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Introduction

Classification of Discoloration

Bleaching

Contraindications for Bleaching

Medicaments Used as Bleaching Agents

Home Bleaching Technique/Nightguard

Bleaching

In-office Bleaching

Thermocatalytic Vital Tooth Bleaching

Non-thermocatalytic Bleaching

Microabrasion

Management of

Discolored Teeth

Bleaching of Nonvital Teeth

Thermocatalytic Technique of Bleaching of

Nonvital Teeth

Intracoronal Bleaching/Walking Bleach of

Nonvital Teeth

Inside/Outside Bleaching Technique

Closed Chamber Bleaching/

Extracoronal Bleaching

Laser Assisted Bleaching Technique

Effects of Bleaching Agents on Tooth andits Supporting Structures

Bibliography

INTRODUCTION

In the pursuit of looking good, man has always tried to beautifyhis face. Since, the alignment and appearance of teeth influence

the personality, they have received considerable attention.

Tooth discolorat ion varies in et io logy, appearance ,

localization, severity and adherence to tooth structure. It may

be classified as intrinsic, extrinsic and combination of both.

Intrinsic discoloration is caused by incorporation of

chromatogenic material into dentin and enamel during

odontogenesis or after tooth eruption. Exposure to high levels

of fluoride, tetracycline administration, inherited developmental

disorders and trauma to the developing tooth may result in pre-

eruptive discoloration. After eruption of the tooth, aging and

pulp necrosis are the main causes of intrinsic discoloration.Coffee, tea, red wine, carrots and tobacco give rise to

extrinsic stains. Wear of the tooth structure, deposition ofsecondary dentin due to aging or as a consequence of pulp

inflammation and dentin sclerosis affect the light-transmitting

properties of teeth, resulting ina gradual darkening of the teeth.

Scaling and polishing of the teeth removes many extrinsic

stains. For more stubborn extrinsic discoloration and intrinsic

stain, a variety of tooth whitening options are available today,

these include over-the-counter whitening systems, whiteningtooth pastes and the latest option laser tooth whitening.

Currently available tooth whitening options are:

1. Office bleaching procedures.2. At home bleaching kits.3. Composite veneers.4. Porcelain veneers.5. Whitening toothpastes.

Among these procedures, bleaching procedures are moreconservative than restorative methods, simple to perform andless expensive.

This chapter reviews discoloration and its correction.Following aspects of discoloration and bleaching proceduresare discussed in this chapter:1. Etiology and types of discoloration.2. Commonly used medicaments for bleaching.3. External bleaching technique, i.e. bleaching in teeth with

vital pulp.4. Internal bleaching technique, i.e. usually performed in

nonvital teeth.5. Efficacy and performance of each procedure.6. Possible complications and safety of various procedures.

Before discussing, bleaching of the discolored teeth, weshould be familiar with the color of natural healthy teeth. Teethare polychromatic so color varies among the gingival, incisaland cervical areas according to the thickness, reflections ofdifferent colors and translucency of enamel and dentin


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Chromosomal anomalies Inherited diseases Tetracycline Childhood illness Malnutrition Metabolic disorders.

Ame logene sis imp erfe cta (AI ): It comprises of a group ofconditions, that demonstrate developmental alteration in the

structure of the enamel in the absence of a systemic disorders.Amelogenesis imperfecta (AI) has been classified mainly intohypoplastic, hypocalcified and hypomaturation type (Fig. 29.2).

Fluorosis:In fluorosis, staining is due to excessive fluoride uptake

during development of enamel. Excess fluoride induces a

metabolic change in ameloblast and the resultant enamel has

a defective matrix and an irregular, hypomineralized structure

(Fig. 29.3).

Staining manifests as:

1. Gray or white opaque areas on teeth.

2. Yellow to brown discoloration on a smooth enamel surface

(Fig. 29.4).

3. Moderate and severe changes showing pitting and brownish

discoloration of surface (Fig. 29.5).

4. Severely corroded appearance with dark brown discoloration

and loss of enamel.

Fig. 29.2:Amelogenesis imperfecta

Fig. 29.3:Fluorosis of teeth

Enamel Hypo plasia and Hypocal cif ica tion due to Othe r Caus es

(Figs 29.6A to C):

1. Vitamin D deficiency results in characteristic white patch

hypoplasia in teeth.

2. Vitamin C deficiency together with vitamin A deficiency

during formative periods of dentition resulting in pitting

type appearance of teeth.

3. Childhood illnesses during odontogenesis, such as

exanthematous fever, malnutrition, metabolic disorder, etc.also affect teeth.

Defects in dentin formation

Dentinogenesis imperfecta. Erythropoietic porphyria. Tetracycline and minocycline (excessive intake). Hyperbilirubinemia.

Dentinogenesis imperfecta (DI) (Figs 29.7A to C): It is anautosomal dominant development disturbance of the dentinwhich occurs along or in conjunction with amelogenesisimperfecta. Color of teeth in DI varies from gray to brownish

violet to yellowish brown with a characteristic usual translucentor opalescent hue.

Fig. 29.4:Fluorosis of teeth showing yellow

to brown discoloration of teeth

Fig. 29.5: Dark brown discoloration caused by fluorosis


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ofEndodontics

Figs 29.6A to C: (A) Amelogenesis imperfecta (hypoplastic, pitted);(B) Acquired enamel hypoplasia; (C) Amelogenesis imperfecta (snow-

capped)

Figs 29.7A to C: (A) Normal tooth; (B) Dentinogenesis

imperfecta; (C) Dentin dysplasia

Tetracycline and minocycline:Unsightly discoloration of bothdentition results from excessive intake of tetracycline andminocycline during the development of teeth. Chelation oftetracycline molecule with calcium in hydroxyapatite crystals

forms tetracycline orthophosphate which is responsible fordiscolored teeth.Classification of staining according to developmental stage,

banding and color (Jordun and Boksman 1984).1. First degree (mild)yellow to gray, uniformly spread

through the tooth. No banding.2. Seconddegree (moderate)yellow brown to dark gray, slight

banding, if present.3. Third degree (severe staining)blue gray or black and is

accompanied by significant banding across tooth.4. Fourth degreestains that are so dark that bleaching is

ineffective, totally.

Fig. 29.8:Discoloration of 21 due to pulp necrosis

Fig. 29.9:Loss of translucency of 11 due to pulp necrosis

Severity of pigmentation with tetracycline

depends on three factors

Time and duration of administration. Type of tetracycline administered. Dosage.

Posteruptive Causes

a. Pulpalchanges:Pulp necrosis usually results from bacterial,

mechanical or chemical irritation to pulp. In thisdisintegration products enter dentinal tubules and causediscoloration (Figs 29.8 and 29.9).

b. Trauma:Accidental injury to tooth can cause pulpal andenamel degenerative changes that may alter color of teeth(Fig. 29.10). Pulpal hemorrhage leads to grayishdiscoloration

and nonvital appearance. Injury causes hemorrhage whichresults in lysis of RBCs and liberation of iron sulphide whichenter dentinal tubules and discolor surrounding tooth.

c. Dentin hypercalcification:Dentin hypercalcificationresults when there are excessive irregular elements in thepulp chamber and canal walls. It causes decrease intranslucency and yellowish or yellow brown discolorationof the teeth.

d. Dental caries:In general, teeth present a discoloredappearance around areas of bacterial stagnation and leakingrestorations (Fig. 29.11).


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Fig. 29.10:Discolored 21 due to traumatic

injury followed by pulp necrosis

Fig. 29.11:Discolored appearance of teeth due to caries

e. Restorative materials and dental procedures:Discoloration can also result from the use of endodonticsealers and restorative materials.

f. Aging:Color changes in teeth with age result from surfaceand subsurface changes. Age related discoloration are

because of: Enamel changes:Both thinning and texture changes

occur in enamel. Dentin deposition: Secondary and tertiary dentin

deposits, pulp stones cause changes in the color of teeth(Fig. 29.12).

g. Functionaland parafunctional changes:Tooth wearmaygive a darker appearance to the teeth because of loss oftooth surface and exposure of dentin which is yellower andis susceptible to color changes by absorption of oral fluidsand deposition of reparative dentin (Fig. 29.13).

Fig. 29.12: Yellowish discoloration of teeth due

to secondary and tertiary dentin deposition

Fig. 29.13:Discoloration of teeth resulting

from tooth wear and aging

Extrinsic Stains

Daily Acquired Stains1. Plaque:Pellicle and plaque on tooth surface gives rise to

yellowish appearance of teeth.2. Foodandbeverages:Tea, coffee, red wine, curry and colas

if taken in excess cause discoloration.3. Tobacco use results in brown to black appearance of teeth.4. Poor oral hygiene manifests as:

Green stain Brown stain Orange stain

5. Swimmers calculus: It is yellow to dark brown stain present on facial and

lingual surfaces of anterior teeth. It occurs due toprolonged exposure to pool water.

6. Gingival hemorrhage.

Chemicals

1. Chlorhexidine stain:The stains produced by use ofchlorhexidine are yellowish brown to brownish in nature.

2. Metallic stains:These are caused by metals and metallicsalts introduced into oral cavity in metal containing dustinhaled by industry workers or through orally administereddrugs.


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ofEndodontics Stains caused by different metals

Copper dustGreen stain. Iron dustBrown stain. MercuryGreenish black stain. NickelGreen stain. SilverBlack stain.

Classification of extrinsic stains (Nathoo in 1997)

N1 type dental stain (Direct dental stain)Here coloredmaterials bind to the tooth surface to cause discoloration. Toothhas same color, as that of chromogen.

N2 type dental stain (direct dental stain)Here chromogenchanges color after binding to the tooth.

N3 type dental stain (Indirect dental stain)In this typeprechromogen (colorless) binds to the tooth and undergoes achemical reaction to cause a stain.

BLEACHING

Bleaching is a procedure which involves lightening of the colorof a tooth through the application of a chemicalagent to oxidizethe organic pigmentation in the tooth.

History of Tooth Bleaching

Bleaching of discolored, pulpless teeth was first described in1864 and a variety of medicaments such as chloride, sodiumhypochlorite, sodium perborate and hydrogen peroxide has beenused, alone or in combination, with or without heat activation.

The Walking Bleach technique was introduced in 1961,involvingplacement of a mixture of sodium perborate andwaterinto the pulp chamber. This technique was later modified andwater replaced by 30-50 percent hydrogen peroxide. Now, thepopular technique night guard vital bleaching technique

describes the use of 10 percent carbamide peroxide in mouth-guard to be worn overnight for lightening tooth color. Laterin 1996, Reyto done the tooth whitening by lasers.

CONTRAINDICATIONS FOR BLEACHING

Poor Case Selection

1. Patient having emotional or psychological problems is not

right choice for bleaching.2. In case selection, if clinician has opinion that bleaching is

not in patients best interest, he should decline doing that.

Dentin Hypersensitivity

Hypersensitive teeth need to provide extraprotection before

going for bleaching.

Extensively Restored Teeth

These teeth are not good candidate for bleaching because:1. They do not have enough enamel to respond properly to

bleaching.2. Teethheavily restored with visible, tooth coloredrestorations

are poor candidate as composite restorations do not lighten,infact they become more evident after bleaching.

Teeth with Hypoplastic Marks and Cracks

Application of bleaching agents increase the contrast between

white opaque spots and normal tooth structure:In these cases, bleaching can be done in conjunction with:

1. Microabrasion2. Selected ameloplasty3. Composite resin bonding.

Defective and Leaky Restoration

Defective and leaky restorations are not good candidate for

bleaching.1. Discoloration from metallic salts particularly silver

amalgam:The dentinal tubules of the tooth becomevirtually saturated with alloys and no amount of bleachingwith available products will significantly improve the shade.

2. Defective obturation:If root canal is not well obturated,then refilling must be done before attempting bleaching.

Contraindications of bleaching

1. Poor patient and case selectiona. Psychologically or emotionally compromised patient.

2. Dentin hypersensitivity.3. Extensively restored tooth.4. Teeth with hypoplastic marks and cracks.5. Defective and leaky restorations.

a. Discoloration from metallic salts particularly mercury.b. Defective obturation.

MEDICAMENTS USED AS BLEACHING AGENTS

An ideal bleaching agent should

Be easy to apply on the teeth. Have a neutral pH. Lighten the teeth efficiently.

Remain in contact with oral soft tissues for short periods. Be required in minimum quantity to achieve desired results. Not irritate or dehydrate the oral tissues. Not cause damage to the teeth. Be well controlled by the dentist to customize the treatment

to the patients need.

Tooth bleaching today is based upon hydrogen peroxideas an active agent. Hydrogen peroxide may be applied directlyor produced in a chemical reaction from sodium perborate orcarbamide peroxide. Hydrogen peroxide acts as a strongoxidizing agent through the formation of free radicals, reactive

oxygen molecules and hydrogen peroxide anions. These reactivemolecules attack the long chained, dark colored chromophoremolecules and split them into smaller, less colored and morediffusible molecules.

Carbamide peroxide also yields urea which is furtherdecomposed to CO2 and ammonia. It is the high pH of

ammonia which facilitates the bleaching procedure.This can be explained by the fact that in basic solution,

lower activation energy is required for formationof free radicalsfrom hydrogen peroxide and the reaction rate is higher, resultingin improved yield rate compared with an acidic environment.


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The outcome of bleaching procedure depends mainly on

the concentration of bleaching agents, the ability of the agentsto reach the chromophore molecules and the duration andnumber of times the agent is in contact with chromophoremolecules.

Constituents of bleaching gels

Carbamide peroxide. Hydrogen peroxide and sodium hydroxide (Li, 1998).

Sodium perborate. Thickening agent-carbopol or carboxy polymethylene. Urea. Surfactant and pigment dispersants. Preservatives. Vehicle-glycerine and dentifrice. Flavors. Fluoride and 3 percent potassium nitrate.

Carbamide Peroxide (CH6N2O3)

It is a bifunctional derivative of carbonic acid. It is available

as:

1. Home bleaching

a. 5 percent carbamide peroxide.

b. 10 percent carbamide peroxide.

c. 15 percent carbamide peroxide.

d. 20 percent carbamide peroxide.

2. In-officebleachinga. 35 percent solution or gel of carbamide peroxide.

Hydrogen Peroxide (H2O2)

H2O2breaks down to water and nascent oxygen. It also forms

free radicalperhydroxyl (HO2) which is responsible for bleachingaction.

Sodium Perborate

It comes as monohydrate, trihydrate or tetrahydrate. It contains

95 percent perborate, providing 10 percent available oxygen.

Thickening Agents

Carbopol (Carboxy polymethylene):Addition of carbopol in

bleaching gels results in:

1. Slow release of oxygen.

2. Increased viscosity of bleaching material, which furtherhelps

in longer retention of material in tray and need of lessmaterial.

3. Delayed effervescencethicker products stay on the teethfor longer time to provide necessary time for the carbamideperoxide to diffuse into the tooth.

4. The slow diffusion into enamel may also allow tooth tobe bleached more effectively.

Urea

It is added in bleaching solutions to: Stabilize the H2O2 Elevate the pH of solution.

Anticariogenic effects.

Surfactants

Surfactant acts as surface wetting agent which allows the

hydrogen peroxide to pass across gel tooth boundary.

Preservatives

Commonly used preservatives are phosphoric acids, citric acidor sodium stannate. They sequestrate metals such as Fe, Cu andMg which accelerate breakdown of H2O2and give gels better

durability and stability.

Vehicle

1. Glycerine:It is used to increase viscosity of preparation

and ease of manipulation.2. Dentifrice.

Flavors

They are added to improve patient acceptability.

Fluoride and 3 percent Potassium Nitrate

They are added to prevent sensitivity of teeth after bleaching.

Mechanism of bleaching

Mechanism of bleaching is mainly linked to degradation of highmolecular weight complex organic molecules that reflect a specific

wavelength of light that is responsible for colorof stain.The resultingdegradation products are of lower molecular weight and composedof less complex molecules that reflect less light, resulting in areduction or elimination of discoloration (Fig. 29.14).

Rate of color change is affected by

Frequency with which solutions are to be changed. Amount of time, the bleach is in contact with tooth. Viscosity of material.

Rate of oxygen release. Original shade and condition of the tooth. Location and depth of discoloration. Degradation rate of material.

Fig. 29.14:Mechanism of bleaching


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ofEndodontics Bleaching technique

1. For vital teetha. Home bleaching technique/Nightguard vital bleaching.b. In-office bleaching

i. Thermocatalyticii. Non-thermocatalyticiii. Microabrasion.

2. For nonvital teetha. Thermocatalytic in-office bleaching.

b. Walking bleach/Intracoronal bleachingc. Inside/outside bleachingd. Closed chamber bleaching/Extracoronal bleaching.

3. Laser assisted bleaching.

HOME BLEACHING TECHNIQUE/

NIGHTGUARD BLEACHING

Indications for Use

Mild generalized staining. Age related discolorations. Mild tetracycline staining.

Mild fluorosis. Acquired superficial staining. Stains from smoking tobacco. Color changes related to pulpal trauma or necrosis.

Contraindications

Teeth with insufficient enamel for bleaching. Teeth with deep and surface cracks and fracture lines. Teeth with inadequate or defective restorations. Discolorations in the adolescent patients with large pulp

chamber. Severe fluorosis and pitting hypoplasia.

Noncompliant patients. Pregnant or lactating patients. Teeth with large anterior restorations. Severe tetracycline staining. Fractured or malaligned teeth. Teeth exhibiting extreme sensitivity to heat, cold or sweets. Teeth with opaque white spots. Suspected or confirmed bulimia nervosa.

Advantages of Home Bleaching Technique

Simple method for patients to use.

Simple for dentists to monitor. Less chair time and cost-effective. Patient can bleach their teeth at their convenience.

Disadvantages of Home Bleaching Technique

Patient compliance is mandatory. Color change is dependent on amount of time the trays

are worn. Chances of abuse by using excessive amount of bleach for

too many hours per day.

Factors that Guard the Prognosisfor Home Bleaching

History or presence of sensitive teeth. Extremelydark gingival thirdof toothvisible duringsmiling. Extensive white spots. Translucent teeth. Excessive gingival recession and exposed root surfaces.

Commonly used solution for nightguard bleaching:

10 percent carbamide peroxide with or without carbopol. 15 percent carbamide peroxide Hydrogen peroxide (1-10%).

Steps of Tray Fabrication

Take the impression and make a stone model. Trim the model. Place the stock out resin and cure it. Apply separating media. Choose the tray sheet material. Nature of material used for fabrication of bleaching tray

is flexible plastic. Most common tray material used is ethyl

vinyl acetate. Cast the plastic in vacuum tray forming machines. Trim and polish the tray.

Checking the tray for correct fit, retention and over-extension.

Demonstrate the amount of bleachingmaterialto be placed.

Thickness of Tray

Standard thickness of tray is 0.035 inch. Thicker tray, i.e. 0.05 inch is indicated in patients with

breaking habit. Thinner tray, i.e. 0.02 inch thick is indicated in patients who

gag.

Treatment Regimen

When and how long to keep the trays in the mouth, dependson patients lifestyle preference and schedule. Wearing the trayduring day time allows replenishment of the gel after 1-2 hoursfor maximum concentration. Overnight use causes decrease inloss of material due to decreased salivary flow at night anddecreased occlusal pressure. Patient is recalled 1-2 weeks afterwearing the tray.

Maintenance After Tooth Bleaching

Additional rebleaching can be done every 3-4 years if necessary

with rebleaching duration of 1 week.

Side Effects of Home Bleaching

Gingival irritationPainful gums after a few daysof wearingtrays.

Soft tissue irritationFrom excessive wearing of the traysor applying too much bleach to the trays.

Altered taste sensationMetallic taste immediately afterremoving trays.

Tooth sensitivityMost common side effect.


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IN-OFFICE BLEACHING

THERMOCATALYTIC VITAL TOOTH BLEACHING

Equipment needed for in-office bleaching are: Power bleach material. Tissue protector. Energizing/activating source. Protective clothing and eye wear. Mechanical timer.

Light Sources Used for In-office Bleach

Various available light sources are:1. Conventional bleaching light.2. Tungsten halogen curing light.3. Xenon plasma arc light.4. Argon and CO2lasers.

5. Diode laser light.

Conventional Bleaching Light

Uses heat and light to activate bleaching material. More heat is generated during bleaching.

Causes tooth dehydration. Uncomfortable for patient. Slower in action.

Tungsten-Halogen Curing Light

Uses light and heat to activate bleaching solution Application of light 40-60 seconds per application per tooth Time consuming.

Xenon Plasma Arc Light

High intensity light, so more heat is liberated duringbleaching.

Application requires 3 seconds per tooth. Faster bleaching. Action is thermal and stimulates the catalyst in chemicals. Greater potential for thermal trauma to pulp and

surrounding soft tissues.

Argon and CO2Laser

True laser light stimulate the catalyst in chemical so thereis no thermal effect

Requires 10 seconds per application per tooth.

Diode Laser Light

True laser light produced from a solid state source

Ultra fast Requires 3-5 seconds to activate bleaching agent No heat is generated during bleaching.

Indications of In-office Bleaching

Superficial stains. Moderate to mild stains.

Contraindications of In-office Bleaching

Tetracycline stains. Extensive restorations

Severe discolorations. Extensive caries. Patient sensitive to bleaching agents.

Advantages of In-office Bleaching

Patient preference. Less time than overall time needed for home bleaching. Patient motivation. Protection of soft tissues.

Disadvantages of In-office Bleaching

More chair time. More expensive. Unpredictable and deterioration of color is quicker. More frequent and longer appointment. Dehydration of teeth. Serious safety considerations. Not much research to support its use. Discomfort of rubber dam.

Procedures (Fig. 29.15)

1. Pumice the teeth to clean off any debris present on thetooth surface.

2. Isolate the teeth with rubber dam.3. Saturate the cotton or gauze piece with bleaching

solution (30-35% H2O2) and place it on the teeth.

4. Depending upon light, expose the tooth/teeth.5. Change solution in between after every 4 to 5 minutes.6. Remove solution with the help of wet gauge.7. Repeat the procedure until desired shade is produced.8. Remove solution and irrigate teeth thoroughly with

warm water.9. Polish teeth and apply neutral sodium fluoride gel.

10. Instruct the patient toavoid coffee, tea, etc. for 2weeks.11. Second and third appointment is given after 3-6 weeks.

This will allow pulp to settle.

Fig. 29.15:Thermocatalytic technique

of bleaching for vital teeth


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1. Superoxol 5 parts H2O2:1 part ether 2. Clean teeth with rubber cup and prophylaxis paste.

2. McInnes solution a. 5 part H2O2 (30%) . pp y petro eum e y to t e t ssues an so ate t e area w tb.

c.

5 part HCl (36%)

1 part ether (0.2%) 4.

rubber dam.

Apply microabrasion compound to areas in 60 secondsTextbook

ofEndodontics

NON-THERMOCATALYTIC BLEACHING

In this technique, heat source is not used.

Commonly used solutions for bleaching

N am e C omp os i t ion

Yellow discoloration of teeth has been reported in somecases after treatment.

Protocol

1. Clinically evaluate the teeth.

3. Modified McInnes solution a. H2O2(30%)b. NaOH (20%)

Mix in equal parts, i.e. (1:1) along with either (0.2%)

Steps

Isolate the teeth using rubber dam. Apply bleaching agent on the teeth for five minutes. Wash the teeth with warm water and reapply the bleaching

agent until the desired color is achieved. Wash the teeth and polish them.

MICROABRASION

It is a procedure in which a microscopic layer of enamel is

simultaneously eroded and abraded with a special compound(usually contains 18% of hydrochloric acid) leaving a perfectlyintact enamel surface behind.

Indications

Developmental intrinsic stains and discolorations limited

to superficial enamel only. Enamel discolorations as a result of hypomineralization or

hypermineralization. Decalcification lesions from stasis of plaque and from

orthodontic bands. Areas of enamel fluorosis. Multicolored superficial stains and some irregular surface

texture.

Contraindications

Age related staining. Deep enamel hypoplastic lesions. Areas of deep enamel and dentin stains. Amelogenesis imperfecta and dentinogenesis imperfecta

cases.

Tetracycline staining. Carious lesions underlying regions of decalcification.

Advantages

Minimum discomfort to patient. Can be easily done in less time by operator. Useful in removing superficial stains. The surface of treated tooth is shiny and smooth in nature.

Disadvantages

Not effective for deeper stains. Removes enamel layer.

intervals with appropriate rinsing.5. Repeat the procedure if necessary. Check the teeth when

wet.6. Rinse teeth for 30 seconds and dry.7. Apply topical fluoride to the teeth for four minutes.8. Re-evaluate the color of the teeth. More than one visit may

be necessary sometimes.

BLEACHING OF NONVITAL TEETH

THERMOCATALYTIC TECHNIQUE OF

BLEACHING FOR NONVITAL TEETH1. Isolate the tooth to be bleached using rubber dam2. Place bleaching agent (superoxol and sodium perborate

separately or in combination) in the tooth chamber.3. Heat thebleachingsolutionusing bleachingstick/light curing

unit.4. Repeat the procedure till the desired tooth color is achieved.5. Wash the tooth with water and seal the chamber using dry

cotton and temporary restorations.6. Recall the patient after 1-3 weeks.7. Do the permanent restoration of tooth using suitable

composite resins afterwards.

INTRACORONAL BLEACHING/WALKING

BLEACH OF NONVITAL TEETH

It involves use of chemical agents within the coronal portionof an endodontically treated tooth to remove tooth dis-coloration.

Indications of Intracoronal Bleaching

Discoloration of pulp chamber origin (Figs 29.16A and B). Moderate to severe tetracycline staining. Dentin discoloration.

Discoloration not agreeable to extracoronal bleaching.

Contraindications of Intracoronal Bleaching

Superficial enamel discoloration. Defective enamel formation. Presence of caries. Unpredictable prognosis of tooth.

Steps

1. Take the radiographs to assess the quality of obtura-tion. If found unsatisfactory, retreatment should bedone.


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Figs 29.16A and B:(A) Preoperative and (B) Postoperative photograph

of nonvital bleaching of maxillary right central incisor (11)

2. Evaluate the quality and shade of restoration if present.If restoration is defective, replace it.

3. Evaluate tooth color with shade guide.4. Isolate the tooth with rubber dam.5. Prepare the access cavity, remove the coronal gutta-

percha, expose the dentin and refine the cavity(Fig. 29.17).

6. Place mechanical barriers of 2 mm thick, preferably ofglass ionomer cement, zinc phosphate, IRM, poly-carboxylate cement on root canal filling material

(Fig. 29.18). The coronal height of barrier should protectthe dentinal tubules and conform to the externalepithelial attachment.

7. Now mix sodium perborate with an inert liquid (localanesthetic, saline or water) and place this paste into pulpchamber (Fig. 29.19).

8. After removing the excess bleaching paste, place atemporary restoration over it.

9. Recall the patient after 1-2 weeks, repeat the treatmentuntil desired shade is achieved.

10. Restore access cavity with composite after 2 weeks.

Fig. 29.17:Removal of coronal gutta-percha

using rotary instrument

Fig. 29.18:Placement of protective barrier over

gutta-percha

Fig. 29.19:Placement of bleaching mixture into pulp chamber and

sealing of cavity using temporary restoration


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ofEndodontics

Complications of Intracoronal Bleaching

External root resorption. Chemical burns if using 30-35 percent H

2O

2.

Decrease bond strength of composite.

Precautions to be Taken forSafer Nonvital Bleaching

1. Isolate tooth effectively.

2. Protect oral mucosa.3. Verify adequate endodontic obturation.4. Use protective barriers.5. Avoid acid etching.6. Avoid strong oxidizers.7. Avoid heat.8. Recall periodically.

INSIDE/OUTSIDE BLEACHING TECHNIQUE

Synonyms

Internal/External Bleaching, Modified

Walking Bleach Technique

This technique involves intracoronal bleaching technique alongwith home bleaching technique. This is done to make thebleaching program more effective. This combination ofbleaching treatment is helpful in treating difficult stains, forspecific problems like single dark vital or nonvital tooth andto treat stains of different origin present on the same tooth.

Procedures

1. Assess the obturation by taking radiographs.2. Isolate the tooth and prepare the access cavity by removing

gutta-percha 2-3 mm below the cementoenamel junction.3. Place the mechanical barrier, clean the access cavity and place

a cotton pellet in the chamber to avoid food packing into it.4. Evaluate the shade of tooth.5. Check the fitting of bleaching tray and advise the patient

to remove the cotton pellet before bleaching.6. Instructions for home bleaching. Bleaching syringe can be

directly placed into chamber before seating the tray orextrableaching material can be placed into the tray spacecorresponding to tooth with open chamber (Fig. 29.20).

7. After bleaching, tooth is irrigated with water, cleaned andagain a cotton pellet is placed in the empty space.

8. Re-assessment of shade is done after 4-7 days.9. When the desired shade is achieved, seal the access cavityinitially with temporary restoration and finally withcomposite restoration after atleast two weeks.

Advantages

More surface area for bleach to penetrate. Treatment time in days rather than weeks. Decreases the incidence of cervical resorption. Uses lower concentration of carbamide peroxide.

Fig. 29.20:Inside/outside techniques in this tray is sealed over an open

internal accessopening, with a cottonpellet placed in open access cavity

Disadvantages

Noncompliant patients. Over-bleaching by overzealous application.

Chances for cervical resorption is reduced but still exists.

CLOSED CHAMBER BLEACHING/

EXTRACORONAL BLEACHING

In this technique, instead of removing the existing restoration,

the bleaching paste is applied to the tooth via bleaching tray.

Indications of closed chamber technique

In case of totally calcified canals in a traumatized tooth. As a maintenance bleaching treatment several years after initial

intracoronal bleaching.

Treatment for adolescents with incomplete gingival maturation.

A single dark nonvital tooth where the surrounding teeth aresufficiently light or where other vital teeth arealso to be bleached.

LASER ASSISTED BLEACHING TECHNIQUE

This technique achieves power bleaching process with the helpof efficient energy source with minimum side effects. Laserwhitening gel contains thermally absorbed crystals, fumed silicaand 35 percent H2O2. In this, gel is applied and is activatedby light source which in further activates the crystals presentin gel, allowing dissociation of oxygen and therefore betterpenetration into enamel matrix. Following LASER have beenapproved by FDA for tooth bleaching:

1. Argon laser.2. CO2 laser.

3. GaAlAs diode laser.

Argon Laser

Emits wavelength of 480 nm in visible part of spectrum. Activates the bleaching gel and makes the darker tooth

surface lighter. Less thermal effects on pulp as compared to other heat

lamps.


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Textbook

ofEndodontics Effects of bleaching agents on tooth

and its supporting structures

Tooth sensitivity. Alteration of enamel surface. Effects on dentin. Effects of bleaching on pulp. Effects on cementum. Effects on restorative materials. Mucosal irritation.

Genotoxicity and carcinogenicity. Toxicity.

Bleaching is safe, economical, conservative and effectivemethod of decoloring the stained teeth due to various reasons.

It should always be given a thought before going for moreinvasive procedure like veneering or full ceramic coverage,depending upon specific case.

QUESTIONS

Q. What are different etiological factors responsible for

discoloration of teeth.

Q. Define bleaching. Explain the mechanism of

bleaching and classify different bleaching procedures.

Q. How will you bleach a nonvital central incisor tooth?

Q. Write short notes on:

a. Contraindication of bleachingb. Nightguard vital bleaching techniquec. Walking bleachd. In-office bleache. Effects of bleaching on teeth

BIBLIOGRAPHY

1. Abou-Rass M. The elimination of tetracycline discoloration byintentional endodontics and internal bleaching. J Endod

1982;8:101.2. AT Hara, LAF Pimenta. Nonvital tooth bleaching: A 2 years

case report. Quintessence Int, 1999;30:748-54.3. CHegedus, et al.An atomic forcemicroscopy studyon the effect

of bleaching agent on the enamel surface. J Dent 1999;27:509-

15.

4. Croll TB. Enamel microabrasion: the technique. Quint Int1989;20:395-400.

5. Croll TP, Cavanaugh RR. Enamel colormodification by controlledhydrochloric acid-pumice abrasion-Part I: Technique andexamples. Quintessence Int 1986;17:81.

6. Curtis WJ, Dickinson GL, Downey MC, Russel CM, HaywoodVB, Myers Ml, Johnson MIL. Assessingthe effects of 10 percentcarbamide peroxide on oral soft tissues. J Am Dent Assoc1996;12:1218-223.

7. Dean HT. Chronic endemic dental fluorosis. J Am Med Assoc

1932;107:1269.8. DederichDN,BushickRD. Lasers in dentistry. J Am DentAssoc

2004;135:204-12.9. Haywood Van B. History safety and effectiveness of current

bleaching techniques and applications of the nightguard vitalbleaching technique. Quintessence Int 1992;23:471-88.

10. Haywood VB, Heymann HO. Nigthguard vital bleaching: Howsafe is it? Quintessence Int 1991;22:515-23.

11. Jorgensen MG, Carroll WB. Incidence of tooth sensitivity afterhome whitening treatment. J Am Dent Assoc 2002;133:1076-82.

12. Laser assisted bleaching: An update. JADA 1998;129:1484-87.13. Leonard Settembrim, et al. A technique for bleaching nonvital

teeth. JADA 1997;1283-85.

14. Mokhils GR, Matis BA, Cochran MA, Eckert GJ. A clinicalevaluation of carbamide peroxide and hydrogen peroxide

whitening agents during daytime use. J Am Dent Assoc 2000;31:1269-77.

15. Nageswar Rao R, Nangrani V. Estimation of dissolution ofcalcium by Old McInnes and New Mcinnes solution.Endodontology 1998;50-53.

16. Nathanson D. Vital tooth bleaching: Sensitivity and pulpalconsiderations. J Am Dent Assoc 1997;1281:41-44.

17. New man SM, Bottone PW. Tray-forming technique for dentist-supervised home bleaching. Quintessence Int 1995;26:447-53.

18. Reinhardt JW, Eivins SE, Swift EJ, Denchy GE. A clinical studyof nigthguard vital bleaching. Quintessence Int 1993;25:379-84.

19. Ronald E Goldstein. Bleaching teeth: New materials-new role.JADA 1987;43-52.

20. Tredwin CJ, Scully C,Bagan-Sebastian JV. Drug induced disordersof teeth. J Dent Res 2005;84(7):596-602.

21. Van B Harywood. Historical development of Whiteners: Clinicalsafety and efficacy. Dental update, 1997 April.

22. Watts A, Addy M. Tooth discolouration and staining: A literaturereview. Br Dent J 2001;190:309-16.


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