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Bleaching of discoloured tooth ppt


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Bleaching of discoloured tooth ppt

  2. 2. Topic under the Project: Introduction- Normal Tooth Colour Discolouration of Tooth & Causes Types of Tooth Discolouration Different Treatments of Tooth Discolouration Introduction Of Bleaching Indication & Contraindication of Bleaching Brief History of Bleaching Ideal Properties Bleaching Materials Different Bleaching Agents Legal Values & Ethical Consideration Of Bleaching Classification of Bleaching Procedure  Vital Tooth Bleaching- Steps, Technique, Complication Non-vital Tooth Bleaching- Steps, Technique, Complication Conclusion References
  3. 3. Human teeth are polychromatic in nature. Normal colour of primary teeth is bluish white. The colour of permanent teeth is grayish- yellow, grayish-white, yellowish-white. The colour of teeth is determined by the translucency and thickness of the underlying dentin, and the colour of the pulp. Tooth colour also varies in different clinical position (incisal/occlusal 3rd , middle 3rd ,cervical 3rd ), from one group of teeth to the next, and from person to person. Factors Modifying Tooth Colour : a) Colour of enamel covering the crown. b) Translucency of enamel. c) Thickness of the enamel at different level. d) Age of the tooth. e) Parafunctional habit of the patient.
  4. 4. Classification of Tooth Discolouration : Tooth discolouration varies with etiology, appearance, localization, severity and adherence to the tooth structure. It can be broadly classified as, 1)Extrinsic discolouration 2)Intrinsic discolouration 3)Combination of both
  5. 5. Extrinsic discolouration The stains deposited on the tooth surface are a result of attractive forces which are long range interactions such as van der Walls and electrostatic forces and short range interactions such as hydratin forces, hydrophobic interactions, and hydrogen bonds. Due to amalgam restoration Due to tobacco smoking
  6. 6. : causes & colours Extrinsic Factors Characteristics Chromogenic bacteria stains Green, black-brown & orange Tobacco Black, brown Amalgam Black, grey Medicaments Silver-nitrate : Grey black Stannous-fluoride : Black brown Chlorhexidine : Black brown Food & Beverages Coffee, tea, wine etc.; colour of food items Iron Black cervical discolouration Classification Based on Chemistry of Staining put forth by Nathoo [1997] : a) N1 Type or Direct Dental Stain: The coloured materials (chromogens) bind to the tooth surface & cause discolouration. The colour of the dental stain is same as the colour of the chromogens. b) N2 Type or Direct Dental Stain: The chromogens change colour after binding to the tooth. This is actually N1 type of food stain darkens with time. c) N3 type or Indirect Dental Stain: Colourless materials or a prechromogen binds to the tooth & undergoes chemical reaction to cause a stain.
  7. 7. Intrinsic Discolouration  Aetiology of Intrinsic Tooth Discolouration-  Within Enamel : Local – caries, idiopathic, injury/infection of primary Pre-decessor, internal resorption. Systemic – amelogenesis imperfecta, drugs e.g. Tetracycline, fluorosis, idiopathic, systemic illness during tooth formation.
  8. 8.  Within Dentin : Local – caries, internal resorption, metallic restorative material, necrotic Pulp tissue, root canal filling materials. Systemic – bilirubin (haemolytic disease of a newborn), Congenital porphyria, dentinogenesis imperfect, drugs e.g. Tetracycline. (causes & colours) Intrinsic Factor Colours Dentinogenesis Imperfecta Yellow or grey-brown Amelogenesis Imperfecta Yellow-brown Dental Fluorosis Opaque white yellow- brown patch Sulphur Drugs Black staining Tetracycline Grey-brown to yellow-brown Ochronosis Brown Hyperbilirubinemia Yellow-green to blue brown & grey Erythropoetic porphyria Red or brown
  9. 9. Treatment Option Indication Advantages Disadvantages No Treatment Patient with poor oral hygiene/caries/la rge anterior restoration/crow ns Non invasive, no cost Will not address patients aesthetic concern Removal of surface stain -scaling & polishing -micro abrasion -Extrinsic staining -Fluorosis/white spot demineralisation/ enamel hypoplasia Non/minimally invasive May not improve aesthetics significantly. Technique sensitive Micro abrasion causing soft tissue irritation Bleaching -Home bleaching -walking bleaching Described in details later Non/minimally invasive Cost, limitation on shade improvement, compliance Restorative Treatment Severely discoloured tooth. e.g. tetracycline staining/ anaesthetic tooth morphology May achieve a more aesthetic result Destructive, irreversible, cost, oral hygiene compliance, maintenance
  10. 10. Ideal Properties of A Bleaching Material :  It should have neutral pH.  It should be easy to apply, maximum patient compliance.  It should not irritate or dehydrate oral tissue.  It should not cause any harm to the tooth being bleached.  It should adhere to the tooth structure i.e., controllable flow.  It should have contrasting colour with the oral structure.  It should have adjustable peroxide concentration.  It should give desired result within short time.  Be well controlled by the dentist to customize to the patient’s need.
  11. 11. HAYWOOD YEAR AUTHOR INNOVATION 1799 Macintosh Chloride of Lime is invented- called Bleaching Powder 1884 Harian 1st used Hydrogen Peroxide. 1958 Pearson Used 35%HP inside tooth & suggested 25% HP with heated lamp. 1961 Spasser Perborate sealed within tooth – ‘Walking Bleach’ 1965 Stewart Thermocatalytic Technique- pellet saturated with superoxyl & heated with an instrument inside pulp chamber. 1987 Feinmann In office bleaching using 30% H2O2 & heat from bleaching light. 1989 Croll Micro abrasion Technique 1989 Haywood & Hayman 10% CP used in trays overnight – ‘Night-guard Vital Bleaching’ 1996 Rayto Laser Tooth Whitening 1997 Settembrini et al. Inside-Outside bleaching technique. 1998 Carillo et al. Open pulp chamber with CP inside. 1990 Numerous authors Bleaching materials were investigated & the FDA called for safety studies. 1991 Numerous authors Power Bleaching using 30% HP & light activation.
  12. 12. Bleaching Agents : Sodium Dioxide -  Historical Interest – limited use.  When sodium dioxide combines with water, the reaction yields sodium hydroxide & oxygen. Na2O2 +H2O = 2NaOH +1/2H2O  The molecular oxygen produced is a powerful antiseptic & bleaching agent.  When used in high concentrations on pulp less teeth, it has a strong caustic effects that render it dangerous for the periodontium. Chloride & Chloride Derivative -  Chlorine acts indirectly as it is capable of releasing the oxygen from a water molecule. Cl2 + H2o = 2HCl + 1/2O2 Hydrogen Peroxide -  It is the main bleaching agent used for tooth whitening, produced by the following reaction. H2O +1/2O2 =H2O  The resulting molecule is unstable & ready to split & release a molecule of oxygen.  The concentration of H2O2 solutions are usually given in percentage or in volumes that indicate the quantity of oxygen released as a result of the breakdown reaction.
  13. 13.  Because molecular dissociation occurs differently depending on the pH, the efficacy of H2O2 can be improved by modifying the pH of the solution.  In an alkaline solution, the hydroxyl groups neutralises the protons & accelerate the bleaching process.  The consumption of an element produced by the oxidation- reduction reaction will modify the balance, leading to the yielding of highly reactive OH2-, a molecule with a low molecular weight, far more oxidative than molecular oxygen. And which diffuses easily through the enamel barrier. Sodium Perborate (BO3Na4H2O) -  It’s a fine white powder, which is antiseptic & chemically stable when anhydrous.  When combined with water, it reacts to produce metaborate & molecular oxygen. Na2[B2(O2)2(OH)4] +2H2O =2NaBO3 = 2H2O BO3Na + H2O =1/2O2 +H2O  Metal peroxides, persulphates, calcium perborate & magnesium perborate (acting as anion breakdown activators) may also yield molecular oxygen, & are used by some in preference to sodium perborate.  The final product is an oxidizing molecule produced by the breakdown of the hydrogen peroxide. Carbamide Peroxide -  It is also known as Urea-Hydrogen Peroxide.  Approved by FDA as an oral antiseptic in 1979 & as a medicament in 1991.  It is most widely used vital tooth bleaching product.
  14. 14.  Obtained by the syncrystallisation of H2O2 & urea into colourless & odourless crystals.  Its chemical formula contains about 30% hydrogen peroxide. In other words, a 10% carbamide peroxide solution breaks down into 3% H2O2. H2N-CO-NH2*H2O2 =H2NCONH2 = H2O2  Carbamide peroxide yields urea that further decomposes into CO2 & ammonia.  A high pH facilitates the bleaching process , i.e., in alkaline solution , the formation of free radicals requires less energy, & the reaction yield is higher, with larger quantities of H2O2 being produced than in an acidic solution.  Improve the efficacy of tooth bleaching products.  Not always clearly mentioned by the manufacturers.  Thickeners such as carbopol (acrylic acid polymer resin) which helps to maintain contact between the gel & dental tissue as long as possible & thus allows a progressive release of the oxidising agents.  Urea, which stabilises the hydrogen peroxide, increases solution pH, & has an anti-cariogenic effect.  Glycerine, which increases the viscosity of the preparation & facilitates its manipulation. The only problem is the tooth dehydration it incures.  Stabilisers (e.g., Citroxain, citric acid, phosphoric acid), which increase the shelf life of bleaching products.  Flavouring agents, which make the product pleasanter to use.
  15. 15. Different Commercially Available Bleaching Agents : General Mode of Action of Bleaching Agent : Mode of action-1
  16. 16. Mode of Action -2
  17. 17. Mode of action - 3
  18. 18. Factors Affecting Bleaching :  Surface cleanliness: Clean enamel surface is important to distinguish between intrinsic & extrinsic stains. Moreover the debris on the surface minimizes the contact of the bleaching agent with the tooth surface.  Concentration of peroxide: The effect of the bleaching is increased with the increased concentration of peroxide. In office bleaching employs 35% hydrogen peroxide which is more caustic in nature. The usual concentration of at home bleaching is 10% carbamide peroxide, which is relatively safe in contact with the soft tissue.  Shelf life: Carbamide per oxide is more stable than hydrogen peroxide & has a shelf life of 1-2 years, while hydrogen peroxide has a shelf life of few weeks.  Temperature: This is of important during in office bleaching. Increase in temperature accelerates the release of oxygen free radicals. The reaction gets doubled with an increase of 10 degree centigrade. However increase in temperature to an uncomfortable level causes tooth sensitivity & irreversible pulpal damage. Local anaesthesia should not be administered during bleaching.  PH: Hydrogen peroxide is active in alkaline pH. The optimum pH for hydrogen peroxide ranges from 9.5 to 10.8.  Time: Concentration of the bleaching agent & the time of contact with the tooth are the most important factors in effective bleaching. Increased contact time increases the bleaching efficacy. However, prolonged contact results in tooth sensitivity.  Sealed environment: This is of relevance in non-vital tooth bleaching. Hydrogen peroxide sealed in the access cavity maintains the required concentration for active bleaching.  Additives: In order to increase the viscosity of the bleaching materials, additives like glycerine, glycol & tooth paste like materials are added. These agents may reduce the efficacy of the bleaching materials.  Other factors: like age of the patient, initial colour of the tooth & gender may also play a vital role in bleaching process.
  19. 19. Vital Tooth Bleaching Indication:  Moderate tooth discolouration –healthy tooth with perfectly sealed coronal fillings (perfectly composite resin fillings), & teeth with no significant structural defect.  Discolouration related genetic disorders.  Permanent acquired discolouration – fluorosis staining, with stains ranging from simple, white, opaque spots to a darker discoloration, or other type of staining caused by excessive intake of fluoride.  Discolouration related to the physiological ageing of teeth.  Post-traumatic discolouration (vital tooth with sclerotic dentin). Relative Indication:  Improvement of the teeth’s natural colour before the placement of a prosthetic restoration in the adjacent area. Relative Contraindication:  Very pronounced tooth stains with dull & saturated coloration, where colour bands are visible, and treatment in this case 9is a prosthetic alternative, i.e.; the application on the affected teeth of a thin layer of covering material (veneer).  Tooth bleaching will be used here primarily to lighten the underlying tooth colour, thus limiting tissue destruction & improving the overall appearance of the restorations.  Teeth with extensive crown filling.  Presence of cervical lesions due to wear, &dentin “islands” caused by occlusal attrition.  Stains mainly due to permeation by metal salts (amalgam).  Relative contraindications specific to the night –guard technique ;  Advanced periodontal disease  Multiple & extensive amalgam restoration or temporary fillings.  Articulation disorders.
  20. 20. Absolute Contraindication:  Young patient aged under 15-16(immature tissues & large pulp volume)  Teeth that shows initial hypersensitivity during the presurgical clinical examination.  Teeth with non leak-proof filling, &initial or recurring caries. It is an absolute prerequisite to any bleaching treatment that carious lesions be fully treated & that all restorations fit perfectly.  Smoking (possible interactions with peroxides) Vital Tooth Bleaching Technique
  21. 21. At Home Bleaching It is the more commonly used technique because it is easy to perform & is usually less expensive for the patient. It uses a custom fit tray with 10% carbamide peroxide. Carbamide peroxide is more stable than hydrogen peroxide & can be active up to several hours. Indication Contraindication Superficial enamel discolouration Severe enamel loss Mild yellow discolouration Hypersensitive tooth Brown fluorosis discolouration Bruxism Age related discolouration Presence of caries & Defective coronal restoration Stages:  Dental & Medical History  Clinical Examination  Radiographs of Tooth to Be Treated  Impression of the dental arches for the construction of Bleaching Tray  Recall visit to assess the progress & compliance Tray Fabrication:  Alginate impressions of the arches are made.  Plaster casts are poured.  Reservoirs are made that deliver the bleaching agent, at a distance of 1 mm from the gingiva. The light-cured resin spacers should be 0.5 mm to 2 mm thick, depending on the technique that will be used & above all, on the concentration of the product & the intensity of the stain.
  22. 22.  Thermo forming a polyvinyl sheet over these models.  Trimming the tray along the gingival line using scissors once the tray has cooled down- or better still, directly on the model using a scalpel with an 11 mm blade.  Smoothing the edges with a micro torch.  Cleaning & cold sterilisation of the mouth guard before delivery. Fitting of the Mouthguard & Choice of Bleaching Product:  The mouth guard should fit the patient’s mouth perfectly.  The tray should be in close contact only with the hard tissues; as this prevents leakage of the bleaching product in the area of the gingiva, & encourages an in-depth action of lower-concentration bleaching agents.  The mouth guard should have a constricting effect in the critical area of the neck of the tooth.  The operator should choose the bleaching product & its concentration according to the case, & determine the length of time during which the mouthguard should be worn  The active compound is carbamide peroxide, which breaks down into urea & H2O2. It usually comes as a gel in a syringe, with concentration ranging from 10% to 35%. It may be combined with thickeners (such as Carbapol) that slow down the degradation process of the Carbamide Peroxide, & with sodium fluoride that prevents dental sensitivity.
  23. 23. Steps: 1. Discoloured Teeth 2. Alginate impression Taken 3. Preparation of a Bleaching Tray on the Cast 4.Proper Shaping of the Tray 5. Prepared Bleaching Tray 6. Applying Bleaching Agent on The Tray 7. Applying the Bleaching Agent in the Mouth 8. Bleached Teeth
  24. 24. Instruction to the Patient:  After through tooth brushing, the patient should use the needle-tipped syringe to fill the reservoirs with moderate quantities of gel.  Then place the tray inside the mouth & finally rinse off any gel that may have leaked onto the gingiva.  The dentist will determine the length of time the mouthguard should be worn according to the product used.  Wearing time will last between three to five hours in one or two sessions every day, depending on the patient’s availability & motivation, on dental sensitivity observed during treatment, & on the results aimed at.  Nightguard systems with concentration ranging from 10% to 16% are highly effective, owing to the fact that the salivary flow is reduced at night & that the bleaching agent & the tooth therefore stay in contact much longer.  After removal, the mouthguard should be washed in cold water & the teeth cleaned thoroughly. Monitoring:  The practitioner should check results every five to six days, in order to adapt the treatment to change in tooth-shade & to clinical signs. To facilitate the monitoring of the process both by the practitioner & by the patient, & for psychological reasons. It is recommended to bleach 1st the upper & then the lower arch. Outcome:  The outcome depends on - A) The length of time during which the treatment mouthguard is worn. B) The duration of the treatment. C) Concentration of & sensitivity to the product. D) On the intensity of the staining.
  25. 25.  In case of light staining, teeth are lightened up to 80% in 5-6 days.  In case of severe staining (tetracycline), tooth shade may be improved to a more or less important extent in the first month of treatment, particularly in the occlusal third, by increasing the duration o0f the treatment. In such cases, the at home treatment may be continued over many weeks, sometimes even for months. In-office Bleaching Used for more severe & patients who are “in a hurry” – Baumgartner et al. 1983. History :  Torres-Zaragoza (1984) : 70% H2O2 be used in associated with a reagent, & a source of heat.  Goldstein (1976), Goldstein & Garber (1995): 35% H2O2 exposed to a beam of light with an adjustable temperature of 45 to 60 degree centigrade.  Baratieri et al. (1995: employed 35% H2O2 activated by the light of curing lamp.  Indication :  Dissatisfaction of tooth colour as a result of mild fluorosis, & tetracycline stains.  In severe discolouration, bleaching could be performed to lighten the tooth colour before restoration with bonded resin or porcelain veneers or crowns.  In order to match the existing colour of the crown that is lighter than the natural teeth.
  26. 26.  Contraindication :  Superficial stains that can be removed with rubber cap & prophylaxis paste.  Carious tooth structure or dark coloured resin restoration.  Hypersensitive teeth.  Children with large pulp chamber.  Pregnant & lactating woman.  Exposed root surface.   Procedure : Take a radiograph to detect the presence of caries, defective restorations, & proximity to pulp horns. Well –sealed small restorations & minimal amounts of exposed incisal dentin are not usually a contraindication for bleaching. Evaluate the tooth colour with a shade guide & take clinical photographs before & throughout the procedure. Protect the gingival tissues with Orabase or Vaseline & isolate the teeth with a rubber dam. Do not inject a local anaesthetic. Place protective sunglasses over the patient’s & the operator’s eyes. Clean the enamel surface with pumice & water. Apply 30-35% hydrogen peroxide liquid on the labial surface of the teeth using a small cotton pellet or a piece of gauze. A bleaching gel containing hydrogen peroxide may be used instead of the aqueous solution. Apply heat with a heating device or a light source. The temperature should be maintained between 125 & 140 degree F (52-60 degree C). The treatment time should not exceed 30 minutes even if the result is not satisfactory. Re move the heat source & allow the teeth to cool down for at least 5 minutes. Pumice is used on the teeth to remove residual exposed gel from enamel surface.
  27. 27. Remove the bleaching agent & irrigate thoroughly. Dry the teeth & gently polish them with a composite resin polishing cup. Apply neutral sodium fluoride gel for 3-5 minutes. Instruct the patient to use to use a fluoride rinse daily for 2 weeks. Any bounded restoration on bleached surfaces must be postponed by 7-10 days. Light Sources Used for In-office Bleach: Conventional Bleaching Light  Uses heat & light to activate bleaching materials.  More heat is generated during bleaching.  Causes tooth dehydration.  Uncomfortable for the patient.  Slower in action. Tungsten Halogen Curing Light  Uses light & heat to activate bleaching solution.
  28. 28.  Application of light 40 to 60 seconds per application per tooth.  Time consuming Xenon Plasma Arc Light  High intensity light, so more heat is liberated during bleaching.  Application requires 3 seconds per tooth.  Faster bleaching.  Action is thermal & stimulates the catalyst in chemicals.  Greater potential for thermal trauma to pulp & surrounding soft tissues. Argon & CO2 Laser  True laser light stimulates the catalyst in chemical so there is no thermal effect.  Requires 10 seconds per application per tooth. Diode Laser Light  The laser light produced from a solid state source.  Ultrafast.  Requires 3 to 5 seconds to activate bleaching agent.  No heat is generated during bleaching. Advantage:  Patient preference.  Less time than overall time needed for home bleaching.  Patient motivation.  Protection of soft tissue. Disadvantage:  More chair time.
  29. 29.  More expensive.  Unpredictable & deterioration of colour is quicker.  Dehydration of teeth.  Serious safety consideration.  Not much research to support its use.  Discomfort of rubber dam. Complications of Vital Tooth Bleaching:  Tooth sensitivity  Enamel damage  Gingival irritation  Mercury release from amalgam restoration Non-vital Tooth Bleaching Indications:  Any discolouration secondary to ; - a loss of pulp vitality, & more particularly to a pulp haemorrhage or to the decomposition of residual pulp tissues that were not removed during root canal therapy (pulp horns) - The use of medication, or the placement of root canal filling materials or non-leak-proof restoration materials.  Blackish coloration of the root, which is visible under a thin gingiva. The bleaching treatment will have to reach deep into the root.
  30. 30. Relative Contraindication:  Stains incurred by root canal filling pastes (phenolic resins, radiopacifiers) or metal salts (amalgam), for which treatment prognosis is guarded.  Teeth with extensive crown restorations. Absolute Contraindication: Permanent teeth in children & young adolescents. Teeth that have undergone a periodontal treatment & root planning procedure. Traumatised teeth (luxation, avulsion, intrusion) Teeth that shows external root resorption. Non-vital Tooth Bleaching Technique Rely on the permeability of the dentin, which allows the oxidising agent to reach the pigments directly, the latter being concentrated mostly at the dentin-enamel-junction. Prognosis is usually extremely good when case selection is correct.
  31. 31. Preliminary Steps : 1 ) Thorough clinical examination of the tooth & sarrounding supporting tissues. 2 ) X-rays are assess the quality of the endodontic treatment & to visualise any root &/or periodontal defects. 3 ) Photographs are taken to keep record of the state of the tooth prior to treatment. 4 ) Conscent- to guarantee the all legal & ethical obligations are met, the practitioners give the patient a precise quote for the bleaching treatment, as well all the usual recommendations & any other relevant information. Initial Tooth Preperation : The first phase of the treatment will focus on the protection of the oral tissues & the preparation of the of the tooth.
  32. 32. The Walking Bleach Technique Indication Contraindication Discolouration of the pulp chamber Superficial enamel discolouration Dentin discolouration Defective enamel formation Discolouration not amenable to extra coronal bleaching Severe dentin loss Presence of caries Methods:  It uses a paste of sodium perborate & distilled water or hydrogen peroxide in a 100 to 130 volume solution.  Paste is placed in the pulp chamber & covered with cotton pellet & sealed with a leak –proof dressing such as Cavit or IRM.  Seal the access cavity to a thickness of 3 mm using an adhesive material. This ensues a tight seal around the margins & prevents the leaching of bleaching materials  The paste is left in place for -  3-6 days if the sodium perborate is mixed with H2O2.  Twenty days if it is mixed with distilled water.  Commercially available preparations such as Superoxol (30% aqueous H2O2 solution) or carbamide peroxide may be used, but gels tend to spread & to weaken the seal formed by the temporary dressing.  The combination of sodium perborate & H2O2 achieves rapid & excellent results, but the technique is contraindicated as it may cause external cervical resorption.
  33. 33.  The mixture of sodium perborate & distilled water is safe & risk- free, but less rapid, & results are generally satisfactory, although the bleaching procedure often needs to be prepared 2 to 3 times before an acceptable shade is achieved.  The final restoration phase is important when composite materials are involved, as the quality of the bonding will greatly determine the longevity of the result.  When products with high concentration of H2O2 are used, the residual oxygen that remains after the procedure is finished momentarily inhibits the polymerisation of the composite resin. The final restoration should therefore be placed 1 week after the full completion of the bleaching treatment. In-office Bleaching It is “Chair-side” or Power” bleaching, uses an activators such as heat, light or more recently, a laser beam. Activators Thermo catalytic Technique Ultraviolet photo- oxidation Laser beam -Cotton pellets saturated with 100 or 130 volume H2O2 & placed in the pulp chamber, where the oxidation reaction is then activated by heat. - The tip of the heat- producing instrument is placed directly onto the saturated cotton pellet, resulting in immediate gas evolution. -The instrument shouldn’t touch the -It applies ultraviolet light to the labial surface of the tooth to be bleached. -A 30 to 35% hydrogen peroxide solution is placed in the pulp chamber on a cotton pellet following by a 2 minute exposure to uv light. -Supposedly, this causes oxygen release, like the thermo catalytic -It can activate high concentration H2O2 (35%) extremely quick & thus help to achieve a satisfactory lightening of pulp less teeth with pathological or acquired stains in just 1 or 2 30 minutes sessions. -The erbium: YAG laser are used for this type of treatment as its beams are rapidly absorbed by water.
  34. 34. dentinal walls, as this may cause infractions & secondary fractures. -The procedure is repeated 5-6 times every 5 minutes. -While heat activation considerably increases the speed & efficiency of reaction, it also increases the risk of complications, which renders this technique obsolete bleaching technique. -Diode lasers that have a deeper penetration depth are also used, although less frequently because of the high increases in temperature they induce. Procedures:  A 35% H2O2 gel is placed inside the pulp chamber & on the labial & lingual surfaces of the prepared tooth that is perfectly isolated.  The tooth is then covered with a clear film (e.g. Whitestrip) fastened to gingival barrier (light cured protection) so that the gel remains slightly compressed during breakdown & stays in place at each new irradiation (frequency 30Hz, energy 60MJ, distance I to 1.5 mm, duration 3 seconds, exposure is repeated 4 to 5 times, with 30 seconds intervals).  Air jet cools the spot where the beam is focused. The gel should be renewed 2-3 times during the procedure.  At the end of the session, the gel & gingival barrier are removed. Catalase or CaOH should be placed inside the pulp chamber & left there over 8-15 days prior to the placement of the final composite restorations so as to neutralise the effects of the H2O2. Complications of Non-vital Tooth Bleaching :  External root resorption.  Chemical burn due to Superoxol.  Inhibition of Resin polymerisation.
  35. 35. A discoloured tooth is always a point of discomfort for the patient and related with psychological and social concerns. Bleaching might be a very easy solution to the patient’s needs but it itself causes a plethora if adverse effects like root resorption, enamel damage, tooth sensitivity and chemical burns occurs. Sadly, often the patient is under too much of social pressure to pay due to attention to these adverse effects results. It then becomes the duty of the dentist to inform the patient of these problems and get an informed consent before proceeding with the treatment. We may conclude by mentioning that though bleaching has its drawbacks, one cannot completely overlook it as an option for restoring tooth aesthetics. A newer bleaching agent that is less deleterious to tooth and surrounding oral tissues might be the answer we are looking for. Discoloured Under Bleaching Bleached (Unhappy) (Happy)
  36. 36. References: Grossman’s Endodontic Practice Text Book of Endodontics- By Amit Garg & Nisha Garg Ingle’ Endodontics An Article of Liverpool University  Guided By: Dr. Anuradha Mukherjee Dr. Soumen Chakraborty THANK YOU