Aesthetic Restorative Dentistry

Aesthetic Restorative Dentistry Principles and PracticeDennis P. TarnowStephen J. ChuJason Kim

Stephen J. Chu

Dr. Stephen J. Chu, DMD, MSD, CDT, is presently the Director of Advanced and International Continuing Dental Education Programsin Aesthetic Dentistry, a Clinical Professor in the Department of Periodontology and Implant Dentistry at the New York UniversityCollege of Dentistry, and is a board member of the Advisory Committee Education Policy at the New York Technical College. He isalso a partner at the New York Center for Specialized Dentistry. He is also Section Editor of the Prosthodontics division for Practical Procedures & Aesthetic Dentistry (PPAD). Over the course of his distinguished career, Dr. Chu has received academic honorsthat include the Columbia Dentoform Corporation Award in Operative Dentistry and Fixed Prosthodontics and the Granger-Pruden Award for Excellence in Prosthodontic Research.

Jason J. Kim

Master Dental Technician, Jason J. Kim Dental Laboratories/Oral Design, New York, NY; Clinical Assistant Professor, New YorkUniversity College of Dentistry, New York, NY. Mr. Kim is a renowned craftsman whose restorations are used by many of the world'smost discriminating clinicians.

Dennis P. Tarnow

As Professor and Chair of the Department of Periodontology and Implant Dentistry at the New York University College ofDentistry, Dr.Tarnow is one of dentistry’s foremost educators and most well-recognized authorities in restorative care. He is arecipient of the University’s prestigious Outstanding Teacher of the Year Award and numerous other honors for his dedication tohis students and his expertise in implant dentistry. Dr.Tarnow has published in leading scientific dental journals for decades and haslectured worldwide on periodontal therapy and implant dentistry.

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Light and Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Stefan J. Paul, DMD

1100Chapter

Elian • Jalbout • Cho • Tarnow • Rosenberg | iv

Current Perspectives on Dental Adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Jorge Perdigão, DMD, MS, PhD • Lorenzo Breschi, DDS, PhD

1111Chapter

Dental Luting Cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Douglas A. Terry, DDS

1122Chapter

The Interdental Papillae: Aesthetic Parameters Between Teeth and Implants . . . . . . . 4Dennis P. Tarnow, DDS

1133Chapter

Laboratory Essentials for the Restorative Dentist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Jason J. Kim, CDT, MDT • Walter Gebhard, MDT

1144Chapter

Restorative Space Management: Precision Tooth Preparation for Aesthetic Restorations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Galip Gurel, DDS • Stephen J. Chu, DMD, MSD, CDT • Jason Kim, CDT, MDT

1155Chapter

Restorative-Orthodontic Interrelationships: Orthodontic Aspects in Aesthetic Restorative Dentistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Frank Celenza, Jr, DDS

1166Chapter

Restorative-Periodontal Interrelationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Robert N. Eskow, DMD, MScD • Robert S. Lowe, DDS • Stephen J. Chu, DMD, MSD, CDT

1177Chapter

Dental Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Nicolas Elian, DDS • Ziad Jalbout, DDS • Sang-Choon Cho, DDS • Dennis P. Tarnow, DDS • Edwin S. Rosenberg, BDS, MScD, HDD, DMD

1188Chapter

Table of ContentsDiagnosis, Etiology, and Treatment Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Stephen J. Chu, DMD MSD, CDT • Dennis P. Tarnow, DDS

11Chapter

Essentials in Aesthetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Alan Sulikowski, DMD

22Chapter

The Anterior and Posterior Determinants of Occlusion . . . . . . . . . . . . . . . . . . . . . . . . . 4Stefano Gracis, DMD, MSD • Stephen J. Chu, DMD, MSD, CDT

33Chapter

Tooth Preparation Principles and Designs for Full-Coverage Restorations . . . . . . . . . . . 4Jacinthe M. Paquette, DDS • Cherilyn G. Sheets, DDS, • Jean C. Wu, DDS • Stephen J. Chu, DMD, MSD, CDT

44Chapter

Porcelain Bonded Tooth Preparation Designs & Principles . . . . . . . . . . . . . . . . . . . . . . 4Cherilyn G. Sheets, DDS • Jacinthe Paquette • DDS, Jean C. Wu, DDS

55Chapter

Restorations of Endodontically Treated Teeth: New Concepts, Materials, and Aesthetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Yoshihiro Goto, DDS, MSD • Jeffrey Ceyhan, DDS, MSD • Stephen J. Chu, DDS, MSD, CDT

66Chapter

Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching . . . . . . . 4Syngcuk Kim, DDS, PhD, MD(hon) • Ming-Lung Yang, DMD

77Chapter

Impression Making . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Ernesto A. Lee, DMD

88Chapter

Provisional Restorations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Ricardo Mitrani, DDS, MSD

99Chapter

Contents

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AESTHETIC MANAGEMENT OF NONVITAL DISCOLORED TEETH WITH INTERNAL BLEACHING

77Chapter }Syngcuk Kim, DDS, PhD, MD(hon)*Ming-Lung Yang, DMD†

Aesthetic considerations have a significantrole in defining the direction of treatment incontemporary restorative dentistry. Presenttrends have established the “perceptualneed” for whiter teeth, since whiteness isassociated with cleanliness and health.Natural teeth display a variety of shades.Color correction or whitening of vital and,more specifically, nonvital teeth has becomean increasing challenge. Among the manyoptions available, internal or intracoronalbleaching provides one of the bestmethodologies to predictably treat nonvitaldiscolored teeth.The benefits include:

• Conservation of remaining coronal toothstructure;

• Nonrestorative intervention (which pre-serves the existing periodontium and rep-resents a cost-effective treatment option);

• Maintenance of original occlusal contactsand relationships;

• Color-matching adjacent teeth withnatural color and translucency; and

• Color correction of the tooth preparationor “stump” shade prior to restoration.

*Louis I. Grossman Professor and Chairman, Department ofEndodontics, University of Pennsylvania School of DentalMedicine, Philadelphia, PA; private practice, New York, NY.

†Clinical Assistant Professor, Department of Endodontics,University of Pennsylvania School of Dental Medicine,Philadelphia, PA; private practice, Falls Church, VA.

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Aesthetic Management of NonvitalDiscolored Teeth With Internal Bleaching }{

The purpose of this chapter is to delineate the history, diagnosis, rationale, techniques, methods, outcomes, and possible complica-tions utilized in the predictable treatment of nonvital discolored teeth. Emphasis is placed on the diagnosis and etiology of discol-oration, which has significant bearing on the predictability of treatment outcomes that can be expected.This is particularly valid whentreating stump shades, which require foundation restorations (see Chapter 6) and subsequent full-coverage restorations.

A. HISTORY OF NONVITAL BLEACHING

The history of internal bleaching can be traced back more than a century. Chloride was first used inside the pulp chamber as aninternal bleaching agent, but the results were not efficacious. In 1958, Pearson was impressed by the positive bleaching effect of 30%hydrogen peroxide on the external surface of teeth.1 The solution was used internally on a pulpless tooth for 3 days with greatsuccess. In 1961, Spasser mixed sodium perborate and water as an internal bleaching medium and placed the mixture into the tooth,employing interval appointments.2 Nutting and Poe furthered the work of Spasser by replacing water with 30% hydrogen peroxideto maximize the bleaching effect.3 The sodium perborate/30% hydrogen peroxide paste was sealed within the pulp chamber fordurations of up to 7 days.This procedure was eventually termed the “walking bleach” technique. With small variations and modifi-cations from the original protocol, the methodology for current internal bleaching techniques has remained intact.

B. ETIOLOGY OF DISCOLORATION

Discolorations may be categorized as either extrinsic or intrinsic. Extrinsic discoloration is attributed to food substances such astobacco, coffee, and tea. Lack of adequate oral hygiene can be a contributory factor. These stains can be removed predictably byprofessional prophylaxis and, in severe situations, in combination with extrinsic bleaching techniques. An intrinsic factor, such asfluorosis, may cause surface defects that can promote the formation of extrinsic stains.

The etiology of intrinsic discoloration covers a broad range and may present significant variations.The basic factors initiating intrinsicdiscolorations include genetic, systemic, medication-related, pulp-related, and dental material-related:

Medication-related—Tetracycline (Figure 7-1);

Fluorosis (Figures 7-2 and 7-3);

Pulp-related—Root canal obliteration due to aging, pulp necrosis, and/or hyperemia due to trauma (Figure 7-4); and

Dental material-related—Restorative or endodontic materials (Figures 7-5 and 7-6).

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Figure 7-1 Figure 7-2 Figure 7-3


Figure 7-1. Clinical depiction oftetracycline staining.

Figure 7-2. Intrinsic discolorationcan also be attributed to thepresence of opaque fluorosis.

Figure 7-3. Illustration ofbrownish fluorosis on theanterior dentition.

Figure 7-4. Clinical image showsgrayish discoloration due topulpal necrosis from trauma.

Figure 7-5. Occlusal view of dis-coloration on surrounding toothstructure due to corrosion fromamalgam filling.

Figure 7-6. Illustration showsmetallic discoloration frompalatal amalgam filling onmaxillary right lateral incisor.



B1. Pulp-Related Discoloration

Most of the intrinsic discoloration encountered in everyday practice is caused by the breakdown of blood products of the pulptissue, due to trauma or a traumatic incident (Figure 7-7).This type of discoloration (ie, blood degradation) occurs during hemolysis,when iron is released from hemin, hemosiderin, hematin, and hematoidin. Through the addition of the bacterial product hydrogensulfide, iron is converted to ferric sulfide, resulting in the discoloration of the tooth.The dental enamel tends to change color eitherto orange, brown, or dark gray in color (Figure 7-8). In addition to blood product breakdown, the degradation of necrotic pulp tissuemay also cause discoloration. Fortunately, most discolorations resulting from these factors can be predictably corrected by utilizingthe present internal bleaching techniques (Figures 7-9 through 7-11).

B2. Dental Materials-Related Discoloration

Stains caused by dental materials are not uncommon (Figure 7-6). Among the discolorants found in dental materials, metallic ions areconsidered to be the most difficult to bleach.The metallic corrosion products may lead to a dark gray or black appearance that willbe visible through the remaining tooth structure, including the root structure (Figures 7-12 and 7-13). The severity of discolorationand the success of bleaching depend upon the amount of metallic ions penetrating the dentinal tubules.Although the severity cannotbe determined prior to the treatment, bleaching should be attempted first. It may be necessary to remove the stained toothstructure mechanically and follow with the restoration using a tooth-colored material to achieve an improved aesthetic result.Discoloration caused by other root canal filling materials has also been reported (Figure 7-14).4-6 Different materials used inside thepulp chamber will penetrate the dentinal tubules and cause varying color changes in the tooth.This type of discoloration is not pre-dictably corrected with internal bleaching (Figures 7-15 and 7-16).

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Figure 7-7. Facial view of atypical dental trauma withvery mild discoloration.

Figure 7-8. Several yearsfollowing dental trauma,more noticeable orangediscoloration is evident.

Figure 7-7 Figure 7-8

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B3. Medication-Related Discoloration

Tetracycline was introduced in the middle of the twentieth century and was used widely for the relief of nausea associated withmorning sickness. In 1963, the Food and Drug Administration (FDA) issued a warning against the use of tetracycline as an antibiot-ic for young children and pregnant women due to irreversible dental staining. Tetracycline affects the teeth during the formationperiod, ranging from the embryo in the second trimester of pregnancy to the eighth year of the child’s life.The tetracycline moleculeaffects the dentin by carrying the hydroxyapatite crystal that causes a yellowish-gray color (Figure 7-1). The severity of the tetracy-cline stains may vary. When the stain is not concentrated or localized as a band, it usually responds well to bleaching (Figure 7-17).When the band of the discoloration becomes noticeably darker, the bleaching technique has limited value. In such cases, a combi-nation of bleaching and veneering techniques might be the recommended course of treatment.

B4. Fluorosis

Fluorosis is the result of an excessive intake of fluoride during enamel formation and calcification, usually the third month of gestationthrough the eighth year after birth. When high concentrations of fluoride are absorbed by the body, the metabolic function of theameloblasts is altered, which leads to defective matrix formation and hypocalcification (Figure 7-2). This type of discoloration canaffect the primary and the permanent dentition. Histologically, a hypomineralized porous subsurface, covered by a well-mineralizedsurface enamel layer, is observed. Based on the severity, fluorosis has a variety of prognoses following bleaching. When the appear-ance of pigmentation is limited to a brownish appearance only (Figure 7-3), fluorosis responds to bleaching well. Once a severeopaque discoloration or pitted surface defects can be observed (Figure 7-18), a bonding technique is usually necessary in additionto bleaching to achieve aesthetic success.

In summary, internal bleaching is not indicated in all clinical situations to correct all forms of discoloration.The majority of discoloredanterior teeth are nonvital, however, and the discoloration is caused by traumatic injury. The efficacy of internal nonvital bleachingtreatment for a predictable aesthetic outcome in these clinical scenarios is high. In dental materials-related discolorations, however,nonvital bleaching has limited and unpredictable results.

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Figure 7-9. Image demonstrates thepresence of a brownish discolorationfrom trauma after teeth have beenprepared for all-ceramic restorations.

Figure 7-10. In order to prevent thediscoloration from showing throughthe all-ceramic restoration, internalbleaching is performed.

Figure 7-11.After bleaching, the teethmatch adjacent teeth in color andtranslucency and provide a more pre-dictable outcome for the anticipatedall-ceramic restoration.

Figure 7-12. Note the black appear-ance on cervical root surface of amaxillary left central incisor withporcelain-fused-to-metal restorationand recessive gingival tissue.

Figure 7-13.A black discoloration,attributed to the corrosion of themetal dowel, is present after thecrown is removed.





C. INDICATIONS AND CONTRAINDICATIONS FOR BLEACHING

Since not all the dental discolorations can be bleached effectively, it is important to recognize the etiology of discoloration and tocommunicate the information to the patient, along with the available treatment options, alternative treatment, and their potentialoutcomes. Nonvital bleaching is indicated when the discoloration is due to pulpal necrosis, pulpal hemorrhage, endodontic fillingmaterials, or mild to moderate tetracycline staining.The most important prerequisite for internal bleaching of a tooth is the qualityof the endodontic therapy. Nonvital bleaching procedure should be avoided when the root canal treatment is inadequate. Superficialenamel stains can be removed by pumice polishing, microabrasion, or an external bleaching technique rather than internal bleaching.If the discoloration is caused by metallic salt, or there is a lack of sound tooth structure caused by extensive restorations, fractures,hypoplastic or severely undermined enamel, a full-coverage restoration or veneer is the recommended treatment.

D. INTERNAL BLEACHING AGENTS

D1. Hydrogen Peroxide (30% to 35%)

Thirty to 35% hydrogen peroxide is the most commonly used solution in nonvital bleaching procedures, and it can be activated byheat or light application. When such solutions are activated, they decompose into perhydroxyl ions and active oxygen, which breakthe double bond of the chromophore structure of the organic molecules into simpler and lighter colored molecules.7 Because 30%to 35% hydrogen peroxide is relatively unstable, storage in a dark container and cool environment is mandatory.These solutions loseapproximately 50% of their oxidizing strength within a 6-month period. In order to achieve the best performance, a fresh amountshould be prepared for each subsequent bleaching.

D2. Sodium Perborate

Sodium perborate is another commonly used agent for nonvital bleaching. It is manufactured in powder form and is alkaline in nature.Based upon the water content, various types of preparations are available. Sodium perborate should be kept dry. When it is mixedwith acid, water, or warm air, it decomposes into sodium metaborate, hydrogen peroxide, and active oxygen. Hydrogen peroxidecontinues to break down into perhydroxyl ions. If sodium perborate is mixed with hydrogen peroxide, more perhydroxyl ions arereleased due to its alkalinity, thereby increasing the effectiveness of the bleaching mixture.8 Several studies have shown that hydrogenperoxide releases more calcium, lowers the calcium to phosphate ratio,9 and decreases the microhardness of the tooth structure.10

It also damages the dental hard tissue surfaces.11 The application of sodium perborate, however, minimizes the negative effect ofhydrogen peroxide on the tooth structure.8-11

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Figure 7-14. Illustration shows dis-coloration caused by gutta-percha.

Figure 7-15. Image of discolorationcaused by the corrosion of themetal dowel. Internal bleaching isto be attempted to resolve thediscoloration.

Figure 7-16. After few bleachingattempts, the tooth structureremains dark in shade.

Figure 7-17. Facial view demon-strates result of bleachingperformed on teeth with less-concentrated tetracycline staining.

Figure 7-18.Teeth that exhibitfluorosis with pitted surface arenot good candidates for bleaching.

Figure 7-14 Figure 7-16Figure 7-15



E. INTERNAL BLEACHING PROCEDURE

E1. Examination and Diagnosis

A thorough examination and inspection for caries, existing restorations, the integrity of the tooth structure and the health of sur-rounding gingival tissue should be made prior to bleaching. Any external stains or existing restorations should be removed. Theetiology of the discoloration should be determined. Root canal obturation should be examined radiographically to ascertain that itis filled to the apex.The coronal seal should be complete to minimize the potential of leakage. Probing should also be performedon the labial, mesial, palatal, and distal aspects of the tooth to evaluate the relationship between the tooth and its surrounding epithe-lial attachment and to establish baselines (Figure 7-19). Finally, treatment procedures, the expected outcome, and the potential forsubsequent complications should be explained to the patient.

E2. Precautions

Bleaching agents are mostly caustic, and the procedure requires that patients are provided with protective eyewear and a plasticdrape.The oral environment must be protected by use of a rubber dam, ligature, and oral protective ointment.The epithelial attach-ment should be reexamined after bleaching. Such examination is necessary, since the bleaching agents are caustic, and an accidentalleakage may cause the breakdown of the epithelial attachment.

E3. Shade Documentation

While matching the color of the bleached tooth to that of the adjacent dentition can present a challenge, it is essential to establisha color baseline prior to initiating the bleaching procedure.The tooth color is compared with the matching shade guide, and a pho-tograph is then taken to maintain a record. During each recall visit, the same procedure should be consistently repeated to monitorthe improvement.

E4.Tooth Isolation

The use of a rubber dam is essential. It should be placed on the teeth to be bleached with waxed dental floss, and the floss shouldbe tightened around the cervical portion of the tooth with a knot. Prior to placing the rubber dam, an oral protective ointmentshould be swabbed around each tooth underneath the dam and on the surrounding gingival tissue for additional protection.

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11

Figure 7-20 and 7-21Figure 7-19


Figure 7-19. Illustration shows probing on the distal, labial, and mesial aspects ofthe tooth to evaluate the relationshipbetween the tooth and its surroundingepithelial attachment and to establish thebase lines.

Figures 7-20 and 7-21.Tooth accessshould be conservative, but no pulphorns or undercuts should be left behind.

Figure 7-22. Image demonstrates the use of an ultrasonic tip #2 to removediscolored dentin.

Figure 7-23. Illustration shows the use of heated instruments to remove gutta-percha from the canal.


E5.Access Cavity Preparation

All restorative material should be removed from the access cavity, using a high-speed handpiece with copious irrigation.The accessshould be as conservative as possible, but care should be taken not to leave any pulp horns or undercuts behind (Figures 7-20 and7-21). Any residual pulp tissue or dental materials left in the chamber might cause further discoloration once the bleaching iscomplete. A slow-speed handpiece may be used to remove the remaining debris on the dentinal wall. Specially fabricated ultrasonictips, attached to a Piezo-ultrasonic unit, can be valuable instruments for carefully ablating the discolored dentin and removing it insmall increments (Figure 7-22).

E6. Space for Barrier

Gutta-percha should be removed from the canal orifice to a level of 2 mm below the corresponding epithelial attachment.This canbe done by using a heated endodontic instrument and heated Glicks instrument.The use of heated endodontic instruments is morefavorable than that of rotary instruments, because they remove gutta-percha more efficiently without damaging any tooth structure(Figure 7-23).

E7. Barrier Placement

Once the space for a barrier is established, it must be sealed with specific materials.The purpose of placing a barrier is to block thepotential leakage of bleaching agents through dentinal tubules to the epithelial attachment.This step is important for prevention ofcervical resorption. The outline of the barrier should follow the corresponding probing of the epithelial attachment (Figure 7-24).Cavit (3M Espe, St. Paul, MN) has been reported to provide better seal as a barrier than either intermediate restorative material ortemporary endodontic restorative material.12,13 The thickness of the barrier is important as well; in order to prevent leakage, thebarrier should be placed 1 mm incisal to the level of the epithelial attachment and extend at least 2 mm apically.

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Figure 7-25 Figure 7-26Figure 7-24

Figure 7-24.The outline ofthe barrier should followthe corresponding probingof the epithelial attachment.

Figures 7-25 and 7-26. Acotton pellet saturated with30% to 35% hydrogenperoxide is placed in thechamber, where heat causesthe bubbling effect.


E8.Application of Bleaching Agents

E8a.The Thermocatalytic Technique

The thermocatalytic technique uses heat to activate 30% to 35% hydrogen peroxide in the chamber. A cotton pellet saturated withthe hydrogen peroxide is placed in the chamber, and the heat causes a bubbling effect (Figures 7-25 and 7-26). The heat applicationcan be as long as 5 minutes, providing the cotton is kept saturated at all times. The temperature should be maintained at 73°C(165°F) to avoid causing any discomfort to the patient.

E8b.The Light Technique

The light technique can also be used to activate hydrogen peroxide in the chamber. As with the thermocatalytic technique, a cottonpellet saturated with superoxide is placed in the chamber, and a bright light source is positioned directly above the crown, nearlytouching the buccal surface, for 3 to 5 minutes.The light source may be a regular desk lamp light; the light of the microscope at fullpower is also an effective light source.

E8c.The “Walking Bleach” Technique

In the “walking bleach” technique, the mixture of sodium perborate and 30% to 35% hydrogen peroxide is placed in the chamberand sealed for 7 days (Figure 7-27). The sodium perborate and 30% to 35% hydrogen peroxide are mixed in a ratio of 2 gperborate/ml of 30% to 35% hydrogen peroxide, which results in a thick, white paste.After placing an adequate amount of the mixingpaste into the chamber, a temporary filling material is used as a sealer. Patients should be informed that the same procedure mayhave to be repeated, if necessary, and that another recall visit is required in 7 days.

E9.After Bleaching the Restoration

After the desired result is achieved, which may take more than one visit, the remaining bleaching agent should be removed thor-oughly from the chamber. If composite resin is the material of choice for the final restoration, the access cavity should be filled com-pletely with a noneugenol temporary base material. A loss of bond strength has been found if glass ionomer or composite resin isbonded to dentin or enamel immediately following bleaching. If increased microleakage may be observed around composite restora-tions, it could be due to the residual bleaching agent within the dentinal tubules and enamel. It is therefore suggested that finalrestoration be delayed for at least one week following bleaching.

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Figure 7-27.The mixture of sodium perborate and 30%to 35% hydrogen peroxide is placed and sealed in thechamber for seven days as the “walking bleach”technique.

Figure 7-27



G. POSSIBLE COMPLICATIONS

Like any other procedure, bleaching has some risks. All potential complications should always be discussed with the patient prior toinitiating the treatment.A chemical burn is commonly seen on the gingival margin of the bleached tooth. It may also appear on otheroral mucosa. Since 30% to 35% hydrogen peroxide is a strong oxidizer, the patient should always be protected with a rubber dam.Dental floss and an oral ointment should be used to complete the seal.

External cervical resorption is the most severe nonvital bleaching complication, although the direct link is still controversial. Severalcase reports have been published, and the contributing factors have been discussed.1,22,24,25 In those reports, most patients were underthe age of 25. Most cases were bleached with heat application, and none of the cases used barrier isolation. Several cases had historyof trauma, which may be the cause of varying types of resorption. Ultimately, however, this correlation is not conclusive. Harringtonand Natkin hypothesized that hydrogen peroxide diffuses through patent dentinal tubules into the epithelial attachment and mayinitiate an inflammatory resorptive process.26 Lado et al believed that hydrogen peroxide denatures the dentin, thereby causing aforeign body reaction.27 Cvek and Lindvall reported that bacteria colonization after initial hydrogen peroxide irritation to the epithe-lial attachment might be the critical factor.28 In the authors’ experience, however, cervical resorption following internal bleachingcannot be documented. In some cases with cervical resorption, a direct correlation with a history of trauma is always present.

H. CONCLUSIONS

Nonvital bleaching can be an effective and economic option to satisfy patients’ aesthetic concerns.Thorough evaluation of a patient’shistory will help determine the cause of discoloration and therefore result in a predictable outcome. Pretreatment precautions andperiodic posttreatment recalls are necessary to reduce the potential of severe complications.

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F. THE RESULTS

Regarding the effectiveness of different bleaching techniques, Freccia et al reported that the thermocatalytic and the “walking bleach”techniques achieve similar results.14 Mixing sodium perborate with different concentrations of hydrogen peroxide or distilled waterwas also studied. It has been claimed that the bleaching effect of the mixture of sodium perborate with distilled water is the sameas that of sodium perborate with 30% hydrogen peroxide.15-17 Other investigations showed that mixing sodium perborate with 30%hydrogen peroxide was more effective than mixing with distilled water.18,19 It is the authors’ experience that thermocatalytic and lighttechniques with 30% to 35% hydrogen peroxide achieve aesthetic results.The “walking bleach” technique may take more than twoto three visits, depending on the concentration of 30% to 35% hydrogen peroxide in the mixture utilized. It is a more conservativeand perhaps less caustic method, due to the use of sodium perborate. For a tooth with mild discoloration, it may be the bestsolution. For a tooth with severe discoloration, we recommend the thermocatalytic technique.

Although nonvital bleaching may be generally successful, several limitations still remain. It should be kept in mind that the bleachingon the gingival third is not as effective as it is on the incisal and middle thirds.This is due to the fact that the dentin is usually thickernear the gingival third and, therefore, it is more difficult for the bleaching agent to reach the outer layer of dentin. In addition, over-placing the barrier in the faciocervical area may also have a role in the outcome.

Color regression over the years has been reported to vary between 4% to 70%.18-23 The causes for the regression are not wellunderstood, although microleakage through the restoration is believed to be a major contributing factor. It is wise to have thebleached teeth examined annually to follow up on any of the color regression. If necessary, the internal bleaching may be repeatedto achieve the desired aesthetic results.

Nonvital bleaching, using the thermalcatalytic or light techniques, should result in an immediate change in tooth color. When usingthe “walking bleach” technique, there are times when the color change is not observed during the first visit. In such cases, repeatedapplication will produce results.



21. Friedman S, Rotstein I, Libfeld H, et al. Incidence of external root resorption and esthetic results in 58 bleached pulpless teeth.Endod Dent Traumatol 1988;4:23-26.

22. Friedman S. Internal bleaching: Long-term outcomes and complications. J Am Dent Assoc 1997;128(Suppl):51S-5S.23. Holmstrup G, Palm AM, Lambjerg-Hansen H. Bleaching of discoloured root-filled teeth. Endod Dent Traumatol 1988;4:197-210.24. Trope M. Cervical root resorption. J Am Dent Assoc 1997;128(Suppl):56S-9S.25. Heithersay GS. Invasive cervical resorption: An analysis of potential predisposing factors. Quint Int 1999;30:83-95.26. Harrington GW, Natkin E. External resorption associated with bleaching of pulpless teeth. J Endod 1979;5:344-348.27. Lado EA, Stanley HR, Weisman MI. Cervical resorption in bleached teeth. Oral Surg Oral Med Oral Pathol 1983;55:78-80.28. Cvek M, Lindvall AM. External root resorption following bleaching of pulpless teeth with oxygen peroxide. Endod Dent

Traumatol 1985;1:56-60.

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References

1. Pearson HH. Bleaching of the discolored pulpless tooth. J Am Dent Assoc 1958;56:64-68.2. Spasser BA. A simple bleaching technique using sodium perborate. NY State Dent J 1961;27:332-334.3. Poe N. A new combination for bleaching teeth. JSCSDA 1963;31:289-291.4. van der Burgt TP, Mullaney TP, Plasschaert AJ. Tooth discoloration induced by endodontic sealers. Oral Surg Oral Med Oral

Pathol 1986;61:84-89.5. Rotstein I, Walton RE. Bleaching discolored teeth: Internal and external. In: Walton RE, Torabinejab M, eds. Principles and

Practice of Endodontics. 3rd ed. Philadelphia, PA: WB Saunders; 2002:405-423.6. Parsons JR, Walton RE, Rick-Williamson L. In vitro longitudinal assessment of coronal discoloration from endodontic sealers.

J Endodont 2001;11:699-702.7. Abbott PV. Aesthetic considerations in endodontics: Internal bleaching. Pract Periodont Aesthet Dent 1997;9:833-840.8. Frysh H, Bowles WH, Baker F, et al. Effect of pH on hydrogen peroxide bleaching agents. J Esthet Dent 1995;9:130-133.9. Rotstein I, Lehr Z, Gedalia I. Effect of bleaching agents on inorganic components of human dentin and cementum. J Endod

1992;18:290-293.10. Lewinstein I, Hirschfeld Z, Stabholz A, Rotstein I. Effect of hydrogen peroxide and sodium perborate on the microhardness of

human enamel and dentin. J Endod 1994;20:61-63.11. Rotstein I, Dankner E, Goldman A, et al. Histochemical analysis of dental hard tissues following bleaching. J Endod 1996;22:23-25.12. Waite RM, Carnes DL Jr., Walker WA 3rd. Microleakage of TERM used with sodium perborate/water and sodium

perborate/superoxol in the "walking bleach" technique. J Endod 1998;24:648-650.13. Hansen-Bayless J, Davis R. Sealing ability of two intermediate restorative materials in bleached teeth. Am J Dent 1992;5:151-154.14. Freccia WF, Peters DD, Lorton L, Bernier WE.An in vitro comparison of nonvital bleaching techniques in the discolored tooth.

J Endod 1982;8:70-77.15. Rotstein I, Zalkind M, Mor C, et al. In vitro efficacy of sodium perborate preparations used for intracoronal bleaching of dis-

colored non-vital teeth. Endod Dent Traumatol 1991;7:177-180.16. Rotstein I, Mor C, Friedman S. Prognosis of intracoronal bleaching with sodium perborate preparation in vitro: 1-year study.

J Endod 1993;19:10-12.17. Weiger R, Kuhn A, Lost C. In vitro comparison of various types of sodium perborate used for intracoronal bleaching of dis-

colored teeth. J Endod 1994;20:338-341.18. Ho S, Goerig AC. An in vitro comparison of different bleaching agents in the discolored tooth. J Endod 1989;15:106-111.19. Warren MA, Wong M, Ingram TA 3rd. In vitro comparison of bleaching agents on the crowns and roots of discolored teeth.

J Endod 1990;16:463-467.20. Feiglin B. A 6-year recall study of clinically chemically bleached teeth. Oral Surg Oral Med Oral Pathol 1987;63:610-613.


Aesthetic Restorative Dentistry

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