RESTORATIVERESTORATIVE DENTISTRY DENTISTRY

An Overview of Bleaching Techniques: 2.Night Guard Vital Bleaching and Non-Vital Bleaching

M. SULIEMAN

Bleaching Material/Regimen Abstract: Night Guard Vital Bleaching (NGVB) or dentist-monitored bleaching technique is probably the most widely used bleaching technique because of its relative Nearly all the bleaching materials on ease of use, low cost, safety and high success rate. There are many non-vital bleaching the market have been shown to work techniques available, all of which have one thing in common, usually a successful result with little difference between them.4 in the procedure returning the discoloured tooth to its original colour and beyond that Generally, the higher concentration, when required. thicker, more viscous materials This article will give an overview of various home bleaching techniques: materials produce a lightening effect more and regimens used, bleaching procedure and treatment of side-effects. In addition, it quickly than lower concentration, less will review various in-surgery and at home techniques used for bleaching non-vital teeth. viscous materials. However, higher Dent Update 2005; 32: 39-46 concentrations tend to produce more cases of thermal sensitivity. Clinical Relevance: Home bleaching is a technique used to improve the shade of The choice of material to use discoloured or ageing teeth and provides an easy, non-invasive option compared to depends on a number of factors, veneers and full coverage crowns. including the type of discoloration present and how dark the teeth are initially. However, the most important consideration has to be the patient, his/her lifestyle, the time available for HOME BLEACHING concentrations of bleaching materials bleaching and whether there are Night Guard Vital Bleaching (NGVB) or and regimens used, has become the existing problems with tooth dentist-monitored bleaching technique gold standard by which other sensitivity. is probably the most widely used techniques are judged. However, it is The bleaching regimen is therefore bleaching technique because of its by no means without disadvantages, determined by the patient’s lifestyle, relative ease of use, low cost, safety as active patient compliance is preference and schedule. If the patient and high success rate (thought to be required and the technique suffers is happy and able to wear trays 98% for non-tetracycline stained teeth from high drop out rates.2 The colour overnight, then 10% carbamide and 86% for tetracycline stained change is dependent on compliant peroxide worn for 8 hours overnight is teeth).1 Coupled with the fact that wear and, as some patients do not the treatment of choice. However, if patients are able to bleach at their own remember to wear the trays everyday, time is at a premium, this regimen is pace, this technique, with its various the results are sometimes less than not recommended, as bleaching time ideal. On the other hand, excessive use will take about 4 weeks in total as top is also possible by some over zealous and bottom teeth are bleached patients, which frequently causes separately. In the author’s experience, M. Sulieman LDS RCS (Eng.), BDS (Lond.), MSc, thermal sensitivity, reported to be as some patients are able to wear both Research Fellow, Division of Restorative Dentistry, high as 67%.3 Although thermal upper and lower trays simultaneously Department of Oral and Dental Science, University sensitivity may be quite high during overnight, thereby cutting down the of Bristol Dental School, Lower Maudlin Street, bleaching period to 2 weeks, but many Bristol BS1 2LY; Private Practitioner, Wimbledon treatment, persistence of sensitivity London. after cessation is extremely rare. patients cannot cope with this

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regimen. Higher concentrations of effects of the bleaching materials on the carbamide peroxide, such as 15 or 20%, foetus have yet to be fully investigated. can be selectively used to treat darker Those patients that present with decay, teeth within an arch, such as canines, periapical lesions, cracks and sensitivity while still using 10% carbamide should have these issues treated before peroxide to bleach the lighter teeth any bleaching procedure is undertaken. within the arch at the same time. Diagnosis of the cause of the Some patients are unable to wear discoloration should be made and trays overnight and prefer daily use, recorded in the patient’s notes. The which has the advantage of more options for treatment can be extrinsic frequent replenishment of the stain removal, bleaching or both. Other Figure 3. Bleaching tray in patient's mouth bleaching gel for maximum bleaching options, such as veneers and crowns, prior to removal of excess bleaching material. effect, but both occlusal pressure and should also be discussed with the increased salivary flow may dilute the patient and recorded in the notes. gel.5 The teeth that are to be bleached should pre-operative photograph with the be identified and checked for: shade tab in situ should always be taken under standardized lighting conditions Case Selection
Vitality; without using the dental operating light The most important aspect of any form
Caries; which would wash out the shade. After of bleaching is an assessment of the
Cracks; all the relevant explanations, options, patient’s expectations. To avoid
Recession, exposed dentine; limitations and prognosis have been problems, the first thing that should be
Developmental defects such as white discussed with the patient, a consent established is the patient’s level of spots. form should be signed and the patient expectation. When it becomes clear that should be referred for a hygiene session the patient wants whiter teeth, the first In addition, the presence of composite about a week to ten days prior to the question to the patient should be “What fillings, veneers, crowns or highly bleaching procedure. do you expect to achieve with this translucent teeth should be noted. whitening procedure?” If the answer is, Patients must be warned that these will Procedure “A dazzling white smile” or film star not change shade but their margins may teeth or words to that effect, use extreme merely be cleaned up by the bleaching Alginate or similar impression material caution when bleaching the teeth of agent acting on the surrounding tooth may be used to take impressions for such patients as they may never be structure. Hence, they may possibly the manufacture of the bleaching satisfied! The more realistic answers are need replacement following the trays. There are many different types a little freshening to the look of the teeth bleaching treatment. Patients need to be of custom-made trays but broadly they or 1 or 2 shades lighter or words to that aware of all these points and the are divided into those that have or do effect. These patients can be information again needs to be recorded not have a reservoir. The function of successfully bleached while alternative in the notes. Any teeth that require root the reservoir is to allow for a greater treatment should be considered for canal therapy should have this carried thickness of bleaching material to those with high expectations. Pregnant out prior to the bleaching procedure. contact the buccal surface of the teeth patients should also be avoided as the Following the assessment of the teeth, to be bleached (Figure 1). There are no the shade should be agreed with the differences in the rate of bleaching patient and recorded in the notes. A with or without reservoirs,6 but reservoirs may be used to aid the seating of the more viscous bleaching materials or for patients with particularly bulbous teeth. Other variations in tray design include scalloping the tray borders to follow the tooth/gingiva interface so that there is minimal soft tissue contact and gingival irritation. However, the scalloping may irritate Figure 1. Bleaching tray showing both Figure 2. Bleaching tray with appropriate the lip or tongue and the ingress of scalloping and buccal reservoirs produced by amount of bleaching material in situ; covering saliva may wash out the bleaching gel placement of spacer material on the buccal two-thirds of the buccal aspect of the tooth to a from the tray. Straight line or non- aspect of teeth on the cast model. thickness of about 1–2 mm.

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scalloped trays may be cut about 2 mm and removal of excess material until not uncommon for those patients who over the labial incisors and may be they are happy with the technique, just want to freshen up the look of easier to use and less traumatic to the before asking them to wash their their teeth to be satisfied with the rest of the mouth with a better border mouths out. shade of their teeth by the first review seal.7 Other tray variations include Written instructions should be given visit. However, most are encouraged at cutting back borders in cases that to the patient to take home and the the review and want to continue to see have pre-existing gingival recession or protocol usually involves starting with their teeth lighten further. If only sensitivity, while windows are cut in brushing and flossing teeth prior to single arch bleaching was undertaken, trays over teeth that do not require the application of the bleaching trays. it is better to complete this arch before bleaching. The bleaching tray Instructions should also include embarking on the opposing arch. The thickness which is usually about relevant tray wearing times, possible contrast between opposing arches 0.9 mm can be increased if the patient side-effects and how to deal with encourages the patient to complete the has a bruxing habit (1.5 mm) or made them. A bleaching log may be given to bleaching to the maximum possible very thin for those that have a the patient to document the frequency whitening effect. Further bleaching gagging tendency (0.5 mm). of use of the bleaching materials, the material is given to the patient who is Another alternative to the normal length of time the trays are worn for, asked to return after 2 weeks. plastic trays are those foam-backed as well as sensitivity levels At the second review the same trays previously used in fluoride experienced. procedure as for the first review is treatment which can be used in a Patients should be reviewed after 10 carried out. At this stage, the shade of straight border design without the days to two weeks. At the review visit the teeth is usually 1–2 shades lighter, need for reservoirs. the patient is asked if any problems or even better, depending on the The patient is recalled after the trays have been encountered and the starting shade and type of are produced and they are tried in the frequency/times with which the discoloration. In most cases, the mouth. They should be checked for bleaching regimen has been used. It is patients are satisfied with the results accuracy of fit and retention, with not unusual for patients to have had a and a final photograph is taken with special attention to the extension of break in treatment as dictated by both start and end shade tabs in situ the trays. The patient is then given a situations arising socially or as a result (Figure 4). If single arch bleaching was demonstration of placement of a small of business commitments. The used, the patient is instructed to amount of bleaching material. About a patient’s mouth is examined for any switch to the opposing arch and a 1–2 mm thickness of material is used to adverse effects on the gingivae, similar review protocol is used until fill less than two-thirds of the labial mucosa or other soft tissues. Signs of the desired effect is reached. aspect of the tooth space on the irritation on the gingiva may be bleaching tray (Figure 2). The patient indicated by extension of the use of is then shown how to insert the tray in trays, which should be modified Home Bleaching Side-Effects the mouth. A mirror is used to show accordingly. The shade of the teeth Some patients experience problems the patient, with special attention should be reassessed and shown to with gingival or soft tissue irritation given to removal of the excess material the patient, along with the start shade during home bleaching, but the vast from the gingivae and soft tissues with prior to bleaching. This tends to majority of problems are those of tooth a cotton wool roll, toothbrush, cotton please the patient and encourages sensitivity, reported to affect about buds or finger (Figure 3). Patients are him/her to continue with treatment if two-thirds of patients.6,8 Painful gums allowed to practice the tray placement further bleaching is felt necessary. It is may be the result of incorrectly-fitting trays impinging on them or the use of excess material in the trays. The trays can be easily trimmed back and polished while the patient can be instructed to use less material if other ab areas of mucosa or soft tissues were irritated. Some patients that bleach teeth overnight report a metallic taste sensation immediately following tray removal but this usually disappears after about 2 hours.9 Thermal tooth sensitivity is a common side-effect noticed by Figure 4. (a) Pre- and (b) post-tooth whitening using home applied 10% carbamide peroxide.

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patients as early as the third day of to the start of bleaching. Treatment emphasis is given to motivating the bleaching, following the removal of can be simple; such as the use of patient to continue with treatment. trays, and may persist for 3–4 hours desensitizing toothpaste for about 3 afterwards. Patients that experience weeks prior to treatment, or placing a severe sensitivity should be advised neutral fluoride gel in the bleaching NON-VITAL BLEACHING to stop bleaching and the sensitivity trays overnight for about 3 weeks prior TECHNIQUES treated. Treatment can take the form of to treatment. Another option is to The oldest bleaching technique, fluoride-containing toothpastes or graduate wearing times, starting with 1 described in 1848, used chloride of neutral sodium fluoride gels in the hour per day for the first week lime.3 There have been many bleaching trays worn overnight. followed by overnight use on the developments since then, all having Desensitizing potassium nitrate or second or third week.11 one thing in common, which is usually a potassium nitrate and fluoride- Single dark teeth, such as central successful result in the procedure containing gels are also available for incisors or canines, can be treated returning the discoloured tooth to its use in trays for about 2 hours before using 17–20% carbamide peroxide until original colour, and beyond that when or after the bleaching procedure. they reach the same shade as the rest required. There are a number of non- Potassium nitrate in toothpastes takes of the teeth, before bleaching the rest vital bleaching techniques used today. about 3 weeks to reduce sensitivity of the teeth. The remainder of the These include: measurably but, when put in a tray for procedure can be finished using 10% 10–30 minutes, relief is almost carbamide peroxide. This can also be
‘walking bleach and modified immediate. Lower degrees of combined with 17–20% carbamide walking bleach’; sensitivity can be treated with peroxide for the darker tooth, if it was
non-vital power bleaching, also desensitizing toothpaste rubbed or felt necessary to use the higher known as ‘thermo/photo brushed onto the cervical necks of the concentration only in the space in the bleaching’; and affected teeth. tray for that tooth, this being marked
‘inside/outside bleaching’. Fluoride acts primarily as a blocker for the patient by cutting a small slot of dentinal tubules, which acts to slow or notch above it. Similarly, combining down the dentinal fluid flow that various concentrations of bleaching Walking Bleach Technique causes sensitivity, while potassium agent can be used in patients that First described by Spasser in 1961,13 nitrate acts like an anaesthetic by have different shades in their mouth the walking bleach technique involved preventing the nerve from repolarizing owing to varying discoloration sealing a mixture of sodium perborate after it has depolarized in the pain aetiologies. with water into the pulp chamber of the cycle.10 Alternatively, the whole arch may be affected tooth, the procedure being Other ways of treating sensitivity are bleached using 10% carbamide repeated at intervals until the desired passive in terms of not involving peroxide and the response assessed at whitening is achieved. The technique specific desensitizing products; they the review stage before a decision is was modified using a combination of are aimed at reducing the taken to treat the teeth that have not 30% hydrogen peroxide and sodium concentration and amount of responded well to treatment perborate sealed into the pulp chamber bleaching gel used or the bleaching selectively, before continuing with the for one week – the ‘modified or time. The trays are trimmed back if rest of the bleaching. Those teeth that combination walking bleach necessary and less gel is used in the have not responded well to treatment technique’.14,15 Sodium perborate is trays, with the excess being should be treated similarly to the dark stable when in the form of a dry thoroughly removed. The patient may tooth scenario described above. It is powder but, in the presence of acid, be instructed to apply the bleaching very important to explain the selective warm air or water, it decomposes to materials on alternate nights or even or combined treatment to the patient form metaborate, hydrogen peroxide every third night to reduce the and reviews should be regular until the and nascent oxygen. Hydrogen problems of sensitivity. This can delay desired result is achieved. peroxide mixed with sodium perborate the treatment time but ensures the Tetracycline staining can be treated potentiates its effect and produces a 16 patient is comfortable with the successfully using home bleaching better bleaching effect. bleaching regimen. but takes periods of 3 to 6 months to Prior to any bleaching procedure, achieve a successful whitening the non-vital tooth must be result.12 The review periods for these radiographed to assess the quality of Home Bleaching Tips patients, after the initial visit at 2 the root canal obturation and the Patients that have existing sensitive weeks, are monthly, where the same apical tissues. Any deficiencies must teeth should have these treated prior review protocol is practised, except be rectified before bleaching.

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Procedure repeated until the desired effect is and the same preparation protection
Shade assessment is carried out and reached. techniques are used on the tooth. a photograph is taken with the The ‘combination bleach technique’ Light activation both internally and shade tab in situ. differs from above only in that sodium externally can be in the form of a
The tooth is isolated using rubber perborate is mixed with 30% hydrogen conventional halogen curing light, dam with caulking putty placed peroxide (or lower concentrations) plasma arc lamp or a diode laser beneath. Ligatures and wedgets instead of water to form the thick utilizing the same three 5-minute pass (Coltene/Whaledent Ltd, Burgess paste which is sealed into the cavity. protocol described for external power Hill, W. Sussex, UK ) are used to The procedure is quicker acting, hence bleaching techniques. Following this provide a good cervical seal around review is after one week. procedure, the tooth is washed and the tooth to prevent leakage dried before being sealed with a under the dam. temporary restoration. The patient is Internal Non-Vital Power
The old restoration is removed and reviewed 2 weeks later when the shade Bleaching the endodontic access cavity is would have stabilized and the tooth is modified to ensure all pulp remnants The procedure is identical, in terms of ready for a definitive restoration to be are removed, including pulp horns isolation and preparation of the tooth, placed, or is further bleached if to prevent their later breakdown as that described above, except that required. and further discoloration. All the the bleaching agent and its dentine is exposed and any application/activation are different. Inside/Outside Bleaching restorative remnants or superficial Hydrogen peroxide gel (30–35%) is stain can be usefully removed using placed in the pulp chamber and This technique is a combination of air abrasion if available. activated either by light or heat. The internal bleaching of non-vital teeth To reduce the risk of external temperature is usually between 50 and with the home bleaching technique. root resorption, the GP root 60 êC maintained for 5 minutes before The preparation of the non-vital tooth filling must be sealed above the the tooth is allowed to cool down for a is exactly the same as that described level of the crestal bone. Hence, the further 5 minutes. The gel is removed above for the ‘walking bleach’ in that a coronal GP should be removed by washing with water for a further protective barrier is placed over the 16 using a Gates-Glidden bur or a minute. The tooth is dried and the root canal system using glass ionomer profile orifice shaper (Dentsply ‘walking bleach technique’ is used and the access cavity is completely Limited, Weybridge, Surrey, UK) to between visits until the tooth is cleaned ready for the bleaching below the level of the cemento-enamel reviewed 2 weeks later to assess if procedure. Rubber dam isolation is not junction by about 2–3 mm measured further treatment is necessary. essential as no caustic materials are using a periodontal probe. A variation on this technique uses used with this technique.
Aglass ionomer base is now used 35% hydrogen peroxide gel applied Procedure to seal the coronal end of the root both internally to the pulp chamber
canal completely so that a barrier is and externally to the labial surface of The patient is instructed on formed between the root canal the tooth, with light activation placement of a cotton wool pellet system and the floor of the pulp internally and externally (Figure 5). into the cavity when not chamber. High temperatures are not involved undergoing the bleaching
The bleaching paste is prepared using sodium perborate with water/ saline or even local anaesthetic solution to a semi-thick consistency. The pulp chamber is a b packed with the paste and excess liquid is removed by tamping with a cotton wool pellet.
Excess paste is removed and a temporary restoration (zinc oxide eugenol or glass ionomer) is packed on top of the paste to ensure a good seal. Figure 5. Internal non-vital bleaching using a modified power bleaching technique after
The rubber dam isolation is (a) preparation of the access cavity and protection of the root canal system using glass removed and the patient is recalled ionomer cement; (b) 35% hydrogen peroxide gel is placed inside and outside of the tooth in 2 weeks. The treatment is and light activated.

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procedure and is asked not to eat utilizes both an internal and an 2. Miller MB. Reality: The Information Source for Esthetic Dentistry 13, 14.Houston, Texas: Reality on the tooth during the bleaching external approach for the bleaching Publishing, 1999 and 2000. period. agent. Use of lower concentrations of 3. Haywood VB. History, safety and effectiveness of
The custom-made bleaching tray is bleach, usually 10% carbamide current bleaching techniques and application of checked for fit and the patient is peroxide, are thought to reduce the the night guard vital bleaching technique. Quintessence Int 1992; 27: 471–488. instructed to remove the cotton risk of external resorption. There is no 4. Lyons K, Ng B. Nightguard vital bleaching: a pellet with a tooth pick prior to need for frequent changes in review and clinical study. N Z Dent J 1998; 94: placement of a small amount of temporary dressings, as was 100–105. bleaching agent directly into the 5. Dunn JR. Dentist prescribed home bleaching: experienced with the walking bleach current status. Compend Contin Educ Dent 1998; cavity straight from the bleaching when the oxygen build up within the 9(8): 760–764. syringe. The space of the tooth on pulp chamber would dislodge the 6. Haywood VB. Nightguard vital bleaching: current the bleaching tray is also filled with dressing. Additionally, the technique concepts and research. J Am Dent Assoc 1997; bleaching agent before the Suppl. 128 (4): 19S–25S. achieves the lightening effects within 7. Touati B, Miara P, Nathanson D. Esthetic Dentistry placement of the tray into the a matter of days compared to weeks. and Ceramic Restorations. London: Martin Dunitz, mouth. Alternatively, extra material The main disadvantages of this 1998. is placed into the space of the tooth technique are the need for patient 8. Nathanson D. Vital tooth bleaching: sensitivity and to be bleached on the tray and the pulpal considerations. J Am Dent Assoc 1997; 128: compliance and the need for enough 41S–44S. material is massaged via the tray manual dexterity to place the bleaching 9. Garber DA. Dentist-monitored bleaching: a slightly into the pulp chamber and agent into the cavity. Also, not only discussion of combination and laser bleaching. any excess removed using a cotton can over use lead to over bleaching, J Am Dent Assoc 1997; Suppl 128 (4): 26S–30S. 10. Haywood VB. A comparison of at-home and in- bud or toothbrush. but the potential for external office bleaching. Dentistry Today 2000; 19(4): 44–
Following a 2-hour bleaching resorption still exists despite being 53. session, the patient irrigates the reduced, so this technique is by no 11. Haywood VB. Current status and cavity with water using a syringe means without its risks. recommendations for dentist-prescribed, at- home tooth whitening. Contemp Esthet Restor provided before replacement of a As with the modified bleaching Prac 1999; 3(Suppl. 1): 2–9. fresh cotton wool pellet. The technique, the inside/outside 12. Haywood VB. Extended bleaching of tetracycline- patient is also instructed to clean bleaching technique has been stained teeth: a case report. Contemp Esthet the pulp chamber and change Restor Prac 1997; 1: 14–21. modified by the use of varying 13. Spasser HF. A simple bleaching technique using cotton wool pellets after meal times. concentrations of carbamide peroxide sodium perborate. NY Dent J 1961; 27: 332–334.
The patient is reviewed at 3–7 days ranging from 5%, 16%, 22% or even 14. Nutting EB, Poe GS. A new combination for depending on the number of times 35%, as used in the waiting room bleaching teeth. J Southern Calif Dent Assoc 1963; the patient is able to repeat the 2- 31: 289. technique. 15. Nutting EB, Poe GS. Chemical bleaching of hour bleaching sessions. Some discoloured endodontically treated teeth. Dent patients prefer night use and sleep Clin North Am 1967; Nov: 655–662. with the tray in place, which will CONCLUSION 16. Rotstein I. Intra-coronal bleaching of non-vital slow down the process owing to teeth. In: Bleaching Techniques in Restorative NGVB using 10% carbamide peroxide Dentistry.London: Martin Dunitz, 2001: pp. 159– less replenishment of fresh gel. in a custom-fitted tray has proven to 163. Ideally, daily wear is preferable for be one of the most cost-effective, safe 17. Carillo A, Trevino MVA, Haywood VB. controlling the lightening process Simultaneous bleaching of vital bleaching and an and effective treatments to whiten open-chamber non-vital tooth with 10% as between 5–8 applications may be teeth. The technique initially requires carbamide peroxide. Quintessence Int 1998; all that is necessary to achieve the examination, diagnosis and a treatment 29(10): 643–648. desired effect.17 The longer the plan relative to the patient’s needs and tooth has been discoloured, or the then continued supervision during the more discoloured it is, the longer it time taken for the patient to bleach DECEMBER will take to bleach back.17 his/her teeth. The dentist should be CPD Answers
After the desired colour has been aware of the relevant indications and achieved, the cavity is dressed with contra-indications of the technique, as 1. A, B, D 6. B, C a temporary filling for about 2 well as other treatment options that weeks to allow the shade to may be required as a result of the use 2. B, C, D 7. B, C stabilize, and for the oxygen to of the technique. dissipate from the tooth, allowing 3. A, C, D 8. A, C the bond strength of the enamel/ composite to improve.17 4. B, C,D 9. A, B, D REFERENCES The advantage of this technique for 1. Leonard RH. Nightguard vital bleaching: dark stains and long-term results. Compend Contin 5. A, C 10. B, C, D bleaching non-vital teeth is that it Educ Dent 2000; 21(Suppl. 28): S18–S27.

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