Whitening the single discolored tooth

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Whitening the Single Discolored Tooth So Ran Kwon, DDS, MS, PhD The single discolored tooth can be a challenge in obtaining an esthetic outcome in the anterior region (Figs. 1–3). Treatment options can vary from restorative procedures such as crowns, veneers, or bonding to more conservative bleaching treatments. The long-term success of the treatment is dictated by proper diagnosis and treatment planning. The cause and severity of the discoloration has to be carefully evaluated when planning for bleaching options. The vitality of the pulp, presence and absence of symptoms, and periapical pathoses usually determine whether an external or internal bleaching approach will be considered. THE INITIAL EXAMINATION Patients presenting with a single discolored tooth should always be questioned about any history of traumatic injury to the tooth. Regardless of the status of the pulp, a former trauma might have caused bleeding into the dentinal tubules resulting in a dark brown to black discoloration. The baseline color may be evaluated with the VITA Classical shade guide (VITA, Bad Sackingen, Germany) or the VITA Bleached- guide (VITA, Bad Sackingen, Germany). However, single discolored teeth usually are outside the range of commercial shade guides so that technology-based color measuring devices such as the VITA Easyshade Compact (VITA, Bad Sackingen, Germany), Spectroshade Micro (MHT, Verona, Italy), or CrystalEye (Olympus, Tokyo, Japan) may be used to obtain a more objective evaluation of the tooth color at baseline and accurate data on the color change before and after bleaching. Another important consideration when evaluating baseline tooth color is the color of the root and the thickness and level of the gingiva. The dentin in the root is different from the anatomic crown, and does not bleach well if at all, regardless of whether internal or external bleaching is attempted. 1 Radiographs, vitality testing with ice and electric pulp testing, and transillumination are additional procedures that should be performed to assess whether root canal treatment is indicated prior to bleaching (Figs. 4–6). The case included in this article has been presented at the 2nd Annual Meeting of the Society of Color and Appearance in Dentistry, September 24, 2010. Department of Operative Dentistry, College of Dentistry, University of Iowa, Iowa City, IA 52242-1001, USA E-mail address: [email protected] KEYWORDS Single discolored tooth Traumatic injury Bleaching techniques Complications Dent Clin N Am 55 (2011) 229–239 doi:10.1016/j.cden.2011.01.001 dental.theclinics.com 0011-8532/11/$ – see front matter Ó 2011 Elsevier Inc. All rights reserved.

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Transcript of Whitening the single discolored tooth

Page 1: Whitening the single discolored tooth

Whitening the SingleDiscolored Tooth

So Ran Kwon, DDS, MS, PhD

KEYWORDS

� Single discolored tooth � Traumatic injury� Bleaching techniques � Complications

The single discolored tooth can be a challenge in obtaining an esthetic outcome in theanterior region (Figs. 1–3). Treatment options can vary from restorative proceduressuch as crowns, veneers, or bonding to more conservative bleaching treatments.The long-term success of the treatment is dictated by proper diagnosis and treatmentplanning. The cause and severity of the discoloration has to be carefully evaluatedwhen planning for bleaching options. The vitality of the pulp, presence and absenceof symptoms, and periapical pathoses usually determine whether an external orinternal bleaching approach will be considered.

THE INITIAL EXAMINATION

Patients presenting with a single discolored tooth should always be questioned aboutany history of traumatic injury to the tooth. Regardless of the status of the pulp,a former trauma might have caused bleeding into the dentinal tubules resulting in adark brown to black discoloration. The baseline color may be evaluated with theVITA Classical shade guide (VITA, Bad Sackingen, Germany) or the VITA Bleached-guide (VITA, Bad Sackingen, Germany). However, single discolored teeth usuallyare outside the range of commercial shade guides so that technology-based colormeasuring devices such as the VITA Easyshade Compact (VITA, Bad Sackingen,Germany), Spectroshade Micro (MHT, Verona, Italy), or CrystalEye (Olympus, Tokyo,Japan) may be used to obtain a more objective evaluation of the tooth color at baselineand accurate data on the color change before and after bleaching. Another importantconsideration when evaluating baseline tooth color is the color of the root and thethickness and level of the gingiva. The dentin in the root is different from the anatomiccrown, and does not bleach well if at all, regardless of whether internal or externalbleaching is attempted.1 Radiographs, vitality testing with ice and electric pulp testing,and transillumination are additional procedures that should be performed to assesswhether root canal treatment is indicated prior to bleaching (Figs. 4–6).

The case included in this article has been presented at the 2nd Annual Meeting of the Societyof Color and Appearance in Dentistry, September 24, 2010.Department of Operative Dentistry, College of Dentistry, University of Iowa, Iowa City, IA52242-1001, USAE-mail address: [email protected]

Dent Clin N Am 55 (2011) 229–239doi:10.1016/j.cden.2011.01.001 dental.theclinics.com0011-8532/11/$ – see front matter � 2011 Elsevier Inc. All rights reserved.

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Fig. 1. Preoperative view of full smile of the patient.

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If the tooth is nonvital and there is absence of periapical radiolucency and symp-toms, endodontic treatment is usually not recommended. However, if the pulp canalis severely obliterated, performing endodontic treatment before the development ofa periapical radiolucency may prevent difficulty and complications associated withthese teeth, and also increase the success rate for teeth treated without periapicalradiolucencies versus teeth treated with periapical radiolucencies.2

CAUSES OF DISCOLORATION

The tooth can discolor from extravasations of blood components into the dentinaltubules associated with pulp extirpation or traumatic injury.3 The blood cells undergohemolysis and release iron, which reacts with hydrogen sulfide, a metabolicby-product of bacteria, to form iron sulfide, which causes the gray staining of thetooth.4 Incomplete removal of pulpal debris, especially in the pulp horn area, is anothercause of discoloration in a single root-filled tooth.5 Root-filling materials can alsocause coronal discoloration.6 Bleaching can be effective in removing stains dependingon the substance. However, discoloration caused by metallic ions cannot be removedby whitening treatments.7 If the pulp survives a traumatic injury, it can undergo pulpcanal obliteration, also referred to as calcific metamorphosis. Calcific metamorphosisis characterized by rapid deposition of hard tissue beginning within the pulp chamberand continuing along the root canal space, resulting in a yellow to brown discolorationof the clinical crown. Studies indicate that 1% to 16% of calcific metamorphosis caseswill eventually undergo pulp necrosis, so that it is advisable to manage cases demon-strating calcific metamorphosis through observation and periodic examination.8

Fig. 2. Frontal view of discolored left central incisor.

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Fig. 3. Lateral view of discolored left central incisor.

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BLEACHING MATERIALS FOR THE SINGLE DISCOLORED TOOTH

Bleaching of discolored teeth was first attempted on nonvital teeth with the use ofvarious bleaching materials including chlorinated lime, oxalic acid, sodium peroxide,sodium hypochlorite, and mixtures of 25% hydrogen peroxide in 75% ether(pyrozone).9 Hydrogen peroxide, the most commonly used bleaching material nowa-days, was reported by Harlan in 1885.10 Hydrogen peroxide was placed into the pulpcavity at chair-side and replaced periodically or activated with electric current,11 heat,

Fig. 4. Periapical radiograph. Note the pulp canal obliteration state on the left centralincisor.

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Fig. 5. Vitality testing with electric pulp testing exhibited a positive response.

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or light12–15 to speed up the bleaching process. The acceleration was assumed tofollow the Q10 rule that for every 10�C increase in temperature, the reaction rateincreases 2 times. The use of a mixture of sodium perborate and distilled water wasdescribed by Salvas16 and reconsidered by Spasser17 as the walking bleach tech-nique. This technique is still widely accepted, with various modifications in the bleach-ing agent placed in the chamber. Nutting and Poe18 used a mixture of sodiumperborate and 30% hydrogen peroxide to speed up the process. Since the first publi-cation on night guard bleaching with the use of 10% carbamide peroxide,19 mixturesof sodium perborate and carbamide peroxide of different concentrations have beenproposed.20,21 The use of carbamide peroxide in nonvital bleaching has also changedthe delivery method whereby the bleaching agent is placed inside the chamber as wellas the outside in a custom-fitted tray.22–24 The use of carbamide peroxide has beenadvocated because of its neutral pH and slow release of active ingredients. However,when 30% hydrogen peroxide is mixed with sodium perborate in a ratio of 2:1 (g/mL)the pH of the mixture is alkaline, which favors the effectiveness of the bleaching agent.So far there seems to be no agreement on which bleaching material is best, but itseems prudent to understand the chemistry of each bleaching agent and apply itcautiously to the proposed treatment technique.

BLEACHING TECHNIQUES

There are several bleaching techniques available for the single discolored tooth. Thedecision is mainly based on the vitality of the tooth and whether the treatment shouldbe performed in the office or at home, or a combination of both.

Fig. 6. Transillumination is used to evaluate existence of severe crack lines.

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Single-Tooth In-Office Bleaching

A single discolored tooth without any symptoms, no periapical pathosis, and a ques-tionable response to vitality testing is a good candidate for in-office bleaching withhighly concentrated hydrogen peroxide that is commonly used in power bleachingfor vital teeth.

Treatment Sequence� Evaluate thecolorwithashadeguideoracolormeasurementdevice (Figs. 7and8).� Clean the tooth with a slurry of pumice and rubber-cup.� Isolate the toothon the facial and lingual sidewitha resinbarrieror rubberdam(Fig.9).� Apply highly concentrated bleaching agent on the facial and lingual.� Place a precut linear low-density polyethylene wrap onto the bleaching agent toprevent evaporation of the bleaching agent and inadvertent contact with thepatient’s soft tissue (Fig. 10).25

� Activate the bleaching agent with light (optional).� Remove bleaching agent after 40 to 60 minutes with a high suction tip or a smallcotton pellet.

� Rinse and remove the resin barrier or rubber dam.� Evaluate the tooth color and reappoint patient for several in-office bleachingsessions until the desired shade is obtained.

Single-Tooth Tray Bleaching

The indication for single-tooth tray bleaching is similar to single-tooth in-office bleach-ing. However, if the patient shows good cooperation and prefers to perform the treat-ment at home, tray bleaching is highly recommended.

Treatment Sequence� Take an alginate impression of the whole arch.� Pour the impression with plaster and avoid any bubbles or defects.� Trim the cast so that the occlusal surface is parallel to the base (Fig. 11).� Use an Omnivacuum machine to fabricate a custom-fitted tray.

Fig. 7. Color map of right central incisor.

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Fig. 8. Color map of discolored left central incisor.

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� Trim the tray in a straight pattern on the facial and lingual side.� Mark the tooth to be bleached and scallop the facial and lingual side of the tray,only at the marked tooth area (Fig. 12).

� Disinfect the tray with a cleaning solution in an ultrasonic cleaner.� Deliver the tray and home bleaching gel (10%–20% carbamide peroxide gel).� Instruct the patient to place the bleaching gel only at the discolored tooth andwear the tray overnight.

� Reappoint the patient to evaluate the progress of the treatment.� Evaluate the color of the tooth and the bleaching change relevant to the adjacentteeth (Figs. 13–15).

Thermocatalytic Bleaching

The thermocatalytic bleaching technique is one of the oldest forms of bleachingnonvital teeth in the office. However, the use of highly concentrated hydrogenperoxide in a liquid state requires utmost attention, and the use of heat has oftenbeen associated with the development of cervical root resorption. Consequently theperformance of the thermocatalytic bleaching technique is decreasing.

Fig. 9. Isolation of discolored tooth with a resin barrier (OpalDam, Ultradent Products Inc,South Jordan, UT, USA).

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Fig. 10. Placement of a 38% hydrogen peroxide gel (Opalescence Boost, Ultradent ProductInc, South Jordan, UT, USA) and a linear low-density polyethylene wrap.

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Walking Bleach Technique

The use of an intracoronal filling of sodium perborate combined with water orhydrogen peroxide continues until today, and has been shown to be a successfultreatment for bleaching nonvital teeth.26

Treatment Sequence� Evaluate the existing root canal filling on the radiograph.� Isolate the tooth with a well-fitting rubber dam.� Clean the pulp chamber and the pulp horns of any debris or pulpal remnants.� Remove the gutta percha root canal filling material with a heated instrument ora low-speed small round burr to 2 mm below the cementoenamel junction.

� Place a cervical barrier of 2 mm thickness with glass-ionomer cement or flowableresin to prevent the leakage of hydrogen peroxide into the surrounding alveolarbone.

� Mix sodium perborate with water or hydrogen peroxide in a ratio of 2:1 (g/mL) toa thick mix.

� Place the mixture into the pulp chamber with an amalgam carrier or anapplicator.

� Use a damp cotton pellet to remove excess material to allow space for thetemporary filling material.

� Use Cavit or glass-ionomer cement as a temporary filling material to properlyseal the access cavity.

Fig. 11. Trimmed cast with reservoir placement on the left central incisor.

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Fig. 12. The custom fitted tray is scalloped only on the single discolored tooth.

Fig

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� Recall the patient after 3 to 5 days to evaluate the progress of the treatment, andrepeat the walking bleach procedure 3 to 5 times until the color matches that ofthe adjacent teeth.

� The final composite restoration should be placed 2 to 3 weeks after the lastwalking bleach procedure to allow for the color to stabilize, and to allow forthe recovery of bond strength to tooth structure that is usually compromisedimmediately after bleaching.27

Inside-Outside Closed Bleaching

This technique comprises the combination of walking bleach and the single-tooth traybleaching to speed up the bleaching process and to reduce multiple appointments inthe office.

Inside-Outside Open Bleaching

The inside-outside open bleaching technique is indicated in patients with good coop-eration, because the bleaching agent has to be applied outside and inside within thepulp chamber.

. 13. Color map of left central incisor after bleaching.

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Fig. 14. Split-tooth image showing the difference of color change before and after bleach-ing, DE 5 7.34.

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Treatment Sequence

� Take an alginate impression of the whole arch and fabricate a custom-fitted trayas for a single-tooth tray bleaching.

� Evaluate the existing root canal filling and place a cervical barrier of 2 mmthickness.

� Instruct the patient to fill the custom-fitted tray of the marked tooth on the labialside and also fill the pulp chamber with 10% to 20% carbamide peroxide. Thetray can be worn every day, overnight until the color of the discolored toothmatches that of adjacent teeth.

� Show the patient how to irrigate the open chamber when debris has accumu-lated inside the chamber.

� Place the final composite restoration 2 to 3 weeks after the last bleaching gelapplication.

Fig. 15. Natural blend-in of color with adjacent teeth after combined in-office and single-tooth tray bleaching.

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COMPLICATIONS

Occurrence of external cervical root resorption has been linked to intracoronal bleach-ing using hydrogen peroxide. The exact mechanism is still unknown, but it is hypoth-esized that hydrogen peroxide penetrates into the alveolar bone, causing aninflammatory response.28 It has also been postulated that hydrogen peroxide dena-tures the collagen initiating a foreign body reaction,29 or decreases the pH resultingin increased osteoclastic activity.30 All theories are based on the microleakage ofhydrogen peroxide into the surrounding alveolar bone. Therefore it seems essentialto place a barrier in order to seal the patent dentinal tubules, especially in youngpatients with wide open tubules, to prevent the development of cervical rootresorption.

SUMMARY

Bleaching is the most conservative, economical, and safe approach for treatinga single discolored tooth. The bleaching technique employed should be based onthe vitality of the tooth and the cooperation of the patient. Whenever the tooth is vitalor exhibits calcific metamorphosis on radiographs, an external approach should beused. In a nonvital tooth with existing root canal fillings, the chamber can be usedfor the walking bleach technique or for the inside-outside bleaching technique.Caution should be exercised as to the time of the placement of the final compositeresin restoration in the pulp chamber. Bonding to the enamel and dentin is affectedimmediately after bleaching, so that the final restoration should be placed 2 to 3 weeksafter the last bleaching session. Failure to do so might affect the long-term colorstability of the treated tooth.

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