INSIDE  Educación  Continua        ODONTOLOGÍA  RESTAURADORA                      PERIODONCIA      

Blanqueamiento  del  diente  unitario  oscurecido  

 Cambiar  el  color  de  un  solo  un  diente  del  sector  anterior  implica  unos  retos  particulares  Por  Van  Haywood  DMD  y  Anthony  J.  DiAngelis    DMD  MPH    

     Cuando   un   paciente   presenta   decoloración   o   tinción,   tanto   intrínseca   como  extrínseca,   que   sugiere   un   tratamiento  mediante   blanqueamiento   dental,   existen  una   serie   de   factores   a   tener   en   cuenta   y   varias   opciones   que   el   clínico   debe  considerar:   ¿Cuál   es   la   causa   de   la   decoloración?   ¿Ha   habido   un   traumatismo  previo?   ¿Ha   sido   el   diente   tratado   con   endodoncia?   ¿Cuál   es   el  mejor  método   a  ofrecer   para   el   estilo   de   vida,  situación   financiera   y   grado   de  compromiso   del   paciente   par   el  cumplimiento   del   tratamiento  domiciliario?.    El   diente   unitario   oscurecido  representa   un   reto   importante   a   la  hora  de  obtener  un  cambio  de  color  y  el  clínico  debe  conocer   los  principios  básicos  del  cambio  de  color  de  uno  o  varios   dientes   con   el   propósito   de  implementar   un   plan   de   tratamiento  exitoso.    

RESUMEN'

El'diente'unitario'oscurecido'representa'un'reto'importante'a'la'hora'de'obtener'los'mejores' resultados' esté:cos' para' la' sonrisa' del' paciente.' Las' opciones' de'tratamiento' incluyen' coronas' unitarias,' carillas' de' cerámica,' composite' de'recubrimiento,' o' blanqueamiento.' El' blanqueamiento' es' la' opción' más'conservadora' a' considerar' si' bien' el' potencial' para' alcanzar' un' tratamiento'exitoso'varía'en'relación'a'la'causa'y'extensión'de'la'decoloración.'

42 INSIDE DENTISTRY | September 2010 | insidedentistry.net

Bleaching the Single Dark ToothChanging the color of just one anterior tooth presents unique challenges.By Van B. Haywood, DMD | Anthony J. DiAngelis, DMD, MPH

W hen a patient presents with either intrin-sic or extrin-sic staining or discoloration and seems to

be a candidate for tooth bleaching, there is a variety of factors and options for the clinician to consider. What is the cause for the discoloration? Is there tooth trauma involved, or has the a!ected tooth been endodontically treated? What is the best delivery method for the patient’s lifestyle, financial situation, and commitment level to home care? Single dark teeth present a unique chal-lenge for color change and the clinician

must be aware of the basic principles of changing the color of one or more teeth in order to implement a successful treat-ment plan.

The Initial ExaminationThe first and most important con-sideration is to determine the cause of the tooth discoloration. A clinical examination is conducted, which in-cludes evaluation of the color of the teeth and the adjacent gingiva (Figure 1). Additionally, transillumination, ra-diographs, and pulp testing may be ap-propriate. Radiographs should always be taken of a single dark tooth, as teeth can undergo pulpal necrosis without any other symptom than becoming dark (Figure 2). From this examination, the determination is made of whether the tooth is vital or not. A vital tooth may be darker due to trauma and resultant bleeding into the dental tubules with-out loss of vitality. Vital teeth may also discolor from internal or external re-sorption, calcific metamorphosis, as well as decay or leaking restorations on the proximal or lingual surfaces. A non-vital tooth may have become darker from the same reasons as a vital tooth, but also have experienced pulpal death. A tooth that has received endodontic treatment may also later darken, especially if there is a poor seal of the endodontic access opening (Figure 3).

Even if a tooth tests as non-vital, it may not require endodontic therapy. If there is no radiographic evidence of pa-thology and no clinical symptoms, then

there is no reason to initiate endodontic therapy based on vitality testing alone. Often single dark teeth are the result of trauma, which should be determined in the dental history. It can take anywhere from 1 to 20 years after the trauma be-fore any pulpal problems develop.

Additional considerations for the single dark tooth are the color of the gingival tissues around the tooth, as well as whether there is any root structure visible due to recession. A smile analysis is used to determine these conditions as well as the movement of the lip during smiling and whether a “gummy smile” exists. The dentin in the root is di!er-ent from the dentin in the anatomic crown, and does not bleach well if at all, regardless of whether internal or external bleaching is attempted. Also, discolorations of the gingiva may cause a tooth that may be a perfect color match to not be harmonious. Either of these conditions is magnified if the lip exposes much of the root or gingiva because of a hyperactive lip or gummy smile.

Trauma and Calcific MetamorphosisMany studies suggest that the preva-lence of traumatic dental injuries (TDI) is high, although significant variation occurs between countries, populations, age, and gender.1-4 Epidemiological studies, while not always comparable, support the growing body of evidence that TDIs represent a significant chal-lenge for clinicians.5 A study by Koste and colleagues reported that 25% of 6- to 50-year-olds in the United States had experienced a TDI.6 Approximately 30% of children have sustained a TDI to their primary dentition, and 25% of all school-aged children have experienced a TDI.7-9 Other reports document that luxations represent the majority of primary teeth injuries, whereas crown fractures constitute the most commonly

occurring injury in permanent teeth.10,11 Also, studies have reported that 71% to 92% of TDIs occur by age 19.12

The etiology of dental injuries varies by age. In the 0 to 6 age group, falls pre-dominate.13 As children enter school, falls, collisions with other children and objects, as well as participation in organized physical activities and sports contribute to dental injuries.9,14-16 TDIs in the teen and young-adult age group are more the result of sports and motor vehicle accidents.14 Several studies have documented that approximately one third of dental injuries are sports-re-lated.15-23 Other causes of TDIs include physical abuse, fights, and assaults—of-ten involving alcohol as an aggravating factor.24-26

The pulp can respond to trauma in a limited number of ways. Primarily it can survive, die, or undergo pulp canal obliteration (PCO), often referred to as calcific metamorphosis.27 The latter represents a common finding subse-quent to luxation injuries, 3.8% to 24%, and root fractures, 69% to 73%.2,28-30

The precise mechanism of PCO is not known but disruption of the neurovas-cular bundle appears to stimulate the rapid formation of hard tissue (dentin or osseous) beginning within the pulp chamber and progressing along the pulp canal walls.31 It may present as partial or total obliteration of the pulp canal space. Although radiographs may reveal what appears to be total oblitera-tion of the pulp canal, generally there remains clinical evidence of a pulp canal and pulpal tissue.32,33 Clinically, the tooth will appear dark yellow due

VAN B. HAYWOOD, DMDProfessor Director of DentalContinuing EducationDepartment of Oral RehabilitationSchool of Dentistry Medical College of GeorgiaAugusta, Georgia

ANTHONY J. DIANGELIS, DMD, MPHChief Department of Dentistry Hennepin County Medical CenterMinneapolis, Minnesota

ProfessorUniversity of MinnesotaMinneapolis, Minnesota

ABSTRACTSingle dark teeth represent a major challenge to obtain best esthetic outcome in a patient’s smile. Treatment options may include single crowns, veneers, bonding, or bleaching. Bleaching is the most conservative option to consider, but the potential for a successful outcome varies based on the cause and extent of the discoloration.

INSIDE CONTINUING EDUCATION RESTORATIVEPERIODONTICS

Learning Objectives

VAN$B.$HAYWOOD,$$DMD$Catedrá5co$Director$de$Educación$Dental$Con5nua$Departamento$de$Rehabilitación$Oral$Escuela$de$Odontología$Facultad$de$Medicina$de$Georgia$Augusta'(Georgia)'

42 INSIDE DENTISTRY | September 2010 | insidedentistry.net

Bleaching the Single Dark ToothChanging the color of just one anterior tooth presents unique challenges.By Van B. Haywood, DMD | Anthony J. DiAngelis, DMD, MPH

W hen a patient presents with either intrin-sic or extrin-sic staining or discoloration and seems to

be a candidate for tooth bleaching, there is a variety of factors and options for the clinician to consider. What is the cause for the discoloration? Is there tooth trauma involved, or has the a!ected tooth been endodontically treated? What is the best delivery method for the patient’s lifestyle, financial situation, and commitment level to home care? Single dark teeth present a unique chal-lenge for color change and the clinician

must be aware of the basic principles of changing the color of one or more teeth in order to implement a successful treat-ment plan.

The Initial ExaminationThe first and most important con-sideration is to determine the cause of the tooth discoloration. A clinical examination is conducted, which in-cludes evaluation of the color of the teeth and the adjacent gingiva (Figure 1). Additionally, transillumination, ra-diographs, and pulp testing may be ap-propriate. Radiographs should always be taken of a single dark tooth, as teeth can undergo pulpal necrosis without any other symptom than becoming dark (Figure 2). From this examination, the determination is made of whether the tooth is vital or not. A vital tooth may be darker due to trauma and resultant bleeding into the dental tubules with-out loss of vitality. Vital teeth may also discolor from internal or external re-sorption, calcific metamorphosis, as well as decay or leaking restorations on the proximal or lingual surfaces. A non-vital tooth may have become darker from the same reasons as a vital tooth, but also have experienced pulpal death. A tooth that has received endodontic treatment may also later darken, especially if there is a poor seal of the endodontic access opening (Figure 3).

Even if a tooth tests as non-vital, it may not require endodontic therapy. If there is no radiographic evidence of pa-thology and no clinical symptoms, then

there is no reason to initiate endodontic therapy based on vitality testing alone. Often single dark teeth are the result of trauma, which should be determined in the dental history. It can take anywhere from 1 to 20 years after the trauma be-fore any pulpal problems develop.

Additional considerations for the single dark tooth are the color of the gingival tissues around the tooth, as well as whether there is any root structure visible due to recession. A smile analysis is used to determine these conditions as well as the movement of the lip during smiling and whether a “gummy smile” exists. The dentin in the root is di!er-ent from the dentin in the anatomic crown, and does not bleach well if at all, regardless of whether internal or external bleaching is attempted. Also, discolorations of the gingiva may cause a tooth that may be a perfect color match to not be harmonious. Either of these conditions is magnified if the lip exposes much of the root or gingiva because of a hyperactive lip or gummy smile.

Trauma and Calcific MetamorphosisMany studies suggest that the preva-lence of traumatic dental injuries (TDI) is high, although significant variation occurs between countries, populations, age, and gender.1-4 Epidemiological studies, while not always comparable, support the growing body of evidence that TDIs represent a significant chal-lenge for clinicians.5 A study by Koste and colleagues reported that 25% of 6- to 50-year-olds in the United States had experienced a TDI.6 Approximately 30% of children have sustained a TDI to their primary dentition, and 25% of all school-aged children have experienced a TDI.7-9 Other reports document that luxations represent the majority of primary teeth injuries, whereas crown fractures constitute the most commonly

occurring injury in permanent teeth.10,11 Also, studies have reported that 71% to 92% of TDIs occur by age 19.12

The etiology of dental injuries varies by age. In the 0 to 6 age group, falls pre-dominate.13 As children enter school, falls, collisions with other children and objects, as well as participation in organized physical activities and sports contribute to dental injuries.9,14-16 TDIs in the teen and young-adult age group are more the result of sports and motor vehicle accidents.14 Several studies have documented that approximately one third of dental injuries are sports-re-lated.15-23 Other causes of TDIs include physical abuse, fights, and assaults—of-ten involving alcohol as an aggravating factor.24-26

The pulp can respond to trauma in a limited number of ways. Primarily it can survive, die, or undergo pulp canal obliteration (PCO), often referred to as calcific metamorphosis.27 The latter represents a common finding subse-quent to luxation injuries, 3.8% to 24%, and root fractures, 69% to 73%.2,28-30

The precise mechanism of PCO is not known but disruption of the neurovas-cular bundle appears to stimulate the rapid formation of hard tissue (dentin or osseous) beginning within the pulp chamber and progressing along the pulp canal walls.31 It may present as partial or total obliteration of the pulp canal space. Although radiographs may reveal what appears to be total oblitera-tion of the pulp canal, generally there remains clinical evidence of a pulp canal and pulpal tissue.32,33 Clinically, the tooth will appear dark yellow due

VAN B. HAYWOOD, DMDProfessor Director of DentalContinuing EducationDepartment of Oral RehabilitationSchool of Dentistry Medical College of GeorgiaAugusta, Georgia

ANTHONY J. DIANGELIS, DMD, MPHChief Department of Dentistry Hennepin County Medical CenterMinneapolis, Minnesota

ProfessorUniversity of MinnesotaMinneapolis, Minnesota

ABSTRACTSingle dark teeth represent a major challenge to obtain best esthetic outcome in a patient’s smile. Treatment options may include single crowns, veneers, bonding, or bleaching. Bleaching is the most conservative option to consider, but the potential for a successful outcome varies based on the cause and extent of the discoloration.

INSIDE CONTINUING EDUCATION RESTORATIVEPERIODONTICS

Learning Objectives

ANTHONY$J$DIANGELIS,$$DMD,$$MPH$Jefe$del$Departamento$de$Odontología$Complejo$Hospitalario$$del$Condado$de$Hennepin$Minneapolis,'Minnesota'Catedrá5co$Universidad$de$Minnesota$Minneapolis,'Minnesota'

 El  Examen  Inicial  La   primera   y   más   importante   consideración   es   determinar   la   causa   de   la  decoloración  del  diente.  Se  lleva  a  cabo  un  examen  clínico  que  incluye  la  valoración  del   color   del   diente   y   la   encía   adyacente   (Figura   1).   Adicionalmente,   pueden   ser  necesarias  la  transiluminación,  pruebas  radiográficas  y  tests  pulpares.                                      Se  deben  realizar  siempre  radiografías  del  diente  oscurecido  porque  puede  haber    una  necrosis  pulpar  sin  otro  síntoma  que  la  decoloración  (Figura  2).  Tras  este  examen  se  determina  si  el  diente  está  vital  o  no.  Un  diente  vital  puede  haberse  oscurecido  debido  al  traumatismo  y  al  sangrado  resultante  dentro  de  los  túbulos  dentinarios  sin  perder  su  vitalidad.  El  diente  vital  puede  decolorarse  por  reabsorción  externa  o  interna,  metamorfosis  cálcificante,  caries,  o  filtraciones  que  afecten  a   restauraciones   localizadas   en   las   superficies  proximales  o   linguales  del  diente.  Un  diente  no  vital  puede  haberse  oscurecido  por  las  mismas  razones  pero  adicionalmente   haber   sufrido   una   necrosis   pulpar.   El   diente   que   ha   recibido  tratamiento   endodóncico   puede   oscurecerse   posteriormente   al   tratamiento   de  conductos,   en   especial   si   no   se   ha   sellado  adecuadamente   la   cavidad   de   apertura  (figura  3).  Aunque  los  tests  pulpares  definan  un  diente  como   no   vital   puede   que   no   requiera  tratamiento   endodóncico   si   no   muestra  evidencias   radiográficas   de   patología   ni  síntomas   clínicos,   en   consecuencia,   no   hay  razones   para   iniciar   un   tratamiento  endodóncico   basándose   únicamente   en   los  test  pulpares.  A  menudo,  el  diente  unitario  decolorado   es   el   resultado   de   un  traumatismo   que   se   aclara   durante   la  historia   clínica   pudiendo   haber   ocurrido  entre  1  y  20  años  antes  de  que  se  desarrolle  cualquier  problema  pulpar.  

44 INSIDE DENTISTRY | September 2010 | insidedentistry.net

INSIDE CONTINUING EDUCATION

the form of a discolored incisor presents a long-term esthetic challenge. The most conservative approach to managing PCO-induced discoloration is bleach-ing without endodontic therapy.

Tray BleachingThere are a number of types of bleach-ing techniques to consider for both vital and non-vital teeth, but these types may be divided mainly into those performed in-o!ce or those continued at home. With the advent of nightguard vital bleaching involving tray application of 10% carbamide peroxide, a method for bleaching single dark teeth became more readily available, and did not in-volve the use of highly caustic chemi-cals.43 The original recommendation for a single dark tooth was to make a non-scalloped, no-reservoir tray, and bleach all the teeth. The tooth that was darker generally took longer, so an “X” was made on that tooth mold of the tray so the patient could continue to bleach that tooth longer than the other teeth. The use of the “X” on the teeth to be bleached was also helpful when the pa-tient already had crowns on some teeth, and placing bleaching material on them was a waste of material. While this tray system was simple and e"ective, it did not always result in a perfect match of the teeth. All the teeth would lighten, but often the darker tooth was not able to lighten as much as the normal teeth, and the resultant outcome was lighter teeth, but still with one tooth slightly darker than the others. Some authors have recommended using a reservoir on the darker tooth, but the use of res-ervoirs has not been shown to increase

bleaching e!cacy.44 It is not possible to “spot bleach” a tooth either, because the bleaching material goes through the enamel and dentin to the pulp in 5 to 15 minutes, and bleaches under res-torations and from one surface to the other (facial to lingual). It has also been shown to bleach beyond the borders of the tray, generally to the cementoe-namel junction (CEJ), even if the tooth is only partially erupted.

The ideal bleaching tray is fabricated on a horseshoe-shaped cast with no vestibule to provide good adaptation of the bleaching tray material. Also, the cast should be trimmed such that the central incisors are vertical to avoid folds on the facial. One challenge in fabrication of the single-tooth or regu-lar bleaching tray is trimming the cast without abrading either the teeth or the gingiva. This outcome is accomplished by trimming the cast from the base rather than the sides (Figure 5).

Single-Tooth Bleaching TrayAn improvement on this concept is the use of the “single-tooth” bleaching tray when one tooth is darker, but the other teeth are reasonably acceptable (Figure 6). In this tray design, a conven-tional non-scalloped, no-reservoir tray is fabricated. Then the teeth molds on either side of the dark tooth are removed (Figure 7 and Figure 8). The patient is given one syringe of bleaching mate-rial and applies it only to the single dark tooth mold and sleeps in the appliance. Teeth will bleach at di"erent rates and to di"erent color levels. The goal is to de-termine how light the single dark tooth will bleach first. If the color of the single

to the increased deposition of under-lying dentin. Additionally, there may be a gradual diminution in response to electrical and thermal pulp testing. PCO occurs more frequently in teeth with open apices and in more severe luxation injuries involving displace-ment.2,34 Extrusive and lateral luxation injuries in immature permanent teeth have demonstrated high rates of PCO.35 A recent study by Netto and colleagues reported the chances of PCO in in-truded permanent teeth to be six times greater than in mature teeth, open vs closed apex, and that PCO occurred in 26.7% of such injuries.36 PCO can oc-cur in subluxated and crown-fractured teeth, although with less frequency.37

As mentioned previously, PCO is a common occurrence after root frac-tures. The location of PCO is thought to be indicative of the type of healing. PCO in the apical segment only is sug-gestive of hard-tissue callus formation, whereas PCO in the coronal segment or in both coronal and apical fracture seg-ments is indicative of connective tissue repair of the fracture.2,38

Pulp necrosis as evidenced by periapi-cal radiolucency is an infrequent sequela to PCO occurring in approxi mately 7% to 16% of cases; consequently, prophy-lactic endodontic therapy is not recom-mended by most authors.28,39-41 Teeth with PCO likely have diminished heal-ing capacity, and it is not well established whether a secondary trauma or addi-tional dental treatment causes necro-sis. In some instances, such as prepar-ing a tooth with PCO for an abutment, it may be prudent to perform prophylactic endodontic therapy before the definitive

restorative procedure. A recent article by daCunha and colleagues suggests implementing endodontic therapy prior to development of a periapical radiolu-cency in a tooth with PCO, based on two major considerations: (1) the technical di!culty and complications that may occur in treating these teeth; and (2) their review of a study that demonstrat-ed a 97.9% success rate for teeth treated without periapical radiolucencies vs a 62.5% success rate for teeth treated with periapical radiolucencies.42 Specific clinical situations will dictate clinical decisions; however, given the relatively low incidence of pulp necrosis in teeth with PCO, endodontic treatment usually is not recommended in the absence of a periapical radiolucency or symptoms. Nonetheless, if a periapical lesion de-velops, endodontic therapy can be both challenging and fraught with complica-tions (Figure 4). The use of operatory microscopes in the hands of a skilled clinician is warranted and improves the chances of a successful outcome.

Most traumas to primary teeth are luxation injuries that frequently result in radiographic evidence of PCO. Although this may or may not result in crown dis-coloration, it ceases to be a concern for the patient, parent, or clinician as the tooth is eventually exfoliated. The only indication for bleaching primary teeth, which are generally very light, is trauma that caused the tooth to become dark and the patient is being a"ected psychologi-cally by the darker teeth. There is no in-dication for endodontic therapy.

In contrast, younger patients who sustain TDIs where development of the permanent tooth is incomplete, PCO in

CLINICAL EXAMPLES (3.) A radiograph will indicate wheth-er the dark color is related to materials remaining in the pulp chamber, leaking restorations, caries, internal resorption, or failed endodontic therapy. (4.) Endodontic therapy was attempted on a tooth with calcific metamorphosis, with subsequent perforation and file fracture in the PDL.

FIG. 4FIG. 1 FIG. 2

CLINICAL EXAMPLES (1.) A clinical examination demonstrates a single, very dark lateral incisor and a moderately dark central incisor with a crown on the adjacent central incisor and several dark gingival areas. (2.) A radiograph finds no pulp chamber in the slightly dark central incisor and a silver point on the darkest lateral incisor. A titrated approach to bleaching was needed us-ing individual tooth treatments.

FIG. 3

Fig.% 1=% El% examen% clínico% muestra% un% único% incisivo% lateral% muy% oscurecido% y% un% incisivo%central% moderadamente% oscuro% con% una% corona% en% el% incisivo% central% adyacente% y% varias%áreas% gingivales% oscuras.% Fig.% 2=% La% radiogra=a% no% detecta% cámara% pulpar% en% el% incisivo%central%ligeramente%oscuro%y%hay%una%punta%de%plata%en%el%incisivo%lateral%más%oscurecido.%Se%necesita% una% tentaAva% evaluaAva% de% blanqueamiento% uAlizando% tratamientos% de% dientes%individualizados.%

44 INSIDE DENTISTRY | September 2010 | insidedentistry.net

INSIDE CONTINUING EDUCATION

the form of a discolored incisor presents a long-term esthetic challenge. The most conservative approach to managing PCO-induced discoloration is bleach-ing without endodontic therapy.

Tray BleachingThere are a number of types of bleach-ing techniques to consider for both vital and non-vital teeth, but these types may be divided mainly into those performed in-o!ce or those continued at home. With the advent of nightguard vital bleaching involving tray application of 10% carbamide peroxide, a method for bleaching single dark teeth became more readily available, and did not in-volve the use of highly caustic chemi-cals.43 The original recommendation for a single dark tooth was to make a non-scalloped, no-reservoir tray, and bleach all the teeth. The tooth that was darker generally took longer, so an “X” was made on that tooth mold of the tray so the patient could continue to bleach that tooth longer than the other teeth. The use of the “X” on the teeth to be bleached was also helpful when the pa-tient already had crowns on some teeth, and placing bleaching material on them was a waste of material. While this tray system was simple and e"ective, it did not always result in a perfect match of the teeth. All the teeth would lighten, but often the darker tooth was not able to lighten as much as the normal teeth, and the resultant outcome was lighter teeth, but still with one tooth slightly darker than the others. Some authors have recommended using a reservoir on the darker tooth, but the use of res-ervoirs has not been shown to increase

bleaching e!cacy.44 It is not possible to “spot bleach” a tooth either, because the bleaching material goes through the enamel and dentin to the pulp in 5 to 15 minutes, and bleaches under res-torations and from one surface to the other (facial to lingual). It has also been shown to bleach beyond the borders of the tray, generally to the cementoe-namel junction (CEJ), even if the tooth is only partially erupted.

The ideal bleaching tray is fabricated on a horseshoe-shaped cast with no vestibule to provide good adaptation of the bleaching tray material. Also, the cast should be trimmed such that the central incisors are vertical to avoid folds on the facial. One challenge in fabrication of the single-tooth or regu-lar bleaching tray is trimming the cast without abrading either the teeth or the gingiva. This outcome is accomplished by trimming the cast from the base rather than the sides (Figure 5).

Single-Tooth Bleaching TrayAn improvement on this concept is the use of the “single-tooth” bleaching tray when one tooth is darker, but the other teeth are reasonably acceptable (Figure 6). In this tray design, a conven-tional non-scalloped, no-reservoir tray is fabricated. Then the teeth molds on either side of the dark tooth are removed (Figure 7 and Figure 8). The patient is given one syringe of bleaching mate-rial and applies it only to the single dark tooth mold and sleeps in the appliance. Teeth will bleach at di"erent rates and to di"erent color levels. The goal is to de-termine how light the single dark tooth will bleach first. If the color of the single

to the increased deposition of under-lying dentin. Additionally, there may be a gradual diminution in response to electrical and thermal pulp testing. PCO occurs more frequently in teeth with open apices and in more severe luxation injuries involving displace-ment.2,34 Extrusive and lateral luxation injuries in immature permanent teeth have demonstrated high rates of PCO.35 A recent study by Netto and colleagues reported the chances of PCO in in-truded permanent teeth to be six times greater than in mature teeth, open vs closed apex, and that PCO occurred in 26.7% of such injuries.36 PCO can oc-cur in subluxated and crown-fractured teeth, although with less frequency.37

As mentioned previously, PCO is a common occurrence after root frac-tures. The location of PCO is thought to be indicative of the type of healing. PCO in the apical segment only is sug-gestive of hard-tissue callus formation, whereas PCO in the coronal segment or in both coronal and apical fracture seg-ments is indicative of connective tissue repair of the fracture.2,38

Pulp necrosis as evidenced by periapi-cal radiolucency is an infrequent sequela to PCO occurring in approxi mately 7% to 16% of cases; consequently, prophy-lactic endodontic therapy is not recom-mended by most authors.28,39-41 Teeth with PCO likely have diminished heal-ing capacity, and it is not well established whether a secondary trauma or addi-tional dental treatment causes necro-sis. In some instances, such as prepar-ing a tooth with PCO for an abutment, it may be prudent to perform prophylactic endodontic therapy before the definitive

restorative procedure. A recent article by daCunha and colleagues suggests implementing endodontic therapy prior to development of a periapical radiolu-cency in a tooth with PCO, based on two major considerations: (1) the technical di!culty and complications that may occur in treating these teeth; and (2) their review of a study that demonstrat-ed a 97.9% success rate for teeth treated without periapical radiolucencies vs a 62.5% success rate for teeth treated with periapical radiolucencies.42 Specific clinical situations will dictate clinical decisions; however, given the relatively low incidence of pulp necrosis in teeth with PCO, endodontic treatment usually is not recommended in the absence of a periapical radiolucency or symptoms. Nonetheless, if a periapical lesion de-velops, endodontic therapy can be both challenging and fraught with complica-tions (Figure 4). The use of operatory microscopes in the hands of a skilled clinician is warranted and improves the chances of a successful outcome.

Most traumas to primary teeth are luxation injuries that frequently result in radiographic evidence of PCO. Although this may or may not result in crown dis-coloration, it ceases to be a concern for the patient, parent, or clinician as the tooth is eventually exfoliated. The only indication for bleaching primary teeth, which are generally very light, is trauma that caused the tooth to become dark and the patient is being a"ected psychologi-cally by the darker teeth. There is no in-dication for endodontic therapy.

In contrast, younger patients who sustain TDIs where development of the permanent tooth is incomplete, PCO in

CLINICAL EXAMPLES (3.) A radiograph will indicate wheth-er the dark color is related to materials remaining in the pulp chamber, leaking restorations, caries, internal resorption, or failed endodontic therapy. (4.) Endodontic therapy was attempted on a tooth with calcific metamorphosis, with subsequent perforation and file fracture in the PDL.

FIG. 4FIG. 1 FIG. 2

CLINICAL EXAMPLES (1.) A clinical examination demonstrates a single, very dark lateral incisor and a moderately dark central incisor with a crown on the adjacent central incisor and several dark gingival areas. (2.) A radiograph finds no pulp chamber in the slightly dark central incisor and a silver point on the darkest lateral incisor. A titrated approach to bleaching was needed us-ing individual tooth treatments.

FIG. 3

Fig.% 3=% La% radiogra-a% indicará% si% el% color% oscuro% está%relacionado% con% materiales% depositados% en% la% cámara%pulpar,% restauraciones% filtradas,% caries,% reabsorción%interna%o%fracaso%de%la%terapia%endodóncica.%Fig.%4=%Se%intentó%una%terapia%endodóncica%en%un%diente%con% metamorfosis% calcificante,% con% subsecuente%perforación%y%fractura%en%el%PDL.%

Otras   consideraciones   respecto   al   diente   unitario   decolorado   son   el   color   de   la  encía  adyacente,  o  si  hay  estructura  radicular  visible  por  causa  de  una  recesión.  El  análisis  de   la   sonrisa  se  utiliza  para  determinar   tales  condiciones,  el  movimiento  del  labio  en  sonrisa,  o  si  existe  sonrisa  gingival.  La  dentina  radicular  es  diferente  a  la   dentina   de   la   corona   anatómica   y   generalmente   no   blanquea   bien    independientemente  de  que  se   intente  un  blanqueamiento  externo  o   interno.  Los  cambios  de  color  de   la  encía  también  pueden  producir  que  un  diente  de  un  color  adecuado  resulte  no  ser  armonioso.  Cualquiera  de  estas  condiciones  se  magnifica  si  el  labio  expone  una  porción  sustancial  de  la  raíz  y  de  la  encía  debido  a  un  labio  hiperactivo  o  a  una  sonrisa  gingival.        Trauma  y  Metamorfosis  Calcificante  La   mayoría   de   los   estudios   publicados   sugieren   que   la   prevalencia   de   lesiones  dentales   traumáticas   (LDT)   es   elevada,   aunque   existen   diferencias   significativas  entre  países,  poblaciones,  edades  y  sexo.1-­‐4  Los  estudios  epidemiológicos,  aunque  no  son  comparables,  sugieren  una  evidencia  creciente  de  que  las  LDT  representan  un   reto   significativo  para   los   clínicos.5  Un   estudio  de  Koste   y   cols.   refiere  que   el  25%  de  los  habitantes  de  EEUU  entre  6  y  50  años  de  edad  ha  experimentado  una  LDT.6  Aproximadamente  el  30%  de  los  niños  ha  sufrido  una  lesión  traumática  en  su  dentición  primaria  y  el  25%  de  los  niños  en  edad  escolar  ha  experimentado  una  LDT.7-­‐9    Otros   trabajos   documentan   que   las   luxaciones   representan   la   mayoría   de   las  lesiones  en  los  dientes  primarios,  mientras  que  las  fracturas  coronales  constituyen  las  más  comunes  en  los  dientes  permanentes.10  11    La  etiología  de   las   lesiones  dentales  varía  con   la  edad.  En  el  grupo  de  0  a  6  años  predominan   las   caídas.13   En   los   niños   en   edad   escolar,   las   caídas,   colisiones   con  otros  niños  u  objetos,  así  como  la  participación  en  actividades  físicas  organizadas  y  deportes,   son   los   contribuyentes   principales   de   las   lesiones   dentarias.9,   14-­‐16   Las  LDT   en   los   adolescentes   y   adultos   jóvenes   son   generalmente   causados   por   los  deportes  y   los  accidentes  de  circulación.14  Varios  estudios  han  documentado  que  aproximadamente   un   tercio   de   las   lesiones   dentales   están   relacionadas   con   el  deporte.15-­‐23  Otras  causas  de  LDT  incluyen  los  abusos  físicos,  peleas  y  asaltos,  que  a  menudo  incluyen  el  alcohol  como  factor  agravante.24-­‐26    La  pulpa  puede   responder  al   traumatismo  con  un  número   limitado  de  variantes.  Fundamentalmente  puede  sobrevivir,  necrosarse  o  resultar  en  una  obliteración  del  canal   pulpar   (OCP),   a   menudo   reseñada   como   metamorfosis   calcificante.27   Esta  última   representa   un   hallazgo   común   posterior   a   las   lesiones   por   luxación   (3,8-­‐24%),  y  más  frecuentemente  a  las  fracturas  radiculares  (69-­‐73%).2,28-­‐30  Aunque  el  mecanismo  preciso  de  la  OCP  no  se  conoce,  parece  que  la  disrupción  del  paquete  neurovascular  estimula  una  rápida   formación  de   tejidos  duros   (dentina  o  hueso)  que  comienza  en  la  cámara  pulpar  y  se  va  extendiendo  a  lo  largo  de  las  paredes  del  canal,31   pudiendo   presentarse   como   una   obliteración   total   o   parcial   del   canal  pulpar.   Aunque   las   radiografías   pudiesen   revelar   lo   que   parece   una   obliteración  total   del   canal   pulpar,   generalmente   permanecen   evidencias   clínicas   de   canal   y  tejido  pulpar.32,33    Clínicamente,   el   diente   aparece   amarillo   oscuro   debido   a   una   aposición  incrementada  de  dentina  subyacente  y  pudiese  haber  una  disminución  gradual  del  la  respuesta  térmica  y  eléctrica  de  los  tests  pulpares.    

La   OCP   ocurre   con   más   frecuencia   en   dientes   con   ápices   abiertos   y   en   las  luxaciones   que   conllevan   un   desplazamiento   lateral   severo.2,34   Los   dientes  permanentes   inmaduros   que   han   sufrido   luxación   lateral   y   extrusiva   han  demostrado  altos  niveles  de  OCP.35  Un  estudio  reciente  realizado  por  Netto  y  cols.  refiere   que   los   eventos   de   la   OCP   en   la   intrusión   dentaria   ocurren   con   una  frecuencia   seis   veces   superior   en   los   dientes   con   ápice   inmaduro,   y   que   se  producen  en  el  26,7%  de  tales  lesiones.36  La  OCP  puede  presentarse  en  los  dientes  con  subluxación  y  fractura  coronaria,  aunque  con  una  frecuencia  inferior.37    Como  se  ha  mencionado  previamente,  la  OCP  es  un  hecho  frecuente  después  de  las  fracturas  radiculares.  Se  cree  que  la  localización  de  la  OCP  es  indicativa  del  tipo  de  cicatrización.  La  OCP  que  se  circunscribe  al  segmento  apical  sugiere  el  desarrollo  de  un  callo  de  tejido  duro,  mientras  que   la   localización  de   la  OCP  en  el  segmento  coronal,  o  en  ambos  segmentos,  coronal  y  apical,  son  indicativos  de  reparación  de  fractura  con  tejido  conectivo.2,38      La   necrosis   pulpar   evidenciada   como   radiolucidez   apical   es   una   secuela  infrecuente   de   la   OCP   que   ocurre   solamente   en   7-­‐16%   de   los   casos;   y   en  consecuencia   la   mayoría   de   los   autores   no   recomienda   la   endodoncia  profiláctica.28,39-­‐41    Los  dientes  con  OCP  suelen  tener  una  capacidad  de  cicatrización  disminuida  y  no  ha  quedado  verificado  si  los  traumatismos  ulteriores  o  tratamientos  odontológicos  adicionales  sobre  el  diente  puedan  causar  necrosis.  En  algunos  casos,  como  cuando  se  prepara  el  diente  como  pilar  para  prótesis   fija,  puede  ser  prudente   realizar   la  endodoncia  profiláctica  antes  de  realizar  el  tratamiento  restaurador  definitivo.    Un   artículo   reciente   de   daCunha   y   cols.   sugiere   realizar   la   terapia   endodóncica  antes  de  que  se  desarrolle  la  radiolucidez  en  un  diente  con  OPC  basándose  en  las  siguientes  consideraciones  principales:  

1. Las  complicaciones  y  dificultades  técnicas  que  pudiesen  ocurrir  durante  el  tratamiento  de  esos  dientes.  

2. Su  reseña  de  un  estudio  que  demostraba  un  porcentaje  de  éxitos  del  97,9%  en  los  dientes  tratados  que  no  presentaban  radiolucidez  periapical,   frente  al  62,5%  en  los  dientes  que  sí  la  presentaban.42  

Situaciones   clínicas   particulares   orientarán   decisiones   clínicas   específicas,   sin  embargo,   dada   la   relativa   baja   incidencia   de   necrosis   pulpar   en   los   dientes   con  OCP,   no   se   recomienda   el   tratamiento   endodóncico   habitual   en   ausencia   de  radiolucidez   periapical   y   síntomas.   No   obstante,   si   se   desarrolla   una   lesión  periapical   la   terapia   endodoncia   puede   ser   tan   dificultosa   como   llena   de  complicaciones  (Figura  4).  El  uso  de  microscopio  de  endodoncia  en  mano  expertas  garantiza  y  mejora  las  posibilidades  de  un  tratamiento  exitoso.      La   mayoría   de   los   traumatismos   de   los   dientes   primarios   sufren   lesiones   por  luxación   que   con   frecuencia   muestran   evidencias   radiográficas   de   OCP.   Aunque  ello   pudiese   resultar   o   no   en   una   decoloración   de   la   corona,   representan   un  problema   para   el   paciente,   los   padres   y   el   odontólogo,   ya   que   el   diente  eventualmente   se   exfolia.   La   única   indicación  para   blanquear   un  diente   de   leche  con   tinción,   que   en   todo   caso   suele   ser   discreta,   sería   la   repercusión  psicológica  que  produzca   la   presencia   del   diente   oscuro   en   el   paciente.  No   existe   indicación  para  la  terapia  endodóncica.    Por  el  contrario,  en  los  pacientes  más  jóvenes  que  padezcan  LDT  sobre  un  diente  permanente   inmaduro,   la   decoloración   y   la  OCP  pueden  producir   un  menoscabo  

estético   duradero   y   en   tales   casos,   el   modo   más   conservador   de   afrontarlo   es  realizar  un  blanqueamiento  coronal  sin  realizar  el  tratamiento  endodóncico.      Blanqueamiento  Con  Cubetas  Hay   diferentes   tipos   de   técnicas   de   blanqueamiento   a   considerar   para   el  tratamiento  tanto  de  dientes  vitales  como  no  vitales,  pero  todos  pueden  dividirse  fundamentalmente   en   aquellos   que   se   realizan   en   el   consultorio   y   los   que   se  continúan  en  el  domicilio.  Tras   la   llegada  del  blanqueamiento  vital  nocturno  con  peróxido  de  carbamida  al  10%  en  cubetas,  el  blanqueamiento  del  diente  unitario  se  ha  transformado  en  un  procedimiento  de  uso  inmediato  que  no  requiere  el  uso  de  productos  químicos  altamente  cáusticos.43    La   recomendación  original   en   el   blanqueamiento  del   diente  unitario   era   fabricar  una   cubeta   no   festoneada   y   sin   reservorio,   y   blanquear   el   total   de   la   arcada.   El  diente  oscurecido  requiere  más  tiempo,    por  lo  que  debería  de  marcarse  con  una  X  en   el   molde   para   que   el   paciente   mantenga   el   blanqueamiento   de   ese   diente  durante  mayor  tiempo  que  el  resto  de  los  dientes.  Marcar  con  una  X  el  diente  del  molde  a  blanquear   también  es  útil   cuando  el  paciente  es  portador  de  coronas  en  algún  diente  para  evitar  que  se  gaste  material  inútilmente.  Este   procedimiento   de   cubetas   era   simple   y   efectivo   pero   no   siempre   conseguía  igualar  el  color  del  diente.  Al  final  todos  los  dientes  finalizaban  más  blancos,  pero  a  menudo   el   diente   oscurecido   no   conseguía   blanquearse   tan   eficazmente   y   el  resultado  era  una  arcada  blanqueada  con  un  diente  ligeramente  más  oscuro  que  el  resto.  Algunos  autores  han  recomendado  el  uso  de  reservorios  en  la  porción  de  la  cubeta  del  diente  a  tratar,  pero  con  el  uso  de  reservorios  no  se  ha  demostrado  una  mayor  eficacia  blanqueadora.44  Tampoco  es  posible  intentar  un  blanqueamiento  localizado  de  la  mancha  porque  el  material  blanqueador  atraviesa  el  esmalte  y  la  dentina  hacia  la  pulpa  en  un  periodo  de   5   a   15   minutos,   blanquea   bajo   las   restauraciones   y   también   desde   una  superficie  a  otra  (desde  vestibular  a  lingual).  Se  ha  visto  que  el  blanqueamiento  se  produce  más  allá  de   los  bordes  de   la  cubeta,  generalmente  hasta   la  unión  amelo-­‐cementaria,  incluso  si  el  diente  no  ha  erupcionado  totalmente.  La  cubeta  de  blanqueamiento  ideal  se  fabrica  con  acabado  en  forma  de  herradura  y  sin  vestíbulo  para  proporcionar  una  buena  adaptación  al  material  blanqueador.  El  molde  debe  recortarse  hasta  que  los  incisivos  centrales  encajen  en  vertical  sin  que  se  produzcan  pliegues  en  la  porción  vestibular  de  la  cubeta.  Uno  de  los  retos  en  la  fabricación   tanto   de   cubetas   de   blanqueamiento   ordinarias   como   de   dientes  unitarios,  es  recortar  el  molde  sin  desgastar  el  diente  o  la  encía,  este  resultado  se  consigue  recortando  el  molde  por  la  base,  en  vez  de  por  los  lados  (Figura  5).        Cubetas  Para  Blanqueamiento  De  Diente  Unitario    Cuando   solamente   un   diente   está   oscuro   pero   el   resto   tiene   un   color  razonablemente   aceptable   (Figura   6)   se   usan   cubetas   de   blanqueamiento   para  diente  unitario.  En  este  diseño, se  fabrica  una  cubeta  convencional  no  festoneada  y  sin   reservorio     y   luego   se   recortan   los   dientes   adyacentes   al   diente   a   tratar  (Figuras  7  y  8).        

 

Se   le   proporciona   al   paciente   una   jeringa   de   material   blanqueador   para   que   lo  aplique   solamente   en   el   diente   oscurecido   y   duerma   con   el   aparato   puesto.   El  diente   irá   blanqueando   progresivamente   en   niveles   de   intensidad   y   color,   el  objetivo  es  determinar  cuanto  se  aclara  el  color  del  diente  en  este  primer  intento.  Si   el   diente   oscuro   no   llega   a   aclararse   hasta   el   nivel   de   color   de   los   dientes  adyacentes,  entonces  no  se  procederá  a  blanquear  el  resto  (Figura  9).  Tampoco  se  hará  si  el  diente  consigue  el  color  deseado,  solamente  si  el  diente  unitario  blanquea  en  mayor  medida  que  el  resto  se  procederá  al  blanqueamiento,  pero  en  este  caso,  se  hará  un  blanqueamiento  diurno  en  intervalos  cortos  para  evitar  que  los  dientes  de  la  arcada  se  blanqueen  más  que  el  diente  blanqueado.  Generalmente,  el  paciente  debe  estar   informado  que  el  procedimiento  para  blanquear  un  diente  unitario  se  prolonga  unas  8  semanas,  aunque  este  periodo  es  muy  variable.      Dientes  anteriores  tratados  con  endodoncia  Si   el   diente   oscurecido   ha   sido   tratado   con   endodoncia,   consideraciones  adicionales   para   el   tratamiento   de   la   decoloración   incluyen   la   presencia   de  materiales   pulpares   dentro   de   la   cámara,   selladores   o   relleno   endodóncico,  restauraciones   oscuras   o   filtradas   en   el   acceso   endodóncico,   así   como   el   fracaso  endodóncico.    El   tipo   de   relleno   es   también   importante   porque   las   puntas   de   plata   plantean  diferentes   consideraciones   respecto   a   las   puntas   de   gutapercha.   Las  consideraciones  terapéuticas  también  dependen  de  cuando  se  ha  hecho  patente  el  oscurecimiento  del  diente,   si  durante   la   terapia  endodóncica  o  en  el   seguimiento  ulterior.    

46 INSIDE DENTISTRY | September 2010 | insidedentistry.net

INSIDE CONTINUING EDUCATION

dark tooth does not get as light as the sur-rounding teeth, then the other teeth are not bleached (Figure 9) and the closest match has been achieved. If the single dark tooth matches the other teeth then, again, the other teeth are not bleached. Only if the single dark tooth gets lighter than the adjacent teeth should they be bleached, and in that case, daytime bleaching in short intervals should be used to avoid getting the adjacent teeth lighter than the single dark bleached tooth. Generally, the patient should be informed that the bleaching time for the single dark tooth is about 8 weeks, although it is highly variable.

Endodontically Treated Anterior TeethIf the dark tooth has already received endodontic therapy, then additional considerations for the discoloration include remaining pulp materials in the pulp chamber, endodontic sealer or filler in the pulp chamber, and dark or leaking restorations in the endodontic access opening, as well as endodontic failure. The type of filler is also impor-tant, as silver points require di!erent considerations from gutta-percha fill-ers. Treatment considerations also may depend on when in the endodontic treatment and subsequent follow-up the tooth was noticed to be dark.

Endodontically treated teeth may be treated from the inside, the outside, or both. The decision for inside or outside depends on a knowledge of what has occurred inside the tooth during the endodontic therapy, as well as the type of restoration used to seal the access opening. The tooth may have received a satisfactory endodontic treatment and

CASE EXAMPLE ONE (5.) Trimming the cast only from the base (with the central incisors horizontal) until the vestibule is removed and a hole oc-curs in the palate will avoid the danger of damaging teeth from traditional trimming as well as create the best cast for use in a vacuum-former. (6.) A single dark tooth from trauma needs to be examined carefully and evalu-ated with a radiograph. The safest approach is to bleach this tooth alone until the tooth’s response and maximum lightening can be determined. (7.) The “single-tooth” bleaching tray has no reservoir or spacers and extends onto the gingiva 1 mm to 2-mm, but avoids frenum movements. The teeth not to be bleached have the tooth molds removed from the tray while maintaining the intact tray. (8.) The single-tooth bleaching tray extended further onto the palate than the traditional tray to preserve the tray integrity when the adjacent teeth molds were removed from the tray. The tray edges are hidden behind rugae and go onto the tissue in all areas. (9.) A reasonable match was obtained from about 8 weeks of single-tooth bleaching. Often patients discontinue treatment when the single tooth is no longer a mismatch, even if the outcome is not ideal. CASE EXAMPLE TWO (10.) This root canal has been successful for 30 years, but the tooth has become slightly discolored. There is no reason from the radiograph to re-enter the pulp chamber, as this will further weaken the tooth. External bleaching by a single-tooth bleaching tray is indicated (11.) The 10% carb-amide peroxide bleaching material was applied externally with the single-tooth bleaching tray nightly until the shade of the endodontically treated tooth returned to match the adjacent teeth. Should the tooth re-darken again, the process can be repeated without danger to the tooth. Figure 10 and Figure 11 courtesy of Meigan Johnson.

FIG. 7 FIG. 8

FIG. 5 FIG. 6

FIG. 9

been subsequently restored with an ac-ceptable lingual composite that matched the tooth color. However, in subsequent years, the tooth may have discolored (Figure 10). In this situation, the deci-sion for bleaching favors external bleach-ing, because going inside the tooth to remove the composite will weaken the tooth (Figure 11). However, the choice not to go inside the endodontic tooth depends on whether the treating dentist is aware of the extent to which the pulp chamber was debrided during endodon-tic therapy, as well as the height in the chamber of the cement and filler.

In-O!ce BleachingIn-o"ce bleaching is the oldest form of bleaching. Attempts to bleach single dark teeth date back to the 1800s, and bleaching a single dark tooth was one of the first bleaching research areas.45 A number of materials have been used, but hydrogen peroxide has been the historic favorite. The high concentra-tion of hydrogen peroxide could be applied externally or internally, and often involved heat and light. The classic non-vital in-o"ce bleaching technique involved the placement of 35% hydrogen peroxide into the pulp chamber, and increasing the chemi-cal reaction by the use of heat or light. However, this technique lacks precise control as to the amount of lightening. More critically, when cases of external or internal resorption were evaluated, there were four common concerns list-ed: 1) teeth had received trauma; 2) high concentrations of peroxide were used; 3) high heat was used to enhance the bleaching, and 4) there was no seal over the gutta-percha. Although the dentist cannot control the trauma, elimination of the other three areas under dental control should be done to lessen the chances of resorption and loss of the tooth. Other possibilities for resorp-tion include the fact that 10% of teeth do not have a connection between the enamel and cementum, with possible percolation of hydrogen peroxide into the surrounding areas, lowering the pH. Using a bleaching product with a higher pH or a salivary catalase are attempts to reduce resorption issues.

Walking Bleach TechniqueThe change in in-o"ce bleaching led to the next step of “walking bleaching.” In this technique, the gutta-percha was removed 2 mm below the CEJ and a

FIG. 10 FIG. 11

“One challenge infabrication of the single-tooth or regular bleaching tray is trimming the cast without abrading either the teeth or thegingiva. This outcome is accomplishedby trimming the cast from the base rather than the sides.”

CASO%EJEMPLO%1%%Fig.% 5=% Recortando% el% molde% solamente% desde% la%base%(con%los%incisivos%centrales%en%horizontal)%hasta%que% se% extrae% todo% el% vesGbulo% y% se% produce% un%hueco%en%el%paladar%evitará%el%peligro%de%dañar% los%dientes% respecto% al% recortado% tradicional% así% como%crea%el%molde%más%idóneo%para%la%máquina%de%vacío.%%FigN% 6=% Los% dientes% unitarios% que% ha% resultado%traumaPzados% precisan% ser% examinados%cuidadosamente%mediante% radiograQas.% La% prácPca%más% segura% es% blanquear% este% diente% en% solitario%hasta% que% la% respuesta% del% diente% y% el% máximo%aclaramiento% pueda% ser% determinado% Fig.% 7=% La%cubeta% de% blanqueamiento% de% diente% unitario% no%Pene% reservorio% ni% espaciadores,% y% se% exPende%sobre% la% encía% 1% o% 2% mm% pero% evitando% los%movimientos%del% frenillo.% Los%dientes%que%no%van%a%blanquearse%se%recortan%de% la%cubeta%manteniendo%el% resto%de% la% cubeta% intacta.% Fig.% 8% =% La% cubeta%de%blanqueamiento%de%diente%unitario%se%exPende%más%sobre% el% paladar% que% la% cubeta% tradicional% para%preservar% la% integridad% de% la% cubeta% % cuando% se%recortan% los% dientes% adyacentes.% Los% límites% de% la%cubeta% se% esconden% bajo% las% rugosidades% y% van%dispuestos% sobre% todas% las%áreas%de% tejido.% Fig.% 9%=%Se%ha%obtenido%un%parecido%de%color%razonable%tras%aproximadamente% 8% semanas% de% blanqueamiento%de% diente% unitario.% A% menudo,% los% pacientes%%interrumpen%el% tratamiento% antes%de%que%el% diente%no%haya% llegado%a%alcanzar%su%color%ópPmo,% incluso%aunque%el%resultado%no%sea%el%ideal.%

   

El   diente   con   terapia  endodóncica   puede   ser   tratado  desde  dentro,  desde  fuera,  o  de  ambas   formas.   La   decisión   de  un   blanqueamiento   externo   o  interno  depende  de  si  sabemos  qué   ha   ocurrido   dentro   del  diente   durante   la   terapia  endodóncica   y   también   el   tipo  de   restauración   que   se   ha  usado   para   el   sellado   de   la  apertura   cameral.   El   diente  puede   haber   recibido   un  tratamiento   endodóncico  satisfactorio   y   haber   sido  

restaurado  con  una  restauración  lingual  de  composite  que  coincida  en  color,  y  que  no  obstante  puede  haberse  oscurecido  en  los  años  posteriores  (Figura  10).  En  esta  situación,  se  prefiere  el  blanqueamiento  externo  porque  la  penetración  dentro  del  diente  mediante  la  remoción  del  composite  podría  debilitar  su  estructura  (Figura  11).   Sin   embargo,   la   decisión   de   penetrar   al   interior   del   diente   tratado  endodóncicamente  depende  de  si  el  dentista  que   lo  trata  es  capaz  de  proceder  al  desbridamiento   completo   del   relleno   de   la   cámara   pulpar   de   la   terapia  endodóncica   original,   así   como   de   acceder   a   la   altura   del   cemento   y   el   relleno  dentro  de  la  cámara.                    Blanqueamiento  en  el  consultorio  El  blanqueamiento  en  el   consultorio  es   la   forma  más  antigua  de  blanqueamiento  dental.   Los   intentos   de   blanquear   los   dientes   se   remontan   al   siglo   XIX   y   el  blanqueamiento   del   diente   unitario   ha   constituido   una   de   las   primeras   áreas   de  investigación.45  Se  han  usado  diferentes  materiales,  pero  el  peróxido  de  hidrógeno  ha  sido  históricamente  el   favorito.  El  peróxido  de  hidrógeno  a  alta  concentración  podía  ser  aplicado  externa  o  internamente,  y  a  menudo  incluía  luz  y  calor.  La   técnica   clásica   de   blanqueamiento   no   vital   en   el   consultorio   implicaba   el  disponer   el   peróxido   de   hidrógeno   al   35%   en   el   interior   de   la   cámara   pulpar   e  incrementar  la  reacción  química  mediante  el  uso  de  luz  o  calor.  Sin  embargo,  esta  técnica  carece  de  un  control  preciso  sobre   la  cantidad  de  blanqueamiento.  De  un  modo  más  crítico,  cuando  se  evaluaban  los  casos  de  reabsorción  externa  e  interna  había  cuatro  problemas  comunes  que  se  detallan:  

1. Los  dientes  habían  sufrido  un  traumatismo.  2. Se  usaban  altas  concentraciones  de  peróxido.  3. Se  utilizaban  altas  temperaturas  para  potenciar  el  blanqueamiento.      4. No  se  hacía  sellado  sobre  la  gutapercha.  

Aunque  el  dentista  no  puede  controlar  el  trauma,  sí  puede  eliminar   las  otras  tres  áreas   que   están   bajo   control   dental   para   reducir   los   eventos   de   reabsorción   y  pérdida  dentaria.    

46 INSIDE DENTISTRY | September 2010 | insidedentistry.net

INSIDE CONTINUING EDUCATION

dark tooth does not get as light as the sur-rounding teeth, then the other teeth are not bleached (Figure 9) and the closest match has been achieved. If the single dark tooth matches the other teeth then, again, the other teeth are not bleached. Only if the single dark tooth gets lighter than the adjacent teeth should they be bleached, and in that case, daytime bleaching in short intervals should be used to avoid getting the adjacent teeth lighter than the single dark bleached tooth. Generally, the patient should be informed that the bleaching time for the single dark tooth is about 8 weeks, although it is highly variable.

Endodontically Treated Anterior TeethIf the dark tooth has already received endodontic therapy, then additional considerations for the discoloration include remaining pulp materials in the pulp chamber, endodontic sealer or filler in the pulp chamber, and dark or leaking restorations in the endodontic access opening, as well as endodontic failure. The type of filler is also impor-tant, as silver points require di!erent considerations from gutta-percha fill-ers. Treatment considerations also may depend on when in the endodontic treatment and subsequent follow-up the tooth was noticed to be dark.

Endodontically treated teeth may be treated from the inside, the outside, or both. The decision for inside or outside depends on a knowledge of what has occurred inside the tooth during the endodontic therapy, as well as the type of restoration used to seal the access opening. The tooth may have received a satisfactory endodontic treatment and

CASE EXAMPLE ONE (5.) Trimming the cast only from the base (with the central incisors horizontal) until the vestibule is removed and a hole oc-curs in the palate will avoid the danger of damaging teeth from traditional trimming as well as create the best cast for use in a vacuum-former. (6.) A single dark tooth from trauma needs to be examined carefully and evalu-ated with a radiograph. The safest approach is to bleach this tooth alone until the tooth’s response and maximum lightening can be determined. (7.) The “single-tooth” bleaching tray has no reservoir or spacers and extends onto the gingiva 1 mm to 2-mm, but avoids frenum movements. The teeth not to be bleached have the tooth molds removed from the tray while maintaining the intact tray. (8.) The single-tooth bleaching tray extended further onto the palate than the traditional tray to preserve the tray integrity when the adjacent teeth molds were removed from the tray. The tray edges are hidden behind rugae and go onto the tissue in all areas. (9.) A reasonable match was obtained from about 8 weeks of single-tooth bleaching. Often patients discontinue treatment when the single tooth is no longer a mismatch, even if the outcome is not ideal. CASE EXAMPLE TWO (10.) This root canal has been successful for 30 years, but the tooth has become slightly discolored. There is no reason from the radiograph to re-enter the pulp chamber, as this will further weaken the tooth. External bleaching by a single-tooth bleaching tray is indicated (11.) The 10% carb-amide peroxide bleaching material was applied externally with the single-tooth bleaching tray nightly until the shade of the endodontically treated tooth returned to match the adjacent teeth. Should the tooth re-darken again, the process can be repeated without danger to the tooth. Figure 10 and Figure 11 courtesy of Meigan Johnson.

FIG. 7 FIG. 8

FIG. 5 FIG. 6

FIG. 9

been subsequently restored with an ac-ceptable lingual composite that matched the tooth color. However, in subsequent years, the tooth may have discolored (Figure 10). In this situation, the deci-sion for bleaching favors external bleach-ing, because going inside the tooth to remove the composite will weaken the tooth (Figure 11). However, the choice not to go inside the endodontic tooth depends on whether the treating dentist is aware of the extent to which the pulp chamber was debrided during endodon-tic therapy, as well as the height in the chamber of the cement and filler.

In-O!ce BleachingIn-o"ce bleaching is the oldest form of bleaching. Attempts to bleach single dark teeth date back to the 1800s, and bleaching a single dark tooth was one of the first bleaching research areas.45 A number of materials have been used, but hydrogen peroxide has been the historic favorite. The high concentra-tion of hydrogen peroxide could be applied externally or internally, and often involved heat and light. The classic non-vital in-o"ce bleaching technique involved the placement of 35% hydrogen peroxide into the pulp chamber, and increasing the chemi-cal reaction by the use of heat or light. However, this technique lacks precise control as to the amount of lightening. More critically, when cases of external or internal resorption were evaluated, there were four common concerns list-ed: 1) teeth had received trauma; 2) high concentrations of peroxide were used; 3) high heat was used to enhance the bleaching, and 4) there was no seal over the gutta-percha. Although the dentist cannot control the trauma, elimination of the other three areas under dental control should be done to lessen the chances of resorption and loss of the tooth. Other possibilities for resorp-tion include the fact that 10% of teeth do not have a connection between the enamel and cementum, with possible percolation of hydrogen peroxide into the surrounding areas, lowering the pH. Using a bleaching product with a higher pH or a salivary catalase are attempts to reduce resorption issues.

Walking Bleach TechniqueThe change in in-o"ce bleaching led to the next step of “walking bleaching.” In this technique, the gutta-percha was removed 2 mm below the CEJ and a

FIG. 10 FIG. 11

“One challenge infabrication of the single-tooth or regular bleaching tray is trimming the cast without abrading either the teeth or thegingiva. This outcome is accomplishedby trimming the cast from the base rather than the sides.”

CASO%EJEMPLO%2%FIG.%10%=%La%endodoncia%ha%funcionado%con%éxito%durante%30%años%pero%el%diente%se%ha%decolorado%ligeramente.%A%la%vista%de%la%radiograIa,%no%hay% razón% para% una% reNentrada% en% la% cámara% pulpar% porque% ello%debilitaría%más%el%diente.%Está%indicada%la%cubeta%de%blanqueamiento%de%diente% unitario.% Fig.% 11% =% El% peróxido% de% carbamida% al% 10%% se% aplica%externamente% con% la% cubeta% de% blanqueamiento% de% diente% unitario%uTlizada% por% la% noche% hasta% que% el% color% del% diente% tratado%endodóncicamente%coincida%con%el%color%de%los%adyacentes.%Si%el%diente%se%vuelve%a%decolorar%puede%repeTrse%el%procedimiento%sin%peligro%de%dañar%el%diente.%(FigN10%y%11%son%cortesía%de%Meigan%Johnson)%

 Otras  circunstancia  a  tener  en  cuenta  respecto  a  la  reabsorción  incluye  el  hecho  de  que  el  10%  de  los  dientes  no  tienen  un  buen  acoplamiento  entre  el  esmalte  y  el    cemento,   y   puede   producirse   la   percolación   del   peróxido   de   hidrógeno   en   los  tejidos   adyacentes   y   disminuir   el   pH.   Se   intenta   reducir   los   fenómenos   de  reabsorción  utilizando  productos  con  un  pH  más  elevado,  o  con  catalasa  salival.        Técnica  de  blanqueamiento  ambulatorio  La  evolución  en  la  técnica  de  blanqueamiento  en  el  consultorio  condujo  a  la  técnica  de  blanqueamiento  ambulatorio.  En  esta  técnica  se  extirpaba  la  gutapercha  2  mm  por  debajo  del  nivel  de  la  línea  amelocementaria  y  se  ponía  una  base  para  aislar  el  sellado   endodóncico   del   espacio   de   la   cámara   pulpar.   Luego,   inicialmente   se  aplicaba  un  peróxido  de  hidrógeno  de  alta  concentración,  se  sellaba,  y  el  paciente  abandonaba   el   consultorio   mientras   el   peróxido   de   hidrógeno   oxidaba   la  decoloración.   El   tratamiento   consigue   el   éxito  después  de  1   a  6   aplicaciones  por  semana.   La   cuestión   es   que   las   altas   concentraciones   de   peróxido   de   hidrógeno  pueden  ser  cáusticas  tanto  para  el  dentista  como  para  el  paciente.    Más   tarde,   esta   técnica   evolucionó   incorporando   al   peróxido   de   hidrógeno   el  perborato   de   sodio   formando   una   mezcla   que   era   más   fácil   de   manipular.   El  perborato   de   sodio   se   disocia   para   generar   alrededor   de   un   3%   de   solución   de  peróxido  de  hidrógeno.  Finalmente  se  eliminó  la  alta  concentración  de  peróxido  de  hidrógeno  y  se  uso  únicamente  perborato  de  sodio.  La  técnica  de  blanqueamiento  interno  continuaba  añadiendo  catalasa  para  neutralizar  el  peróxido  de  hidrógeno  y  elevar   el   pH   a   todo   lo   largo   del   diente.   Con   cualquier   tratamiento   blanqueador  debe  darse   tiempo  para   la   estabilización  del   tono  y   la  disipación  del  oxígeno  del  diente.   Si   se   inicia   la   restauración   inmediatamente   después   del   blanqueamiento  hay   un   25%   de   reducción   de   las   fuerzas   de   adhesión   debido   a   la   inhibición   del  fraguado  del  composite  por  el  oxígeno  remanente,  resultando  en  un  acortamiento  de  los  tags  o  indentaciones  del  material  en  el  esmalte.  La  estabilización  de  color  y  el   retorno   de   la   adhesión   a   la   normalidad   ocurre   aproximadamente   en   dos  semanas.  Más   tarde,   se   encontró   que   el   peróxido   de   carbamida   era   tan   efectivo   como   el  perborato  de  sodio  para  el  blanqueamiento  interno,    a  la  misma  concentración  con  el    beneficio  adicional  de  que  causa  una  elevación  del  pH  que  puede  ser  beneficioso  para  evitar  las  reabsorciones.    Una   solución   de   peróxido   de   carbamida   al   10%   es   equivalente   a   peróxido   de  hidrógeno  al  3,  5%  y  6,5%  de  urea.  Es  la  urea  la  que  causa  el  incremento  del  pH,  a  niveles   de   8   dentro   de   los   5   primeros   minutos   de   aplicación,   algo   que   no   se  consigue   con   las   presentaciones   que   solo   contienen   peróxido   de   hidrógeno.  Además,    el  peróxido  de  carbamida  produce  una  lenta  liberación  de  peróxido  y  éste  es  activo  durante  más  tiempo  que  en  las  formulaciones  de  peróxido  de  hidrógeno  en  solitario.  Esta  liberación  retardada  de  peróxido  parece  que  favorece  las  tasas  de  cambio  de  color.          

   

   Debido  a  que  el  trauma  es  uno  de  los  iniciadores  de  la  reabsorción,  su  influencia  no  puede  ser  totalmente  eliminada  y  en  los  dientes  que  no  han  sido  blanqueados  cabe  la  posibilidad  de  que  puedan  comenzar  un  proceso  de  reabsorción.  Los  dientes  que  han  sufrido  un  traumatismo  deben  ser  revisados  radiográficamente  cada  uno  o  dos  años  tanto  si  han  sido  blanqueados  como  si  no.        Blanqueamiento  interno  Cuando  realizamos  blanqueamiento   interno  en  un  diente  que  ha  sido  sometido  a  terapia   endodóncica   es   importante   la   limpieza   del   interior   de   la   cámara   pulpar  (Figura  12).  A  menudo,   cuando   se  hace  una   endodoncia   terapéutica  debido   a  un  traumatismo   la  cámara  pulpar  es  amplia  y  con   los  cuernos  pulpares  elevados,  en  ese   caso,   la   apertura   cameral   hacia   el   ápice   puede   no   haber   incluido   el  desbridamiento   total   de   la   cámara   pulpar   (Figura   13).   El   dentista   que   realice   la  restauración   debe   abrir   suficientemente   el   acceso   extendiéndose   tanto   a   nivel  incisal   como   lateral   de   la   cámara   pulpar.   Con   frecuencia,   la   remoción   del   tejido  cameral   remanente  modificará   de   forma   significativa   el   color   del   diente   incluso  antes  de  que  el  blanqueamiento  haya  empezado  (Figura  14).      

48 INSIDE DENTISTRY | September 2010 | insidedentistry.net

INSIDE CONTINUING EDUCATION

base was applied to seal the endodontic filling material from the pulp chamber. Then, initially, a high concentration of hydrogen peroxide was applied, sealed, and the patient “walked out of the o!ce” while the hydrogen peroxide oxidized the discoloration. This treatment took anywhere from 1 to 6 weekly applica-tions. The challenge was that the high concentration of hy drogen peroxide could be caustic to either the dentist or the patient. Later, this technique evolved into mixing the hydrogen per-oxide with sodium perborate to form a mixture that was easier to handle. Sodium perborate breaks down into about a 3% solution of hydrogen per-oxide. Finally, the high concentration of hydrogen peroxide was eliminated and sodium perborate alone was used. Internal bleaching treatment was fol-lowed by the use of a catalase to neu-tralize the hydrogen peroxide and el-evate the pH around the tooth. With any bleaching treatment, time should be allowed for the shade to stabilize and the oxygen to dissipate from the tooth. If bonding is initiated immediately af-ter bleaching, there is a 25% reduction in bond strengths due to the inhibition of the composite set from the oxygen in the tooth, resulting in shorter enamel tags. It generally takes about 2 weeks or longer for the shade to stabilize and the bond strength to return to normal.

Later, 10% carbamide peroxide was found to be equally as e"ective as so-dium perborate for internal bleaching, at the same concentration, with the additional benefit of causing a rise in pH, which may be beneficial to avoid resorption. A 10% solution of carb-amide peroxide is equivalent to 3.5% hydrogen peroxide and 6.5% urea. It is the urea that causes the increase in pH within 5 minutes after application to a level above 8, which cannot be ac-complished with hydrogen peroxide alone. Also, the carbamide peroxide has a slower peroxide release and is active longer than hydrogen peroxide. This slower application of peroxide seems to favor the rate of color change. Because trauma is one of the initia-tors of resorption, that event cannot be totally eliminated. Even teeth that have not been bleached can begin to have resorption, so there is always that possibility. Traumatized teeth should have recall radiographs taken every 1 to 2 years, whether they have been bleached or not.

Inside BleachingWhen performing internal bleaching on a non-vital tooth that has received endodontic therapy, it is important to clean out the inside of the pulp cham-ber (Figure 12). Often, when endodon-tic therapy is performed because of trauma, the pulp chamber is large, with high pulp horns. The access opening to the apex may not include debride-ment of the chamber (Figure 13). The restorative dentist should open the access opening enough to access both the incisal extent as well as the lateral extent of the pulp chamber. Often, re-moval of the remaining pulp chamber will significantly alter the color of the tooth, even before the bleaching has begun (Figure 14).

Inside-Outside Closed BleachingOne of the best options for an endodon-tically treated tooth is to use both the inside and outside techniques in combi-nation. Entering the inside of the tooth will allow removal of any pulp tissue, filler, or cement sealer, as well as discol-ored restorations in the chamber. The classic walking-bleaching treatment is performed as described above (Figure 15 and Figure 16), then the tooth is temporarily sealed while a single-tooth bleaching tray is fabricated. Bleaching continues at home externally using the single-tooth tray approach until the sin-gle dark tooth has reached its maximum lightness (Figure 17). Then the patient waits 2 weeks for the shade to stabilize and the bond strengths to return to normal. Upon return to the dentist, a comparison of the single tooth is made to the adjacent teeth. If the endodon-tically treated tooth remains slightly darker than the remaining teeth, an opaque stark-white composite is used internally to fill the pulp chamber and provide an additional slight lightening of the tooth (Figure 18). The final ori-fice is closed with the appropriate color-matched composite to the external por-tion of the tooth. Some clinicians prefer to use a resin-modified glass ionomer internally to improve the bond to dentin, followed by the traditional composite restoration to close the opening. This approach of both inside and outside bleaching with a closed pulp chamber gives the benefits of both techniques. The inside bleaching segment allows the tooth to be cleaned as well as tem-pers the final color with a composite

FIG. 13FIG. 12

FIG. 14

FIG. 16

FIG. 15

FIG. 17

CASE EXAMPLE THREE (12.) The initial examination and radiograph determined that the dark lateral incisor was abscessed. After endodon-tic therapy, the tooth was then ready for bleaching. Had bleaching been performed without the radiograph, the abscess would have remained untreated and further damaged the tooth. (13.) The endodontic access opening should be enlarged until it can be certain that all the remaining brown pulp tissue has been removed from the lateral walls of the pulp chamber as well as the incisal extent. Pulps that became necrotic when the tooth was young often have pulp chambers much larger than the endodontic access opening. (14.) Even before bleaching the tooth, the re-moval of the brown necrotic pulp remnants and dental materials makes the tooth much lighter. This occurrence demonstrates how the materials inside the tooth a!ect the color of the outside. (15.) For internal bleaching, the gutta-percha should be removed 2 mm below the CEJ. (16.) Once the gut-ta-percha has been removed to the appropriate depth and from the walls of the pulp chamber, the endodontic filler is sealed from the pulp chamber with a resin-modified glass ionomer. Etching is not required for bleaching. (17.)The patient may bleach externally (as well as internally) with a full tray rather than a "single-tooth tray" to lighten all the teeth or because there are crowns that will not change color. To identify the dark tooth for ad-ditional treatment, an “X” is placed on the tooth mold for the placement of the bleaching material. If the tray is to be worn during the day rather than at night, the “X” should be placed on the lingual. (18.) After the tooth being bleached has reached its maximum lightening, the bleaching process should be stopped for 2 weeks to allow the shade to stabilize and the bond strengths to return to normal. Then an opaque whiter composite can be placed in the chamber if needed to further harmonize the tooth color.

FIG. 18

CASO%EJEMPLO%3%Fig.%12%=%El%examen%inicial%y%la%radiogra>a%determinaron%que%el% incisivo% lateral% oscurecido% estaba% abscesificado.% Tras% la%terapia% endodóncica,% el% diente% estará% entonces% preparado%para% el% blanqueamiento.% Si% se% hubiese% hecho% el%blanqueamiento% sin% radiogra>a,% el% absceso% quedaría% sin%tratar%con%daño%adicional%para%el%diente.%Fig.%13%=%El%acceso%endodónico% debe% agrandarse% hasta% estar% seguros% de% que%todo% el% tejido% pulpar% remanente% ha% sido% exOrpado% de% las%paredes%laterales%de%la%cámara%pulpar%así%como%de%la%porción%incisal.%En%las%pulpas%que%se%necrosaron%cuando%el%diente%era%joven% la% cámara% pulpar% es% mucho% mayor% que% la% apertura%endodóncica.Fig.% 14% =% % % % Incluso% antes% de% blanquear% el%diente,% la% exOrpación% de% los% remanentes% necróOcos%marrones%de%la%pulpa%y%de%los%materiales%dentales%hacen%que%el%diente%aparezca%mucho%más%claro.%Este%hecho%demuestra%en%qué%medida%los%materiales%dentro%del%diente%afectan%a%la%apariencia% de% color% externa.% Fig.% 15% =% % Para% el%blanqueamiento% interno% la% gutapercha% debe% exOrparse% a% 2%mm%por%debajo%de%la%unión%amelocementaria.%Fig.%16%=%%Una%vez%que%se%ha%extraído%la%gutapercha%a%la%altura%adecuada%y%de% todas% las% paredes% de% cámara% pulpar,% el% relleno%endodóncico% se% sella% desde% la% cámara% pulpar% con% un%ionómero%de%vidrio%modificado%con%resina.%El%grabado%no%se%requiere% para% el% blanqueamiento.% Fig.% 17% =% El% propio%paciente% puede% blanquear% externamente% (así% como%internamente)%con%una%cubeta%completa,%mejor%que%con%una%“cubeta%de%diente%único”%para%blanquear%todos%los%dientes%o%quizá%porque%en%su%boca%Oene%coronas%que%no%cambiarán%de%color.% %Para% idenOficar%el%diente%oscurecido%en% la%cubeta%se%pondrá%una%X%en%el%diente%del%molde%para%marcar%la%posición%donde%se%dispondrá%el%material%blanqueador.%Si%la%cubeta%es%para%ser%usada%durante%el%día%y%no%durante%la%noche%la%X%se%marcará%en%lingual.%Fig.%18%=%Después%de%que%el%diente%se%ha%blanqueado% hasta% alcanzar% su% máxima% clarificación,% el%proceso% de% blanqueamiento% ha% de% pararse% durante% 2%semanas% para% permiOr% la% estabilización% de% los% maOces% de%color%y% la%normalización%de% las% fuerzas%de%adhesión.% Luego,%puede% ponerse% en% la% cámara% un% composite% opaquer% si% se%necesita%una%armonización%de%color%adicional.%

   Blanqueamiento  ambulatorio  externo  e  interno  Una  de  las  mejores  opciones  para  un  diente  tratado  mediante  endodoncia  es  usar  las   técnicas   externa   e   interna   en   combinación.   El   acceso   al   interior   del   diente  permitirá  la  remoción  de  cualquier  resto  pulpar,  rellenador  o  cemento  sellante,  así  como  restauraciones  decoloradas  dentro  de  la  cámara.  El  tratamiento  ambulatorio  clásico   se   realiza   como   se  describía   antes   (Figuras  15   y  16),   y   a   continuación   se  sella  el  diente  temporalmente  mientras  se  fabrica  la  cubeta.    El   blanqueamiento   externo   continua   en   el   domicilio   sondeando   con   la   cubeta  de  diente  unitario  los  máximos  niveles  de  aclaramiento  del  diente  oscurecido  (Figura  17).  Luego  el  paciente  espera  dos  semanas  para  que  la  estabilización  del  tono  y  de  las  fuerzas  de  adhesión  retornen  a  la  normalidad.  En  cuanto  vuelva  al  dentista  se  hará   una   comparación   entre   el   diente   tratado   y   los   adyacentes.   Si   el   diente   se  mantiene   levemente   más   oscuro   que   el   resto   se   utiliza   un   composite   opaquer  ultrablanco  para  rellenar  la  cámara  pulpar  y  proporcionar  un  ligero  aclaramiento  adicional   al  diente   (Figura  18).  El   orificio   se   rellena   finalmente   con  el   composite  del  color  del  diente  en  su  porción  más  superficial.  Algunos  clínicos  prefieren  el  uso  de  ionómeros  modificados  con  resinas  en  el  interior  para  mejorar  la  adhesión  a  la  dentina,   seguido   de   un   composite   convencional   de   restauración   para   cerrar   la  apertura.   Este   intento   de   blanqueamiento   tanto   interno-­‐externo   con  una   cámara  pulpar  cerrada  aporta  los  beneficios  de  ambas  técnicas.  La  parte  dedicada  al  blanqueamiento  interno  permite  que  el  diente  esté  limpio  y  al  mismo  tiempo  calibra  el  color  final  con  la  restauración  composite,  mientras  que  el  periodo   de   blanqueamiento   interno   permite   al   paciente   blanquear   durante   el  tiempo   necesario   para   obtener   el   máximo   aclaramiento   del   diente   hasta   que  regresa  al  consultorio  (Figuras  19  y  20).    

 Debido   a   que   ya   disponemos  del   molde   con   el   que  fabricamos   la   cubeta   de   diente  unitario,   y   en   caso   de   que   éste  haya   blanqueado   más   que   el  resto,   se   puede   fabricar   una  nueva   cubeta   para   que   el  paciente   la   use   diariamente   y  hasta  alcanzar  el  color  deseado  semejante   al   diente   que   fue  tratado.   El   tiempo   medio   de  tratamiento   para   el   diente  unitario   parece   ser   de   8  semanas,   aunque   existe   un  amplio   rango   de   intervalos   de  

tiempo.  Mientras  el  peróxido  de  carbamida  al  10%  se  utiliza  generalmente  en  los  tratamientos  nocturnos,  se  pueden  usar  concentraciones  más  elevadas  una  vez  que  se  ha  determinado  que  la  sensibilidad  no  es  un  problema.        

INSIDE CONTINUING EDUCATION

restoration, while the outside bleaching segment allows the patient to bleach as long as necessary to obtain the maxi-mum whitening of the tooth without returning to the o!ce (Figure 19 and Figure 20). Because a cast already ex-ists for the single-tooth tray, should the single tooth get lighter than adjacent teeth, a new bleaching tray can be fab-ricated and the patient can use it for day wear to titrate the color to a final match. The average treatment time for single dark teeth seems to be 8 weeks, although there is a wide range of treat-ment times. While 10% carbamide per-oxide is generally used for traditional overnight treatment, higher concentra-tions may be used once it is determined that sensitivity is not a problem.

Inside-Outside Open BleachingIn special patients and situations, the dentist may chose to perform inside and outside bleaching while leaving the ac-cess opening unrestored. In this situa-tion, the patient injects carbamide per-oxide into the pulp chamber and the tray, then seats the tray in the mouth to pro-tect the opening. While this may shorten treatment time due to the continued ap-plication of fresh bleaching material, it is essential that the patient be able to perform their part, and also return to the o!ce to have the opening closed. While the tooth will not get any tooth decay during the bleaching process due to the increase in pH a"orded by the carbamide peroxide,46 there is the dan-ger that the patient may cease bleach-ing but not return in a timely fashion to have the orifice sealed. If the o!ce is not equipped to fabricate the additional

single-tooth tray, then the standard re-placement of the internal carbamide peroxide is performed weekly, taking 1 to 6 o!ce visits for completion. A pro-visional restoration maintains the seal, and the patient is instructed to call the o!ce immediately if occlusion or food disrupts the provisional seal.

Bleaching or Crown DecisionsThe question is often asked why the an-terior endodontically treated tooth is not crowned today as it once was in the past. One reason for the resurgence of bleaching single anterior teeth is that the research has shown that while pos-terior teeth that have received a root ca-nal should be crowned, anterior teeth should only be crowned if they needed a crown regardless of the endodontic therapy. The reason is because the single greatest predictor of survival of an end-odontically treated tooth is the amount of remaining dentin. If an intact anterior tooth has a root canal, the external enam-el and dentin is still intact. Preparing the tooth for a crown after the endodontic treatment removes the remaining den-tin and results in a premature loss of the tooth. Research has also shown that the post does not strengthen the tooth, and cannot compensate for the loss of dentin. Hence, the tooth has a better prognosis to be bleached and restored with composite than to receive a post, core, and crown.

Conclusion The single dark tooth is an esthetic challenge regardless of the treatment approach. Bleaching the single tooth alone is the safest, most conservative approach to determining the response of the single tooth before changing the

adjacent tooth colors. A “single-tooth” bleaching tray is the tray of choice for external bleaching. Single dark teeth with calcific metamorphosis should not be treated endodontically unless there are clinical symptoms of pain or radio-graphic evidence of an abscess.

For internal bleaching of an end-odontically treated tooth, a “walking bleach” approach using 10% carbamide peroxide internally seems to a"ord the safest approach over previous tra-ditional methods. The combination of one internal bleaching appointment to debride the pulp chamber, followed by tray bleaching with a single-tooth tray or full non-scalloped, no reservoir tray pro-vides the flexibility of unlimited time of treatment without incurring significant in-o!ce charges. Additionally, waiting 2 weeks after bleaching for the shade to stabilize and the bond strengths to re-turn to normal and then using internal composite bonding can harmonize final shade discrepancies. Regardless of the technique used for bleaching, a relapse is possible in 1 to 3 years, and is generally best addressed by outside bleaching in a single-tooth tray with 10% carbamide peroxide to re-bleach the tooth until it matches the surrounding teeth.

References1. Glendor U, Halling A, Andersson L, Eilert-Petersson E. Incidence of traumatic tooth injuries in the county of Västmauland, Sweden. Swed Dent J. 1996;20:15-28.2. Andreasen JO, Andreasen FM, Andersson L. Textbook and Color Atlas of Traumatic Injuries to the Teeth. 4th ed. Oxford, England: Blackwell Munskgaard; 2007.3. Davis GT, Knott SC. Dental trauma in Australia. Aust Dent J. 1984;29:217-221.4. Brunner F, Krasti G, Filippi A. Dental trauma in adults in Switzerland. Dental Traumatol. 2009;25:181-184.5. Glendor U. Epidemiology of traumatic dental injuries—a 12 year review of the literature. Dent Traumatol. 2008;24:603-609.6. Kaste LM, Gift HC, Bhat M, Swango PA. Prevalence of incisor trauma in persons 6-50 years of age: United States, 1988-1991. J Dent Res. 1996;75:696-705.7. Petti S, Tarsitani G, Arcadi P, et al. The preva-lence of anterior tooth trauma in children 6 to 11 years old. Minerva Stomatol. 1996;45:213-218.8. Rocha MJ, Cardoso M. Traumatized perma-nent teeth in Brazilian children at the Federal University of Santa Catarina, Brazil. Dent Traumatol. 2001;17:245-249.9. Flores MT. Traumatic injuries in the primary dentition. Dent Traumatol. 2002;18:287-298.

10. Hedegård B, Stalhane I. A study of trauma-tized permanent teeth in children aged 7-15 years. Part 1. Swed Dent J. 1973;66:431-450.11. Gelbier S. Injured anterior teeth in chil-dren. A preliminary discussion. Br Dent J. 1967;123:331-335.12. Davis GT, Knott SC. Dental trauma in Australia. Aust Dent J. 1984;29:217-221.13. Kramer PF, Zembruski C, Ferreira SH, Feldens CA. Traumatic dental injuries in Brazilian preschool children. Dent Traumatol. 2003;19:299-303.14. Skaare AB, Jacobsen I. Dental injuries in Norwegians aged 7-18 years. Dent Traumatol. 2003;19:67-71.15. Hosnik A. Emergency treatment of dentoal-veolar trauma. Phys Sports Med. 2004;32(9):1-10.16. Onetto JE, Flores MT, Garbarino ML. Dental trauma in children and adolescents in Valparaiso, Chile. Endo Dent Traumatol. 1999;10:223-227.17. Cornwell H. Dental trauma due to sport in the pediatric patient. Calif Dent Assoc J. 2005; 33(6)457-461.18. Zerman N, Caralleri G. Traumatic injuries to permanent incisors. Endod Dent Traumatol. 1993;9:61-64.19. Skaare AB, Jacabsen I. Etiological factors related to dental injuries in Norwegians aged 7-18 years. Dent Traumatol. 2003;19:304-8.20. Gassner R, Bösch R, Tulit, Emskoff R. Prevalence of dental trauma in 6000 patients with facial injuries: Implications for treatment. Oral Surg Oral Med Oral Path Oral Radiol Endod. 1999;87:27-33.21. Brunner F, Krasti G, Filippi A. Dental trauma in adults in Switzerland. Dent Traumatol. 2009;25:181-184.22. Promoting oral health: interventions for preventing dental caries, oral and pharyngeal cancers and sports related craniofacial injuries: a report on recommendations of the Task Force on Community Preventive services. MMWR. 2001;50(RR21):1-13.23. Tuli T, Hachl O, Hohlrieder M, et al. Dentofacial trauma in sports accidents. Gen Dent. 2002;50(3):274-279.24. Needleman HL. Orofacial trauma in child abuse: types, prevalence, management and the dental profession. Pediatr Dent. 1986;8:71-80.25. Dimitroulis G, Eyre J. A 7-year review of maxillofacial trauma in a central London hos-pital. Br Dent J. 1991;170:300-302.26. Perkeentupa U, Laukkanen P, Veijola J, et al. Increased lifetime prevalence of dental trauma is associated with previous non-dental injuries, mental distress and high alcohol consumption. Dent Traumatol. 2001;17:10-16.27. Feiglin B. Dental pulp response to traumatic injuries—a retrospective analysis with case reports. Endod Dent Traumatol. 1996;12:1-8.28. Amir FA, Gutmann JL, Witherspoon DE.

FIG. 19

CASE EXAMPLE FOUR ((19.) The endodontically treated canine is much darker than the adjacent teeth, but in this less-esthetic area, a full tray was used to lighten all the teeth. The canine was bleached internally with one treatment and externally to completion. (20.) After 3 weeks of external bleaching with 10% carbamide peroxide at night, the adjacent teeth reached their maximum lightness. While the other teeth are slightly lighter than the canine, the color match was much closer and pleasing to the patient.

FIG. 20

50 INSIDE DENTISTRY | September 2010 | insidedentistry.net

CASO%EJEMPLO%4%Fig.%19%=%El%canino%tratado%con%endodoncia%es%mucho%más%oscuro%que%los%dientes%adyacentes,%pero%en%esta%zona%menos%estéGca%se%uGliza%una%cubeta% completa% para% blanquear% todos% los% dientes.% El% canino%internamente% en% una% sesión,% y% externamente% hasta% el% final% del%tratamiento.% Fig.% 20% =% Después% de% 3% semanas% de% blanqueamiento%externo% nocturno% con% peróxido% de% carbamida% al% 10%% los% dientes%adyacentes% alcanzaron% su% máxima% clarificación.% Aunque% los% otros%dientes% son% ligeramente%más% claros% que% el% canino,% % el% color% combina%mejor%y%el%paciente%está%saGsfecho.%

Blanqueamiento  interno  y  externo  abierto  En  determinados  pacientes  y  situaciones,  el  dentista  puede  optar  por  realizar  un  blanqueamiento  externo-­‐interno  mientras  deja  abierto  el  acceso  sin  restauración.  En   esta   circunstancia,   el   paciente   inyecta   peróxido   de   carbamida   dentro   de   la  cámara  pulpar  y  de   la  cubeta,   luego  asienta   la  cubeta  en   la  boca  para  proteger   la  apertura.   Aunque   esta   técnica   acorta   el   tiempo   de   tratamiento   debido   a   la  aplicación   continua   de  material   nuevo,   es   esencial   que   el   paciente   sea   capaz   de  realizar  su  parte  y  también  volver  al  consultorio  para  cerrar  la  apertura.  A  pesar  de  que   el   diente   no   sufrirá   ninguna   caries   durante   el   proceso   de   blanqueamiento  debido  al   incremento  de  pH  conseguido  por  el  peróxido  de  carbamida,46  existe  el  peligro  de  que  el  paciente  abandone  el  tratamiento  blanqueador  pero  no  regrese  a  la  consulta  en  el  momento  más  adecuado  para  sellar  el  orificio.  Si  el  consultorio  no  está  equipado  para  fabricar  la  cubeta  tradicional  de  diente  unitario  se  procederá  al  reemplazo   clásico  de  peróxido  de   carbamida   interno   realizado   semanalmente,   lo  que   ocupará   de   1   a   6   visitas   para   completar   el   tratamiento.   En   este   caso,   se  mantiene  el  sellado  con  una  restauración  provisional  y  se  instruye  al  paciente  para  que  llame  al  consultorio  inmediatamente  si  la  oclusión  o  el  alimento  desmoronan  la  restauración  provisional.        Toma  de  decisiones:  Blanqueamiento  o  corona  La   cuestión   que   se   plantea   actualmente   es   por   qué   un   diente   anterior   tratado  endodóncicamente    no  se   trata  con  corona  de  recubrimiento  como  se  hacía  en   le  pasado.   Una   de   las   razones   del   resurgimiento   del   blanqueamiento   del   diente  unitario   del   sector   anterior   es   que   la   investigación   ha   demostrado   que   el   diente  posterior   tratado   con   endodoncia   debe   ser   tratado   con   corona,   los   dientes  anteriores   solamente   deben   ser   enfundados   si   necesitan   una   corona   con  independencia   de   la   terapia   endodóncica.   La   razón   es   que   el   único   factor   que  predice   la   supervivencia   del   diente   endodonciado   es   la   cantidad   de   dentina  remanente.  Si   un   diente   del   sector   anterior   intacto   sufre   una   endodoncia,   la   dentina   y   el  esmalte   exterior   permanecen   igualmente   intactos.   Si   hacemos   una   preparación  para   corona   extirpamos   la   dentina   remanente   y   se   producirá   una   pérdida  prematura   del   diente.   Los   estudios   también   han   demostrado   que   los   postes  intrarradiculares  no  refuerzan  el  diente  y  no  compensan  la  pérdida  de  dentina.  Por  tanto,  el  diente  tiene  mejor  pronóstico  si  se  blanquea  y  se  restaura  con  composite  que  si  recibe  un  poste,  reconstrucción  y  una  corona.        Conclusión  El   diente   unitario   oscurecido   es   un   reto   estético   independientemente   de   la  estrategia  de  tratamiento.  Blanquear  solamente  el  diente  oscurecido  es  el   intento  más  conservador  y  seguro  para  determinar  su  respuesta  antes  de  cambiar  el  color  de   los   dientes   adyacentes.   La   cubeta   de   blanqueamiento   de   diente   unitario   es   la  cubeta  de  elección  para  el  blanqueamiento  externo.  El  diente  único  oscurecido  que  sufre  metamorfosis  calcificante  no  debe  ser  tratado  con  endodoncia  a  menos  que  haya  síntomas  clínicos  de  dolor  o  evidencia  radiográfica  de  un  absceso.          

Para   el   blanqueamiento   interno   de   un   diente   tratado   endodóncicamente,   un  intento  de  blanqueamiento  ambulatorio  utilizando  peróxido  de  carbamida  al  10%  internamente  parece  ofrecer  el  método  más  seguro  frente  a  métodos  tradicionales  previos.  La  combinación  de  una  cita  de  blanqueamiento  interno  para  desbridar  la  cámara   pulpar,   seguido   por   una   cubeta   de   blanqueamiento   de   diente   unitario,   o  una  cubeta  completa  no  festoneada  y  sin  reservorio,  proporciona  la  flexibilidad  del  tiempo  ilimitado  de  tratamiento  sin  incurrir  en  gastos  de  consulta  significativos.    Adicionalmente,   esperar  2   semanas  después  del  blanqueamiento  para  estabilizar  el   tono   y   la   normalidad   de   las   fuerzas   de   adhesión   y   luego,   utilizando   una  restauración   de   composite   se   pueden   armonizar   discrepancias   finales   de   color.  Cualquiera   que   sea   la   técnica   utilizada   para   blanquear,   es   posible   una   recidiva  entre   1   y   3   años   después,   y   esta   es   habitualmente  mejor   aceptada   si   se   usa   una  técnica   ambulatoria   de   cubeta   de   diente   unitario   con   peróxido   de   carbamida   al  10%     que   vuelva   a   blanquear   el   diente   hasta   que   coincida   con   el   color   de   los  dientes  adyacentes.      ,

BIBLIOGRAFÍA  1. Glendor  U,  Halling  A,  Andersson  L,  Eilert-­‐Petersson  e.  incidence  of  traumatic  

tooth   injuries   in   the   county   of   Västmauland,   sweden.   Swed   Dent   J.  1996;20:15-­‐28.  

2. Andreasen   JO,   Andreasen   FM,   Andersson   L.   Textbook   and   Color   Atlas   of  Traumatic   Injuries   to   the   Teeth.   4th   ed.   Oxford,   england:   Blackwell  Munskgaard;  2007.    

3. Davis   Gt,   Knott   SC.   Dental   trauma   in   Australia.  Aust   Dent   J.  1984;29:217-­‐221.    

4. BrunnerF,KrastiG,FilippiA.   Dental   trauma   in   adults   in   Switzerland.  Dental  Traumatol.  2009;25:181-­‐184.    

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