1. Introduction Discoloration Causes Bleaching Indications & contraindications Mechanism of Bleaching Bleaching Materials Intacoronal Bleaching & its adverse effects Extracoronal Bleaching & its adverse effects

2. Extrinsic Coffee and tea stains Cigarette Diet Tobacco Nasmyths membrane (seen in children caused due to reduced enamel epithelium) 3. 1. Tetracycline stains 1st degree 2nd degree 3rd degree 4th degree 2. Fluorosis stains 3. Trauma to tooth 4. Systemic condition Erythoblastosis foetalis Jaundice Amelogenesis imperfecta Enamel hypoplasia due to deficiency of vitamin A,C,D. 5. Iatrogenic discoloration Amalgam Intracanal medicaments (Kerr root sealer, Grossman sealer, Procosol sealer). 4. Tetracycline staining: more susceptible during the second trimester in vitro to roughly 8 years after birth. Tetracycline molecules chelate with calcium and gets incorporated into the hydroxyapatite crystals. Severity of stains depends on the time and duration of drug administration. 5. 4 Degrees: 1st Degree - Light yellow, brown stains - Uniformly distributed - No banding or localized concentration - Responds to bleaching in 2 or 3 session 2nd Degree - Dark gray stains - Extensive than 1st degree - Responds to bleaching in 4-6 session 3rd Degree - Dark gray stains with banding. - Responds to bleaching best bands will be evident. 4th Degree - Does not respond to bleaching. 6. 1st Degree 2nd Degree 3rd Degree 4th Degree 7. High concentration of fluoride in more than 4ppm cause moderate to severe discoloration. Prevalence Premolars, 2nd molars and mandibular and maximum incisors. Types Mild fluorosis - Brown pigmentation on a smooth enamel surface - Responds well to bleaching Moderate - Opaque fluorosis appear gray with white flecks on enamel surfaces. Severe - With pitting and dark pigmentation with surface defects. - Does not respond to bleaching 8. Mild fluorosis Severe fluorosis 9. Traumatic Injuries: Causes rupture of blood vessel in the pulp.Causing diffusion of blood into dentinal tubules. Dark pink immediate after trauma and changes to pinkish brown after some days. Causes: Haemoglobin degrades into hemin, hematin, hematoiden and haemosidrin. Hydrogen sulphide produced by bacteria combines with hemoglobin & gives dark colour to tooth 10. Erythroblastosis foetalis: (Rh factor incompatibility between mother and foetus) characterized by breakdown of erythrocytes. Jaundice: Bluish green or brown stains in dentin caused by bilirubin or biliverdin. Amelogenesis imperfecta: is a genetic condition which interfere with the normal enamel matrix formation. Enamel hypoplasia: caused by deficiency of vitamins i.e. A, C, D and calcium and phosphorus 11. a] Trauma during pulp extirpation hemorrhage b] Failure to removal of all pulpal remnants. c] Amalgam restoration cause dark gray. d] Gold dark brown when combined with products of decay. e] Break down of restoration i.e. acrylic, silicate and composite resins can cause the tooth to look grayer and discolore f] Silver containing root canal sealers i.e. Kerr root, grossman sealer. g] Volatile oils yellowish brown stain. . 12. Bleaching is a treatment modality involving an oxidative chemical that alters the light-absorbing and/or light-reflecting nature of a material structure, thereby increasing its perception of whiteness. 13. Discolouration of anterior teeth after R.C.T. Tetracycline stains (mild) Fluorosis Haemorrhagic discolouration . Discolouration due to ageing Medication discolouration 14. Hypoplastic or severely undermined enamel. Deep microcracks Sensitive teeth Opaque or white spots Extensive silicate, acrylic or composite restorations. 15. The active ingredient in tooth bleaching materials is peroxide compounds. Currently a variety of bleaching materials are available, the most commonly used peroxide compounds are: Hydrogen peroxide Sodium perborate Carbamide peroxide 16. In-office bleaching concentration(typically25% to 38%) At-home concentration (3% to 7.5%) H20 2 at high concentration caustic burns tissues on contact 17. Sodium perborate (NaB03 ) is available in powdered form or as various commercial preparations. When fresh, it contains about 95% perborate, corresponding to 9.9% of the available oxygen. Sodium perborate is stable when dry. In the presence of acid, warm air, or water, however, it decomposes to form sodium metaborate, H20 2, and nascent oxygen. Three types of sodium perborate preparations are avail able: monohydrate, trihydrate, tetrahydrate. Commonly used sodium perborate preparations are alkaline. material of choice in most intracoronal bleaching procedures 18. exists in the form of white crystals or as a crystallized powder containing approximately 35% H20 2. It forms H20 2 and urea in aqueous solution. mostly used in home-use bleaching materials with concentrations ranging from 10 to 30% (equivalent to approximately 3.5% to 8.6% H20 2) Bleaching preparations containing carbamide peroxide usually also include glycerine or propylene glycol, sodium stannate, phosphoric or citric acid, and flavor additives. In some preparations, carbopol, a water soluble polyacrylic acid polymer, is added as a thickening agent . Carbopol also prolongs the release of active peroxide and improves shelf life 19. Bleaching mechanism: The mechanism is oxidation / reduction process called as Redox process. In this process the oxidizing agent has a free radical with unpaired electrons, which it gives up, becoming reduced. The reducing agent (i.e. the substance being bleached) accepts the electrons and becomes oxidized. Reducing agent Oxidising agent Tooth Bleaching material After the process Tooth is oxidized Bleaching material is reduced (Organic pigmentation of tooth oxidized) In addition to the chemical effect other mechanisms include cleansing of tooth surface temporary dehydration of enamel during the bleaching process, change of enamel surface. 20. The methods most commonly employed to bleach endodontically treated teeth are: 1. "walking bleach" 2. Thermocatalytic techniques. Walking bleach is preferred 21. coined by Nutting and Poe in 1961 Involves the following steps: :Familiarize the patient Radiographically assess the status Evaluate tooth color with a shade guide Isolate the tooth with a rubber dam Remove all restorative materials from the access cavity, expose the dentin, and refine the access. Remove all materials to a level just below the labial-gingival margin. Apply a sufficiently thick layer, at least 2 mm, of a protective white cement barrier, Prepare the walking bleach paste pack the pulp chamber with the paste. Evaluate the patient 2 weeks later 22. This technique involves placement of the oxidizing chemical, generally 30% to 35% H20 2 (Superoxol), into the pulp chamber followed by heat application either by electric heating devices or specially designed lamps avoid overheating of the teeth and the surrounding tissues. Intermittent treatment with cooling breaks preferred. In addition, the surrounding soft tissues should be protected with Vaseline, Orabase, or cocoa butter during treatment to avoid heat damage. Potential damage - external cervical root resorption 23. This technique applies ultraviolet light to the labial surface of the tooth to be bleached. A 30% to 35% H202 solution is placed in the pulp chamber on a cotton pellet followed by a 2-minute expoure to ultraviolet light. 24. External Root Resorption Chemical Burns Inhibition on Resin Polymerization and Bonding Strength 25. Restoration with a lightshade, light- cured, acid-etched composite resin. Placing white cement beneath the composite. Waiting for at least 7 days after bleaching, prior to restoring the tooth with resin composites, recommended. 26. Extracoronal bleaching may be used for whitening vital or nonvital teeth as well as a single tooth or whole arch. It has experienced a dramatic advancement in materials as well as techniques after at-home extracoronal bleaching was first introduced 27. Bleaching procedures are performed in the clinic by a dental professional. Current commercial in -office bleaching materials are almost exclusively in the form of a gel, with 25% to 38% H20 2 In-office extracoronal bleaching may be perfomed using a bleaching gel alone or a gel with a light. 28. The light source can be a laser (e.g., argon, CO2) , halogen, plasma arc, or light-emitting diodes (LED). The wavelength may range from high ultraviolet spectra, low visible blue light spectra, to invisible infrared spectra such as the CO2 laser. The light exposure is intended to enhance the bleaching efficacy by activating the bleaching gel either through a specific catalyst or heat. 29. The action is to stimulate the catalyst in the chemical. There is no thermal effect and less dehydration of enamel. Argon laser of 488 nm wave-length for 30 seconds to evaluate the activity of bleaching gel. As the laser energy is applied, the gel is left in place for 3-4 minutes and then removed. This procedure is repeated for 4-6 times. Another product uses Ion laser technology. Argon laser is used as described before. Then CO2 laser is employed with another peroxide solution to provide penetration of the bleaching agent into the tooth to provide bleaching below the surface. Argon laser is in the form of blue light and is absorbed by dark colour. It is an ideal instrument to be used in tooth whitening when used with 50% H2O2. The affinity to dark colour ensures that the yellow brown colour can be easily removed. 30. CO2 laser. It is unrelated to the colour of tooth and energy is emitted in the form of heat. It is invisible and penetrates only 0.1 mm into water and H2O2 where it is absorbed. This energy can enhance the effect of whitening after the initial argon laser process. Diode laser light: A true laser light produced from a solid- state source. It is ultra fast, taking 3-5 seconds to activate the bleaching of agent. This type of laser produces no heat. 31. Over-the-counter (OTC) tooth bleaching products available directly to consumers. Contains; Acid-citric or phosphoric acid Gel-acidic ph;applied for 2min Post bleach polishing cream- toothpaste containing titanium dioxide White strips: Which is a thin flexible polyetheline strips which contains 5.3% hydrogen peroxide in gel form. The strips are used for 30 minutes twice daily for 14 days. 32. Commonly observed clinical side effect during or afterextracoronal bleaching of vital teeth, with an incidence of up to 50% . The sensitivity, usually mild to moderate and transient, often occurs during the early stages of treatment and usually persists for 2 to 3 Days Enamel Damage The effect of extracoronal bleaching on enamel has been conducted mainly using in vitro systems to examine changes in enamel surface microhardness and morphology. Most SEM studies showed little or no morphological changes in the bleached enamel surface. 33. The amount of mercury release may vary. Avoid extracoronal bleaching for teeth with extensive amalgam restorations.