 Hello everyone welcome back to another session in dentistry and more. Today's topic in conservative dentistry is teeth bleaching or teeth whitening process. How the teeth is from a darker shade to lighter shade get changed by using chemicals. So that is what we are going to learn in today's class. So teeth bleaching first of all let's directly jump to classification we have process which is done on vital tooth and non vital tooth. So it can be done professionally from the dental office and from house itself okay by the person. So in dental office that is in office bleaching we have power bleach thermo catalytic bleach and photo thermo catalytic bleach. From the person himself can do at home that is night guard bleaching which comes under vital bleaching whereas non vital bleaching we have in office that is professionally done at dental clinic that is thermo catalytic bleaching and working bleach. So what are the materials commonly used for bleaching we have three materials one is hydrogen peroxide then carbamide peroxide and sodium pervirate. So ultimately it is hydrogen peroxide it is done the process of bleaching okay. So first we need to learn the mechanism of bleaching. So it is an oxidation reduction reaction which is known as redox reaction okay. So tooth and bleaching agent which is undergoing a redox reaction. So tooth is a reducing agent and bleach is an oxidizing agent. So how bleach will become oxidizing agent because the hydrogen peroxide or carbamide peroxide or sodium pervirate after the chemical reaction it releases hydrogen peroxide. So carbamide peroxide also it releases hydrogen peroxide. So the first product is urea and hydrogen peroxide urea will be converted to ammonia and carbon dioxide carbon dioxide will be changed to carbonic acid. So this hydrogen peroxide that is what actually is becoming the oxidizing agent okay. So oxidizing agent is nothing but which oxidizes the other product that is oxidizes the tooth. So what it is exactly oxidizing is chromogenic pigments. So chromogenic pigment is what gives the tooth a darker shade okay. So it has unpaired electrons that is free radicals. So you can see hydrogen peroxide after chemical reaction or after reaction with saliva it becomes free radicals that is hydroxyl and parhydroxyl free radicals. So this dotted one is free radicals and also super oxide anions. So all having unpaired electrons okay. So these unpaired electrons will be donated to the reducing agent that is a tooth okay. So this oxidizing agent with free radicals that is with unpaired electron will be donated to the reducing agent and this reducing agent is oxidized and become whiteened tooth because it has a darker shade chromogenic pigments. So this chromogenic pigments will be double bonded okay it has double bond. So it will be converted to single bond okay. So double bond will be always a darker shade it will become single bond it will be a lighter shade that is a reaction which is happening okay that is oxidation of tooth for the tooth surface. So on the tooth surface we have this chromogenic pigments okay. So how this pigments is coming we are going to see that is we have the stains intrinsic stains and extrinsic stains. So this is the mechanism which is happening. So let it be sodium perforate or carbamide peroxide the hydrogen peroxide which is converting to the free radicals. So this free radicals with free unpaired electrons will be giving the electron to reducing agent that is tooth and it becomes oxidized that is the chromogenic pigment with a double bond changing to single bond that is chemical reaction. So this double bond will be oxidized to become single bond. So the color also will be changed to a lighter shade okay. So that is the mechanism of bleaching now we are going to see about the indications contraindications and various types of pigments and all the bleaching techniques. So the first product is hydrogen peroxide it is used as a whitening agent usually in the range of 5 to 35 percentage it has low molecular weight which can penetrate the dentine it is clear colorless and odorless liquid which is very unstable and it is kept away from heat. So case should be taken while handling because it has ischemic effect on skin and mucus membrane. So it is commonly used in walking bleaching technique whereas sodium perburet which is a stable white powder it has got three types that is sodium perburet monohydrate trihydrate and tetrahydrate. So when mixed into a paste with super oxal this paste decomposes into sodium metabolite water and oxygen. So it is used in walking bleach. So whereas a carbamide peroxide we already discussed it is urea hydrogen peroxide it is carbamide peroxide it is differentiated it is dissociated into urea and hydrogen peroxide this is forming hydroxyl ions which is creating free radicals with electrons splitting the double bond into single bond. Okay so that is the three products commonly used for bleaching hydrogen peroxide carbamide peroxide and sodium perburet. So there can be basically two types of stain which we are trying to remove or make it to lighter shade using bleaching that is intrinsic and extrinsic stain. Intrinsic stains which is present or which is present within or which is internal to the tooth extrinsic stains which is present on the outer surface of teeth. Stain internalization is nothing but extrinsic stain which is going inside through the defect in the enamel structure. So there are many courses for intrinsic stain it can be metabolic inherited urea atrogenic traumatic adiopathy can aging courses whereas extrinsic as we all know it is related to diet bacterial stains ginger hemorrhage, chloroxidine stain, tobacco stains. So this internalization is due to dental caries, ginger blood recession, tooth wearing. So metabolic courses so we can have metabolic courses so this itself can be a short note that is the types of stains. So metabolic courses it can be alcaptone urea, congenital erythropoietic pophyrea and congenital hyper bilirubinemia and inherited discoloration the most common amelogenesis imperfecta, dentinogenesis imperfecta, AI, DI, then dentin displays here. So vitamin D rickets then epidomolysis bullosa, earlose, downlose syndrome so all can cause intrinsic stains which is in the inherited course. So trauma related discoloration is basically due to the pulp necrosis and again another reason is dentin hypercalcification, dentin hypercalcification then pulpal necrosis. So then atrogenic discoloration like due to the amalgam filling, pins and post placement and various obstetting materials, composite material, intra canal medicaments, pulp tissue remnants so all can give intrinsic stains and also the medication that is tetracycline staining which is due to the usage of tetracycline during the pregnancy time. So again another one is fluorosis you know consumption of water with fluoride more than one ppm gives various ranges of fluorotic enamel it ranges from minimal white flecks to severe brown discoloration. So that is fluorosis again it could be due to the normal aging process. So enamel becomes thinner, dentin becomes thicker and more yellow and grayish yellow. So that is about intrinsic staining whereas the extrinsic one means it can be due to metallic and non-metallic causes. So metallic basically associated with occupational exposure whereas non-metallic is associated with tobacco, tea stains, coffee stains induced by chlorxidine, stain from use of antibiotics and also from chromogenic bacteria. So that is extrinsic stain which is actually easy to remove compared to the intrinsic one. Now let's see the indications of bleaching. So it is indicated when there is mild discoloration on surface, evenly distributed discoloration without bands or white spots, teeth discolored as their innate colors or aging, hemorrhagic discoloration, discoloration of anterior teeth after RCT or medication discoloration. But it is contraindicated in sensitive teeth that is in the case of attrition, aberration, erosion or abfraction, teeth with cracks, hypoplastic or severely undermined enamel then if there is any extensive restoration, the discoloration in the gray, blue, gray or black range which is very difficult to get to a light to shine after bleaching and discoloration by metallic salts particularly silver amalgam. The pulp chamber is enlarged so in such cases also it is contraindicated. And also if patient complains factor in pregnant and nursing ladies also we need to take precaution because there is a reported history of peroxide allergy. So that is about various types of stains. Now let's see the various types of bleaching. So for bleaching we have two techniques vital and non vital. So in vital can be done at office that is one is power bleaching. So power bleaching then thermo catalytic bleaching catalytic bleaching and photo thermo catalytic photo thermo catalytic. Second one is done at home that is night guard bleaching. So question might come as night guard bleaching or walking bleaching. So both are done at home. One is vital and another one is non vital and again non vital also we can done the thermo catalytic bleaching. So thermo catalytic nothing but the reaction starts using the heat source that is why thermo catalytic the heat becomes a catalyst. So we'll start with the night guard bleaching that is done under vital tooth bleaching done at home. So this is the most commonly used technique because it is very easy to perform and less expensive. The only thing is so we need to create a custom tray based on the patient's teeth. Then only we can give the material for the patient to perform the bleaching at home. So it commonly uses 10% carbamide peroxide. So it is indicated in superficial enamel discoloration or mild yellow discoloration or brown fluorosis discoloration or age related discoloration. So contraindicated in severe enamel loss hypersensitivity, bruxism carries any defective coronal restoration or any type of allergy. So the steps the main step is to fabricate the tray for the patient. Okay so first we need to take a impression then make the stone model trim the model place the stock stock out resin and cure it apply the separating media then choose the tray sheet material. So nature of material used for fabrication of bleaching tray is flexible plastic need to be very flexible so that patient can easily wear it. So the most common material is ethyl vinyl acetate okay so ethyl acetate. So then cast the plastic in vacuum tray forming machine trim and polish the tray checking the tray for correct fit retention and overextension then demonstrate the amount of bleaching material to be placed because we need to teach the patient how much material to be taken and how to apply it because the person is going to do this at home there is no dentist is there to monitor the patient. So we need to demonstrate it so the main thing is we need to keep a pre-operative photographs because the patient might argue after that the patient has not improved so we need to keep a pre-operative photograph. So before doing this we need to instruct that patient has to brush his teeth because this surface debris minimize the effective contact of bleaching agent then place enough bleaching agent into the tray to cover the facial surface of the teeth. So this is how we teach the patient okay then tray should be worn for a period of four hours okay four hours for every session. So if there is any problem that is sensitivity then patient need to reduce the time period and then patient can repeat the bleaching session for a second time in same day okay. So this is one day so he need to remove the tray from the second molar region in a peeling action okay. So after that rinse of the bleaching agent from the surface of the teeth tray should be gently brushed to remove any of the bleaching residue. So the number of days required to achieve the desired results is chiefly dependent on the original extent of two discoloration. If the person's discoloration is very mild he might get a good prognosis in a very recent time. So if it is very darker shades it takes a longer period so it can the results can be seen as early as two to 14 days or may take six to twelve months okay can take up to six to twelve months or can be as early as two to 14 days okay. So that is the process of night guard that is done at home so we need to teach the patient how to done how to apply it how to remove it and what procedures before applying the tray and how long he should keep it and what after to be done that is how to clean it and on what occasion you need to reduce the timing all things we should teach the patient that is a night guard bleaching. So next is a in-office bleaching that is a bleaching of vital teeth at dental clinic so this is a basic one is thermocathletic bleaching. So the equipment required are power bleaching material then there should be a tissue protector then there should be a activating source basically thermo activator then protecting cloth and eyewear there should be a mechanical timer so most commonly we are going to use a light source it could be conventional bleaching light tungsten halogen curing light or xenon plasma light or argon and carbon dioxide lasers or diode laser light so these lights can initiate the process so we are going to do the procedure using a thermo catalyst or mainly a light source so it is commonly indicated in mild fluorosis and tetracycline stains then also the superficial stain so in order to match the existing color of the crown that is lighter than the natural teeth so it is contraindicated in extensive carries hypersensitivity root exposure severe discoloration and extensive restoration so the procedure okay first evaluate the tooth color with a shade guide we can use a 3d shade guide and we need to evaluate the shade of the tooth then protect the ginger well tissues with a vaseline or oro base and isolate the teeth with a rubber damp place a protective sunglass over the patients and operators eye because we are going to use a light source which is very harmful for the eye okay then clean the enamel surface with pumice and water then we need to apply it the apply the bleaching agent so that is 30 to 35 percentage of hydrogen peroxide okay so this is the agent so night guard we used 10 percentage carbamide peroxide here we are using 30 to 35 percentage hydrogen peroxide so it is applied as a liquid or gel on the label surface of the teeth using cotton pellet then we are going to apply heat with a heating device the temperature should be maintained between 120 to 140 degree 120 to 140 degree fahrenheit or it is 50 to 60 degree Celsius so the treatment time should not exceed 30 minutes so it should be less than 30 minutes so if it is going beyond 30 minutes the result will not be satisfactory so after that remove the heat source and allow teeth to cool down for at least five minutes pumice is used to on the teeth to remove the residual exposed gel from enamel surface then irrigate thoroughly dry the teeth and gently polish them then we need to apply the neutral sodium fluoride gel for three to five minutes so any bonded restoration on the bleaching surface and tea coffee etc and all this should be avoided for two weeks okay so that was the thermo catalytic where we use a light source okay light source so we can also have non thermolytic bleaching so in this technique the heat source is not used so the commonly used bleaching material is super oxal ether sorry super oxal so it consists of hydrogen peroxide and ether that is H2O2 and ether so super oxal is five part of H2O2 and one part of ether then we can have another solution that is macan solution macan solution is nothing but five parts of H2O2 then five parts of HCl then one part of ether okay so that is without using a light source okay so that is either super oxal or macan solution super oxal is nothing but H2O2 and ether and if I used one combination then macan solution is along with this we have five parts of HCl so next we have the bleaching of non vital tooth okay so non vital tooth the first one is walking bleaching it involves use of chemical agents within the coronal portion of an enterontically treated tooth to remove the tooth discoloration so indicated discoloration of pulp chamber dentine discoloration discoloration which is not amenable to extra coronal bleaching so this is basically extra coronal bleaching this is like intra coronal bleaching we are trying from outside it outside the enamel surface so it is contraindicated in superficial enamel discoloration defective enamel formation or severe dentine loss or presence of caries or discolored composites now the steps so first take a radiograph to assess the quality of objuration then evaluate the quality and shade of the restoration if present if restoration is defective then replace it then evaluate tooth color with shade guide isolate the tooth with rubber damp reestablish the access cavity remove the coronal ghatapacha expose the cavity and refine the cavity then seal the orifice of the root canal with at least one mm intra coronal barrier over the ghatapacha to prevent percolation of the bleaching air in into the apical area okay so we need to this is a tooth we have endodontically ghatapacha here this is access cavity so seal the orifice of the root canal with at least one mm intra coronal barrier keeping it intra coronal so there should be a barrier here so that the bleaching agent we are placing here will not percolate into this periapical area so GIC MTA or any other material can be used as a barrier material of which this MTA is very good so this level of barrier material should be one mm incisal to the CEJ okay so here it is a CEJ cementer nomination one mm incisal to the CEJ so it is important to confine the bleaching agents to the crown of the tooth above the level of bone so we have a bone here so it should be above bone then we are going to mix sodium perborate with distal water okay so sodium perborate we are going to use for the walking bleaching it will be mixed with distal water in case of severe stains we can also use 3 percentage hydrogen peroxide then carry this this thick paste into the pulp chamber so we are going to place it here we are going to place it here make sure that entire facial surface of the pulp chamber is covered with the paste okay then place a small cotton pellet slightly moistened with H2O2 over the bleaching paste then seal the excess cavity to a thickness of 3 millimeter using an adhesive material so the maximum bleaching effect is attained about 24 hours after the treatment 24 hours so patient should return in 3 to 7 days for evaluation of results if too dark shade we need to go for additional bleaching and if the shade is too light the tooth should be permanently restored so that is a procedure of walking bleaching then we use sodium perborate and 3 percentage H2O2 which is done on the enteronically treated tooth keeping a barrier here using MTA which is 1 mm to the CEJ and alveolar bone keeping this barrier not to percolate the bleaching agent into a peckle area so covering the bleaching agent on the facial side and sealing it and asking the patient to return in 3 to 7 days and do the restoration if it is not attained the result we need to repeat it whereas the thermo catalytic bleaching that is non-vital in office bleaching so after preparation of the tooth as previously described so the same procedure we need to repeat a loose mat of cotton is placed on the labial surface and another is placed in the pulp chamber of the tooth to be pleased so the cotton mans are saturated with 30 percentage of hydrogen peroxide then the solution is activated by exposing to the light and heat from a powerful light so here we are using powerful light source to activate the solution so the tooth is subjected to usually 5 to 6 minutes exposure and replenishes the bleaching solution in frequent intervals so on completion of the bleaching a pellet of cotton is moistened with hydrogen peroxide or sodium perborate is sealed in the pulp chamber until the following appointment the main complications of this intra coronal bleaching is external root resorption chemical burn or inhibition of resin polymerization so that is all about the non-vital bleaching or vital bleaching so question is mostly asked about the night guard or walking bleaching or it is commonly asked as a vital bleaching or non-vital bleaching so it's very commonly asked question and again regarding the hydrogen peroxide, carbamide peroxide and sodium perborate so hope you understood the concept of bleaching so we were discussing the bleaching concept in the first part of this video then we discussed about various types of stains then about the bleaching techniques that is vital bleaching and non-vital bleaching techniques so i'll come up with a new topic in the conservator industry thank you