Aesthetic Restorative Dentistry


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Aesthetic Restorative Dentistry

  1. 1. Dennis P. TarnowAs 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 to Aesthetic Restorative Dentistry Principles and Practicehis 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. Dennis P. Tarnow Stephen J. Chu Jason KimStephen J. ChuDr. 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 forPractical 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. KimMaster 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 worldsmost discriminating clinicians.
  2. 2. Table of ContentsContents Chapter 1 Diagnosis, Etiology, and Treatment Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Stephen J. Chu, DMD MSD, CDT • Dennis P Tarnow, DDS . Chapter 10 Light and Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Stefan J. Paul, DMD Chapter 2 Essentials in Aesthetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Alan Sulikowski, DMD Chapter 11 Current Perspectives on Dental Adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Jorge Perdigão, DMD, MS, PhD • Lorenzo Breschi, DDS, PhD Chapter 3 The Anterior and Posterior Determinants of Occlusion . . . . . . . . . . . . . . . . . . . . . . . . . 4 Stefano Gracis, DMD, MSD • Stephen J. Chu, DMD, MSD, CDT Chapter 12 Dental Luting Cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Douglas A. Terry, DDS Chapter 4 Tooth Preparation Principles and Designs for Full-Coverage Restorations . . . . . . . . . . . 4 Jacinthe M. Paquette, DDS • Cherilyn G. Sheets, DDS, • Jean C. Wu, DDS • Stephen J. Chu, DMD, MSD, CDT Chapter 13 The Interdental Papillae: Aesthetic Parameters Between Teeth and Implants . . . . . . . 4 Dennis P Tarnow, DDS . Chapter 5 Porcelain Bonded Tooth Preparation Designs & Principles . . . . . . . . . . . . . . . . . . . . . . 4 Cherilyn G. Sheets, DDS • Jacinthe Paquette • DDS, Jean C. Wu, DDS Chapter 14 Laboratory Essentials for the Restorative Dentist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Jason J. Kim, CDT, MDT • Walter Gebhard, MDT Restorations of Endodontically Treated Teeth: Chapter 6 New Concepts, Materials, and Aesthetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Yoshihiro Goto, DDS, MSD • Jeffrey Ceyhan, DDS, MSD • Stephen J. Chu, DDS, MSD, CDT Chapter 15 Restorative Space Management: Precision Tooth Preparation for Aesthetic Restorations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Galip Gurel, DDS • Stephen J. Chu, DMD, MSD, CDT • Jason Kim, CDT, MDT Chapter 7 Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching . . . . . . . 4 Syngcuk Kim, DDS, PhD, MD(hon) • Ming-Lung Yang, DMD Chapter 16 Restorative-Orthodontic Interrelationships: Orthodontic Aspects in Aesthetic Restorative Dentistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Frank Celenza, Jr, DDS Chapter 8 Impression Making . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Ernesto A. Lee, DMD Chapter 17 Restorative-Periodontal Interrelationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Robert N. Eskow, DMD, MScD • Robert S. Lowe, DDS • Stephen J. Chu, DMD, MSD, CDT Chapter 9 Provisional Restorations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Ricardo Mitrani, DDS, MSD Chapter 18 Dental Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Nicolas Elian, DDS • Ziad Jalbout, DDS • Sang-Choon Cho, DDS • Dennis P Tarnow, DDS • Edwin S. Rosenberg, BDS, MScD, HDD, DMD . Elian • Jalbout • Cho • Tarnow • Rosenberg | iv
  3. 3. Aesthetic considerations have a significant role in defining the direction of treatment in contemporary restorative dentistry. Present trends have established the “perceptual need” for whiter teeth, since whiteness is associated with cleanliness and health. Natural teeth display a variety of shades. Color correction or whitening of vital and, } more specifically, nonvital teeth has become an increasing challenge. Among the many AESTHETIC MANAGEMENT OF 7 options available, internal or intracoronal bleaching provides one of the bestChapter NONVITAL DISCOLORED TEETH methodologies to predictably treat nonvital discolored teeth.The benefits include: WITH INTERNAL BLEACHING • Conservation of remaining coronal tooth Syngcuk Kim, DDS, PhD, MD(hon)* structure; Ming-Lung Yang, DMD† • Nonrestorative intervention (which pre- serves the existing periodontium and rep- resents a cost-effective treatment option); • Maintenance of original occlusal contacts and relationships; • Color-matching adjacent teeth with natural color and translucency; and • Color correction of the tooth preparation or “stump” shade prior to restoration. *Louis I. Grossman Professor and Chairman, Department of Endodontics, University of Pennsylvania School of Dental Medicine, 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. Kim • Yang | 2
  4. 4. { Aesthetic Management of Nonvital Discolored 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 when treating stump shades, which require foundation restorations (see Chapter 6) and subsequent full-coverage restorations. Figure 7-1. Clinical depiction of A. HISTORY OF NONVITAL BLEACHING tetracycline staining. The history of internal bleaching can be traced back more than a century. Chloride was first used inside the pulp chamber as an Figure 7-2. Intrinsic discoloration internal bleaching agent, but the results were not efficacious. In 1958, Pearson was impressed by the positive bleaching effect of 30% can also be attributed to the hydrogen peroxide on the external surface of teeth.1 The solution was used internally on a pulpless tooth for 3 days with great presence of opaque fluorosis. success. 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 peroxide Figure 7-3. Illustration of to maximize the bleaching effect.3 The sodium perborate/30% hydrogen peroxide paste was sealed within the pulp chamber for brownish fluorosis on the durations of up to 7 days. This procedure was eventually termed the “walking bleach” technique. With small variations and modifi- anterior dentition. cations from the original protocol, the methodology for current internal bleaching techniques has remained intact. Figure 7-1 Figure 7-2 Figure 7-3 Figure 7-4. Clinical image shows grayish discoloration due to pulpal necrosis from trauma. B. ETIOLOGY OF DISCOLORATION Figure 7-5. Occlusal view of dis- Discolorations may be categorized as either extrinsic or intrinsic. Extrinsic discoloration is attributed to food substances such as coloration on surrounding tooth tobacco, coffee, and tea. Lack of adequate oral hygiene can be a contributory factor. These stains can be removed predictably by structure due to corrosion from professional prophylaxis and, in severe situations, in combination with extrinsic bleaching techniques. An intrinsic factor, such as amalgam filling. fluorosis, may cause surface defects that can promote the formation of extrinsic stains. Figure 7-6. Illustration shows metallic discoloration from The etiology of intrinsic discoloration covers a broad range and may present significant variations.The basic factors initiating intrinsic palatal amalgam filling on discolorations include genetic, systemic, medication-related, pulp-related, and dental material-related: maxillary right lateral incisor. Figure 7-4 Figure 7-5 Medication-related—Tetracycline (Figure 7-1); Figure 7-6 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).3 Kim • Yang | 4
  5. 5. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } B1. Pulp-Related Discoloration Most of the intrinsic discoloration encountered in everyday practice is caused by the breakdown of blood products of the pulp tissue, 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 hydrogen sulfide, iron is converted to ferric sulfide, resulting in the discoloration of the tooth.The dental enamel tends to change color either to orange, brown, or dark gray in color (Figure 7-8). In addition to blood product breakdown, the degradation of necrotic pulp tissue Figure 7-7. Facial view of a may also cause discoloration. Fortunately, most discolorations resulting from these factors can be predictably corrected by utilizing typical dental trauma with very mild discoloration. the present internal bleaching techniques (Figures 7-9 through 7-11). Figure 7-8. Several years B2. Dental Materials-Related Discoloration following dental trauma, more noticeable orange Stains caused by dental materials are not uncommon (Figure 7-6). Among the discolorants found in dental materials, metallic ions are discoloration is evident. considered to be the most difficult to bleach.The metallic corrosion products may lead to a dark gray or black appearance that will be visible through the remaining tooth structure, including the root structure (Figures 7-12 and 7-13). The severity of discoloration and the success of bleaching depend upon the amount of metallic ions penetrating the dentinal tubules. Although the severity cannot be determined prior to the treatment, bleaching should be attempted first. It may be necessary to remove the stained tooth structure mechanically and follow with the restoration using a tooth-colored material to achieve an improved aesthetic result. Figure 7-7 Figure 7-8 Discoloration caused by other root canal filling materials has also been reported (Figure 7-14).4-6 Different materials used inside the pulp 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).5 Kim • Yang | 6
  6. 6. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } B3. Medication-Related Discoloration Tetracycline was introduced in the middle of the twentieth century and was used widely for the relief of nausea associated with Figure 7-9. Image demonstrates the morning sickness. In 1963, the Food and Drug Administration (FDA) issued a warning against the use of tetracycline as an antibiot- presence of a brownish discoloration ic for young children and pregnant women due to irreversible dental staining. Tetracycline affects the teeth during the formation from trauma after teeth have been period, ranging from the embryo in the second trimester of pregnancy to the eighth year of the child’s life.The tetracycline molecule prepared for all-ceramic restorations. affects 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). Figure 7-10. In order to prevent the discoloration from showing through When the band of the discoloration becomes noticeably darker, the bleaching technique has limited value. In such cases, a combi- the all-ceramic restoration, internal nation of bleaching and veneering techniques might be the recommended course of treatment. bleaching is performed. B4. Fluorosis Figure 7-9 Figure 7-10 Figure 7-11 Figure 7-11. After bleaching, the teeth match adjacent teeth in color and Fluorosis is the result of an excessive intake of fluoride during enamel formation and calcification, usually the third month of gestation translucency and provide a more pre- through the eighth year after birth. When high concentrations of fluoride are absorbed by the body, the metabolic function of the dictable outcome for the anticipated ameloblasts is altered, which leads to defective matrix formation and hypocalcification (Figure 7-2). This type of discoloration can all-ceramic restoration. affect the primary and the permanent dentition. Histologically, a hypomineralized porous subsurface, covered by a well-mineralized surface enamel layer, is observed. Based on the severity, fluorosis has a variety of prognoses following bleaching. When the appear- Figure 7-12. Note the black appear- ance on cervical root surface of a ance of pigmentation is limited to a brownish appearance only (Figure 7-3), fluorosis responds to bleaching well. Once a severe maxillary left central incisor with opaque discoloration or pitted surface defects can be observed (Figure 7-18), a bonding technique is usually necessary in addition porcelain-fused-to-metal restoration to bleaching to achieve aesthetic success. and recessive gingival tissue. In summary, internal bleaching is not indicated in all clinical situations to correct all forms of discoloration.The majority of discolored Figure 7-13. A black discoloration, attributed to the corrosion of the anterior teeth are nonvital, however, and the discoloration is caused by traumatic injury. The efficacy of internal nonvital bleaching metal dowel, is present after the treatment for a predictable aesthetic outcome in these clinical scenarios is high. In dental materials-related discolorations, however, crown is removed. nonvital bleaching has limited and unpredictable results. Figure 7-12 Figure 7-137 Kim • Yang | 8
  7. 7. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } 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 to communicate the information to the patient, along with the available treatment options, alternative treatment, and their potential outcomes. Nonvital bleaching is indicated when the discoloration is due to pulpal necrosis, pulpal hemorrhage, endodontic filling materials, or mild to moderate tetracycline staining. The most important prerequisite for internal bleaching of a tooth is the quality of the endodontic therapy. Nonvital bleaching procedure should be avoided when the root canal treatment is inadequate. Superficial Figure 7-14. Illustration shows dis- enamel stains can be removed by pumice polishing, microabrasion, or an external bleaching technique rather than internal bleaching. coloration caused by gutta-percha. 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. Figure 7-15. Image of discoloration caused by the corrosion of the metal dowel. Internal bleaching is to be attempted to resolve the D. INTERNAL BLEACHING AGENTS discoloration. D1. Hydrogen Peroxide (30% to 35%) Figure 7-14 Figure 7-15 Figure 7-16 Figure 7-16. After few bleaching attempts, the tooth structure Thirty to 35% hydrogen peroxide is the most commonly used solution in nonvital bleaching procedures, and it can be activated by remains dark in shade. heat or light application. When such solutions are activated, they decompose into perhydroxyl ions and active oxygen, which break the double bond of the chromophore structure of the organic molecules into simpler and lighter colored molecules.7 Because 30% Figure 7-17. Facial view demon- to 35% hydrogen peroxide is relatively unstable, storage in a dark container and cool environment is mandatory.These solutions lose strates result of bleaching approximately 50% of their oxidizing strength within a 6-month period. In order to achieve the best performance, a fresh amount performed on teeth with less- should be prepared for each subsequent bleaching. concentrated tetracycline staining. Figure 7-18.Teeth that exhibit D2. Sodium Perborate fluorosis with pitted surface are Sodium perborate is another commonly used agent for nonvital bleaching. It is manufactured in powder form and is alkaline in nature. not good candidates for bleaching. Based upon the water content, various types of preparations are available. Sodium perborate should be kept dry. When it is mixed Figure 7-17 Figure 7-18 with acid, water, or warm air, it decomposes into sodium metaborate, hydrogen peroxide, and active oxygen. Hydrogen peroxide continues to break down into perhydroxyl ions. If sodium perborate is mixed with hydrogen peroxide, more perhydroxyl ions are released due to its alkalinity, thereby increasing the effectiveness of the bleaching mixture.8 Several studies have shown that hydrogen peroxide 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 of hydrogen peroxide on the tooth structure.8-119 Kim • Yang | 10
  8. 8. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } 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. The etiology of the discoloration should be determined. Root canal obturation should be examined radiographically to ascertain that it Figure 7-19. Illustration shows probing is filled to the apex. The coronal seal should be complete to minimize the potential of leakage. Probing should also be performed on the distal, labial, and mesial aspects of on the labial, mesial, palatal, and distal aspects of the tooth to evaluate the relationship between the tooth and its surrounding epithe- the tooth to evaluate the relationship lial attachment and to establish baselines (Figure 7-19). Finally, treatment procedures, the expected outcome, and the potential for between the tooth and its surrounding subsequent complications should be explained to the patient. epithelial attachment and to establish the base lines. E2. Precautions Figures 7-20 and 7-21.Tooth access should be conservative, but no pulp Bleaching agents are mostly caustic, and the procedure requires that patients are provided with protective eyewear and a plastic Figure 7-19 Figure 7-20 and 7-21 horns or undercuts should be left behind. drape.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 accidental Figure 7-22. Image demonstrates the leakage may cause the breakdown of the epithelial attachment. use of an ultrasonic tip #2 to remove discolored dentin. E3. Shade Documentation Figure 7-23. Illustration shows the use While matching the color of the bleached tooth to that of the adjacent dentition can present a challenge, it is essential to establish of heated instruments to remove gutta- a color baseline prior to initiating the bleaching procedure.The tooth color is compared with the matching shade guide, and a pho- percha from the canal. tograph is then taken to maintain a record. During each recall visit, the same procedure should be consistently repeated to monitor the improvement. Figure 7-22 Figure 7-23 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 should be tightened around the cervical portion of the tooth with a knot. Prior to placing the rubber dam, an oral protective ointment should be swabbed around each tooth underneath the dam and on the surrounding gingival tissue for additional protection.11 Kim • Yang | 12
  9. 9. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } E5. Access Cavity Preparation All restorative material should be removed from the access cavity, using a high-speed handpiece with copious irrigation. The access should be as conservative as possible, but care should be taken not to leave any pulp horns or undercuts behind (Figures 7-20 and 7-21). Any residual pulp tissue or dental materials left in the chamber might cause further discoloration once the bleaching is complete. A slow-speed handpiece may be used to remove the remaining debris on the dentinal wall. Specially fabricated ultrasonic tips, attached to a Piezo-ultrasonic unit, can be valuable instruments for carefully ablating the discolored dentin and removing it in Figure 7-24.The outline of small increments (Figure 7-22). the barrier should follow the corresponding probing of the epithelial attachment. E6. Space for Barrier Figures 7-25 and 7-26. A Gutta-percha should be removed from the canal orifice to a level of 2 mm below the corresponding epithelial attachment.This can cotton pellet saturated with be done by using a heated endodontic instrument and heated Glicks instrument.The use of heated endodontic instruments is more 30% to 35% hydrogen favorable than that of rotary instruments, because they remove gutta-percha more efficiently without damaging any tooth structure peroxide is placed in the (Figure 7-23). chamber, where heat causes the bubbling effect. E7. Barrier Placement Figure 7-24 Figure 7-25 Figure 7-26 Once the space for a barrier is established, it must be sealed with specific materials.The purpose of placing a barrier is to block the potential leakage of bleaching agents through dentinal tubules to the epithelial attachment. This step is important for prevention of cervical 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 or temporary endodontic restorative material.12,13 The thickness of the barrier is important as well; in order to prevent leakage, the barrier should be placed 1 mm incisal to the level of the epithelial attachment and extend at least 2 mm apically.13 Kim • Yang | 14
  10. 10. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } 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 with the hydrogen peroxide is placed in the chamber, and the heat causes a bubbling effect (Figures 7-25 and 7-26). The heat application can 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 cotton pellet saturated with superoxide is placed in the chamber, and a bright light source is positioned directly above the crown, nearly touching the buccal surface, for 3 to 5 minutes.The light source may be a regular desk lamp light; the light of the microscope at full Figure 7-27.The mixture of sodium perborate and 30% power is also an effective light source. to 35% hydrogen peroxide is placed and sealed in the chamber for seven days as the “walking bleach” E8c.The “Walking Bleach” Technique technique. In the “walking bleach” technique, the mixture of sodium perborate and 30% to 35% hydrogen peroxide is placed in the chamber and sealed for 7 days (Figure 7-27). The sodium perborate and 30% to 35% hydrogen peroxide are mixed in a ratio of 2 g perborate/ml of 30% to 35% hydrogen peroxide, which results in a thick, white paste. After placing an adequate amount of the mixing paste into the chamber, a temporary filling material is used as a sealer. Patients should be informed that the same procedure may have to be repeated, if necessary, and that another recall visit is required in 7 days. Figure 7-27 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 is bonded 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 final restoration be delayed for at least one week following bleaching.15 Kim • Yang | 16
  11. 11. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } F. THE RESULTS G. POSSIBLE COMPLICATIONS Regarding the effectiveness of different bleaching techniques, Freccia et al reported that the thermocatalytic and the “walking bleach” Like any other procedure, bleaching has some risks. All potential complications should always be discussed with the patient prior to techniques achieve similar results.14 Mixing sodium perborate with different concentrations of hydrogen peroxide or distilled water initiating the treatment. A chemical burn is commonly seen on the gingival margin of the bleached tooth. It may also appear on other was also studied. It has been claimed that the bleaching effect of the mixture of sodium perborate with distilled water is the same oral mucosa. Since 30% to 35% hydrogen peroxide is a strong oxidizer, the patient should always be protected with a rubber dam. as that of sodium perborate with 30% hydrogen peroxide.15-17 Other investigations showed that mixing sodium perborate with 30% Dental floss and an oral ointment should be used to complete the seal. hydrogen peroxide was more effective than mixing with distilled water.18,19 It is the authors’ experience that thermocatalytic and light techniques with 30% to 35% hydrogen peroxide achieve aesthetic results. The “walking bleach” technique may take more than two External cervical resorption is the most severe nonvital bleaching complication, although the direct link is still controversial. Several to three visits, depending on the concentration of 30% to 35% hydrogen peroxide in the mixture utilized. It is a more conservative case reports have been published, and the contributing factors have been discussed.1,22,24,25 In those reports, most patients were under and perhaps less caustic method, due to the use of sodium perborate. For a tooth with mild discoloration, it may be the best the age of 25. Most cases were bleached with heat application, and none of the cases used barrier isolation. Several cases had history solution. For a tooth with severe discoloration, we recommend the thermocatalytic technique. of trauma, which may be the cause of varying types of resorption. Ultimately, however, this correlation is not conclusive. Harrington and Natkin hypothesized that hydrogen peroxide diffuses through patent dentinal tubules into the epithelial attachment and may Although nonvital bleaching may be generally successful, several limitations still remain. It should be kept in mind that the bleaching initiate an inflammatory resorptive process.26 Lado et al believed that hydrogen peroxide denatures the dentin, thereby causing a on 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 thicker foreign body reaction.27 Cvek and Lindvall reported that bacteria colonization after initial hydrogen peroxide irritation to the epithe- near the gingival third and, therefore, it is more difficult for the bleaching agent to reach the outer layer of dentin. In addition, over- lial attachment might be the critical factor.28 In the authors’ experience, however, cervical resorption following internal bleaching placing the barrier in the faciocervical area may also have a role in the outcome. cannot be documented. In some cases with cervical resorption, a direct correlation with a history of trauma is always present. Color regression over the years has been reported to vary between 4% to 70%.18-23 The causes for the regression are not well understood, although microleakage through the restoration is believed to be a major contributing factor. It is wise to have the H. CONCLUSIONS bleached teeth examined annually to follow up on any of the color regression. If necessary, the internal bleaching may be repeated to achieve the desired aesthetic results. Nonvital bleaching can be an effective and economic option to satisfy patients’ aesthetic concerns.Thorough evaluation of a patient’s history will help determine the cause of discoloration and therefore result in a predictable outcome. Pretreatment precautions and periodic posttreatment recalls are necessary to reduce the potential of severe complications. Nonvital bleaching, using the thermalcatalytic or light techniques, should result in an immediate change in tooth color. When using the “walking bleach” technique, there are times when the color change is not observed during the first visit. In such cases, repeated application will produce results.17 Kim • Yang | 18
  12. 12. { Aesthetic Management of Nonvital Discolored Teeth With Internal Bleaching } References 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. 1. Pearson HH. Bleaching of the discolored pulpless tooth. J Am Dent Assoc 1958;56:64-68. 22. Friedman S. Internal bleaching: Long-term outcomes and complications. J Am Dent Assoc 1997;128(Suppl):51S-5S. 2. Spasser BA. A simple bleaching technique using sodium perborate. NY State Dent J 1961;27:332-334. 23. Holmstrup G, Palm AM, Lambjerg-Hansen H. Bleaching of discoloured root-filled teeth. Endod Dent Traumatol 1988;4:197-210. 3. Poe N. A new combination for bleaching teeth. JSCSDA 1963;31:289-291. 24. Trope M. Cervical root resorption. J Am Dent Assoc 1997;128(Suppl):56S-9S. 4. van der Burgt TP, Mullaney TP, Plasschaert AJ. Tooth discoloration induced by endodontic sealers. Oral Surg Oral Med Oral 25. Heithersay GS. Invasive cervical resorption: An analysis of potential predisposing factors. Quint Int 1999;30:83-95. Pathol 1986;61:84-89. 26. Harrington GW, Natkin E. External resorption associated with bleaching of pulpless teeth. J Endod 1979;5:344-348. 5. Rotstein I, Walton RE. Bleaching discolored teeth: Internal and external. In: Walton RE, Torabinejab M, eds. Principles and 27. Lado EA, Stanley HR, Weisman MI. Cervical resorption in bleached teeth. Oral Surg Oral Med Oral Pathol 1983;55:78-80. Practice of Endodontics. 3rd ed. Philadelphia, PA: WB Saunders; 2002:405-423. 28. Cvek M, Lindvall AM. External root resorption following bleaching of pulpless teeth with oxygen peroxide. Endod Dent 6. Parsons JR, Walton RE, Rick-Williamson L. In vitro longitudinal assessment of coronal discoloration from endodontic sealers. Traumatol 1985;1:56-60. 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;63:610-613.19 Kim • Yang | 20