth integration into daily schedule
• gentle application
• touching up of previously whitened teeth
105. OVER THE COUNTER PREPARATIONS
Whitening strips(The Trayless Approach to Tooth
Whitening)
Thin,flexible polyethylene strips coated one side with a film
of H2O2
Worn for 30mins , twice a day
106. Duration:
6% coated H2O2 worn over 14 days
10% coated H2O2 worn over 10 days
Adv:
No tray is needed
Less visible
No gagging, salivation, speech problem, jaw joint
problem.
More convenient & compatible
108. It is a procedure in which a microscopic layer of enamel
is simultaneously eroded and abraded with a special
compound leaving a perfectly intact enamel surface
behind.
INDICATIONS
All surface stains from external sources such as tea, coffee ,
tobacco
Incipient carious lesion, usually located near the gingival
margin, appear as opaque or chalky white when dried but are
invisible when hydrated.
Developmental discoloured spot ,may be traumatic event or
idiopathic
Surface discolouration due to fluorosis , if the discolouration is
within 0.2 – 0.3 mm removal depth limit.
109. •Contraindications
Deep enamel and dentin stains
•Compound used( Croll)
Paste containing 11%HCl and silicon carbide particles
(marketed as Prema)
110. M ICROABRASION TECHNIQUE
Compound applied with ahand application device or with a rubber cup in a
low-speed hand piece. Periodically the paste is rinsed away to assess defect
removal. Care must be taken not to remove exessive tooth structure.
The treated area is polished with a fluoride containing prophy paste to restore
surface luster. Immediately following treatment a topical fluoride is applied to
enhance remineralization. Final results are seen in fig.
111.
112. NONVITALBLEACHING
• Darkening and loss of translucency may follow loss of vitality, both before
and subsequent to endodontic therapy.
In case of
• Acute trauma.
• Seepage of toxins from a necrotic pulp
• Staining form medicaments, cements, metal posts , or the optical effects of
dehydration
113. Successful bleaching depends upon two important criteria-
The root canal obturation must be complete. In order to
prevent an endodontic failure, the root canal system must be
filled in three dimensions
The remaining tooth structure must be intact
114. Intracoronal bleaching:
The material is sealed into the access cavity during in-office visits
and requires frequent changing of dressings:
• Walking Bleaching Technique: Sodium perborate and water
sealed into the tooth .
• Modified intracoronal bleaching technique : Various
increasing hydrogen peroxide concentrations and sodium
perborate is used.
• Intracoronal bleaching using the thermocatalytic technique or
other forms of heat or heating instruments
115. Open chamber bleaching.
Combining intra- and extracoronal bleaching; the material
is applied into the pulp chamber directly and retained with a
home bleaching matrix.
• Inside/Outside technique with bleaching tray using different
concentrations of Carbamide peroxide
Closed chamber bleaching
The bleaching material is placed on the external surfaces of the
tooth.
• Power bleaching using 35% hydrogen peroxide
• Nightguard Vital Bleaching using 10%, 15% or 20% applied only to
the non-vital tooth in the tray
116. INDICATIONS CONTRAINDICATIONS
Discoloration of pulp chamber
origin
Superficial enamel discolorations
Dentin discolorations Defective enamel formation
Discolorations not amenable to
extra coronal bleaching
Presence of caries
Discolored composite restoration
Severe dentin loss
117.
118. Familiarize the patients with
possible causes of
discoloration. Radiograph to
assess the status of periapical
tissues and quality of
endodontic obturation.
Evaluate tooth color with the shade guide
Isolate the tooth with rubber dam
119. Cavit and GIC
base at least 2
mm thick to
cover the
endodontic
obturation.
120. Remove all restorative material from the access
cavity. Remove all the materials to a level just
below the labial gingival margin
Apply a sufficient thick layer , at least 2mm of
protective white cement barrier ,such as zinc
phosphate cement ,GIC, intermediate restorative
materials
The material is placed at correct depth snugly,
using a flat plastic or endodontic plugger
121. Prepare the walking bleach paste by mixing
sodium perborate and inert liquid , such as water
etc.
Pack the pulp chamber with the paste. remove
the excess liquid by tamping with a cotton pellet.
Carefully pack the temporary filling at least 3mm
thick, to ensure a good seal
123. • Hydrogen peroxide gel (30-35%) is
placed in the pulp chamber and
activated either by light or heat.
• The temperature is usually between 50
and 60°C maintained for 5 minutes
• The gel is removed by washing with
water for a further minute. The tooth
is dried and the 'walking bleach
technique' is used between visits until
the tooth is reviewed 2 weeks later to
assess if further treatment is
necessary.
124. • External root resorption
• Chemical burns
• Damage to the restoration
Suggestions for safer non vital bleaching
Isolate the tooth effectively
Protect oral mucosa- Vaseline, catalase applied to oral tissues
Verify adequate endodontic obturation.
Use protective barriers.
Avoid acid etching
Avoid excessive heat
Recall patients periodically.
125. • Inside/Outside bleaching technique
•Internal/External bleaching,
•Patient-administered intracoronal bleaching technique
•Modified walking bleach technique.
The technique combines the intracoronal bleaching technique with
the home bleaching technique. It is used to lighten non-vital teeth
in a simple manner.
After barrier replacement the access cavity is left open so that the
bleaching material which is normally 10% carbamide peroxide,
can be placed into the pulp chamber while the bleaching tray is
applied to the tooth to retain the material on the tooth. Bleaching
can thus take place internally and externally at the same time. This
technique is a modification of the intracoronal bleaching
technique.
126.
127. Benefits
• More surface area is available both internally and externally for the
bleach to penetrate.
• A lower concentration (10% Carbamide peroxide with neutral pH) of the
bleach is used.
• This technique will hopefully eliminate the incidence of cervical
resorption that has been reported with the conventional intracoronal
bleaching technique.
• The need to change the access cavity dressing is eliminated as the
access cavity is left open.
• Treatment time is reduced to days rather than weeks
• No heat is required to activate the bleaching material.
128. There have been many reports regarding the relationship
between bleaching agents and the bond strength of composite
materials to enamel following bleaching. Many investigators
have reported a severe decrease in the average bond strength
of composite to bleached versus unbleached enamel .
• Surface roughening and etching may occur and tensile
strength is affected (Singleton and Wagner ,1992)
• It has been noted that the resin tags are reduced in number,
less defined and shorter in bleached enamel .
• Bleaching has been shown to increase the micro leakage of
existing restorations.
129. Effect of bleaching agents on other materials:
• Microstructural changes in amalgam.
• Alteration in the matrix of glass ionomers.
• IRM becomes cracked and swollen.
• Provisional crowns made from methyl methacrylate
discolor and turn orange.
130. BriteSmile Whitening Pen
• Easy to use
• Dries rapidly.
• Just two easy 30-second
applications a day for two weeks,
then use as desired.
• Each Whitening Pen last for 30
days of whitening applications
132. • Nite White ACP has been
clinically proven to
remineralize teeth while
also whitening them.
• Nite White rebuilds tooth
enamel, making teeth
stronger and less
susceptible to caries.
133.
134.
135. The use of bleaching agents provides an effective and conservative
approach to the removal of unesthetic discolorations from vital &
non-vital teeth. As with all therapeutic modalities, proper diagnosis
and planning is essential.
conclusion
136.
137.
138.
139. Argon laser:
A true laser is delivered to
chemical agent
488nm WL, Blue light, absorbed
by dark colour
Action is to stimulate the catalyst
in the chemical.
Adv: No thermal effect, Less
dehydration of enamel,
Less time(10sec/tooth)
TYPES OF LASERSIN BLEACHING
140. Carbon dioxide laser:(10,600nm)
• Invisible infrared light, energy is
emitted in the form of heat
• Directly interacts with
catalyst/peroxide and
• Deeper penetration
Diode laser light (power bleaching)
- 830 and 980 nm
- It is ultra fast 3-5 sec to activate
the bleaching agent
Adv: Produce no heat
141. Othertechniques
Waiting room bleaching (35% CP)
• Uses custom made tray
• gel injected from syringe under hot water
• Placed in mouth, excess wiped
• Asked to sit in waiting room for 30 mins
• Gel suctioned ,rinsed and dried.
142. Compressive Bleaching technique
• Power bleaching technique reported by Miara
• 35% HP gel
• Custom made tray is sealed using light cured resin
material
• Light activated for 30 mins
Ultrasonic technology(Soni white)
oUses ultrasonic technology with 6-7.5% HP gel
oTwo cycles of 5 mins each
In the modern civilized, cosmetically conscious world, well –contoured and well- aligned white teeth set the standard for beauty. Such teeth are not only considered attractive, but are also indicative of nutritional health, self-esteem and hygienic pride. The current trend toward cosmetic dentistry has generated more interest in bleaching as it is simple, least invasive,least expensive means to lighten discolored teeth . Bleaching is a purely cosmetic treatment, which can even be performed by the patient under the guidance of the dentist.
A professional response to the unrelenting quest for whiter teeth dates back at least 2000 years.
In 14th century, Guy De Chauliac cleaned teeth gently with honey and burnt salt to which some vinegar was added. This was done for over 300 years.
In1864 Truman used chlorine and acetic acid for non vital tooth bleaching. The commercial derivative of this, known as Labarrque’s solution, was a liquid chloride of soda.
A professional response to the unrelenting quest for whiter teeth dates back at least 2000 years.
The appearance of teeth depends on their absorptive or reflective properties of light and is influenced by all the structures that make up the tooth, including the enamel, dentin and pulp. Any changes to these structures during formation or throughout development and post eruption (3 months in utero to 20 years) can cause a change in the light transmission properties and hence discoloration.
Intrisic discolorations are often due to systemic or pulpal origin.
Intrisic discolorations are often due to systemic or pulpal origin.
Incomplete metabolism of tyrosine and phenylalanine- build up of homogentisic acid-affects the permanent dentition by causing a brown discoloration
Deposition of bile pigments in calcifying dental hard tissue, particularly at the neonatal line
Error in porphyrin metabolosm leading to accumulation of porphyrin in bone marrow, red blood cells , urine and teeth.
, periapical inflammation of a primary tooth, or other infections in the area of a developing tooth bud.
Discoloration is usually white or yellow-brown
it usually is limited to the facial enamel surface of one or two teeth, usually the maxillary incisors.
Intrapulpal hemorrhage and lysis of erythrocytes are a common result of traumatic injury to a tooth. Blood disintegration products, presumably iron sulphides, flow into the tubules and discolor the surrounding dentin.such teeth have a dark pinkish hue almost immediately after the accident and turn pinkish brown some days afterward.
At times hydrogen sulfide produced by bacteria combines with the hemoglobin to darken the tooth.
Haemolysis of red blood cells would follow and release the haem group to combine with the putrefying pulpal tissue to form black iron sulphide.
Silver amalgam produces a stain ranging from slate gray to dark gray. Stains from amalgam are likely to occur when dentinal wall is thin and the filling material almost shimmers through the enamel.
Pulp tissue remnants:Tissue remaining in the pulp chamber disintegrates gradually and may cause discoloration. Pulp horns must always be included in the access cavity to ensure removal of pulpal remnants and to prevent retention of sealer at a later stage. Intracoronal bleaching in these cases is usually successful.
Intra canal medicaments:Phenolics or iodoform-based medicaments
Obturating materials:Incomplete removal of obturating materials and sealer remnants in the pulp chamber, mainly those containing metallic components, often results in dark discoloration. This is easily prevented by removing all materials to a level just below the gingival margin.
The tetracycline molecules appear to chelate with calcium and becomes incorporated into the hydroxyapatite crystals.
The tetracycline involves predominantly the dentin.
Jordan and Boksman have proposed three categories of discoloration of the dentin:
The first two categories normally respond well to bleaching. The third category is less amenable to bleaching.
Simple fluorosis staining appears as brown pigmentation on a smooth enamel surface.
Responds well to bleaching.
Opaque fluorosis appears as flat gray or white flakes on enamel surface.
Responds poorly to bleaching .
Fluoride staining with pitting has dark pigmentation with surface defects, necessitates bleaching followed by composite resin bonding.
With age enamel becomes thinner because of abrasion and erosion, and the dentin becomes thicker because of the deposition of secondary and reparative dentin, which produce color changes in the teeth during one’s life. Teeth of elderly persons are usually more yellow or grayish yellow than those of younger persons.
Caries is a primary cause of pigmentation, appearing as opaque, white halo or gray discoloration.
Bacterial degradation of food debris in areas of tooth decay or decomposing filling can cause even deeper brown to black discolorations.
Possible etiological agents include dietary components, beverages, tobacco, mouth rinses and other medicaments. Chromogenic bacteria have been cited in children.
Discoloration in the gray, blue gray or black range does not respond well to bleaching and tend to darken more rapidly.
Periapical or other pathologic condition.
Caries
Defective restorations
Any enlargement of the pulp that may make a tooth unusually sensitive to the planned or contemplated bleaching technique.
Cracks and hypoplastic or severely undermined enamel.
Extensive silicate, acrylic or composite restorations.
these teeth may not have enough enamel to respond properly to bleaching.
Discolouration by metallic salts, particularly silver amalgam, the dentinal tubules can become virtually saturated by these alloys causing stains that no amount of bleaching can significantly improve.
Enlargement of the pulp or other disease that makes the tooth sensitive to bleaching solutions or may require special care and desensitization.
Generalized dental caries
Lack of compliance
For bleaching of vital or pulpless teeth, contraindicated may include the following:
Pregnancy and nursing
Peroxide allergy: A carefully applied rubber dam can help prevent reactions.
Discoloration in the gray, blue gray or black range does not respond well to bleaching and tend to darken more rapidly.
Periapical or other pathologic condition.
Caries
Defective restorations
Any enlargement of the pulp that may make a tooth unusually sensitive to the planned or contemplated bleaching technique.
Cracks and hypoplastic or severely undermined enamel.
Extensive silicate, acrylic or composite restorations.
these teeth may not have enough enamel to respond properly to bleaching.
Discolouration by metallic salts, particularly silver amalgam, the dentinal tubules can become virtually saturated by these alloys causing stains that no amount of bleaching can significantly improve.
Enlargement of the pulp or other disease that makes the tooth sensitive to bleaching solutions or may require special care and desensitization.
Generalized dental caries
Lack of compliance
For bleaching of vital or pulpless teeth, contraindicated may include the following:
Pregnancy and nursing
Peroxide allergy: A carefully applied rubber dam can help prevent reactions.
Rotary cutting instruments- group of instruments that turn on an axis to perform a work such as cutting, abrading, burnishing, finnishing or polishing tooth tissues or a restoration.
Many different bleeching agents are available todayMost commonly used materials are
Hydrogen peroxide and carbamide peroxide mainly indicated in extra coronal bleaching.
Sodium perborate indicated in intra coronal bleaching.
Most of the bleeching agents contain hydrogen peroxide in some form.
it has been shown that the delivery of hydrogen peroxide in an alkaline medium improves its oxidizing efficiency.
When S.P. is mixed with H2O2 it decomposes into Sodium metaborate, water and oxygen.
When S.P. is mixed with H2O2 it decomposes into Sodium metaborate, water and oxygen.
However, popular commercial preparations contain about 10% carbamide peroxide, with a mean Ph of 5 to 6.5.
CARBOPOL, a water-soluble polyacrylic acid polymer is added as a thickening agent, resulting in better retention in the night guard. Carbopol also:
Increase in length of bleaching-solution strength for carbamide peroxide bleaching preparations with carbopol vs those without carbopol.
Slows rate of oxygen release extending duration of bleaching action. Improves shelf life.
The bleaching process is based on the oxidation of the bleaching agent. Oxidation is the chemical process by which organic materials are converted into carbon dioxide and water. The oxidation-reduction reaction that takes place in the bleaching process is called the REDOX REACTION.
Before the bleaching process, tooth is the reducing agent and bleaching material is the oxidizing agent. The oxidizers act on the organic structure of the dental hard tissues, slowly degrading them into chemical by-products, such as carbon dioxides, that are lighter in color. Inorganic molecules do not usually break down as well. After bleaching, tooth is oxidized i.e. organic pigment of tooth is oxidized and the bleaching material is reduced.
The free radicals produced by the peroxides are perhydroxyl and nascent oxygen. Of these, the perhydroxyl is a move potent free radical, which is responsible for a better bleaching action.
In order to promote the formation of perhydroxyl radicals, the peroxide is buffered to a pH range of 9.5 to 10.8. The buffering provides a greater amount of perhydroxyl free radicals, which result in a better bleaching effect.
Mechanism of bleaching is mainly linked to degradation of high molecular weight complex organic molecules that reflect a specific wavelength of light that is responsible for color of stain. The resulting degradation products of low molecular weight and composed of less complex molecules that reflect less light, resulting in a reduction or elimination of discoloration.
Mechanism of bleaching is mainly linked to degradation of high molecular weight complex organic molecules that reflect a specific wavelength of light that is responsible for color of stain. The resulting degradation products of low molecular weight and composed of less complex molecules that reflect less light, resulting in a reduction or elimination of discoloration.
If the degradation process continues, there is further decomposition of organic matrix, which can lead to complete oxidation with generation of carbon dioxide and water, resulting in a total loss of enamel matrix protein.
Common oxidation processes associated with bleaching teeth. The saturation point, at which the optimal amount of bleaching has occurred, is located in the middle of the diagram.
The following steps would aid in a good case selection and a better outcome.
Ask the patient about previous and current use of tobacco, coffee or tea, and highly colored beverages and foods. If microcracks or other structural problems are observed, also ask about habits such as eating ice or chewing on objects like pencils or eyeglasses. Deep micro cracks may let the bleaching solution enter too deeply in to the tooth causing substantial pain.
But even shallower micro cracks may affect the results of bleaching by creating a prismatic effect in which the area around the micro crack is lighter due to the deeper absorption of the bleaching solution. The uneven colour thus created can detract from the overall appearance of the tooth.
Determining soundness of individual teeth, to ascertain the presence of any possible :
Periapical or other pathologic condition.
Caries
Defective restorations
Any enlargement of the pulp that may make a tooth unusually sensitive to the planned or contemplated bleaching technique.
Focus on any systemic problems or medications that might have affected or be affecting tooth coloration. Since many such problems begin during critical periods of tooth development, this history needs to be investigated through the prenatal period.
The patient should be draped with a protective cape to prevent spillage of the bleaching agent on hands, skin, or clothing.
The patient should be supplied with protective eyewear.
No local anesthesia should be administered that could otherwise inhibit patient feedback about pain or discomfort.
Before application of the rubber dam, Oraseal (a light-cured resin) or orabase paste can be applied liberally to protect the labial and lingual tissues
Next the clinician should place a heavy gauge rubber dam, ligating the individual teeth with floss. Oraseal can also be applied to any amalgam restorations, reducing the build up of heat from the light source. The punched holes should be smaller than normal, rendering them further apart to ensure adequate coverage of the proximal gingival.
Vaseline should be applied to the patients’ lips before mounting the rubber dam frame. Wet gauze can also be placed over the patients’ lips to prevent thermal trauma from the heat lamp. It is important to keep rewetting the gauze during the procedure.
A thorough prophylaxis, often including the use of a Prophy-Jet 30 (Dentsply), will enable the visualization of the extent of deep stains and to better prepare the teeth for treatment.
A through prophylaxis using the Prophy-jet at times may remove enough of extrinsic stain, calculus and plaque to satisfy some patients without further bleaching.
A thorough prophylaxis, often including the use of a Prophy-Jet 30 (Dentsply), will enable the visualization of the extent of deep stains and to better prepare the teeth for treatment.
A through prophylaxis using the Prophy-jet at times may remove enough of extrinsic stain, calculus and plaque to satisfy some patients without further bleaching.
Combining both we have
This technique basically involves application of 30 to 35% hydrogen peroxide and heat or a combination of heat and light or ultraviolet rays to the enamel surface. Heat is applied either by electric heating devices or heat lamps. The technique involves the following steps:
This technique basically involves application of 30 to 35% hydrogen peroxide and heat or a combination of heat and light to the enamel surface. Heat is applied either by instrument,electric heating devices or photoflood. The technique involves the following steps:
As an optional procedure, acid etch the darkest or most severely stained areas with buffered phosphoric acid for 10 seconds and rinse with water for 60 seconds.
A gel form of acid provides optimum control. Enamel etching for extracoronal bleaching is controversial and should not be carried out routinely.
Place a small amount of 30-35% hydrogen peroxide solution into a dappen dish. Apply the hydrogen peroxide liquid on the labial surface of the teeth using a small cotton pellet or a piece of gauze. A bleaching gel containing hydrogen peroxide may be used instead of the aqueous solution.
Apply heat with a heating device or a light source. The temperature should be at a level the patient can comfortably tolerate, usually between 52 degree Celsius to 60 degree Celsius. Rewet the enamel surface with hydrogen peroxide as necessary. If the teeth become too sensitive, discontinue the
bleaching procedure immediately. Do not exceed 30 minutes of treatment even if the result is not satisfactory
Remove the heat source and allow the teeth to cool down for at least 5 minutes. Then wash with warm water for 1 minute and remove the rubber dam. Do not rinse with cold water since the sudden change in temperature may damage the pulp or can be painful to the patient.
Dry the teeth and gently polish them with a composite resin-polishing cup. Treat all of the etched and bleached surfaces with a neutral sodium fluoride gel for 3 to 5 minutes.
Re-evaluate the patient approximately 2 weeks later on the effectiveness of bleaching. Take clinical photographs with the same shade guide used in the preoperative photographs for comparison purposes. If necessary, repeat the bleaching procedure.
The main advantages of power bleaching technique are-
The time factor-produces immediate results, which can be used to motivate the patient to continue with home bleaching.
Avoiding problems with home bleaching procedures such as:
Wearing trays that may cause patients to gag;
Distaste for home bleaching gel.
DISADVANTAGES OF POWER BLEACHING
Disadvantages of power bleaching include:
The caustic nature of the 35-50% hydrogen peroxide makes isolation and protection mandatory;
More time required, making the procedure more expensive for the patient;
Dehydration of the teeth may occur, thereby giving a falsely lighter shade immediately post treatment.
The main advantages of power bleaching technique are-
The time factor-produces immediate results, which can be used to motivate the patient to continue with home bleaching.
Avoiding problems with home bleaching procedures such as:
Wearing trays that may cause patients to gag;
Distaste for home bleaching gel.
DISADVANTAGES OF POWER BLEACHING
Disadvantages of power bleaching include:
The caustic nature of the 35-50% hydrogen peroxide makes isolation and protection mandatory;
More time required, making the procedure more expensive for the patient;
Dehydration of the teeth may occur, thereby giving a falsely lighter shade immediately post treatment.
The main advantages of power bleaching technique are-
The time factor-produces immediate results, which can be used to motivate the patient to continue with home bleaching.
Avoiding problems with home bleaching procedures such as:
Wearing trays that may cause patients to gag;
Distaste for home bleaching gel.
DISADVANTAGES OF POWER BLEACHING
Disadvantages of power bleaching include:
The caustic nature of the 35-50% hydrogen peroxide makes isolation and protection mandatory;
More time required, making the procedure more expensive for the patient;
Dehydration of the teeth may occur, thereby giving a falsely lighter shade immediately post treatment.
As tooth whitens blue light will be reflected rather than absorbed.
. Argon lasers emit fairly short wavelengths (488 nm) with higher – energy photons; conversely, plasma –arc lamps, halogen lamps, and other heat lamps emit short wavelengths as well as longer invisible infrared thermal wavelengths (750 nm to 1 mm) with low- energy photons and predictable high thermal character. This high thermal energy can create unfavorable pulpal responses.
Both 830 nm and 980 nm wavelength diode lasers can be used for tooth bleaching in combination with 35-50% hydrogen peroxide gel. The gel is produced by mixing the hydrogen peroxide liquid with a powder mainly containing fumed silica and a blue dye. The blue dye absorbs the laser wavelength and heats up to cause the controlled breakdown of the hydrogen peroxide to oxidizing per hydroxyl free radicals.
The system is also based on applying 2-3mm of gel to teeth in the smile zone and three 10-minute passes with activation using 1-2 W of laser energy for 30 sec per tooth. It is essential that all present, including the dentist, patient and nurse are correctly protected with eye protective glasses as ocular damage is a real risk with the use of these lasers.
One company uses the argon laser with a wavelength of 488nm for 30 second to accelerate the activity of its bleaching gel. After the laser energy is applied, the gel is left in place for 3-4 minutes and then removed. This procedure is repeated 4-6 times.
Another product uses Ion Laser Technology. The argon laser is used as previously described. Then the CO2 laser is employed with another peroxide solution to promote penetration of the bleaching agent into the tooth to provide bleaching below the surface.
Fig. 20.35
Argon laser energy is in the form of a blue light and is absorbed by the dark colour. It seems to be the ideal agent to be used in tooth whitening when used with 50% H2O2 and a patented catalyst. The affinity to dark stains ensures that the yellow-brown colours can be easily removed.
The CO2 laser has no colour requirement. It is unrelated to the colour of the tooth. Energy is emitted, in the form of heat. It is invisible and penetrates only 0.1mm into water and H2O2, where it is absorbed. This energy can enhance the effect of whitening after the initial argon laser process.
Faster due to high concentration of an active ingradient.
Disadvantages
Expensive
Time consuming
Post operative sensitivity can be high.
The latest addition to in-office bleaching systems is the Soni Whitening system, which utilizes ultrasonic technology with a 6-7.5% hydrogen peroxide gel in upper and lower trays. The procedure only involves approximately two cycles of 5 minutes but it is thought that the use of the ultrasonic energy indirectly encourages the production of more oxygen-free radicals that permeate through the tooth to produce the whitening effect.
, but some systems use three or four 20-minute passes with lower concentrations of hydrogen peroxide, while others use 3-minute passes repeated five times with total bleaching time being 15 minutes.
The laboratory fees for making the bleaching tray are not expensive
The main advantages of power bleaching technique are-
The time factor-produces immediate results, which can be used to motivate the patient to continue with home bleaching.
Avoiding problems with home bleaching procedures such as:
Wearing trays that may cause patients to gag;
Distaste for home bleaching gel.
DISADVANTAGES OF POWER BLEACHING
Disadvantages of power bleaching include:
The caustic nature of the 35-50% hydrogen peroxide makes isolation and protection mandatory;
More time required, making the procedure more expensive for the patient;
Dehydration of the teeth may occur, thereby giving a falsely lighter shade immediately post treatment.
The main advantages of power bleaching technique are-
The time factor-produces immediate results, which can be used to motivate the patient to continue with home bleaching.
Avoiding problems with home bleaching procedures such as:
Wearing trays that may cause patients to gag;
Distaste for home bleaching gel.
DISADVANTAGES OF POWER BLEACHING
Disadvantages of power bleaching include:
The caustic nature of the 35-50% hydrogen peroxide makes isolation and protection mandatory;
More time required, making the procedure more expensive for the patient;
Dehydration of the teeth may occur, thereby giving a falsely lighter shade immediately post treatment.
In cases of endemic fluorosis a solution of
A study by Dr. Varsha Nagrani showed that the use of old Mc Innes solution resulted in loss of contour of teeth. The time taken by new Mc Innes solution was double than that of old Mc Innes solution but it did not show loss of contour of the teeth.
Also available in pastes and tray based systems,
Adv:less cost
Dis adv:no dentist supervision and its abuse potential.
Worn for 30mins a day, twice a day
In 1984, Mc Closkey reported the use of 18% hydrochloric acid swabbed on teeth for the removal of superficial fluorosis stains. In 1986, Croll modified the technique to include the use of pumice with the hydrochloric acid to form a paste that was applied with a tongue blade. This technique was called Microabrasion. Later Croll further modified the technique by reducing the Hcl percentage to 11% and increasing the abrasiveness of the paste by using silicon carbide particles.
Compound applied with ahand application device or with a rubber cup in a low-speed hand piece. Periodically the paste is rinsed away to assess defect removal. Care must be taken not to remove exessive tooth structure. The procedure continued until the defect is removed or until it is deemed imprudent to continue further. The treated area is polished with a fluoride containing prophy paste to restore surface luster. Immediately following treatment a topical fluoride is applied to enhance remineralization. Final results are seen in fig.
Microabrasion is a technique for removing about 25 microns of the enamel surface. It is particularly useful for eliminating white or brown spots or surface roughness. The original protocol called for the use of 18% hydrochloric acid and pumice. Proprietary products, such as Prema (Premier Dental Products) consist of a water-soluble gel containing a dilute concentration of hydrochloric acid and an abrasive compound. The gel is applied to the enamel surface with special rubber cups in a contra-angle
handpiece. The application time is short, about 10 seconds per tooth, and teeth must be rinsed well with water. An assessment is made of colour change and degree of tooth removal, and the process is repeated as required. When the desired result has been relieved, teeth are rinsed thoroughly with water and the residual solution is neutralized with sodium bicarbonate. The teeth are rinsed again with water, dried and polished with a fine, fluoride-containing prophy paste.
Successful bleaching depends upon two important criteria-
The root canal obturation must be complete. In order to prevent an endodontic failure, the root canal system must be filled in three dimensions
The remaining tooth structure must be intact
Successful bleaching depends upon two important criteria-
The root canal obturation must be complete. In order to prevent an endodontic failure, the root canal system must be filled in three dimensions
The remaining tooth structure must be intact