Kwon 2011 Dental Clinics of North America

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W h i t e n i n g t h e S i n g l eDiscolored Tooth

So Ran Kwon, DDS, MS, PhD

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 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 baselineand 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 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]

KEYWORDS

Single discolored tooth Traumatic injury Bleaching techniques Complications

Dent Clin N Am 55 (2011) 229–239doi:10.1016/j.cden.2011.01.001 dental.theclinics.com

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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 of

a periapical radiolucency may prevent difficulty and complications associated with

these teeth, and also increase the success rate for teeth treated without periapical

radiolucencies versus teeth treated with periapical radiolucencies.2

CAUSES OF DISCOLORATION

The tooth can discolor from extravasations of blood components into the dentinal

tubules associated with pulp extirpation or traumatic injury.3 The blood cells undergo

hemolysis and release iron, which reacts with hydrogen sulfide, a metabolic

by-product of bacteria, to form iron sulfide, which causes the gray staining of the

tooth.4 Incomplete removal of pulpal debris, especially in the pulp horn area, is another

cause of discoloration in a single root-filled tooth.5 Root-filling materials can also

cause coronal discoloration.6 Bleaching can be effective in removing stains depending

on the substance. However, discoloration caused by metallic ions cannot be removed

by whitening treatments.7 If the pulp survives a traumatic injury, it can undergo pulp

canal obliteration, also referred to as calcific metamorphosis. Calcific metamorphosis

is characterized by rapid deposition of hard tissue beginning within the pulp chamber

and 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 cases

will eventually undergo pulp necrosis, so that it is advisable to manage cases demon-

strating calcific metamorphosis through observation and periodic examination.8

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

Fig. 2. Frontal 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 of

various 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 pulp

cavity 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.

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

Whitening the Single Discolored Tooth 231



or light12–15 to speed up the bleaching process. The acceleration was assumed to

follow the Q10 rule that for every 10C increase in temperature, the reaction rate

increases 2 times. The use of a mixture of sodium perborate and distilled water was

described 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 sodium

perborate 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 mixtures

of sodium perborate and carbamide peroxide of different concentrations have been

proposed.20,21 The use of carbamide peroxide in nonvital bleaching has also changed

the 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 been

advocated 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 it

seems prudent to understand the chemistry of each bleaching agent and apply it

cautiously to the proposed treatment technique.

BLEACHING TECHNIQUES

There are several bleaching techniques available for the single discolored tooth. The

decision is mainly based on the vitality of the tooth and whether the treatment should

be performed in the office or at home, or a combination of both.

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

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

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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 with

highly concentrated hydrogen peroxide that is commonly used in power bleaching

for vital teeth.Treatment Sequence

Evaluate the colorwith a shadeguide or a color measurement device ( Figs. 7 and 8 ). Clean the tooth with a slurry of pumice and rubber-cup. Isolate the tooth onthe facialand lingual sidewith a resin barrier or 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 to

prevent evaporation of the bleaching agent and inadvertent contact with the

patient’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 small

cotton pellet. Rinse and remove the resin barrier or rubber dam. Evaluate the tooth color and reappoint patient for several in-office bleaching

sessions 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.




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 and

wear 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 adjacent

teeth ( Figs. 13–15 ).

Thermocatalytic Bleaching

The thermocatalytic bleaching technique is one of the oldest forms of bleaching

nonvital teeth in the office. However, the use of highly concentrated hydrogen

peroxide in a liquid state requires utmost attention, and the use of heat has often

been associated with the development of cervical root resorption. Consequently the

performance of the thermocatalytic bleaching technique is decreasing.

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

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

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Walking Bleach Technique

The use of an intracoronal filling of sodium perborate combined with water or

hydrogen peroxide continues until today, and has been shown to be a successful

treatment 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 or

a 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 flowable

resin to prevent the leakage of hydrogen peroxide into the surrounding alveolar

bone. Mix sodium perborate with water or hydrogen peroxide in a ratio of 2:1 (g/mL) to

a thick mix. Place the mixture into the pulp chamber with an amalgam carrier or an

applicator. Use a damp cotton pellet to remove excess material to allow space for the

temporary filling material. Use Cavit or glass-ionomer cement as a temporary filling material to properly

seal the access cavity.

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

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




Recall the patient after 3 to 5 days to evaluate the progress of the treatment, and

repeat the walking bleach procedure 3 to 5 times until the color matches that of

the adjacent teeth. The final composite restoration should be placed 2 to 3 weeks after the last

walking bleach procedure to allow for the color to stabilize, and to allow for

the recovery of bond strength to tooth structure that is usually compromised

immediately after bleaching.27

Inside-Outside Closed Bleaching

This technique comprises the combination of walking bleach and the single-tooth tray

bleaching to speed up the bleaching process and to reduce multiple appointments in

the 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 the

pulp chamber.

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

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

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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 mm

thickness. Instruct the patient to fill the custom-fitted tray of the marked tooth on the labial

side and also fill the pulp chamber with 10% to 20% carbamide peroxide. The

tray can be worn every day, overnight until the color of the discolored tooth

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

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




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 an

inflammatory response.28

It has also been postulated that hydrogen peroxide dena-tures the collagen initiating a foreign body reaction,29 or decreases the pH resulting

in increased osteoclastic activity.30 All theories are based on the microleakage of

hydrogen peroxide into the surrounding alveolar bone. Therefore it seems essential

to place a barrier in order to seal the patent dentinal tubules, especially in young

patients with wide open tubules, to prevent the development of cervical root

resorption.

SUMMARY

Bleaching is the most conservative, economical, and safe approach for treating

a single discolored tooth. The bleaching technique employed should be based on

the vitality of the tooth and the cooperation of the patient. Whenever the tooth is vital

or exhibits calcific metamorphosis on radiographs, an external approach should be

used. In a nonvital tooth with existing root canal fillings, the chamber can be used

for 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 composite

resin restoration in the pulp chamber. Bonding to the enamel and dentin is affected

immediately after bleaching, so that the final restoration should be placed 2 to 3 weeks

after the last bleaching session. Failure to do so might affect the long-term color

stability of the treated tooth.

REFERENCES

1. Haywood VB, Diangelis AJ. Bleaching the single dark tooth. Inside Dent 2010;

6(September):42–52.

2. daCunho FM, deSouza IM, Monnerat J. Pulp canal obliteration subsequent to

trauma: perforation management with MTA followed by canal localization and

obturation. Brazilian J Dent Traumatology 2009;1(2):64–8.

3. Goldstein RE, Garber DA. Complete dental bleaching. Berlin: Quintessence;1995.

4. Grossmann LI. Endodontic practice. 5th edition. Philadelphia: Lea and Febiger;

1960.

5. Brown G. Factors influencing successful bleaching of the discolored root-filled

tooth. Oral Surg Oral Med Oral Pathol 1965;20:238–44.

6. Van der Burgt TP, Plaesschaert AJ. Tooth discoloration induced by dental

materials. Oral Surg Oral Med Oral Pathol 1985;60:666–9.

7. Glockner K, Ebeleseder K. Indikationen und Grenzfaelle fuer das Bleichen von

devitalen verfaerbten Frontzaehnen. Quintessenz 1993;44:519–27 [in German].

8. Amir FA, Gutmann JL, Witherspoon DE. Calcific metamorphosis: a challenge inendodontic diagnosis and treatment. Quintessence Int 2001;32:447–55.

9. Attin T, Paque F, Ajam F, et al. Review of the current status of tooth whitening with

the walking bleach technique. Int Endod J 2003;36:313–29.

10. Harlan AW. The removal of stains from teeth caused by administration of medical

agents and the bleaching of a pulpless tooth. Am J Dent Sci 1884/1885;18:521.

11. Westlake A. Bleaching teeth by electricity. Am J Dent Sci 1895;29:101.

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12. Rosenthal P. The combined use of ultra-violet rays and hydrogen dioxide for

bleaching teeth. Dent Cosmos 1911;53:246–7.

13. Prinz H. Recent improvements in tooth bleaching. A clinical syllabus. Dent

Cosmos 1924;66:558–60.

14. Brininstool CL. Vapor bleaching. Dent Cosmos 1913;55:532.

15. Merrel JH. Bleaching of discolored pulpless tooth. J Can Dent Assoc 1954;20:

380.

16. Salvas CJ. Perborate as a bleaching agent. J Am Dent Assoc 1938;25:324.

17. Spasser HF. A simple bleaching technique using sodium perborate. N Y State

Dent J 1961;27:332–4.

18. Nutting EB, Poe GS. A new combination for bleaching teeth. J South Calif Dent

Assoc 1963;31:289.

19. Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int 1989;

20:173–6.

20. Aldecoa EA, Mayordomo FG. Modified internal bleaching of severe tetracycline

discolorations: a 6-year clinical evaluation. Quintessence Int 1992;23:83–9.

21. Yui KC, Rodrigues JR, Mancini MN, et al. Ex vivo evaluation of the effectiveness of

bleaching agents on the shade alteration of blood-stained teeth. Int Endod J

2008;41:485–92.

22. Liebenberg WH. Intracoronal lightening of discolored pulpless teeth: a modified

walking bleach technique. Quintessence Int 1997;28:771–7.

23. Settembrini L, Gultz J, Kaim J, et al. A technique for bleaching non-vital teeth:

inside/outside bleaching. J Am Dent Assoc 1997;128:1283–4.

24. Carillo A, Trevino MV, Haywood VB. Simultaneous bleaching of vital and an open

chamber non-vital tooth with 10% carbamide peroxide. Quintessence Int 1998;29:643–8.

25. Kwon SR, Ko SH, Greenwall L. Tooth whitening in esthetic dentistry. Berlin:

Quintessence; 2009.

26. Attin T, Kielbassa AM. Die Bleichbehandlung-ein fester Bestandteil aesthetischer

Zahnheilkunde. Zahnarztl Mitt 1995;85:2674–80 [in German].

27. Shinohara MS, Rodrigues A, Pimenta AF. In vitro microleakage of composite

restorations after non-vital bleaching. Quintessence Int 2001;32:413–7.

28. Harrington GW, Natkin E. External resorption associated with bleaching of pulp-

less teeth. J Endod 1979;5:344–8.

29. Lado EA, Stanley HR, Weismann MI. Cervical root resorption in bleached teeth.Oral Surg Oral Med Oral Pathol 1983;55:78–80.

30. McCormick JE, Weine FS, Maggio JD. Tissue pH of developing periapical lesions

in dogs. J Endod 1983;9:47–51.


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