Download - Bleeching of Discolored Teeth
-
8/3/2019 Bleeching of Discolored Teeth
1/130
BLEACHING OF
DISCOLORED TEETH
-
8/3/2019 Bleeching of Discolored Teeth
2/130
Contents
Introduction
History
Causes of Tooth Discolouration
Bleaching Materials
Bleaching Techniques
Non-vital bleaching
Vital bleaching
Conclusion
References
-
8/3/2019 Bleeching of Discolored Teeth
3/130
INTRODUCTION
Discoloration of anterior teeth is a cosmetic
problems that is often the patients primary
concern. Although restorative procedures
are available, discoloration can often becorrected totally or partially by a moreconservative approach i.e. bleaching, whichis relatively simple to perform and lessexpensive.
-
8/3/2019 Bleeching of Discolored Teeth
4/130
BLEACHING
Defined : as the whitening of a tooth through theapplication of chemical agent to oxidise/reduce theorganic pigmentation in the tooth.
Advantage
Safe procedure
Painless to adults
No tooth reduction required No anesthesia necessary
Least expensive to treatment altenatives
-
8/3/2019 Bleeching of Discolored Teeth
5/130
Disadvantage
Normal tooth colour may be restored
Bleaching can caused discomfort in childrenbecause of their large pulps.
Extended treatment time may be necessary.
-
8/3/2019 Bleeching of Discolored Teeth
6/130
INDICATIONS
Discoloured teeth due to either extrinsic orintrinsic stains.
-
8/3/2019 Bleeching of Discolored Teeth
7/130
Contra-indications to bleaching Patient selection
Patients with emotional or psychologic problem or those with unrealisticgoals do not make good candidates for bleaching.
Dentinal hypersensitivity
These symptoms may be associated with severe cases ofattrision,erosion,abrasion or abfraction .
Suspected or confirmed bulimia
Application of bleaching agent in such cases may result in acute pulpitis.Bulimia patients may require a comprehensive course of restorative
treatment involving veneers and crowns.
-
8/3/2019 Bleeching of Discolored Teeth
8/130
Generalized dental caries and leaking restoration
Use of bleaching agents for such patients who fall in this category maylead to severe, generalized hypersensitivity
Heavily restored teeth
Teeth with visible,tooth colored restorations respond poorly tobleaching because the composite restorations do not lighten andbecome more evident after bleaching.
Teeth with opaque white spots
Teeth slated for bonded restorations or orthodontic bracketing.
Oxygen produced during bleaching remains in the enamel or dentinoxygen interferses with the bonding agent and induses bonding failure.
-
8/3/2019 Bleeching of Discolored Teeth
9/130
HISTORY
A professional response to the unrelenting quest for white teeth
dates back at least 2000 years.
First century Roman physicians maintained that brushing teethwith urine, particularly Portuguese urine, whitened teeth.
In the 1300s, after abrading the enamel with coarse metal files,aquafortis, a nitric acid solution was applied to whiten the teeth.
Guy de Chauliac, in 14th century recommended a toothwhitening procedure in which teeth were gently cleaned with a
mixture of honey and burnt salt to which some vinegar wasadded, which was considered authoritative for nearly 300 years.
-
8/3/2019 Bleeching of Discolored Teeth
10/130
The introduction of clinical procedure of vital tooth bleaching wasdone by Chapple in 1877, who used oxalic acid as the bleachingagent.
The first mention of peroxide as a bleaching agent was in 1884by Harlan, which he called hydrogen dioxide.
In 1888, Taft and Atkinson suggested calcium hypochlorite to be
an effective tooth whitening solution.
In 1916, Kane proposed the use of 18% HCl to the brown fluoridestain. Although not regarded as the bleaching agent, it is capableof removing the stains as it dissolves the surface of teeth.
In 1918, Abbot found that the bleaching action of hydrogenperoxide could be greatly enhanced by the addition of heat andlight.
-
8/3/2019 Bleeching of Discolored Teeth
11/130
In 1937, Ames proposed the combination of 5parts of 100% H2O2 with 1part of etheractivated by heat as the treatment for the
stains caused by fluoride.
In 1939, Younger proposed the use of 30%
H2O2, ether and heat for the stains causedby fluoride.
-
8/3/2019 Bleeching of Discolored Teeth
12/130
In 1966, the use of HCl combined with H2O2 was advocated byMcInnes for the stains caused by fluoride.
Non-vital bleaching was introduced by Garretson in 1895 whoapplied chloride to the tooth surface but could not achieve verygood results.
In 1958, Pearson reported the use of superoxol sealed within thepulp chamber. He found that within 3 days, the oxygen releasingcapacity of the solution had whitened the experimental teeth tosome extent.
In 1967, Nutting and Poe refined this method and termed aswalking bleach where they packed a mixture of 30% H2O2 and
sodium perborate in the pulp chamber for 1 week.
-
8/3/2019 Bleeching of Discolored Teeth
13/130
In 1989, Haywood and Heymann introduced atechnique for bleaching vital teeth which they calledNight guard vital bleaching. In this technique, theuse of Carbamyl peroxide was introduced which wasplaced in a molded tray, which the patient placesover his teeth for hours at a time.
In 1992, Rembrandt introduced whitening toothpastes and enzyme based dentifrices.
-
8/3/2019 Bleeching of Discolored Teeth
14/130
In 1994, Light activation of the bleaching agents wasintroduced which further led to activation ofbleaching agents by argon laser, CO2 laser andplasma arc.
In 1999, Diode laser was introduced as a vector intooth whitening.
From 1995 till date a variety of concentrations ofbleaching gels containing remineralising agents,fluoride and peroxide free chemicals have beenavailable.
-
8/3/2019 Bleeching of Discolored Teeth
15/130
Etiology of Tooth Discolouration
The etiology of tooth discolouration may beextrinsic or intrinsic or both.
Extrinsic stains
Diet related
Bacterial strains
Medications
Habits
-
8/3/2019 Bleeching of Discolored Teeth
16/130
Pipe smoking
Bacterial products
Mouth wash
Tobacco stains Mouth wash
-
8/3/2019 Bleeching of Discolored Teeth
17/130
Intrinsic stains1. Pre-eruptiveAlkaptonuriaAmelogenesis imperfecta
FluorosisErythroblastosis foetalisPorphyriaTetracycline stainingJaundice
2. Post eruptiveAgePulpal necrosisIntrapulpal haemorrhageDentin hypercalcification
Iatrogenic discolorationRemnants of pulpal tissuesIntra canal medicamentsObturating materialsRestorations
-
8/3/2019 Bleeching of Discolored Teeth
18/130
Enamel hypoplasia Trauma Mild fluorosis
Severe flourosis Tetracycline staining Mild tetracycline stains
Dentinogenesisimperfecta
Amelogenesis
imperfecta
Pulpal
heamorrhagicproduct
-
8/3/2019 Bleeching of Discolored Teeth
19/130
-
8/3/2019 Bleeching of Discolored Teeth
20/130
Extrinsic Stains:
These are caused by the daily intake of substances
such as food and beverages or the use of tobaccoproducts.
These substances tend to adhere to the enamels
hydroxyapetite structure and here by discolour theteeth or reduce the whiteness of teeth.
Over a period they may penetrate the enamel layerand gradually give rise to intrinsic discolorations.
-
8/3/2019 Bleeching of Discolored Teeth
21/130
Nathoos Classification(for extrinsic dental stain)
N1 type dental stain or direct dental stain: Colouredmaterial(chromogen) binds to the tooths surface and
causes discoloration. The color of chromogen is similar tothat of dental stain.
N2 type dental stain or direct dental stain: Coloredmaterial(chromogen) changes color after binding to thetooth.
N3 type dental stain or indirect dental stain: Colourlessmaterial or a pre-chromogen binds to the tooth and
undergoes a chemical reaction to cause a stain.
-
8/3/2019 Bleeching of Discolored Teeth
22/130
CAUSES OF EXTRINSIC STAINS:
1. Diet:
These stains affects multiple teeth and appears as yellow or brown
stains of varying intensities. Consumption of strong tea or coffeeimmediately after orange or grape juice is a common cause ofexternal discoloration.
Black current juice or cola drinks act by both etching and stainingthe tooth simultaneously.
2. Bacterial Strains:
Chromophilic bacteria frequently seen in the deciduous or mixeddentition can cause a dotted or black-line stain.
It has been documented that this type of bacteria is associated withlower-than normal caries rates and the removal may result inrecolonization of the oral cavity by a more cariogenic flora.
-
8/3/2019 Bleeching of Discolored Teeth
23/130
3. Medication:
Chlorhexidine acts in reducing plaque formation by disturbing thepellicle matrix formation, which attracts more extrinsic strains not
readily removed by tooth brushing.
4. Habits:
Smoking marijuana may produce characteristic linear, greencircumferential rings at the cervical margins.
Smoking tobacco causes a yellow-brown discolourationespecially on the lingual aspects of the teeth.
Chewing tobacco causes a black-brown stain that is most
noticeable on the buccal surfaces of the mandibular posteriorteeth.
-
8/3/2019 Bleeching of Discolored Teeth
24/130
5) Gingival Hemorrhage
Chronic gingivitis may induce staining fromthe breakdown of blood in the gingival sulcus.
-
8/3/2019 Bleeching of Discolored Teeth
25/130
Intrinsic Stains
These are stains which are incorprated within the
matrix of enamel and dentin and are caused by thedeposition or incorporation of substances within thesestructures. These stains may be caused during thedevelopmental stage i.e., pre-eruptively or after theeruption into the oral cavity.
1. Pre-eruptive discolorations:
Alkaptonuria:-Also known as phenylketonuria or ochronosis. It is arecessive genetic disorder resulting in dark brown
pigmentation of the permanent teeth.
-
8/3/2019 Bleeching of Discolored Teeth
26/130
Amelogenesis imperfecta:- It affects both primary and permanentdentition and can be further subdivided into
Hypomaturtion: where the enamel is chipped off from theunderlying dentin
Hypo calcification: where the thickness of enamel is normalbut is soft in consistency and completely abrades soon after
eruption, which results in a tooth with crown that ranges inappearance from a dull opaque white to a dark brown. Inaddition, these teeth are usually rough and pitted.
Hypo plastic: where the enamel is quiet thin, smooth, hard
and yellow in appearance, with occasionally pitting.
-
8/3/2019 Bleeching of Discolored Teeth
27/130
Dentinogenesis Imperfecta:
is a hereditary developmental disturbance of dentin that may be seen
alone or in conjuction with systemic disorder of bone (osteogenesisimperfecta).
This disorder is autosomal dominant .
WITKOP outlined three descriptive classification of this disorder
1.Dentinogenesis imferfecta2.Heriditary with opalescent dentine3.Brandy white isolate.
Usually affects the primary teeth more seriously than the permanent
dentition.
The clinical crowns appear reddish-brown to grey opalescent.
-
8/3/2019 Bleeching of Discolored Teeth
28/130
FluorosisBlack and McKay first reported this condition in 1916.
The optimum concentration of fluoride in the drinking water forthe dental development is 1ppm.
When the intake approaches 2ppm, noticeable white spotsoccur in the enamel.
when it approaches 3ppm, patchy brown discolouration of theenamel occurs. Higher concentrations than this can result inpitting and anomalies in the enamel formation.
The high concentration of fluoride is believed to cause ametabolic alteration in the ameloblasts which results in adefective matrix and improper calcification.
The teeth can be affected by fluorosis from the second
trimester in utero through age 9.
-
8/3/2019 Bleeching of Discolored Teeth
29/130
Erythroblastosis fetalis:- This is a blood disorder of theneonate which might discolour the teeth .This disease inthe fetus or new born results from Rh incompatibilitywhich leads to massive lysis of erythrocytes.
The discolouration ranges from brown to greenish-blue.This condition is usually self-treating and the stainingresolves as the child matures.
Porphyria:- is a metabolic disease.In this condition, the haematoporphyrin pigment createsa characteristic reddish-brown discolouration of the teethknown as Erythrodontia.
More commonly seen in the primary dentition than the
permanent dentition. The colouration is dispersed throughout the enamel,
dentin and cementum and fluoresces red underultraviolet light.
-
8/3/2019 Bleeching of Discolored Teeth
30/130
Tetracycline staining
The tooth discolouration caused by incorporation of systemic
tetracycline was first reported in 1956 by Schwashman andSchuster. Since, it crosses the placental barrier it can affect boththe primary and permanent dentition.
Though the exact mechanism of staining is not fully understood, it
is believed that the tetracycline molecule binds to the calcium ofthe tooth forming tetracycline orthophosphate.
The clinical appearance of tetracycline-stained teeth ranges fromlight yellow to dark grey bands.
Usually the darker shades are confined to the gingival 1/3rd of theteeth and the lighter shades will often be located exclusively in theincisal 1/3rd.
-
8/3/2019 Bleeching of Discolored Teeth
31/130
When the tetracycline stained teeth are exposed to sunlight, theygradually turn to shades of dark grey or brown.
Cohen and Parkins: suggest this as the reason why labialsurfaces of the incisors darken while the molars remain yellow for
a longer period of time.
Studies have shown that further exposure of such teeth tovarious light sources such as sunlight, incandescent or ultravioletlights produces a subsequent lightening of the tetracycline stain.
It has been postulated that tetracycline incorporated intohydroxyapetite, when oxidized by light produces the red quinoneproduct 4, 12 anhydro-4-oxo-4-dedimethylamino tetracycline(AODTC).
-
8/3/2019 Bleeching of Discolored Teeth
32/130
Tetracycline is a bacteriostaticantimicrobial,which was commomly given for
treatment of
Chronic middle ear infection in children
Long term therapy for acne valgarius. Cystic fibrosis
Rocky mountain spotted fever.
-
8/3/2019 Bleeching of Discolored Teeth
33/130
The severity of tooth discolouration depends on four factorsassociated with tetracycline administration.
Age at the time of administration: Anterior primary teeth aresusceptible to discolouration by systemic tetracycline from 4months in utero through 9 months post partum.
Anterior permanent teeth are susceptible from 3 months postpartum to 8 years.
Duration of administration: Severity is directly proportional tothe length of time the medication was administered.
Dosage: Severity is directly proportional to the administered
dosage.
-
8/3/2019 Bleeching of Discolored Teeth
34/130
Type of Tetracycline:
Chlortetracycline (Aureomycin): Gray-brown
Dimethylchlortetracycline (Ledermycin): Yellowstain
Doxycycline (Vibramycin): Does not cause stain
Oxytetracycline (Terramycin): Yellow stain
Tetracycline (Achromycin): Yellow stain
-
8/3/2019 Bleeching of Discolored Teeth
35/130
Jordan and Boksman has classified the tetracyclinestaining as follows
Primary staining: Light yellow or light grey, slightbut uniformly distributed without banding.
Secondary staining: Darker or more extensiveyellow or grey staining without banding.
Tertiary staining: Severe staining characterized bydark grey or blue discoloration, usually with banding.
-
8/3/2019 Bleeching of Discolored Teeth
36/130
First degree tetracycline stains Second degree tetracycline stains
Third degree tetracycline stains
-
8/3/2019 Bleeching of Discolored Teeth
37/130
Minocycline Staining:
It is found that Minocycline, a semisyntheticderivative of tetracycline .unlike tetracycline it ispoorly absorbed in gastroinstestinal track.
Minocycline, although combines poorly with calcium,has the ability to chelate with iron and form insolublecomplexes,forming a yellow grey discolouration .
Minocycline stains may be responsive to bleachingwhile others with severe banding may requireveneers.
-
8/3/2019 Bleeching of Discolored Teeth
38/130
-
8/3/2019 Bleeching of Discolored Teeth
39/130
2. Post-eruptive discolorations:
a) Age
In older patients, colour changes in the crown occurphysiologically as a result of extensive secondary dentinformation, thinning and optical changes of the enamel.
Food and beverages also have a cumulative discolouring effectbecause of the inevitable crack, crazing and incisal wear of theenamel and underlying dentin.
In addition, amalgam and other coronal restorations thatdegrade over time cause further discoloration.
-
8/3/2019 Bleeching of Discolored Teeth
40/130
2) Pulpal Necrosis:
Bacterial, mechanical or chemical irritation to thepulp may result in tissue necrosis. Tissue
disintegration by products are then released thatmay penetrate tubules and discolour the
surrounding dentin.
The degree of discolouration is directly related tohow long the pulp has been necrotic.
The longer the discolouration products are present inthe pulp chamber, the greater the discolouration.
-
8/3/2019 Bleeching of Discolored Teeth
41/130
c) Intrapulpal haemorrhage:
It is the most common result of traumatic injury to a tooth, which
results in disrupted coronal blood vessels, haemorrhage andlysis of erythrocytes.
Blood disintegration products, presumably as iron sulfidespermeate dentinal tubules to stain the surrounding dentin, which
tends to increase with time.
If the pulp becomes necrotic, the discoloration usually remains.
If the pulp survives, the discolouration may resolve and the tooth
reverts to its original shade.
Sometimes, mainly in young individuals the tooth remainsdiscoloured even if the pulp responds to vitality.
-
8/3/2019 Bleeching of Discolored Teeth
42/130
d) Dentin hypercalcifiation/calcific metamorphosis
It is the extensive formation of tertiary or irregular secondary
dentin in the pulp chamber or on canal walls, which may occurfollowing certain traumatic injuries which did not result in pulpalnecrosis.
In such cases, temporary disruption of blood supply occurs
followed by partial destruction of odontoblasts.
These are replaced by undifferentiated mesenchymal cells thatrapidly form irregular dentin on the walls of the pulp lumen.
As a result, the translucency of the crowns of such teethgradually decreases, giving rise to a yellowish or yellow-browndiscoloration.
-
8/3/2019 Bleeching of Discolored Teeth
43/130
e) Iatrogenic Discolouration
Remnants of pulpal tissues:
Pulp fragments remaining in the crown,
usually in the pulp horns, may cause gradualdiscoloration.
The pulp horns must be opened up and
exposed during access to ensure removal ofpulpal remnants and to prevent retention ofsealer at a later stage.
-
8/3/2019 Bleeching of Discolored Teeth
44/130
2. Intracanal medicaments
Several intracanal medicaments are liable to cause
internal staining of the dentin.
Phenolics or iodoform based medicaments sealed inthe root canal and chamber are in direct contact withdentin sometimes for longer periods, allowingpenetration and oxidization.
These compounds have a tendency to discolour thedentin gradually.
Idoform induced discolourations tend to be moresevere.
-
8/3/2019 Bleeching of Discolored Teeth
45/130
3. Obturating materials:
It is a frequent and severe cause of single toothdiscolouration.
Incomplete removal of obturating materials and
sealer remnants in the pulp chamber, mainly thosecontaining metallic components, often results in darkdiscoloration.
Such discolouration can be prevented by removing allthe obturating material to a level just cervical to thegingival margins.
-
8/3/2019 Bleeching of Discolored Teeth
46/130
4. Coronal Restorations:Amalgam
Silver alloys have severe effects on dentin becauseof the dark coloured metallic components that canturn the dentin dark grey.
When used to restore lingual access preparations ora developmental groove in anterior teeth as well asin premolars, amalgam may discolour the crown.
such discolorations are difficult to bleach and tend to
rediscolour with time. Replacing the amalgamrestoration with an esthetic restoration usuallycorrects the problem.
-
8/3/2019 Bleeching of Discolored Teeth
47/130
b) Pins and Posts:
Metal pins and prefabricated posts are sometimesused to reinforce a composite restoration in theanterior teeth.
Discolorations from inappropriately placed pins andposts is caused by a metal seen through thecomposite or tooth structure.
In such cases, coverage of the pins with a whitecement or removal of the metal and replacement ofthe composite restoration is indicated.
-
8/3/2019 Bleeching of Discolored Teeth
48/130
c) Composites:
Microleakage around composite restoration causesstaining.
Open margins may allow chemicals to enter between
the restoration and the tooth structure and discolourthe underling dentin.
In addition, composites may become discoloured
with time, affecting the shade of the crown, whichneeds to be replaced with a new well sealedrestoration.
Bl hi M t i l
-
8/3/2019 Bleeching of Discolored Teeth
49/130
Bleaching Materials:
The most commonly used bleaching agents in dentistry are
Hydrogen peroxideSodium perborateCarbamide peroxide.
Hydrogen Peroxide:
It is a clear, colourless and odourless liquid.
Higher concentrations of these solutions must be handled with care as they arethermodynamically unstable and may explode unless refrigerated and kept in a darkcontainer.
Because of its ischemical effect on skin and mucous membrane it resembles a chemicalburn.
It is especially painful if it comes in contact with the nail bed or the soft tissue under the
finger nail.
It can be used for both intra and extra-coronal bleaching.
Ch i f bl hi
-
8/3/2019 Bleeching of Discolored Teeth
50/130
Chemistry of bleaching:
Bleaching is a chemical process, which occurs mostly by theoxidation during which the organic materials are eventuallyconverted into carbondioxide and water.
The most commonly used bleaching agent is hydrogen peroxidewhich requires the least time for the desirable action.
In the bleaching process, the oxidizing agent i.e. the bleachingagent has free radicals with unpaired electrons which it gives upand becomes oxidized, whereas the reducing agent i.e., thesubstance being bleached accepts the electrons and becomesreduced.
-
8/3/2019 Bleeching of Discolored Teeth
51/130
Hydrogen peroxide bleaching:
H2O2 has the ability to produce free radicals i.e.,
H2O (perhydroxyl-stronger free radical) and O.(nasant oxygen-weaker free radical).
In pure aqueous form, hydrogen peroxide
acid
reduced breakdown extended shelf life.
I i ti
-
8/3/2019 Bleeching of Discolored Teeth
52/130
Ionization:-H2O2 H2O + O (Higher percentage of the weaker free radical)
H + HO2 (Lower percentage of stronger free radical)
The perhydroxyl is the more potent free radical in the bleachingprocess. In order to promote the formation of perhydroxyl, thehydrogen peroxide needs to be made alkaline.
Optimum pH 9.5 to 1.8 at which ionization takes place.
H2O2 H2O + O (Lower percentage of weaker free radical)
H + HO2 (Higher percentage of stronger free radical)
-
8/3/2019 Bleeching of Discolored Teeth
53/130
This reaction results in greater bleaching efficacy inthe same time as at other pH levels. Thus, H2O2 ismost effective between pH of 9.5 10.8.
In the presence of decomposition catalysts andenzymes the H2O2 ionises as follows.
2H2O2 2H2O + O2
Where no free radicals are produced and thebleaching is ineffective. Some of these enzymesmay be present in the mouth.
Therefore, it is important to make the teeth free ofdebris and dry when applying the bleaching agent.
-
8/3/2019 Bleeching of Discolored Teeth
54/130
Mode of Supply:
Hydrogen peroxide:-
Solution: Various concentrations of hydrogenperoxides are available, but 30% to 35% stabilizedsolutions are the most commonly used. They can beused either alone or mixed with sodium perborate.
Gel: Also available in the form of Silicon dioxide gelscontaining various concentrations of hydrogenperoxide (6 to 38%).
Recently introduced is the Opalescence xtra boostwhich contains 38% hydrogen peroxide for quickerresults and which does not even require lightactivation (Syringes).
-
8/3/2019 Bleeching of Discolored Teeth
55/130
These gels are also available in preloaded disposable whiteningtray where the concentration of hydrogen peroxide is about 9%.
It is available as crest white from ultradent which consists of adelivery tray (outer tray with handle) and a disposable adaptivetray (inner tray without handle).
The inner tray consists of a gingival barrier gel on the border ofthe tray and 9% H2O2 gel inside the tray.
Both the trays are centered on the arch and lightly pressed intoplace, the outer tray is then removed and the inner tray is
adjusted. It is advised to wear 30 to 60 min/7-10 days.
-
8/3/2019 Bleeching of Discolored Teeth
56/130
Teeth whitening strips:-
These are flexible pieces of plastic or polyethylenethat have been coated on one side with a thin film ofhydrogen peroxide gel.
The idea of the teeth whitening strips was to reducethe thickness of the peroxide gel.
The thickness of the bleaching gels on the whiteningstrips is about 0.2mm while that of a paper is0.1mm. It is to 1/5th quantity compared to the traybleaching.
-
8/3/2019 Bleeching of Discolored Teeth
57/130
The concentration of the hydrogen peroxide gels on the whitening
-
8/3/2019 Bleeching of Discolored Teeth
58/130
The concentration of the hydrogen peroxide gels on the whiteningstrips varies from 6% to 10%.
The teeth whitening strip kit consists of half the strips designed to
adapt the upper arch and half the lower arch.
It is advised to use these strips for 30 min twice a day. 6% gel stripsfor 14 days and 10% gel strips for 7 days.
Disadvantage:- The length of the strips is small so that they adaptonly to the anterior teeth.
Adverse effects:
Gingival irritation: As there is no barrier to restrict these gels.
Sensitivity
H d id i i
-
8/3/2019 Bleeching of Discolored Teeth
59/130
Hydrogen peroxide toxicity
Cervical root resorption after internal (non vital) tooth bleaching.
Increased sensitivity after external(vital) tooth bleaching.
For resorption to occur ,there must be a combination of
Deficiency in the cementum(exposing the dentin)
Injury to the periodontal ligament
Infection(sustaining the inflammation).
HYDROGEN PEROXIDE TOOTH WHITENING
-
8/3/2019 Bleeching of Discolored Teeth
60/130
HYDROGEN PEROXIDE TOOTH-WHITENING(BLEACHING)PRODUCT:REVIEW OF ADVERSEEFFECTS AND SAFETY . BDJ vol 2000 no 7 apr 2006
Hydrogen peroxide in the form of carbamide peroxide iswidely used for tooth whitening (bleaching),both inprofessionallyand in self administered product.
Cervical root resoption is a possible consequense ofinternal bleaching and is more frequently observed inteeth treated with the thermo-cataytic procedure.
Direct contact with H2O2 induces genotoxic effects .
Several carcinogenesis studies indicated H202 might actlike a promotor.
Eff f bl hi h f
-
8/3/2019 Bleeching of Discolored Teeth
61/130
Effect of bleaching on the structure of
enamel
Surface alteration in enamel topographyfollow vital bleaching using hydrogenperoxide.
High concentration of hydrogen peroxide
damage enamel surface intergrity.
Eff f h bl hi h
-
8/3/2019 Bleeching of Discolored Teeth
62/130
Effect of tooth bleaching on tooth
restoration
Bleaching with hydrogen peroxide increase thesolubility of glass ionomer and other cements andreduce the bond strength between enamel and resinbased filling in the first 24 hour.
Hydrogen peroxide residues in the enamel mayinhibit the polymerisation of resin based materialand reduce bond strength.
So ,hydrogen peroxide should not be used prior totreatment with resin based material
Sodium Perborate
-
8/3/2019 Bleeching of Discolored Teeth
63/130
Sodium Perborate:
It is supplied in a granular form, that has to
be ground into a powder before using.
It is either mixed with water or hydrogen
peroxide to form a thick paste and is packedinto the pulp chamber.
When fresh ,it contains 95% perborate .
S di b i bl h d b i
-
8/3/2019 Bleeching of Discolored Teeth
64/130
Sodium perborate is stable when dry,but inthe presence of acid,warm air,or water it
decompses to form sodiummetaborate,hydrogen peroxide and nascentoxygen.
Various forms of sodium perborate
-
8/3/2019 Bleeching of Discolored Teeth
65/130
Various forms of sodium perborate
monohydrate
trihydrate
tetrahydrate
They differ in there oxygen content which
determines the bleaching efficacy.
Commonly used sodium perborate are alkaline and
there pH depends on the amount of hydrogenperoxide released and residual sodium metaborate.
Ch i f bl hi
-
8/3/2019 Bleeching of Discolored Teeth
66/130
Chemistry of bleaching
Sodium perborate:-
Sodium perborate when mixed with water
decomposes to form sodium metaborate andhydrogen peroxide releasing O2.
When mixed with superoxol it decomposes to form
sodium metaborate and water releasing O2. Theoxidation is slow and is active over a long period oftime
Ad f di b
-
8/3/2019 Bleeching of Discolored Teeth
67/130
Advantage of sodium perborate
-
8/3/2019 Bleeching of Discolored Teeth
68/130
Carbamade peroxide:-Also known as urea peroxide, cabramyl peroxide, perhydrol urea,perhydelure, carbamide urea, urea H2O2 and H2O2 carbamide.It is a clear, colourless odourless liquid. When used as ableaching agent it breakdowns to hydrogen peroxide.
Previously used only for extracoroanl bleaching.Lee et al (2004), found that carbamide peroxide had very lowlevels of extraradicular diffusion of peroxide in the presence ofcemental defects. Therefore, it could be an alternative to theother intracoronal bleaching agents. 35% carbamide and 35%
H2O2 were more effective than Na perborate after 7 days.
-
8/3/2019 Bleeching of Discolored Teeth
69/130
Bleaching preparations containing carbamideperoxide usually include glycerine orpropylene glycol, sodium stannate,
phosphoric or citric acid and flavour additives.Some preparations contain carbapol, a watersoluble polyacrylic acid polymer as athickening agent which prolongs the release
of active peroxide and improves shelf-life.
-
8/3/2019 Bleeching of Discolored Teeth
70/130
Carbamide peroxide:The most common mode of supply is in the form of gels, whichare supplied in syringes. It is available in various concentrationsranging from 3 to 45%. However, popular commercialpreparation contain about 10% carbamide peroxide with a mean
pH of 5 to 6.5.Leonard et al. studied the use of different concentrations ofcarbamide peroxide for bleaching teeth and found that lowerconcentrations of carbamide peroxide take longer time to whitenteeth but eventually achieve the same result as higherconcentrations, which may cause increased sensitivity.
-
8/3/2019 Bleeching of Discolored Teeth
71/130
Enzymes:-There are certain enzymes which are found to havea considerable bleaching efficiency on both extrinsicand intrinsic stains. These enzymes are obtainedeither from plants or microorganisms. Theseenzymes are effective either without peroxides orwith very little % of peroxides (0 to 1%).
Laccases act on the molecular oxygen and yieldhydrogen peroxide without any need for hydrogen
peroxide. They are obtained from fungi E.g.Mycelipthora thermophila. These enzymes are foundto be effective against intrinsic stains.
-
8/3/2019 Bleeching of Discolored Teeth
72/130
Oxidases act on the molecular oxygen and yield hydrogenperoxide. E.g. L-amino acid oxidase Trichoderma harzianum,glucose-oxidase Aspergillus species, Xylitol oxidaseStreptomyces species. They are found to be effective againstextrinsic stains.
Peroxidase:- Act on hydrogen peroxide and yield water. Theseenzymes require very little % of hydrogen peroxide for theiraction. They are obtained from plants e.g. Horse radishperoxidase or from microorganisms. E.g. Haloperoxidase fromCurvularia species. They are found to be effective against bothextrinsic and intrinsic stains along with Laccases
-
8/3/2019 Bleeching of Discolored Teeth
73/130
Enzymes:-
These enzymes either alone or in combinationwith peroxides are added to the mouth
washes or tooth pastes. Their concentrationranges from 0 to 20% with 0 to 1% ofperoxides if used.
-
8/3/2019 Bleeching of Discolored Teeth
74/130
Sodium perborate:-
Sodium perborate when mixed with waterdecomposes to form sodium metaborate and
hydrogen peroxide releasing O2. Whenmixed with superoxol it decomposes to formsodium metaborate and water releasing O2.The oxidation is slow and is active over along period of time
-
8/3/2019 Bleeching of Discolored Teeth
75/130
Carbamide peroxide chemistry:Carbamide peroxide used as bleaching agentbreaks down into H2O2. 10% carbamide
peroxide produces 3.6% H2O2.CH2 N2O H2O2
NH3 H2O2
CO2
Then, the ionization of H2O2 is the same.
BLEACHING TECHNIQUES:
-
8/3/2019 Bleeching of Discolored Teeth
76/130
BLEACHING TECHNIQUES:
Before carrying out the bleaching process, it
is important to assess the type of stain.Certain extrinsic stains can be removed byregular intense mechanical brushing withcleaning agents containing abrasives or
surfactants.
-
8/3/2019 Bleeching of Discolored Teeth
77/130
Basically bleaching techniques are:-
Non-vital
Walking bleach
Thermocatalytic
UV light photooxidation
Vital
In-office
Night guard
Over the counter
-
8/3/2019 Bleeching of Discolored Teeth
78/130
1. Non-vital bleaching:These procedures are carried out for endodontically treatedteeth.
Indications:- Discolouration of pulp chamber
Dentin discolouration Discolourations not amenable to extracoronal bleachingContraindications:- Superficial enamel discolourations Defective enamel formation
Severe dentin loss Presence of caries Discoloured composites Extensive restorations
In any of the non-vital bleaching techniques, there are
-
8/3/2019 Bleeching of Discolored Teeth
79/130
y g q ,certain steps which are common.
Radiographic assessment of the status of theperiapical tissues and the quality of endodonticobturation. If the obturation is inadequate, the toothshould be retreated prior to bleaching.
If there are any leaking or discoloured restorations,they have to be replaced.
Evaluate the tooth colour with a shade tab by takingphotographs at every appointment. Orabase or vaseline should be applied to the
gingival tissues, followed by isolation with rubberdam which should fit tightly at the cervical margin of
the tooth to prevent possible leakage of thebleaching agent onto the gingival tissues. Opal damcan also be used.
-
8/3/2019 Bleeching of Discolored Teeth
80/130
Remove all restorative material from the accesscavity, expose the dentin and refine the access.Verify that the pulp horns and other areascontaining pulp tissue are clean.
Remove the obturation material to just below labialgingival margin. Orange solvent, chloroform orxylene on a cotton pellet may be used to dissolvesealer remnants.
Next is the application of the barrier material. Thisis one of the most important step as the improperlocation, material and the shape of the barriermaterial could lead to external cervical resorption.
Walking Bleach:
-
8/3/2019 Bleeching of Discolored Teeth
81/130
Walking Bleach:
In this technique, a mixture of sodium perborate andinert liquid such as water, saline or anaesthetic
solution or even H2O2 can be used but preferablylower concentrations are placed in the pulp chamber.Studies have shown more number of external cervicalresorption cases with the combination of sodium
perborate and 30% hydrogen peroxide. Studies with different types of sodium perborae, water
and H2O2 have shown that the combination of sodiumtetraborate with water was quiet effective.
Timpavat et al. found the bond strength to be better withNaperborate + H2O. Excess liquid from sodiumperborate should be removed by tamping with a cotton
pellet.
-
8/3/2019 Bleeching of Discolored Teeth
82/130
Excess bleaching paste from the undercuts inthe pulp horns should be removed and theaccess cavity should be sealed with a temporaryfilling (Preferably IRM) which should be at least
3mm. Rubber dam should e removed and the patient
should be informed that bleaching agents workslowly and significant lightening may not beevident for several days.
Patient should be evaluated after 2 weeks andthe procedure should be repeated if necessary.
Thermocatalytic:
-
8/3/2019 Bleeching of Discolored Teeth
83/130
Thermocatalytic:
This technique involves placement of the oxidizingagent, generally 30% to 35% H2O2 in the pulpchamber followed by heat application either byelectric heating devices or specially designedphotoflood lamps for 5min. this process should becontinued until the desirable results are achieved.Should not be repeated for more than 5-6 times.Care should be taken that the temperature of theheating device does not exceed 114F. Lamp unitshould be 13 inches away from patient. Metal
clamps should not be used. Recall the patient in aweek to assess the colour after rehydration. Repeatthe procedure, if necessary.
-
8/3/2019 Bleeching of Discolored Teeth
84/130
Photo-oxidation:
In this technique, 30% to 35% of H2O2 solution isplaced in the pulp chamber on a cotton pelletfollowed by exposure to the curing light for 20-30sec. For plasma arc or laser 3-5 seconds ofexposure time is sufficient. If the bleaching gels areused they have to be expressed into the accesscavity and onto the labial surface of the tooth and
should be exposed to the curing light from both thesides.
-
8/3/2019 Bleeching of Discolored Teeth
85/130
Adverse effects: External cervical root resorption:- It is one of the most
commonly noticed complication with intracoronal bleachingusing hydrogen peroxide. It is asymptomatic and is
generally noticed during routine examination. The exactcause of this response is not fully understood, although anumber of mechanisms have been postulated.
In 10% of all teeth, the cemento-enamel junction is defectiveor absent, resulting in a portion of the tooth being devoid of
cementum coverage. 35% H2O2 may denature the dentin,involving a foreign body response by elements in the
approximating gingival tissue causing cervical resorption.
-
8/3/2019 Bleeching of Discolored Teeth
86/130
Internally applied 35% H2O2 may directly contactperiodontal membrane may passing through patentdentinal tubules or lateral canals or accessory foramina.
Bleaching agents may infiltrate between the gutta-percha and root canal walls. They could then
communicate with the periodontal ligament throughdentinal tubules, lateral canals or apex which can causeresorption anywhere along the length of the canal.
Heat application while using high concentrations ofH2O2 may enhance external cervical root resorption.
35% H2O2 mixed with sodium perborate can lower thepH in the periodontal membrane, which may increasethe likelihood of cervical resorption.
-
8/3/2019 Bleeching of Discolored Teeth
87/130
Chemical burns:- 35% H2O2 is caustic and may causechemical burns and sloughing of the gingiva. Therefore,when using such solutions the soft tissues should alwaysbe protected with Vaseline or orabase and rubber dam orwith opal dam.
Coronal fracture:- Increased brittleness of the coronaltooth structure, particularly when hat is applied, is alsothought to result from bleaching. This may be due to
dessication of the dentin and enamel. This was noticedclinically but has not yet proven conclusively.
-
8/3/2019 Bleeching of Discolored Teeth
88/130
Suggestions for safer bleaching: Verification of adequate endodontic obturatiion This provides
an additional barrier against damage by oxidizers to theperiodontal ligament and periapical tissues.
Protect the oral mucosa by Vaseline or orabase.
Effective isolation by opaldam or rubber dam. Use ofinterproximal wedges and ligatures may provide a better seal.
Use of protective barriers In most of the clinical reports of thepost bleaching cervical root resorption protective barrier was notused. The barrier of adequate thickness should protect the
dentinal tubules and confirm to the external epithelial attachment.
-
8/3/2019 Bleeching of Discolored Teeth
89/130
Acid etching should be avoided as it doesnot enhance the bleaching process, butcauses undesirable periodontal ligament
irritation. Avoid strong oxidizers.
Avoid heat.
Recall the patient periodically and examineclinically and radiographically.
-
8/3/2019 Bleeching of Discolored Teeth
90/130
Post bleaching tooth restoration:Permanent restoration of the tooth is essential forlong-term successful bleaching. Coronalmicroleakage especially that of lingual accessrestoration and a leaking restoration may lead to
rediscolouration. Therefore, a composite restorationis advised as early as possible. This should beplanned 1 or 2 weeks after complete removal of thebleaching materials. This time period is for theelimination of residual peroxides.
The use of catalase for 3 min has been proposed forthe removal of residual peroxides where adequatebonding can be acquired.
-
8/3/2019 Bleeching of Discolored Teeth
91/130
In case of thermocatalytic or photooxiationbleaching, it has been advised to packCa(OH)2 paste in the pulp chamber for a few
weeks prior to placement of final restorationto counteract acidity caused by bleachingagents and to prevent root resorption.
-
8/3/2019 Bleeching of Discolored Teeth
92/130
Vital bleaching techniques:
There are various techniques for bleachingvital teeth depending on the degree of
staining. In-office or Power
Mouth guard or Night guard or At-home
Over-the counter
1. In-office:
-
8/3/2019 Bleeching of Discolored Teeth
93/130
Indications:-
Light enamel discoloration
Mild tetracycline discoloration
Endemic fluorosis discoloration
Age related discoloration
Contraindications: Severe dark discolorations
Severe enamel loss
Proximity of pulp horns
Hypersensitive teeth Presence of caries
Large/ poor coronal restorations
-
8/3/2019 Bleeching of Discolored Teeth
94/130
Techniques:-Familiarize the patient about causes of discoloration,
procedure to be followed and the treatmentoutcome.
Make radiographs to detect the presence of caries,defective restorations and proximity to pulp horns.
Evaluate tooth colour with shade tabs by takingphotographs at all the appointments.
Apply Vaseline or oraseal and then isolate with rubber
dam by using waxed dental floss or wedgets foradditional sealing. Avoid using metal clamps, asthey are subjected to heat.
-
8/3/2019 Bleeching of Discolored Teeth
95/130
Do not inject a local anesthetic. Position protective sunglasses over the patients and operators
eyes.
Clean the enamel surface with pumice and water.
For the darkest or most severely stained areas acid etch with
35% phosphoric acid for 5 to 10 seconds and rinse with waterfor 60 seconds.
Place a small amount of 30 to 35% H2O2 solution into adappen dish. Apply the H2O2 liquid on the labial surface of theteeth using a small cotton pellet or a piece of gauze. Bleaching
gel can also be used instead of solution which can be bettercontrolled.
-
8/3/2019 Bleeching of Discolored Teeth
96/130
Apply heat with a heating device or light source. Thetemperature should be controlled that the patient does not feelany discomfort, usually between 125F and 140F (52C to60C). Rewet the enamel surface with H2O2 as necessary. Ifthe tooth becomes too sensitive, discontinue the bleachingprocedure immediately. Do not exceed 30 min even ifsatisfactory results are not obtained.
Heating can be carried out by thermostatically controlledelectric heating device or a stainless steel instrument such asWoodson No.2 heated over flame. There are different lightsources available for photo-oxidation conventional bleaching
light. This supplies energy to enhance the bleaching action ofH2O2 by adding heat. The heat causes more vigorous releaseof oxygen and facilitates the dissolution of pigments. It is slowand often uncomfortable for the patient.
-
8/3/2019 Bleeching of Discolored Teeth
97/130
Tungsten-Halogen curing light:
These curing light provides heat andstimulates the initiation of the chemical
reaction by activating the light sensitivechemicals in the bleaching agent. This is atime consuming process (i.e., 40 to 60 secper application per tooth).
-
8/3/2019 Bleeching of Discolored Teeth
98/130
Argon laser:
It emits a visible blue light. The action it is tostimulate the catalyst in the chemical. There
is no thermal effect with this. It is easy to useand is best for removal of initial dark stains,such as those caused by tetracycline.However, it becomes less effective as theteeth whitens and when there are fewer stainmolecules.
-
8/3/2019 Bleeching of Discolored Teeth
99/130
Carbon dioxide laser:
It emits invisible infra red light. They interactsdirectly with the catalyst-peroxide
combination. It removes the stains regardlessof the tooth colour. It emits heat and canenhance the bleaching effect initiated by theargon laser.
-
8/3/2019 Bleeching of Discolored Teeth
100/130
Xenon plasma arc light:-
It is a non-laser, high intensity light whichproduces a great deal of heat; therefore, it
can be applied only for a brief 3 sec period.The action is thermal and stimulates thecatalyst in the chemical. Although it is veryfast, there is a greater potential for thermaltrauma to the pulp and surrounding softtissues than with other light sources.
-
8/3/2019 Bleeching of Discolored Teeth
101/130
Diode laser light:- It is a true laser light produced from solid-state source. It is
ultra fast taking 3 to 5 sec to activate the bleaching agent. Thisdoes not produce heat.
Remove the heat source and allow the teeth to cool down for
at least 5 min. Then wash with warm water for 1 minute and thenremove the rubber dam. Do not rinse with cold water since thesudden change in temperature may damage the pulp or can bepainful to the patient.
Dry the teeth and gently polish them with a composite resinpolishing cup.
Treat all the etched and bleached surfaces with 1.1% neutralsodium fluoride gel for 3 to 5 min.
-
8/3/2019 Bleeching of Discolored Teeth
102/130
Inform the patient that cold sensitivity iscommon, especially during the first 24 hrsand advise to use a fluoride rinse daily for 2
weeks. Recall the patient after 2 weeks and
evaluate the effectiveness of bleaching bysing the same shade tab used pre-operativeassessment. Repeat the procedure ifnecessary.
-
8/3/2019 Bleeching of Discolored Teeth
103/130
Adverse effects:-1. Post operative pain:
A common immediate postoperative problem ispulpalgia characterized by intermittent shootingpain. It may occur during and after the bleachingsession and usually persists for between 24 and 48hrs. The intensity of pulpalgia is related to theduration and temperature of the bleachingprocedure. Therefore, shorter bleaching periods arerecommended. If long term sensitivity to colddevelops, topical fluoride treatments anddesensitizing tooth pastes should be used toalleviate these systems.
-
8/3/2019 Bleeching of Discolored Teeth
104/130
. Pulpal damage:-Extra coronal bleaching with hydrogen peroxide andheat has been associated with some pulpaldamage. Although no significant irreversible effects
on the pulp have been found, these procedureshould be carried out with caution and not in thepresence of caries, areas of exposed dentin or inclose proximity to pulp horns. Defective restorations
must be replaced prior to bleaching.
-
8/3/2019 Bleeching of Discolored Teeth
105/130
Dental hard tissue damage:
Hydrogen peroxide causes morphologic andstructural changes in enamel, dentin and
cementum and reduces the micro-hardnessof these structures. These changes maycause dental hard tissues to be moresusceptible to degradation and to secondarycaries formation. Therefore, teeth should bewell polished after the bleaching procedure.
Mucosal damage:
-
8/3/2019 Bleeching of Discolored Teeth
106/130
Ulceration and sloughing of the mucosa may becaused when the highly concentrated peroxide
substances come in contact with the mucosa.Generally, the mucosa appears white but does not
become necrotic or leave scar tissue. Theassociated burning sensation is extremely
uncomfortable for the patient and can be treated byextensive water rinses until the whiteness isreduced. In more severe cases, a topical anesthetic,limited movements and good oral hygiene aid
healing. Application of protective cream or catalasecan prevent mot of these complications. Vitamin Eoil can also be applied immediately after contact.
Night guard vital bleaching:Indications:-
-
8/3/2019 Bleeching of Discolored Teeth
107/130
Indications:- Superficial enamel discolorations
Mild yellow discolorations Brown fluorosis discolorations Age-related discolorationsContraindications:-
Severe enamel loss Hypersensitive teeth Presence of caries Defective coronal restorations
Allergy to bleaching gels Bruxism Pregnant and lactating 8. Smoking
Technique:-This technique has been widely advocated as a
-
8/3/2019 Bleeching of Discolored Teeth
108/130
This technique has been widely advocated as ahome bleaching technique with a wide variety ofmaterials. Numerous products are available, mostlycontaining 1.5 to 10% hydrogen peroxide or 10 to15% carbamide peroxide, that degrade slowly torelease hydrogen peroxide. Carbamide peroxideproducts are the more commonly used at homebleaching agents.
Familiarize the patient with the probable causes ofdiscolouration, procedure to be followed and theexpected outcome.
Carry out thorough oral prophylaxis
Assess the colour of the teeth with a shade tab bytaking photographs at all the appointments.
-
8/3/2019 Bleeching of Discolored Teeth
109/130
Make alginate impressions of both the arches. Castthe impression by taking care not to incorporatevoids or drags in the impression. Applyapproximately 0.5mm thickness of block out materialto the desired labial surfaces to provide reservoirspaces in the tray. It should be 1 to 15mm short ofthe gingival margin and should not extend onto theincisal edges and occlusal surfaces. Extending theblock-out material onto the incisal edges or occlusal
surfaces can cause the margins of the tray to openupon occluding or the tray to impinge on the softtissues.
1. Cure the block-out material on each tooth for 20 to40 seconds Now heat the tray material on the
-
8/3/2019 Bleeching of Discolored Teeth
110/130
40 seconds. Now heat the tray material on thevacuum former unit until it sags approximately 2 inches, then adapt it to the cast and allow it tocool. It is then trimmed with a scalpel or elasticknife approximately 0.25 to 0.3mm occlusally fromthe gingival margin facially and lingually in ascalloped manner. The tray is then placed on thecast and the extensions are checked. Now gentlyflame polish the edges one quadrant at a time witha torch. While still warm, hold the periphery ofeach segment firmly against the model for 3 secwith a water-moistened finger. Otherwise, aftertrimming the tray with scalpel a rubber wheel in a
micromotor can be used to smoothen the roughedges.
Insert the mouth guard to ensure proper fit.Remove and apply the bleaching agent in the
-
8/3/2019 Bleeching of Discolored Teeth
111/130
pp y g gspace of each tooth to be bleached. Reinsert themouth guard over the teeth and remove excess
bleaching agent. Familiarize the patient with the use of bleaching
agent and wearing the mouth guard. Theprocedure is usually performed 3 to 4 hrs a dayand the bleaching agent is replenished every 30 to
60 min. Some clinicians recommend wearing theguard during sleep for better long-term estheticresults. The duration of wearing the mouth guardand replenishing the bleaching agent depends onthe severity of staining, concentration of the
bleaching agent and the manufacturersinstructions.
Instruct the patient to brush and rinse their teethft l Th d h ld t b ti
-
8/3/2019 Bleeching of Discolored Teeth
112/130
after meals. The guard should not be worn eating.
Inform the patient about thermal sensitivity and
minor irritation of soft tissues and to discontinueuse of the guard if uncomfortable.
Treatment may be carried out for 4 to 24 weeks.Recall the patient every 2 weeks to monitor stain
lightening. Check for tissue irritation, oral lesions,enamel etching and leaky restorations. Ifcomplications occur, stop the treatment and re-evaluate the feasibility of continuation at a later
date. Rediscoloration with this technique is notmore frequent than the other technique.
Adverse effects:
-
8/3/2019 Bleeching of Discolored Teeth
113/130
Systemic effects: Controlled mouth guard bleachingis considered relatively safe. However, accidentalingestion of large amounts of these gels may betoxic and cause irritation to the gastric and respiratormucosa. Bleaching gels containing carbopol areusually more toxic. Therefore, it is advisable to pay
specific attention to any adverse systemic effectsand to discontinue treatment immediately if theyoccur.
Dental hard tissue damage:- In vitro studies indicate
morphologic and chemical changes in enamel,dentin and cementum associated with some agentsused for mouth guard bleaching.
Tooth sensitivity: Transient tooth sensitivity to coldmay occur during or after mouth guard bleaching
-
8/3/2019 Bleeching of Discolored Teeth
114/130
may occur during or after mouth guard bleaching.In most cases, it is mild and ceases on terminationof treatment. Treatment for sensitivity consist of
discontinue the use of mouth guard for few days orthe reduction of wearing or the use of desensitizingagents.
Mucosal damage:- Minor irritations or ulcerationsof the oral mucosa have been reported to occurduring the initial course of treatment. Possiblecauses are mechanical interference by the mouthguard, chemical irritation by the bleaching agentand allergic reactions to gel components. In mostcases, readjustment and smoothing the borders ofthe guard will suffice. However, if tissue irritationpersists, treatment should be discontinued.
Damage to restorations: Some in vitrodi h d f bl hi
-
8/3/2019 Bleeching of Discolored Teeth
115/130
studies suggest that damage of bleachinggels to composite resins may be caused bysoftening and cracking of the resin matrix.However, there are few other studies whichdid not find any significant adverse effects
on either surface texture or colour ofrestorations. Generally, if compositerestorations are present in estheticallycritical areas, they may need replacement toimprove colour matching followingsuccessful bleaching.
-
8/3/2019 Bleeching of Discolored Teeth
116/130
It has also been reported that both 10%carbamide peroxide and 10% hydrogenperoxide may enhance the liberation ofmercury and silver from amalgam
restorations and may increase exposure ofpatients to toxic byproducts. Coverage of theamalgam restorations with a protective layerof dental varnish prior to the bleaching gel
application may prevent such hazards.Unpolished restorations corrode more.
-
8/3/2019 Bleeching of Discolored Teeth
117/130
Occlusal disturbances:- Typcially, occlusalproblems related to the mouth guard may bemechanical or physiologic. From a mechanicalpoint of view, the patient may occlude only on theposterior teeth rather than on all teethsimultaneously. Removing posterior teeth from theguard until all of the teeth are in contact rectifiesthe problem. From a physiologic point of view, ifthe patient experiences TMJ pain, the posterior
teeth can be removed from the guard until only theanterior guidance remains. In such cases, wearingtime should be reduced.
-
8/3/2019 Bleeching of Discolored Teeth
118/130
Studies have found that At-home bleaching for 2weeks is more effective than in-office bleaching 3times at 3 different appointments.
Leonard et al. studied the desensitizing agent
efficacy during whitening in an at-risk population andsuggests that the use of an active 3% KNO3 and0.11% F desensitizing agent for 30 min prior towhitening may decrease tooth sensitivity when
compared with placebo in a population at risk fortooth sensitivity.
-
8/3/2019 Bleeching of Discolored Teeth
119/130
Gamze (2003) had suggested that 10 gm ofCarbamide peroxide/ day can be consideredas a safe dose for the prevention of systemic
effects in a person / day can be consideredas a safe dose for the prevention of systemiceffects in a person of 70 kg wt.
-
8/3/2019 Bleeching of Discolored Teeth
120/130
Alternative Techniques: 1. Acid-pumice technique:-
In this technique, 18% HCl is mixed with fine flour ofpumice to make a thick paste.
This paste is applied to the enamel surface with a piece ofwooden tongue blade or crushed orange wood stick.Exerting firm pressure, the paste is worked into the enamelsurface with a swirling motion for 5 seconds. The enamelsurface is then rinsed for 10 seconds with water.
The paste is re-applied until the desired lightening isachieved.
-
8/3/2019 Bleeching of Discolored Teeth
121/130
The thick paste of sodium bicarbonate and waterare applied to neutralize the surface.
Polish with a fine fluoride prophylaxis paste andsuperfine aluminium oxide composite resin
polishing discs.
Apply 1.1% neutral sodium fluoride gel for 4 min.
This technique can be used in combination
with the night guard bleaching using lowerconcentration bleaching agents.
-
8/3/2019 Bleeching of Discolored Teeth
122/130
2. McInnes technique:- This technique uses a combination of 5
parts of 30% H2O2, 5 parts of 36% HCl and 1part of diethyl ether. The solution is applieddirectly to the stained areas for 1 to 2 minuteswith cotton applicators. While the surface iswet, a fine cuttle disc is run over the stainedsurfaces for 15 seconds. This process isrepeated until the desirable results areachieved, during subsequent appointments.
-
8/3/2019 Bleeching of Discolored Teeth
123/130
Macro abrasion: This technique can be combined with
night guard vital bleaching to achieve better
results. In this technique the severely darkstains are removed with diamond points,followed by finishing with carbide burs andpolishing by using the composite polishing
disc. Further lightening is achieved by nightguard bleaching.
-
8/3/2019 Bleeching of Discolored Teeth
124/130
Over-the-counter:Many home bleaching products are available over the counter orthrough mail order, radio and television advertisements. Thisapproach is not recommended as overuse and abuse are aconcern.
These systems include
Tooth pastes AP-24, Rembrandt Mouth rinses Crest Tooth brushes Spine brush pro whitening Dental floss Super smile Teeth whitening strips Crest
Chewing gums Brits smile, Happy dent Pain on varnish Vivastyle Brite smile stick or pen
-
8/3/2019 Bleeching of Discolored Teeth
125/130
Tooth brushes:Certain powered tooth brushes are available which are said toremove the extrinsic stains mechanically. E.g. Spin brush pro-whitening.
Paint on varnish:-
Applied with a brush. On application it contains 6% carbamideperoxide. Once, it is dried the concentration increases.
Insoluble in saliva and remains on teeth for 20 min. subsequentlyremoved with a tooth brush.
Advantages:-
Can be applied exactly wherever it is needed.Contains D-panthenol Provitamin
Noticeable after 7 days
Chewing gums:
B it il H d t
-
8/3/2019 Bleeching of Discolored Teeth
126/130
Brite smile, Happy dent
Supersmile whitening floss: It is the worlds first floss treated with Calprox
(not waxed) to safely whiten between teethand baking soda for fresher breath. Removesstubborn stains and odour causing plaqueunder the gum.
Calprox is a clinically proven whitening agent
which gently dissolves the protein pellicle,removing stains and plaque in the process.
Boil and Bite:-
-
8/3/2019 Bleeching of Discolored Teeth
127/130
Boil a pot of water and then submerge the
mouthpiece into it for 5 to 15 sec. Mouthpiecebegin to wilt.
Place the mouthpiece into the mouth andpress against the front of your teeth with your
fingers an the back of your teeth with yourtongue. Let it cool.
Remove the mouthpiece from the mouth andcut the handle.
Squeeze whitening gel and place it for 1-3hrs.
-
8/3/2019 Bleeching of Discolored Teeth
128/130
Tooth pastes:- They contain enzymes that are thought to
help to break down the organic protein
components of the stains. E.g.Rembrandt whitening contaisn citroxain,
derived from papaya
Janina ultrawhite opal contains Bromelain,which is derived from Pineapple.
-
8/3/2019 Bleeching of Discolored Teeth
129/130
Tooth brush:- It is clinically proven that it whitens the teeth
in 14 days. Removes up to 88% of surface
stains tobacco, wine, tea and coffee after14 days of use.
Increased bristle density, concave polishingstrips and new cup shaped pattern designedto enhance the retention of dentifrice at thebrush-tooth surface interface.
-
8/3/2019 Bleeching of Discolored Teeth
130/130