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(1)Hegde Mithra N et al. IRJP 2012, 3 (11) INTERNATIONAL RESEARCH JOURNAL OF PHARMACY www.irjponline.com. ISSN 2230 – 8407 Review Article. OVERVIEW OF IN-OFFICE BLEACHING OF VITAL TEETH Hegde Mithra N.*, Shetty Krishna R., Shetty Shishir Department Of Conservative Dentistry and Endodontics, A.B. Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangalore – 575018, Karnataka, India Article Received on: 04/09/12 Revised on: 09/10/12 Approved for publication: 08/11/12. *Email: mithra_hegde@yahoo.com ABSTRACT The importance of tooth whitening for patients has shown a dramatic increase in the number of products and procedures over recent years. Vital tooth bleaching refers to chair-side clinical application of a chemical solution to a tooth surface in order to achieve whitening effect of the teeth. Vital bleaching have found to be very effective but they also have their the drawbacks. The current article gives knowledge of vital tooth whitening with respect to external bleaching methods. the external bleaching of vital teeth focuses on patient selection, mechanisms, bleaching procedure and various in-office bleaching systems and techniques and their disadvantages Keywords: Halogen light, Plasma arc light, Laser bleaching, Chemical Bleaching. INTRODUCTION Tooth plays a major role in the beauty and personality of an individual. Tooth whitening has become increasingly popular and the desire for whither teeth has become global. With the advantage of new materials and techniques, dentists can often meet or even exceed the expectations of the patients. Color of the tooth is of particular importance to the patient because of social and psychological concern. Chairside bleaching technique has always been a challenge as the treatments results were uncomfortable for the patients due to the lengthy time required for the process and also because its effectiveness is not long term1. Yet, patients seek for immediate results. The benefit of chairside whitening procedures for the dental office is that they can be implemented by auxiliary staff and the average color change per appointment has been reported to be 2.1 to 3.7 units on a 16-scale VITA Classic shade guide. (Vident)1,2. The demand for tooth whitening procedures is high enough that, for most dentists, tooth whitening procedures are a “must have” in their dental clinic. DETERMINING THE ETIOLOGY OF DISCOLOURATION Most discoloration falls primarily into one of three categories. The most common staining is • Extrinsic stains are superficial, resulting from excessive use of food substances such as coffee, tea, highly colored food or tobacco3. • Intrinsic stains are discolorations of the tooth structure that may occur due to ingestion of certain drugs, excessive exposure to fluids, or exposure to dental restorative materials4. • Age related discoloration usually results from a combination of extrinsic staining thinned enamel and darkened dentin4.. Colours produced by various causes of tooth discoloration T ypes of di scol orat i on Extrinsic stains Plaque/poor oral hygiene Tea, coffee and other foods Chlorhexidine Mouthwash Cigarettes/cigars Intrinsic Stains Fluorosis Tetracycline medication Amelogenisis and Dentinogenesis imperfecta Stains due to trauma Pulpal haemorrhage products Aging Internalized Caries Restorations. PATIENT SELECTION Di a gn osi s of t h e et i ol og y of t oot h di scol or a t i on pl a ys a m a jor r ol e i n th e succe ss of a n y t oot h bl ea ch in g. It a l so d epen ds on t h e c on di t i on s of t h e t eet h l i ke · Decay, Size and vitality of the pulp to predict sensitivity levels and even presence of any periapical pathology5 and personal factors like · The in di vi dua l pa t i ent ’s desi r es and expe ct a t i on s a bout t h e est h et i c out c om e. Color produced Yellow/ brown Brown to black Black and brown Yellow/ brown to black White, yellow, grey or black Brown and black banding appearance Brown and black Pink spot Yellow Orange to brown Grey and black. · Wi l l in gn ess t o sp en d t i m e in th e den t al cha ir a n d or t o co- op er a t e a t h om e; an d · Ac cept a n ce of r esp on si bi l i t y t o m odi fy beh a vi or th a t ca n a ffect t oot h col or a t i on 6 . THE BLEACHING MATERIALS T h er e h a ve be en n um er ous ch a n ges t o m a t er i a ls si n ce h om e bl ea ch in g m a t er i a l s wer e i ntr oduc ed. Fi r st gen er a t i on m a t er i al s wer e i n li qui d for m . T h ese m a t er ia l s di d n ot r em a in in tr a ys for a l ong t i m e. E g. Gl yoxi de 7 . Page 12.

(2) Hegde Mithra N et al. IRJP 2012, 3 (11) Se c on d gen era t i on m at er i al s ar e curr ent ly a va i l a bl e wh i ch a r e m or e vi s c ous a n d in gel for m . Th i s i s t o st op m a t er i a l s l ea ch in g out of t ra y a n d ca usi n g soft t i ssu e i r r it a ti on E g. Pr ox yg el 7 . T hir d gen era t i on di ffer s i n t h eir veh i cl e a nd c ol or . Consti t ue nt s of B l e ac hi ng 8 , 9 · Ca r ba m i de per oxi de -10% - 35% · Hydr og en per oxi de a n d sodi um h ydr oxi de – 10 – 50% · Non - h ydr og en per oxi de con t a i nin g m a t er i a l s i . e. sodi um per bor a t e · T hi cken in g a gent ca r bop ol or pol yx- h el ps i n sl ow r el ea s e of ox yg en m ol ecul e s fr om gel s a n d pr ol on gs t h e a ct i on of t h e bl ea ch i n g m a t eri a l. · Ur ea -i t s us ed t o st a bi l i z e h ydr og en per oxi de a n d el eva t e t h e ph of s ol ut i on · Veh i cl e( gl yc er i n, den t i fr i ce, gl yc ol )en han ces vi sc osi t y of t h e bl ea ch i n g gel · Sur fa ct a n t - enh an ce wet t i n g a bi l i t y a n d pen et r at i on of h ydr ogen per oxi de i n t o th e t oot h · Pr eser va t i ves- gi ve s bl ea ch in g m a t eri a l bet t er st a bi l i t y a n d dura bi l i t y · Fl a vor i ngs- t o enh an ce pa t i en t a ccept a bi l i t y r ecen t pr oduct s to r educ e · Fl uor i de(i n sen si t i vi t y) MECHANISM OF BLEACHING Mechanism of whitening by oxidizing agents is not actually understood. Th e t ech ni que wor ks by l i gh t enin g t he en a m el t o gi ve t h e a ppear an ce of wh i t en ess. On e t h eor y st a t es t h a t th e l ar ge c ol or ed or ga n ic m ol e cul es r esp on si bl e for t h e st a i n s ar e r educe d t o sm a l l er , l ess n ot i cea bl e m ol e cul es by t h e oxi da t i on pr oce ss. T h e h ydr ogen per oxi d e a ct s bot h a s an ox yg en a t or a s wel l a s oxi da n t 1 0 , 1 1 . An ot h er th eor y i s t h a t th e per oxi de pen et r a t es i nt o en a m el an d den t in e a n d oxi di z es t oot h di sc ol or a t i on s. Th e pa ssa ge of n a sc en t ox yge n i nt o t h e t oot h st r uct ur e oc cur s fi r st i n en am el and t h en in den tin e 1 1 , 1 2 . B LEACH ING PRO CEDURE · Pa t i en t is a ssess ed cl i n i ca l l y and r a di ogr a ph i ca l l y · Shade assessment with the teeth being wet and dry · Pr oposed t r ea t m en t pl annin g i s don e · Pr e oper a t i ve ph ot ogr a ph s of t e et h ar e ta ken · Isolation: there are many forms of isolation that can be used, depending on the type of bleaching procedure used, or the dentist's particular preference. - Rubber dam is a good method of isolation . Ligation of the teeth are done with waxed dental floss to prevent seepage of the fizzing hydrogen peroxide solution through to the underlying tissues - Opal dam (Ultradent Products, South Jordan, Utah, USA). These are light cured resin barrier materials that are painted on to the gingiva around and in between the teeth to be bleached. · Soft tissue retraction: -Cheek and lip retractors are placed to pull these tissues away from the teeth and bleaching gel.. -NOLA Full Arch isolation (NOLA Full Arch isolation, Orthocare-UK) within built suction facility · Tongue guard to prevent the forward movementof the tongue on to the teeth and bleaching gel. · Gauze and cotton wool rolls placed inside the lips and cheeks to keep them away from the gel · T eet h ar e cl ea n ed wi t h pum i ce pr oph yl a xi s pa st e · Bl ea ch in g m at er ia l i s n ow a ppl i ed t o t h e t e et h . 2–3 mm layer of freshly mixed gel should be applied to all the labial surfaces of teeth in the smile zone and lipped over to cover the incisal edge, smile zone varies from patient to patients but is commonly from the first or second premolar · Activation with or without a light source depends on the bleaching system used -If Light is used they are applied close to the teeth - If laser is used Gel is placed at a thickness of 1-2 mm on to the buccal surface of the teeth to be bleached laser light is applied for 30 seconds about 1-2 cm from the buccal surface of each tooth. Laser light is applied slowly for 30 seconds and moved from right to left over the tooth’s surface. -If pl a sm a ar c l i ght i s used, th e l i gh t i s a ppl i ed 6-7 m m a wa y fr om t h e gel . It em i t s 3 s e c on ds bur st s of l i gh t, wh i ch i s a ppli ed on t o ea ch t oot h i n t urn . Th i s i s gen er a ll y c on t in ued for a per i od of t hr ee, 3-m in ut e in t er va l (depen di n g on i n str uct i on s) or 10-15 m i n ut es, a n d th e bl ea ch i s r em oved fr om th e t eet h vi a th e h i gh vol um e a spi ra t or . · The gel is left in place for a length of time dependent on the system and concentration of hydrogen peroxide used, usually about 10 minutes, but can range from 3–20 minutes at a time10. · T eet h ar e th en wa sh ed, an d th e bl ea ch i s r ea ppl i ed for a fur th er 10 m in ut es a n d th e pr oce ss i s r epea t ed for 45 m in ut es t o 1 h our . · T eet h a r e pol i sh ed wi t h di a m on d pol i sh in g pa st e or a l umin um oxi de di sc s. · Da m i s t h en r em oved. M out h i s r i n sed a n d sh a de of t h e t eet h i s n ow a ss es sed. A post op er a t i ve ph ot ogr a ph can be t a ken . · Application of a neutral colourless fluoride gel may help in cases where there was sensitivity experienced during the procedure7,13. · Pa t i en t i s ca l l ed 3-6 week s l a t er an d th i s pr oce ss ca n be r epea t ed i n 6 we eks i n cr em en t un ti l th e desi r ed sh a de i s a ch i eved. · Patients should be given postoperative instructions: Use of a fluoride gel or potassium nitrate containing toothpaste in cases that experience thermal sensitivity. Dietary advice to avoid acidic drinks, fruits, tea, coffee and smoking for 48 hours. It is thought that the oxidizing free radicals are still active within the teeth for a further 48 hours post bleaching Shade regression of about half a shade unit tends to occur about a week to ten days post bleaching. Patients should be made aware of this to avoid disappointment. · Top up home bleaching kits should be given to those cases that require further bleaching. CHAIRSIDE BLEACHING SYSTEMS Curing Lights Different types of curing lights are used for the activation of the bleaching gel. Initially, it was the conventional curing Page 13.

(3) Hegde Mithra N et al. IRJP 2012, 3 (11) lights but then these were quickly joined by lasers and plasma arc lamps. In addition others utilize a dual activation system. H al oge n Li ght Curing lights system has been widely used in dentistry for bleaching. This in-office bleaching system is a xenonhalogen bleaching light that launch a blue-green coloration. Halogen light bleaching system uses 35% Hydrogen Peroxide that contains carotene that converts light energy to heat and therefore increases the activation of the hydrogen peroxide based bleaching compound with a pH of 5.535. Each bleaching session in-office is broken down into three individual applications, with the duration of each application being 8 minutes. It means that the cumulative exposure to the gel is 24 minutes to delivers 2 - 4 shades 14,15,,35. Metal Halide Lamp Metal halide light produced from fired up mercury atoms to activate and boost the teeth whitening solution. It is incorporated with an IR (infra-red) filter and emits insignificant amounts of UV(ultra-violet) emissions to minimize heat at the surface of the tooth. Its makes use of specific peroxide-based gel and it is provided an activator34. These two resources are combined together during the whitening procedure creating whitening gel that is very basic (features a pH range that's usually somewhere between 7.5 and 8.5) and is 25% hydrogen peroxide. This technique employs three 20-minute passes followed by the application of sodium fluoride gel15,22. Plasma Arc Lamp Plasma is the fourth state of matter, Pl a sm a ar c l amp wa s i n tr oduc ed i n 1993; it consists of charged particles, radicals, and a strong electric field. Plasma has potential biomedical applications because it is non thermal and nontoxic and can be realized in a simple hand-held device . Furthermore, it also generates energetic ions, free electrons, and hydroxyl radicals (.OH) that contribute significantly to tooth bleaching, so that plasma might have a synergic effect on tooth bleaching by H2O216. Tooth bleaching method with plasma that we can be complementary to the conventional method because it provides effective bleaching without thermal damage Gas Plasma Light Gas plasma light system which consists of a lamp filtered to emit light in the blue-green region of the spectrum (approximately 400-500 nanometers) and a patented delivery device, which illuminates all smile teeth at once 15,17. The Gas Plasma Light is used in combination with a patented peroxide gel, which has been optimized to obtain a maximal whitening effect and to ensure patient safety 10,17. The patented chemistry consists of a 15% hydrogen peroxide gel buffered at an approximately neutral pH that is compatible with tooth enamel. The gel also contains other ingredients such as glycerine and highly purified water to prevent tooth dehydration and to further ensure safety. The gel also contains a patented photo-initiator, which assists in chromophore destruction at the tooth's surface17,18. The plasma light technique consists of two 20 mins cycle. A study by the prestigious Forsyth Institute also confirmed the 9+ shades average improvement achieved using the BriteSmile process17. Plasma Arc Light Source The plasma arc light employs a hydrogen peroxide-based bleaching gel and has a 25% Hydrogen Peroxide, a pH of 8.5. The higher doses of peroxide make the mix stronger, and better able to remove stuck-on stains, like coffee, tea or cigarettes19,22. The plasma arc light system consists of one 30. mins cycle, after the 1st cycle within results are evaluated and it is determined if 2nd 30 mins cycle is necessary. Che mi c al Ac ti vate d B le ac hi ng Chemically-activated in office bleaching agent. Its based on 38% hydrogen peroxide two part gel system21. It consists of one syringe, containing hydrogen peroxide, which is mixed with the second syringe and is chemically activated, activation is due to a unique proprietary activator that increases the pH to 7 for maximum activation. When mixed together, the bleaching agent is supercharged that does not require light or laser activation22,35. Teeth typically become at least 6 - 10 shades whiter. Chemically-activated in office bleaching technique consists of 3 cycles of 10-15 mins each. Lase r B l e ac hi ng Tec hni q ue T h e wor d “l a ser ” i s an a cr on ym for l i ght a m pl i fi ca t i on by st i m ul a t ed em i ssi on of r a di a t i on. La ser bl ea ch i n g offi ci a l l y st a r t ed in 1996 wi t h t h e a ppr ova l of Ion La ser T ech n ol og y’s a r gon a n d car bon di oxi de l a ser s by t h e FDA. T h er e i s l i t t l e dat a t o pr ove t h a t l a ser s ar e m or e effe ct i ve t han th e tra di t i ona l bl ea ch in g m et h ods. · Ca r bon di oxi de (10600 nm ) · Nd: YAG · E r cr : YSGG · Ar gon (515 n m ) · Di od e (980 nm ) · KT P (532 n m ) · Com bi n a ti on s These units create output that lies in the near-infrared portion of the spectrum (In comparison, most bleaching units primarily emit visible light).The use of one these lasers is that their output (a specific wavelength) "activates" a catalyst within the whitener that, in turn, increases its effectivenes20. Laser Whitening Gel is a unique mix of laser activated Crystals integrated into a gel of highly processed Fumed Silica and 35% Hydrogen Peroxide20,36. This translucent, semi-viscous bleaching gel is applied to the teeth and a high intensity light source (laser light) is used to activate the Crystals to absorb the thermal energy from the light and allowing better disassociation of the oxygen to better penetrate the enamel matrix and increase the lightening effect on the teeth20. In this system Gel is laser-activated in 15-second intervals and repeated as necessary. The laser can be exposed to a few teeth at a time. The effect of shade change of chemical oxidation, Light Activation and Laser technique are the same but the bleaching time required for Laser system is comparatively lesser compared to the other two systems and there is no effect on the longevity of the process of bleaching35. BLEACHING TECHNIQUES Wai ti ng Room B l e ac hi ng Tec hni que In th i s t echn i que 35% car ba m i de per oxi de ( wh i ch br ea ks down t o 10% h ydr ogen per oxi de) i s use d a s a bl ea ch i n g a gen t. Th e t eet h ar e pol i sh ed wi t h pr oph yl a xi s pa st e. T h e 35% ca r ba m i de per oxi de i s h ea t ed gen t l y by h ol di n g th e s yr i n ge un der h ot r unn in g wa t er for 2-3 m i n ut es. Hea t of t h e s yr i n ge a ccel er a t es t h e a ct i vi t y of t h e m a t er ial be for e i t i s l oa ded i n t o t h e m out h gua r d. The 35% ca r ba m i de per oxi de i s pl a c ed i n t o a cu st om m a de bl ea ch i n g tr a y 6 . Page 14.

(4) Hegde Mithra N et al. IRJP 2012, 3 (11) Aft er exc ess m a t er i a l i s r em oved, t h e pa t i en t is sea t ed i n th e wa i t i n g r oom for a per i od of a bou t 30 m in ut es wi t h th e bl ea ch i n g tra y i n th e m out h. Aft er 30 min ut es, bl ea ch i s suct i on ed off t h e t eet h be for e r i n sin g 6 . Th i s pr ocedur e ca n be r epea t ed 2-3 in a sin gl e sessi on . Compr e s si ve B l e ac hi ng Te c hni que Mi a ra (2000) suggest ed t h a t th e power bl ea ch i ng t ech n i que coul d be m a de m or e e ffe ct i ve by c om pr essi n g th e bl ea ch i n g ma t eri a l on th e t oot h . In th i s t echn i que n a cen t ox yg en m ust be gui de d un der pr essur e for per m ea t i on of t h e oxi di z ing i on s t hr ough th e en am el . It s r ecom m en ds t o u s e 35% h ydr og en Per oxi de i n a bl ea ch i n g tr a y, sea l i n g th e tra y edge s wi t h li gh t cur ed r esi n to pr even t da m a ge t o th e soft t i ssu es 2 0 . Th e gel i s ei t h er a ct i va t ed by h a l ogen l i gh t or pla sm a a rc l i gh t . T hi s i s a r el a ti vel y n e w t e ch n i que an d is un der goin g cl i n i ca l eva l ua t i on . On e of t h e m a j or c on cer n s a bout t h i s t ech n i que i s probable penetration of hydrogen peroxide into the pulp chamber after only 15–20 minutes24. D ual Ac ti vate d Te c hni q ue T h e in -offi c e bl ea ch i n g syst em i s a ct i va t i on by c om bi n a t i on of bot h l i gh t an d ch em i cal a ct i va t i on . It con si st s of fer r ous sul ph a t e, wh i ch ser ves a s a ch em i ca l a ct i va t or th at com pl et es t h e bl ea ch in g pr oces s i n 7-9 m in ut es 2 5 . In a ddi t i on, the for m ul at i on a l so i n cl udes m a n gan es e sul ph a t e, wh i ch i s l i gh t a ct i va t ed a n d ca n a cc el er a t e t h e bl ea ch i n g pr oc ess t o a s l i t t l e a s 24 m in ut es. Thi s t echn i que uses h ydr oge n per oxi de i n a str on g con cen t ra t i on of 19-35% 2 5 . Act i va t i on t im e Ch em i ca l a ct i va t i on : a ppr ox. 15-20 m in s Li gh t a ct i va t i on : 8-10 m in s DISADVANTAGE OF VITAL TOOTH BLEACHING - Because of the causative nature of the bleaching agent isolation is necessary. - Dehydration of the teeth causes a falsified lighter shade immediately post bleaching procedure26. - The bleaching procedure is can work out expensive for the patient. EFFECTS OF BLEACHING AGENT Dental tissue and Oral mucosa Whitening effects of hydrogen peroxide on teeth and oral mucosa have been documented. Number of cases show undesirable effects such as hypersensitivity (2.62–3.38%) and gingival irritation (0.23–0.85%) have been reported27. Changes are also seen in enamel microhardness, micromorphological defects due to demineralization, and effects on restorative materials have also been reported 28,29,30. Tooth se n si ti vi ty T oot h sen si t i vi t y i s a com m on si de-e ffe ct of ext er n al t oot h bl ea ch in g. Dat a fr om va r i ous st udi es of 10% ca r ba m i de per oxi de i n di ca t e t hat fr om 15 t o 65% of t h e pa t i en t s r epor t ed i n cr ea sed t oot h sen si t i vi t y 3 1 . Hi gh er i n ci den ce of t oot h sen si t i vi t y ( fr om 67 t o 78%) wa s r epor t ed a ft er in -offi c e bl ea ch i n g wi t h h ydr og en per oxi de i n c om bi n a t i on wi th h ea t. T oot h sen si t i vi t y n or m a l l y p er si st s for up t o 4 da ys a ft er th e ces sa t i on of bl ea ch in g tr ea tm en t,. but a l on ger dur a ti on of up t o 39 da ys h a s bee n r epor t ed 3 2 , 3 3 . T oot h sen si t i vi t y wa s a l s o a c om m on s ym pt om i n pa t i en t s wh o ha d n ot bl ea ch ed t h ei r t eet h , and t h eir s ym pt om wa s c or r el at ed wi t h gi ngi val r e c e ssi on 3 4 . Pa t i en t s wi t h a pr evi ous h i st or y of t oot h sen si t i vi t y m a y t h us h a ve a h i gh er r i sk for such a n a dver se e ffect fr om ext er n al t oot h bl ea ch in g, an d th i s sh oul d be t a k en in t o a cc oun t be for e t r ea tm en t begi n s. CO NCLUSIO N In office bleaching techniques are used in patient who seek immediate results and do not wish to spend more time on achieving results from home bleaching systems. Owing to the caustic nature of the 35% hydrogen peroxide meticulous care should be on performing bleaching. For better effect of bleaching more than one visit would be required, the results vary from patient to patient for many one visit would be enough to satisfy the aesthetic needs of the patients and a second visit wouldn’t be necessary In office techniques with easier and simpler isolation methods and improved bleaching gels and improved whitening lights have made bleaching results very efficient .Improved bleaching materials and technique, as described above, result in less sensitivity and better. REFERENCES 1. Joyce L. Bassett, Gregori M.Kurtzman. Simplified Chairside Whitening. Dentistry today 2011 2. De Silva Gottardi M, Brackett MG, Haywood VB. Number of in-office light-activated bleaching treatments needed to achieve patient satisfaction. Quintessence Int. 2006;37:115-120. 3. Watts A, Addy M. Tooth discoloration and staining: A review of the literature. British Dental Journal 2001;190:309-16. 4. ADA Specifications. 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