Issue 10 2013 How to whiten a non-vital anterior tooth. Background: A recent study found that almost two-thirds of bleached non-vital teeth had still retained their lightened colour after 16 years. The results were obtained using the traditional walking-bleach technique which involved the use of heat and a high (31%) concentration of hydrogen peroxide. Since then however there have been a number of modifications to improve many aspects of the procedure. Three types of bleaching techniques: 1 Inside/outside - 3-day method. 2,3 Above: Photograph of two teeth, the upper right central and lateral incisor, that that had been bleached with the inside/outside technique. Details of case are given on page 55. a b c root filling open access cavity 10% carbamide peroxide syringe tip special custom tray 10% carbamide peroxide Root filling is removed to the appropriate level, a is placed and the access cavity is left open. 2 At home, the patient injects 10% carbamide peroxide into the access cavity. Inside/outside - traditional method + tray whitening. Except for meal times, a special custom tray containing 10% carbamide peroxide is worn day and night for 2-3 days. The carbamide peroxide in the access cavity and tray is replenished every 2 hours during the day. root filling special custom tray thick paste of sodium perborate, hydrogen peroxide/ water sodium perborate paste sealed in 10% carbamide peroxide Root filling is removed to the appropriate level, a is placed and the access cavity is filled with a sodium perborate, hydrogen peroxide/water The sodium perborate paste is sealed in and replenished at weekly intervals if needed. External bleaching is carried out using 10% carbamide peroxide in a custom tray for 2 weeks.
Three types of bleaching techniques: (cont) 3 Inside - traditional walking bleach. a b c root filling 31-35% hydrogen peroxide on pellet of cotton wool followed by heat. thick paste of sodium perborate, hydrogen peroxide/ water sodium perborate paste sealed in Root filling is removed to the appropriate level and a is placed. Hydrogen peroxide (31-35%) is introduced into access cavity on a pellet of cotton wool and heat applied. NB: Use of heat is now contra-indicated. A thick paste comprising sodium perborate with hydrogen peroxide or water is placed in the access cavity. The sodium perborate paste is sealed in and replenished at weekly intervals if needed. Note: The above techniques only give a general outline of the procedures involved. There are many variations. 10 useful tips... 1 Ensure access cavity is clean Barrier placement: The need for the access cavity to be totally clean and free of any root filling material, base or restorative material is well established. The combination of 1% sodium hypochlorite followed by EDTA as used in root canal preparation is helpful as a finishing step. EDTA helps remove the smear layer and open up the dentinal tubules. In solution form, EDTA is easy to inject and remove from the depths of an access cavity. 2 Be wary if discolouration is from amalgam The migration of tin from a old amalgam in the palatal access cavity can cause a type of discolouration that is difficult to remove. 3 Whereas a bleaching agent can readily breakdown discolouring agents that originate from the pulp this does not hold true for metal ions that have come from amalgam. Even so bleaching can be tried with the appropriate caution given to the patient about the likelihood of a totally successful result. Internal should also cover the dentinal tubules finishing in the areas shown. The occlusal surface of a should follow the scalloped contour of the cemento-enamel junction (CEJ). Rather than finish the barrier with a flat surface to coincide with the most apical part of the CEJ as shown (left), it should be curved and sloped to ensure that the dentinal tubules finishing in the shaded areas (left and right) are covered. This can be done just before the GIC sets by using the curved outer surface of a spoon excavator.
3 Try 3-day procedure if rapid whitening needed Some patients require rapid whitening for a special occasion such as a wedding. However, they must be motivated as it requires persistence over a few days. In addition good manual dexterity is needed (i) to insert the nozzle tip into the access cavity and (ii) to place and remove the pellet of cotton wool into and from the access cavity before and after eating. Details of the technique are given below. 4 Avoid using heat Photograph showing the type of modification made to a bleaching tray when a single tooth is being whitened using an inside/outside bleaching method. Heat is no longer required or desirable in non-vital bleaching. 3 The traditional walking-bleach method involved the use of heat to accelerate the bleaching action of high concentrations of hydrogen peroxide. This combination has been associated with the development of invasive cervical resorption. Teeth that have been subjected to trauma are particularly vulnerable. 5,6 5 Use lower-concentration hydrogen peroxide Although it is the combination of heat and high concentrations of hydrogen peroxide (>30%) have been associated with invasive cervical resorption it is probably still advisable to use lowerconcentration hydrogen peroxide preparations. The correct use of sodium perborate can help offset the need for the higherconcentration products. When mixing sodium perborate with hydrogen peroxide or water make the mixture very thick (see next page). It should be so thick that an increment retains its shape whilst it is being ejected out of an amalgam gun into an access cavity. Procedure for 3-day whitening : In the surgery: 1. Check that the existing root filling is of good quality. 2. Take an impression and have a bleaching tray constructed that allows the bleaching of a single tooth (see next page). 3. Remove the restoration from the access cavity and clean out the contents of the pulp chamber, especially in the area of the pulp horns. 4. Take the existing root filling down to a point 2 to 3 mm below the cemento-enamel junction. 5. Place a 1-2 mm layer of glass-ionomer cement to seal off the root filling. The endodontic access cavity is left open. 6. Rehearse the steps that need to be carried out at home to ensure that the patient is fully familiar with them. 7. Issue patient with syringes containing 10% carbamide peroxide, cotton-wool pellets and an instrument to remove the pellets from the opening to the access cavity. 8. Schedule an appointment to coincide with the end of treatment. At home: 1. The patient inserts the tip of of the syringe with the bleaching gel into the endodontic access cavity and injects some material. 2. The appropriate area in the bleaching tray is loaded with the bleaching gel and the tray is inserted. 3. Excess material is wiped away with a finger, tissue or soft toothbrush. 4. The above procedure is repeated every 2 hours during the day and done just before retiring at night.>
6 7 Take care with the A good not only blocks off the root filling but any dentinal tubules that radiate out from the base of the access cavity and exit apical to the cemento-enamel junction. Because the cemento-enamel junction follows a scalloped outline when placing the GIC use the outer curved surface of a small spoon excavator to put in a curved surface mesiodistally and to slope the GIC coronally towards the lingual wall. A check radiograph will help confirm the correct barrier shape. Make sodium perborate paste thick An anecdotal observation from successful cases in which sodium perborate paste has been used is that the paste must be made thick - very thick. Whether mixing sodium perborate with water or 3%, 6% or 35% hydrogen peroxide use enough powder to make a thick mix then add more. This is the trick. Take the time to incorporate as much powder as possible, just like making a good, thick, mix of IRM (Caulk). Note: Some operators like mixing sodium perborate with 35% hydrogen peroxide, others with 6% or 3% hydrogen peroxide or water alone. In the final analysis if the paste is mixed properly there will be so little of the liquid phase remaining that any difference between the above solutions is likely to be minimal.* * Sodium perborate mixed with water has been reported to be as effective as when mixed with hydrogen peroxide. Radiograph showing how the occlusal surface of the is curved to follow the contour of the cemento-enamel junction. spoon excavator showing slope towards lingual surface The outer curved surface of a spoon excavator can be used to shape the barrier just before the GIC sets. curved surface of Procedure for 3-day whitening (cont) : The tray is left in place overnight. 5. Before each replenishment of bleaching gel, the access cavity is cleaned with the tip of a suitablysized interdental brush. 6. To prevent the packing of fibrous food into the access cavity at mealtimes a pellet of cotton wool can be inserted into the access cavity beforehand. At the end of the meal the cotton wool is removed with the help of a probe or the end of a coarse barbed broach. Following that the patient injects some new gel to help flush out any of the remaining debris. Reassessment: 1. The patient should stop the bleaching procedure when the required degree of lightening has been achieved. This may be as early as 2 days. 2. As soon as possible after the procedure is completed the patient returns to the surgery. 3. The access cavity is flushed out and cleaned thoroughly. (Hydrogen peroxide applied at a concentration of 3% or 6% is useful for bubbling out any debris and for cleaning the cavity walls). 4. Place some calcium hydroxide paste into the access cavity and seal in with a glass-ionomer cement or a temporary sealing material such as Cavit G (3M Espe). 5. Delay placement of the final restoration for at least one week to allow residual oxygen to diffuse out of the treatment site.
8 Wait before final sealing of cavity Once bleaching is completed wait 1-2 weeks before the access cavity is finally sealed with a bonded restoration. With any bleaching procedure there is a period in which oxygen is released from the tooth. If a resin-composite is used too early the oxygen release can inhibit full polymerisation of the material. Example case: 9 10 Use calcium hydroxide as a dressing In the period between completing bleaching and placing a resin-composite restoration it is desirable to have an eugenol-free, non-staining, easy-to-remove dressing inside the access cavity. Calcium hydroxide, such as Pulpdent paste, fulfils these criteria.* It is sealed in place with glass-ionomer cement or a temporary sealing material such as Cavit G (3M Espe). * Calcium hydroxide was originally recommended to counteract any untoward effects of high-concentration hydrogen peroxide and heat in the initiation of invasive cervical erosion. 9 Thoroughly seal access cavity To help prevent any relapse in tooth colour the access cavity should be completely sealed. Some operators prefer to place the appropriate shade of glass-ionomer cement in the body of the access cavity followed by sealing the opening with a resin-bonded composite restoration. Others prefer to use a lightcoloured resin for the body and then seal the entrance area with a resin composite. Most operators tend to err on the side of making the body colour slightly too light to compensate for any shade relapse with time. The upper right central and lateral incisor were whitened using the inside/outside bleaching technique. The whitening agent used inside the access cavity was a mixture of 6% hydrogen peroxide and sodium perborate. It was changed one week later. The outside bleaching agent was 10% carbamide peroxide used overnight in a custom tray. A final brief burst was done with a 16% carbamide peroxide gel overnight. At the end of the treatment and after waiting the appropriate period the base of the access cavity was filled with an a self-curing resin BisFil 2B (Bisco). The remainder of the access cavity was filled with Tetric Ceram HB (Ivoclar Vivadent). Note: A factor that the operator believes to be of importance in getting a good result is swabbing the access cavity with alcohol just before placing the hydrogen peroxide/ sodium perborate mixture. It is thought that this may help draw the whitening agent into the dentinal tubules. (Courtesy Dr Sally Crowley - Manly, NSW) References: 1. Amato M, Scaravilli MS, Farella M, Riccitiello F. Bleaching teeth treated endodontically: Long-term evaluation of a case series. J Endod. 2006;32:376-378. 2. Settembrini L, Gultz J, Kaim J, Scherer W. A technique for bleaching nonvital teeth: Inside/outside bleaching. J Am Dent Assoc.1997:128;1283-84. 3. Poyser NJ, Kelleher MG, Briggs PF. Managing discoloured non-vital teeth: The inside /outside bleaching technique. Dent Update 2004;31:204-214. 4. Steiner DR, West JD. Bleaching pulpless teeth. In Complete Dental Bleaching Eds. Goldstein RE, Garber DA. 1995 Quintessence. Chicago. pp. 101-136. 5. Harrington GW, Natkin E. External resorption associated with bleaching of pulpless teeth. J Endod 1979;5:344-348. 6. Heithersay GS. Invasive cervical resorption: An analysis of potential predisposing factors. Quintessence Int 1999;30:83-95. 7. Rosensteil SF, Gegauff AG, Johnston WM. Randomized clinical trial of the efficacy and safety of a home bleaching procedure. Quintessence Int 1996;27:413-424. 8. Rotstein I, Zalkind M, Mor C, Tarabeah A, Friedman S. In vitro efficacy of sodium perborate preparations used for intracoronal bleaching of discolored non-vital teeth. Endod Dent Traumatol. 1991;7:177-180. 9. Walton RE, Rotstein I.Bleaching discoloured teeth:internal and external. In Principles and Practice of Endodontics. Vol 2.Walton RE ed. 1996 Saunders. Philadelphia. pp. 385-400.
How to select a suitable implant abutment. (cont) how to technique