Bleaching in Dentistry

Bleaching in Dentistry

1. BLEACHING In Dentistry Dr.Athul Chnadra.M

2. contents Introduction Tooth discoloration A brief History of bleaching Chemistry of bleaching Diagnosis and treatment planning Bleaching techniques Combining the techniques Bleaching and the micro abrasion technique Bleaching with restorative dentistry Bleaching with direct composite restorations Safety issues Home bleaching instructions

3. Intoduction ‘Everyone wants a whiter teeth !’ Does that mean we can provide treatment to every patient?

4. Esthetics is an important factor in patient’s decision to undergo endodontic treatment. But the teeth can and do discolour sometimes before or sometimes after endodontic treatment,In spite of all precautions we take to prevent it. When teeth discolour, BLEACHING should be considered as a means of restoring the tooth esthetics !

5. BLEACHING ! Is defined as, the lightening of the colour of tooth through the application of a chemical agent to oxidize the organic pigmentation in the tooth . (GROSSMAN)

6. Goal of bleaching To restore the normal colour to a tooth by decolorizing the stain with a powerful oxidizing agent known as bleaching agent.

7. Teeth are polychromatic (LOUKA 1989) The color varies from the gingival, incisal and cervical areas according to the thickness of enamel and dentin. The normal color of the primary teeth is bluish white. The permanent teeth is, grayish yellow. Greyish white Yellowish white

8. The tooth colour is determined primarly by the dentine and modified by : the translucency and thickness of the enamel, (enamel thickness is more at the occlusal / incisal edge and thinner at the cervical third of the tooth. Dayan et al 1983) the thickness and color of the underlying dentin, the color of the pulp . Any alteration in the color may be due to physiologic or pathogenic and endogenous or exogenous in nature.

9. With age, the enamel becomes thinner due to abrasion and erosion The dentin becomes thicker due to secondary and reparative dentin deposition, which produces color changes. Elderly persons usually have yellow or grayish yellow teeth than younger persons.

10. Before we commence a bleaching therapy the essential question to the patient should be to determine the aetiology of the discoloration.

11. Tooth discoloration A very common problem Can Occur at any age. In both primary and secondary teeth. Different parts of the tooth can take up different stains. The aetiology is multifactorial.

12. Principal causes (Grossman) are:- decomposition of pulp tissue trauma excessive hemorrhage following pulp extirpation calcific metamorphosis filling material endodontic materials (root canal medicaments) aging Iatrogenic

13. decomposition of pulp tissue In decomposed necrotic pulp The intensity of discoloration is directly related to the duration of time th epulp has been necrotic.

14. trauma Trauma -> rupture of blood vessels in the pulp -> diffusion into the dentinal tubules. dark pinkish hue- Almost immediately after the accident. It will turn pinkish brown after a few days. The discoloration will persist even after the pulp is extripated or if the pulp recovers.

15. When the pulp succumbs to trauma, Hemoglobin breaks down Form various colored coompunds like HEMIN, HEMATIN, HEMATOPORPHYRIN, HEMOSIDRIN. Hydrogen sulphide produced by bacteria will combines with the haemoglobin to darken the tooth.

16. Pulpal hemorrhage during extripation Discoloration occurs if haemorrhage is excessive during the pulp extirpation. If haemorrhage persists – it indicates there is still vital pulp fragment remaining inside. What to be done? Irrigate thoroughly to remove blood elements from the dentinal tubules.

17. Calcific metamorphosis Condition characterized by rapid deposition of hard tissue within the root canal. Usually in anteriors followed by trauma In certain traumatic injuries- transient disruption of blood supply-cause destruction of odontoblasts . They are replaced by cells of undifferentiated mesenchymal cells that laydown teritiary dentin. Thus the tooth becomes opaque due to loss of translucency.

18. Dental Filling materials Silver amalgam stain from slate gray to dark grey. Copper amalgam cause bluish black to black stain. amalgam stains occur when the dentinal walls are thin and the filling matrial almost shimmers through the enamel. Old resin composite restoration cause dark marginal discoloration of the dentin during microleakag e . Metal posts maybe seen through the enamel or may release metallic ions.

19. Root canal medicaments Some stain the tooth directly and others stain only on decomposing or combining with some other agents from endodontic treatment. Eg : essential oil from resinous substance discolour tooth structure.

20. Aging Physiologic deposition of secondary dentin affects the light transmitting properties of teeth. Result- more opaque hue

21. Classification of tooth discoloration. (aetiology based) DAYAN et al 1983 Intrinsic stains Extrinsic stains Pre-eruptive Post-eruptive disease medication

22. Abbott, 1997 (causes and colors ) Extrinsic discoloration Intrinsic discoloration Extrinsic & Intrinsic discoloration Genetic systemic Systemicmedications during development body byproducts body pulp changes Iatrogenic causes

23. Extrinsic stains They are found on the outer surface of teeth Usually of local origin. Thus can be easily removed by scaling or polishing . The stains deposit on the tooth surface due to attractive forces which are long range interactions such as vander waals and electrostatic forces Short range interactions such as hydrophobic forces, hydrophobic interactions and by hydrogen bonds.

24. Plaque, chromogenetic bacteria, surface protein denaturation. Mouthwashes, eg . Chlorexidine Beverages, eg,tea , coffee,red wine,cola . Foods. Curry, cooking oil, fried food, colored food, berries,beetroot . Dietary precipitate Illness Antibiotics. erythromycin, amoxicillin Iron supplements.

25. Classification of Extrinsic stains Metallic & non metallic stains this classification could not explain the mechanism of stain and all metals do not stain teeth. Newer classification is based on chemistry of staining-by Nathoo 1997 .

26. Nathoo’s classification 1997 N1 type or direct dental stain: The colored material bind to tooth surface Same color of both stain and the chromogen N2 or direct dental stain: Chromogen changes color after binding to the tooth. N3 or indirect dental stain: Colorless material or prechromogen binds to the tooth to have a chemical reaction to form stain.

27. Intrinsic stains Is due to the presence of chromogenic material within enamel or dentin,incorporated either during odontogenesis or after tooth eruption. It can be related to the periods of tooth development. Eg , amelogenesis imperfect or dentinogenesis imperfect. Or after tooth development. eg ., pulp necrosis. Or even excess ingestion of flourides , tetracyclines during odontogenesis . Or interaction of antibiotics eith hydroxyapaptite crystals during mineralization. Intrinsic colors are determined by optical properties of enamel and dentin.

28. Stains from the developmental phase are almost impossible to eliminate. Stains from the pulp necrosis can be removed by BLEACHING!

29. History of bleaching

30. Most attempts to bleach the tooth in the 19 th centuary were done on non vital tooth and the materials used were highly dangerous and caustic. Then from the early 1860’s, chlorine produced from a solution of calcium hydrochloride and acetic acid was highly efficient for bleaching non vital teeth. Commmercialy they called it the LABARRAQUE’S SOLUTION, a liquid chloride of soda.

31. By the late 1800s, several oxidizing agents were used directly used on the organic parts of the vital teeth, such as, Aluminium chloride Pyrozone (ether peroxide) Hydrogen dioxide (hydrogen peroxide or perhydrol ) Sodium peroxide Sodium hypophoshate Chloride of lime Potassium cyanide Reducing agent often used was sulphurous acid. Of these, considered the most effective was Pyrozone Superoxyl Sodium dioxide.

32. Bleaching agents were divided based on which stains they most effectively removed. Iron stains were removed with oxalic acid, Silver and copper stains removed with chlorine Iodine stains removed with ammonia Cyanide of potassium also removes metal stains but was an active poison. Amalgam restorations were the most resistant to bleaching.

33. The bleaching agent was applied to the outside Buccal surface and was expected to penetrate through the enamel. 1958, PEARSON found that lack of pulp in the non vital teeth as an advantage and place the bleaching material directly into he pulp chamber. SPAAER,1961, gave a mixture of sodium perborate with water to be placed in pulp chamber and leave it for a week in situ. This technique became popular as the “WALKNG BLEACH”.

34. NUTTING & POE, 1963,1967,modified this by combining 30% hydrogen peroxide and sodium perborate sealed into the pulp chamber for a week. The synergistic effect helped and this technique was popularised as “COMBINATION WALKING BLEACH”. 1965,STEWART, placed an oxidizing chemical in the pulp chamber applied a heated instrument either directly into the pulp or on the Buccal surface of the tooth. This was called “THERMOCATALYTIC TECHNIQUE”. Special heating lamps were also used. the problem with this technique was cervical resorption due to high conc of H2O2 WITH HEAT.

35. SETTEMBRINI et al (1997) AND CARILLO et al (1998) came up with “INSIDE/OUTSIDE TECHNIQUE”. Patient will apply the beaching agent directly into the pulp chamber with a syringe. Then bleaching tray custom made is seated into the mouth. Bleaching thus occurs from both inside and outside simultaneously. WALKING BLEACHING COMBINATION WALKING BLEACH THERMOCATALYTIC INSIDE/OUTSIDE TECHNIQUE Intracoronal / internal bleaching

36. A chance discovery in 1960s, a 10%cabamide peroxide was placed in a custom fitted tray which was placed in the mouth for several hours or overnight and the teeth lightened in a few days, week, months depending on the nature of the stain. Dr.VAN HAYWOOD & DR.HARALD HEYMANN published this as the NIGHTGAURD VITAL BLEACHING.1989. This seemed to be safe, efficient and was widely accepted in mainstream dentistry.

37. In 1918, ABBOT introduced bleaching at the dentist’s chairside with a high intensity light. This was thus called “IN-OFFICE POWER BLEACHING”. But the high temperature intolerance and faster regression rate caused tooth sensitivity. Now light units like HALOGEN CURING LIGHT, PLASMA ARC OR XENON POWER ARC which do not generate heat, activates the bleach.

38. Bleaching materials

39. The goal of bleaching procedures is the restoration of normal color to the tooth by decolorizing the stain with a powerful oxidizing agent known as bleaching agent.  The most commonly employed bleaching agents are as follows: A . Hydrogen peroxide B. Sodium perborate C. Carbamide peroxide D. Over-the-counter(OTC) agents

40. constituents of the bleaching gels Carbamide peroxide H2O2 and sodium hydroxide Non-hydrogen peroxide containing material, Sodium perborate . Thickening agent –CARBOPOL/POLYX UREA Vehicle- glycerine, dentrifice , glycol Surfactant and pigment dispersants Preservatives Flavouring Fluoride (reduces sensitivity)

41. Hydrogen peroxide Whitening agent in dentistry in a conc of 5-35%. Peroxides are InOrganic : if hydrogen atoms are substituted with metals Organic : if h2 atoms are substituted with organic radicals. They are strong oxidisers Low molecular weight. Clear Odourless Colorless liquid Stored in light proof amber bottles. Unstable and must be kept away from heat as it can explode. Decomposes in open air-thus store in sealed refrigerated containers.

42. Can penetrate dentin Release oxygen These released O2 breaks down the double bond of inorganic and organic compounds inside the tubule. How to use? Dispense 1-2mL into a clean dappen dish. Discard any remaining solution. H2O2 can be used alone or mixed with sodium perborate into a paste (walking bleach). 3-7.5% H2O2 are used in home bleach.

43. Concentrations of h202

44. Caution! Ischemic effect on skin and mucous membrane causes chemical burn. Painful if it contacts the nailbed or soft tissue under fingernails.

45. Sodium perborate Stable white powder Water soluble powder Supplied as granules Granules grouped into powder for usage. 3 types based on oxygen content: Monohydrate Trihydrate Tetrahydrate Thus used in “WALKING BLEACH”. Na PERborate + water = Na METAborate + H 2 O2+ O2 Na PERborate + SUPEROXOL = Na METAborate + H2O+ O2

46. Carbamide peroxide CH6N2O2 UREA HYDROGEN PEROXIDE Conc. : 3- 45% depending on at-home or in-office bleach. Commonly in home bleaching. 10% is used in commercial preparations. 10% carbamide peroxide decompose into 6.65% urea+ ammonia+ CO2+ 3.5%H2O2. 15% CH6N2O2 => 5.4% H2O2 20% => 7% H2O2 35% solution => 10% H2O2

47. Home bleaching – 5 percent carbamide peroxide – 10 percent carbamide peroxide – 15 percent carbamide peroxide – 20 percent carbamide peroxide . • In office bleaching – 35 percent solution or gel of carbamide peroxide.

48. In addition flavouring agents and glycerine, sodium stannate , phosphoric or citric acid are added. Thickening agent : CARBOPOL- water soluble polyacrylic acid polymer This prolongs the active peroxide release Thus more shelf life.

49. Thickening agents Carbopol ( carboxypolymethylene ) is generally used. TROLAMINE, a neutraliser is often added to carbopol to reduce the ph of the gel to 5-7. Solution with carbopol will release oxygen slowly and sustain for 10hours. Maximal release occurs by 2-3 hours. Other solutions release O2 in less than an hour. The rate of oxygenation affects the frequency of solution replacement during bleaching. Carbopol enhances the viscosity thus better retention of the gel in the tray and to the tooth. Also Less material is thus required for the treatment. (29mL per arch) The increased viscosity prevents the saliva from breaking down the H2O2.

50. POLYX is a thickener used in the colgate platinum system. The composition of which is a trade secret still.

51. Urea It stabilizes the H2O2 by giving a loose association with it. Elevates the pH. Enhance anti cariogenic effects Enhance saliva stimulation Enhance wound healing properties. The effect of ph depends on the concentration of the urea and duration of its application.

52. Vehicle GLYCERINE: carbamyl peroxide with glycerine base has enhanced viscosity and ease of manipulation. Side effects :- dehydrates the tooth Tooth loose the translucency thus. Sore throat in some patients DENTRIFICE: vehicle for Colgate platinum system GLYCOL: this is anhydrous glycerine.

53. Surfactant & pigment dispersants Wets the surface allowing H2O2 to diffuse across the gel-tooth boundary. Pigment dispersant keep pigments in suspension. These containing kits are more efficient and has more active gel. Eg : Nu-Smile and Brite Smile.

54. Preservatives Citroxain , phosphoric acids, citric acid or stannous stannate . They sequestrate transitional metals like iron, Cu,Mg , thereby accelerating the breakdown of H2O2. They give the gel more durability and stability. They have a mildly acidic ph.

55. Flavourings Gives a choice of bleaching agent Improve patient acceptability of the product. Eg : melon, banana, mint.

56. OVER-THE COUNTER(OTC) BLEACHING AGENTS: These includes : Tray systems  Trayless systems Chewing gums Toothpastes  Bleaching strips and Paint- on products These products primarily work by removing extrinsic surface stain only.

57. Over the counter kits (OTC) Acid rinse: usually citric acid/phosphoric acid Bleaching gel: applied for 2 minutes have acidic ph Post-bleach polishing cream : toothpaste with titanium dioxide that gives a temporary painted white effect.

58. Mechanism of bleaching

59. Hydrogen peroxide has a low molecular weight and enamel being semipermeable membrane, diffuse the H2O2 through the enamel matrix. The free radicals interact with organic molecules to attain stability. Bleaching agent opens up the highly pigmented carbon ring (yellow color ) and converts them to hydroxyl groups,thus the amount of light absorbed is reduced. Thus the tooth appears more light in color . if bleaching is continued beyond this point then the tooth structure will be weaken and will lead to its fracture.

60. H2O2 is a oxygenator and an oxidant. The yellow pigment (XANTHOPTERIN) is oxideised to the white pigments (LECOPTERIN) The hydrogen peroxide breaks down to water and oxygen and a free radical HO2. perhydroxyl , which is short lived but very reactive and a great oxidative agent. It can break up a large macromolecular stain into smaller stain molecules which get expelled to the surface by diffusion. It can attach to the protein structure and protein matrix. it can oxidise tooth discoloration. Carbamide peroxide, breaks down to water oxygen urea CO2 and ammonia.

61. Factors affecting bleaching

62. SURFACE CLEANLINESS: CONCENTRATION OF PEROXIDE: SHELF LIFE: TEMPERATURE: PH: TIME: SEALED ENVIRONMENT: ADDITIVES: OTHER FACTORS:

63. Classification of bleaching

64. Non vital bleach Thermocatalytic / in-office Walking bleach / out-of-office / Home technique Inside/outside bleaching Closed chamber/ extracoronal bleaching Vital bleach .. Laser bleach Power bleach / in-office Night guard / dentist prescribed home technique

65. 1) Intracoronal (for endodontically treated/ nonvital teeth) At-home /walking bleach in-office thermocatalytic bleach. 2) extracoronal bleaching (vital tooth) in-office vital bleach. At-home vital bleach.

66. Thermocatalytic 35% /h2O2 liquid Accelerating by heated instrument

67. Walking bleach – spasser and nutting Superoxol (30% h2o2 by volume) Superoxol + Sodium perborate

68. Power bleach 35% h2o2 Oxidation heat

69. Night guard 10-15% carbamide peroxide 3% h2o2 (active ingredient) + 7%urea Degrades into

70. 1961 Spasser Walking bleach Sodium perborate +water in pulp chamber

71. Non vital bleaching

72. Walking bleach Less chairtime Safer Comfort for the patient

73. Indications Superficial enamel discolouration’ Defective enamel formation. Severe dentin loss Discolored composites Presence of caries. ContraIndications Discolored pulp chamber Discolored dentin Discolorations are not amenable to extracoronal bleaching

74. How to do walking bleach? Preparation Always examine and evaluate the crown as it should be intact. Crowns weakened by wide access cavities, large multiple restorations and caries should be managed. Restore them with posts and core and a full veneer crown for best f untional and esthetic result. Obturation should be checked radio graphically for voids and adaptation. If the bleaching agent percolates through it, then it can lead to acute apical periodontitis. If silver cones are used to obturate , substitute it with gutta-percha cones.

75. Method Polish the tooth with prophylaxis paste to clear the surface. evaluate the shade guide and take clinical radiographs at every step of the treatment to appreciate the results. Apply petroleum jelly on the gingiva and around the tooth for protection. Adapt rubber dam and clamp. Re-establish the access cavity. Remove any excess gutta percha in the pulp chamber by hot finger plugger and condense it 1mm apical to the CEJ. Use a periodontal probe to assure it by placing it in the pulp chamber and reproducing the same in the gingival sulcus.

76. Use small round bur to remove any residual stains or debris inside the chamber or on the pulp horn. Seal the orifice of the root canal with atleast 1mm intracoronal barrier over the gutta-percha using GIC,Cavit , MTA or resin GIC. MTA is shown to be superior . The level of the barrier should be 1mm incisal to the CEJ so as to confine the bleaching agent only to the crown above the level of the bone. Keeping it away from the cervical area can prevent cervical resorption. Protect the patient face by draping it and give a pair of glasses for the eyes.

77. Plastic apron over the patients clothes. Operator must wear gloves. Mix sodium perborate + distl.water . Use 3% h2o2 to a thick paste in a dappen dish for severe stains. Use amalgam carrier or plastic instrument to carry this thick paste into the pulp chamber and cover entire facial surface with it.

78. Place moistened cotton pellet with h2o2 over this bleaching paste. Seal the cavity to 3mm thickness using an adhesive material. If you use IRM then press it against the cavity with gloved finger till it sets to ensure it is not displaced with oxygen release.

79. After 24hours maximum results will be obtained. Recall the patient after 3-7 days. If the shade is too dark,do additional bleaching. If too light shade, permanently restore it. Bleached teeth with too light shade might revert back shortly after bleaching. This could be due to the ingress of saliva into the dentin through the enamel, whose permeability could have increased by bleaching.

80. Thermocatalytic / In-office bleaching.

81. Light Sources Used for In-office Bleach Various available light sources are : • Conventional bleaching light • Tungsten halogen curing light • Xenon plasma arc light • Argon and CO2 lasers • Diode laser light.

82. 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

83. Tungsten-Halogen Curing Light • Uses light and heat to activate bleaching solution • Application of light 40 to 60 seconds per application per tooth • Time consuming

84. Argon and CO2 Laser • True laser light stimulate the catalyst in chemical so there is no thermal effect • Requires 10 seconds per application per tooth

85. Diode Laser Light • True laser light produced from a solid state source • Ultra fast • Requires 3 to 5 seconds to activate bleaching agent. • No heat is generated during bleaching

86. 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 and stimulates the catalyst in chemicals • Greater potential for thermal trauma to pulp and surrounding soft tissues.

87. 30-35b % H2O2 is placed in the pulp chamber Heat/ light or both are applied on it. Familiarize the patient with the expected outcome and the possibility of future rediscoloration . Analyse radiographically the endodontic periodontic condition of the tooth. Assess and Replace defective restorations. Use a shade guide and take photographs. Apply a protective cream on gingival tissue and a rubber dam. If a heat lamp is used then avoid metal clamps to avoid discomfort. No anesthesia . Use Protective sunglasses for doctor and patient

88. apply 2mm of sufficient thick layer of protective cement barrier like polycarboxylate / ZnPO4 or GIC / IRM or even cavit over the obturation. Soak a small cotton pellet in 30-35% H2O2 solution place in the pulp chamber. A bleaching gel of H2O2 can also be used instead. Apply heat with a heating device or a light source. Keep the light at 2feet from the tooth. Temperature should be between 50-60’C Re-wet and replace the cotton pellet as necessary. The must be limited to 5minutes of separate periods than using it continuously for long time.

89. If too much sensitivity develops discontinue the procedure. Remove the heat/light source and allow the tooth to cool down every 5-6 minutes. Then wash with warm water for 1min. Remove the rubber dam. Dry the tooth

90. Place walking bleach paste (h2o2+ sodium perborate ) in the pulp chamber. Recall the patient after 2weeks and check the effectiveness. Compare with the pre-op photographs and the same shade guide. If necessary repeat the therapy.

91. A study invitro , compared the bleaching with H2O2 and heat for 12 minutes to pacj =king it with walking bleach paste for 7days or a combination of both the techniques. NO significant difference was shown in the results. The walking bleach consumes least time and no special equipment is the method of choice.

92. Intentional endodontics and intracoronal bleaching In treating intrinsic tetracycline discolorations. The tooth is endodontically treated deliberately and intrinsic bleaching is done. Only intact teeth without coronal defects caries or restorations should be treated.

93. ADVERSE EFFECTS OF INTRACORONAL BLEACHING

94. How do I give a composite restoration then? Assure complete removal of residual H2O2 in the pulp chamber. Inject CATALASE before bonding( ROSTEIN 1993) Removes the residual oxygen from the dentine. Sodium ascorbate - a buffered form of Vit.C (90% ascorbic acid + 10% Na) can also be used as anti oxidant. Give a GIC restoration immediately and cut back space for composite after 2 weeks.

95. Suggestions for safer non vital bleaching

96. Vital teeth Bleaching

97. Night guard/ home bleaching 1989 - haywood & heymann

98. Home bleaching 1989 - haywood & heymann A simple predictable technique 98% success in non-tetracycline stained teeth and 86% success in tetracycline stained. The dentist gives a custom tray + 10% carbamide peroxide + a bleaching protocol. Patient has to wear the tray with the material for several hours –day/night depending on his/her schedule. Cheaper and popular.

99. Also known as “NIGHTGAURD VITAL BLEACHING” – since patients slept with the tray in the mouth . Matrix bleaching dentist assisted/ prescribed home-applied bleaching Dentist-supervised at-home bleaching At-home bleaching. Internal/External bleaching , modified walking bleach technique.

100. Indications (GREENWALL 1999) Mild generalised staining Yellowing with age Mild tetracycline stains Very mild fluorosis Acquired stains superficially Smoking and tobacco Absorbed or penetrated stains from tea/coffee Pulpal necrosis induced Patient who desires a minimal dental treatment for a better color shift Young conscious patients with inherited grey or yellow hue.

101. Contraindications (GREENWALL 1999) Severe tetracycline stain Severe pitting hypoplasia Severe fluorosis Adolecent patient with large pulp Unrealistic expectations about the results. Defective existing restorations Attrited,abraded,eroded tooth. Surface cracks, fractures. Large anterior restorations Periapical pathologies Non compliance patients (i.e. lack of co-operation) Pregnant or lactating (effects on fetus unknown) Smokers hypersensitivity

102. Commonly used Solution for Night Guard Bleaching 10 percent carbamide peroxide with or without carbopol • 15 percent carbamide peroxide • Hydrogen peroxide (1 to 10%).

103. Treat sensitivity with flouride applications or a bonding agent or a bonded restoration prior to bleaching. Fractured teeth or maligned teeth can be treated best with a porcelain veneer or orthodontic treatment.

104. this technique requires methodological documentation and execution of: Dental & medical history Clinical examination Radiograph of the teeth to be treated. Impression of dental arches for the construction of bleaching tray. Recall visits to assess the progress and compliance.

105. Fabricating the vaccum pressed tray Trim the base of the cast to 0.5 inch thickness eliminating the vestibule,tongue and palatal regions. Use a light polymerised resin as reservoir on the labial surface to a thickness of 0.5-1mm for the space for the bleaching agent to seat. Reservoir should terminate 1mm short of the free gingival margin. Do a de-waxing before placing the cast in vaccum forming machine, if wax is used to make reservoir.

106. Impression making for trays Alginate or elastomers can be used Make sure to eliminate air bubbles Pour the cast as soon as possible to avoid distortions

107. Ideal tray properties Strong enough to defend damages during wear Should not distort during use or storage Bioinert material Non irritating Thin enough for comfort Smooth and well polished Should not impinge anywhere Comfortable fit not too tight No undercuts Freedom of movement for frenum attachments Good Retention Easy to clean and rinse

108. pictures

109. The viscosity of the bleaching material determines the extent of the tray. Scalloped margins for highly viscous, ie , terminating incisal to the free gingival margin. Nonscalloped if non viscous and must extend on the gingival tissues.

110. Instructions to the patient Check the tray fit and comfort in the second visit. Patient must brush away any debris on teeth before using the tray to enhance the effectiveness. The bleaching agent on the tray should cover the facial surface of the teeth. Wipe away any excess bleaching agent from the gingiva. Wear it for min 4hours for every session. If no sensitivity then he can use it twice daily. Always remove the tray from the second molar first in a peeling action to protect the soft tissues. Brush and rinse off the material from the tray after every use.

111. Store the bleaching agent in cool or warm temperature. The results should be expected by 2-14days to 6-12 months. Patient should be well informed of the treatment outcome. If the discoloration is uneven, the load the tray in areas corresponding to that teeth which require further bleaching. Cut the tray ain areas of ceramic crowns or crowns to avoid etching and weakening of ceramic. Regular checkup visits are mandatory.

112. The occlusal pressure and salivary flow dilute the gel. Thus the gel have to replenished every 1-2hrs if the tray is worn in the day. (DUNN 1998) Overnight can eliminate this problem as there will be reduced salivary flow and reduced occlusal pressure. Thus for maximum benefit and compliance wear overnight. (HAYWOOD 2000)

113. Further treatment Ask the patient to return the trays to protect him from over bleaching with obsession. Renew composite restorations If any after two weeks. Preparation of anterior crowns or porcelain veneer should be delayed by a month. This is to avoid rebound shade shift

114. Adverse effects reassure the patients that these are minor and transient that it will disappear soon after completion of treatment Tooth sensitivity Enamel damage Gingival irritation Mercury release from amalgam restoration. Altered taste sensation.

115. Possible causes of sensitivity and gingival irritation Adding carbol or other thickenening agents Patients below 40yrs Anhydrous based whitening products Carbamide peroxide byproducts Chemical interaction of tray Conc. Of the whitening solution. Dissolving media Exposure time Frequency of application Inherent patient sensitivity Medical status of the patient pH of the whitening solution Women more than men Tray rigidity and tray material.

116. Power bleaching

117. Combining bleaching techniques

118. Why combine the bleaching treatments? To make it more effective To motivate the patient to continue the treatment at home. To treat a single discoloured vital/non vital tooth. To sequence and stage bleaching in a complex treatment plan. To treat difficult stains like ttracycline Treat stains of different origin on the same tooth.

119. Inside-/ outside combination bleaching technique

120. Inside-/ outside combination bleaching technique Also called as Internal / external bleaching (SETTEMBRINI,1997 ) Patient- admimistered intracoronal bleaching Modifies walking bleach (LIEBENBERG 1997) This is intracoronal bleaching + home bleach A more simpler method to bleach non vital teeth

121. Indication for inside/outside bleach Adolescents with incomplete gingival maturation Single dark non vital tooth with adjacent teeth sufficiently light.

122. Preparation of the barrier Gp is removed 2-3mm below CEJ for barrier space. Use GIC or resin cement to build up the barrier. Clean the access cavity Remove any remaing pulp horns. Etch to clean the internal surface Place a cotton pellet to avoid food impaction Shade assessment Record Pre-operative shade of the non vital and the adjacent teeth. Procedure

123. Instructions for home bleaching Check for fit and comfort of tray Tel patient not to bite with the anterior teeth during the treatment tenure Ask to remove the cotton pellet with a tooth pick Apply the bleaching syringe directly in the cavity before seating the tray. Remove the excess with a toothbrush or tissue Irrigate the cavity with water after bleaching. Keep a fresh cotton wool After every meal- irrigate again and replace the cotton.

124. Treatment timing The more often the solution is changed the quicker the bleaching will occur. If patient can change the solution every 2 hours, then 5-8 applications is enough for desired results Night application will be slower than twice daily application Unless severely discoloured. Apply bleach during day as then it can be better controlled.

125. Reassessment of the shade and the results Recall after 3-7 days Terminate if desired results are achieved. Seal the access cavity Use temporary restoration Permannet restoration after 2weeks. If in a hurry-then first irrigate cavity NaOHCl then clean using CATALASE. The longer the tooth had been discoloured the longer the treatment the darker the shade the longer the duration

126. Review Periodic review Annual radiographic review to check for cervical inflammation

127. Benefits More area of penetration for both internal and external bleach Lower conc. Of bleach (10% carbamide peroxide with neutral pH) May eliminate side effects (cervical resorption). [not 100%] The access cavity is left open, No need to change dressing Oxygen free to escape No build up pressure Duration is reduced to days Catalase can reduce the residual oxygen. No heat activation required.

128. Options to treat non vital teeth

129. Intra + extracornal bleaching. Applied directly into the pulp chamber and retained with home bleaching matrix. Inside/outside technique with beaching tray, uses 10% carbamide peroxide 5% 16% 22% differing concentrations 35% carbamide peroxide open chamber bleaching

130. Material is placed on the external surface of the tooth. Other operations Power bleaching using 35% hydrogen peroxide Nightgaurd Vital Bleaching using 10% 15% 20% applied only to the non vital tooth in the tray. Assisted bleaching applied to the external surface on its own via a bleaching tray. closed chamber bleaching- extracoronal

131. Combing power bleach + home bleach

132. One or two power bleach in-office bleach sessions followed by home bleaching. GARBER advises patients to use matrix system for only 30-45 minutes at night instead of the longer times proposed for conventional home bleach. Advises alternate days for the first week Then once per week till the desired results.

133. benefits Eliminates the repeated sittings and multiple rubber dam application Best results from combination The procedure can adapt to the lifestyle and need of the patient Power bleach provides a jumpstart and gives improvement while the tray is being made

134. MICROABRASION & BLEACHING

135. What is enamel microabrasion ? A microscopic layer of enamel is simultaneously eroded and abraded with a special compound, leaving a perfectly intact enamel surface behind. (CROLL,1991) CROLL, called it “ ENAMEL DYSMINERALIZATION” Treating, Hypermineralization Hypomineralization Staining

136. Microabrasion VS bleaching Microabrasion improve the tooth color by permanently eliminating the superficial discoloured enamel.this is preffered when general tooth colour changes are not needed but a defined isolated surface discoloration is present. Bleaching improves tooth colour by lightning, whiteing and brightening teeth. But bleaching preserves the intact fluoride rich layer of enamel and tooth shape. The tooth may rebound to slightly darker shade over the years but never to their original darker shade.

137. Microabrasion + Bleaching The yellow or darker shade that may appear after microabrasion can be eliminated by bleaching.

138. Hydrochloride acid 10% Hydrochloride acid + pumice are the main ingredients. Its use depends on the decalcification of enamel. should be selectively applied and well controlled. Normally less than 200micronmeter in total of enamel is removed. maybe much less. Its effects are non-selective and superficial. Adding an abrasive like pumice can enhance the technique

139. Indication Developmental intrinsic stains Superficial enamel surface stains and opacities Yellow-brown areas Multicolored stain Superficial hypoplastic enamel /enamel dysmineralization Enamel fluorosis White patches and spots decalcification leasions from plaque stasis and orthodontic brackets Irregular surface textures

140. Contraindications Age-related staining Tetracycline stain Deeper enamel and dentin hypoploastic lesions Most amelogenesis imperfect Most dentinogenesis imperfect Carious lesions underlying decalcified regions.

141. Treatment Planning Saliva acts as a camouflage-hides the residual stains left. thus the teeth should be in their usual moist state before and after they are evaluated for microabrasion . So It is okay to not completely remove the stains. Discuss with the patient the side effects benefits and further options such as bleaching, veneers, crowns etc. Never raise their expectations. In fact give a pessimistic prognosis thus you don’t end up disappointing them. Assess the enamel from incisal edge for labiolingual thickness of the tooth and enamel lesion.

142. How to micro abrade the enamel? Clean the enamel with rubber cup and prophylaxis paste Isolate the teeth. Use Vaseline on lips Protect soft tissues Use a FINE GRIT DIAMOND/ TUNGSTEN CARBIDE BUR(CROLL 1997) to start on the lesion. Apply the microabrasion compound to th eareas of interest for 60s intervals with rinsing. Over duration of application can be harmful to both teeth and soft tissues. (whitening or ulcerations) Wipe off first before the wash to prevent splashing. Check labiolingually that minimal enamel reduction is taking place.

143. Repeat the procedure Polish using fine grit fluoridated prophylaxis paste. Rinse Remove the rubber dam Apply topical fluoride application to the teeth for 4minutes. Re-evaluate the result. More than one visit. Review the patient 4-6 weeks later.

144. Advantages Easily performed Conservative treatment It is inexpensive Teeth require minimal subsequent maintenance It is f ast acting removes yellow-brown, white multi-coloured stain It is effective Results are permanent

145. Disadvantages Removes enamel Hydrochloric acid componds are caustic Require protective apparatus for patient,dentist and assistant Require a visit to the dental office It cannot be delegated and must be carried out by dentist.

146. Microabrasion + home bleach After 6weeks of micro abrasion treatment make trays instrusct the patient how to use bleach and the trays. Home bleaching protocols are the same. Results are encouraging. Microabrasion + adjuctive treatment deep lesions may need a composite restoration the enamel surface of the lesion is roughened with acoarse diamond bur to expose fresh enamel for etching. Etch for 60seconds instead of the usual 15-30sec. (reason why because the mineral pattern and enamel density changes)

147. Laser Assisted Bleaching Technique This technique achieves power bleaching process with the help of efficient energy source with minimum side effects. Laser whitening gel contains thermally absorbed crystals, fumed silica and 35 percent H2O2. In this, gel is applied and is activated by light source which further activates the crystals present in gel, allowing dissociation of oxygen and therefore better penetration into enamel matrix. Following laser have been approved by FDA for tooth bleaching: • Argon laser • CO2 laser • GaAlAs diode laser .

148. 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. CO2 Laser • Emits a wavelength of 10,600 nm • Used to enhance the effect of whitening produced by argon laser • Deeper penetration than argon laser thus more efficient tooth whitening • More deleterious effects on pulp than argon laser. GaAlAs Diode Laser (Gallium Aluminum –Arsenic ) Emits a wavelength of 980 nm.

149. SAFETY ISSUES “the dose makes the poison”- Ottoboni 1989

150. Is carbamide peroxide toxic? carbamide peroxide is formed from urea and hydrogen peroxide. Urea moiety in nightgaurd vital bleach is non toxic to the human body. The metabolism requires oxygen free radicals,including H2O2. H2O2 is decomposed by enzymes particularly by catalase and various peroxidases which are found highest in liver spleen duodenum kidney, blood and mucous membrane. in blood catalase degrade gram quantities of H2O2 in just few minutes.

151. Does carbamide peroxide cause resorption? Invasive cervical resorption is seen very occasionally in bleached root-filled teeth. (FASARARO 1992) Main causes are trauma followed by heat and very high conc for H2O2. ( COHEN & PARKINS 1970) Thus, only when a combination of high concentration of H2O2 and heat are used on teeth with a history of trauma the resorption will result. Incidentally there are no reported cases with carbamide peroxide.

152. Carabamide peroxide cause sensitivity??? Increased sensitivity is associate dwith use of high concentrations of H2O2 with heat. For nightgaurd vital bleaching ,neither heat or high conc are used.

153. Hardness of teeth and bleaching If needed, there are any changes in tooth hardness by bleaching they are certainly likely to be less than those from removal of the enamel prior to veneer application or microabrasion . (HAYWOOD, SHANNON)

154. Conclusion Noticeable discoloration of teeth is a physical handicap which impacts the persons self image, self-confidence, attractiveness and employability. It should not be therefor ebe dismissed as a matter of no more than cosmetic importance. Bleaching is not achieved solely by a surface effect. H2O2 dissociated from carbamide peroxide penetrates through the enamel into the dentine. Low concentration gels are completely safe. When properly used there are no more than minimal adverse effects on dental pulp or soft tissues of the mouth and these are very transitory.

155. References BLEACHING TECHNIQUES IN RESTORATIVE DENTISTRY –GREENWALL GROSSMAN’S ENDODONTICS COMPLETE DENTAL BLEACHING – RONALD.E.GOLDSTEIN & DAVID.A.GARBER