Internal Bleaching of Severe Tetracycline Discolorations: Four-Year Clinical Evaluation Eduardo Anitua* / Borja Zabalegui** / Jaime Gil*** / Francisco Gascon****

Endodontics

Internal bleaching of severe tetracycline discolorations: four-year clinical evaluation Eduardo Anitua* / Borja Zabalegui** / Jaime Gil*** / Francisco Gascon****

Two hundred fifty-eight teeth severely discolored by tetracycline were treated with an internal bleaching technii/ue. Endodontic treatmeni was required in all teeth before ¡he walking bleaching procedute could be undertaken. Four years of clinical and radio- graphic evaluation revealed good esthetic results for all patients. Endodontic procedures were considered to be suLces.\ful, and not one patient showed external cervical résorp- tion after 4 years. This type of treatment is a valid alternative to porcelain laminate veneers for those teeth that exhibit severe tetracycline discoloration and in which the dental enamel and anatomic crown are intact. (Quintessence Int 1990:21:783-788.)

Introduction The therapeutic methods used to bleach pathologic discolorations bave two main approaches: external ap- Patbologic discoloration of the teeth can be caused by plications to the teeth (teeth maintain tbeir pulpal tis- external or internal factors. Among the external fac- sues) or internal activation (teeth do not maintain tors, tbe most frequent are generally inappropriate tbeir puipal tissues). diets {tea and coffee) or barmful babits (tobacco).' A review of tbe literature reveals tbe following ex- These problems can be easily solved by eitber a change ternal bleaching techniques^"': (I) use of 35% hydro- in the habits or by means of conventional therapeutic gen peroxide (H^O-) (Superoxol, Union Broach Co): treatments (bicarbonated spray solutions and pohsb- (2) use of anesthetic solutions, such as ether plus 35% ing and brushing tecbniques). HJOT at a 1:5 ratio in cases of fluorosis: and (3) use Patients with severe internal discolorations of tbeir of various acids, such as 36% hydrochloric acid, phos- teetb present a problem in treatment.'"' Internal dis- phoric acid, or pumaric acid on specific fluorosis colorations are reported to be due mainly to ingestion stains. of tetracycline by the patient at a young age, or by Hydrogen peroxide solutions can be activated by the patient's mother during pregnancy, or to fluo- heat."* Two methods of application have been de- rosis.' scribed: light activation" or custom-thermotray activation.'- The most commonly used internal bleaching technique is the "walking" bleaching technique, which in- volves the use of monohydrate-peroxyborate solutions mixed witb oxygen peroxide. The solution is placed inside tbe pulpal cbamber and sealed witb dental ce- Private Practice, San Antonio Street 15, 3", Vitoriii, Spain 01005. ment, and the bleacbing agent is reapplied in subse- Private Practice, Edificio Albia 1, Bilbao, Spain 48001. quent appointments. Professor, Deparlment of Prosthodontics, Pais Vasco Uni- Tbc purpose of tbis paper is to present tbe 4-year versity, School of Dentistry, Bilbao. Spain. clinical evaluation of the internal bleaching treatment Professor of Proslhetics and Occlusion, Department of Pros- thodontics, Valencia University, School of Dentistry, Valen- of teetb that had suffered from severe tetracycline dis- cia, Spain. colorations. Attempts to treat these teeth with external

Quintessence International Volume 21. Number 10/1990 783 Endodontics

Fjg 1 Pretreatment appearance of an 18-year-old woman Fig 2 Four years after the completion cl treatment, the with severely stained teeth. The maxillary and mandibular results are still satislactory, A slight and uniform darkening anterior teeth were treated. The bleaching was accom- is detectable, but the teeth do not require re-treatment. plished in tbree sessions witb a 10-day interval between sessions.

Table 1 Distribution of the patients by age and sex first phase, and the treatment of the mandibular anterior teeth in only a few patients in a second phase, Age A total of 258 teeth were treated. The technique consisted of intentional endodontic Sex IÛ-19 20-29 30-39 Total treatment, as described by Abou-Rass,"''' of teeth sus- Male 4 4 0 8 eeptible to internal bleaching. The root canals were obturated with laterally condensed gutta-percha and Female 10 11 2 23 AH 26 cement (De Trey/Dentsply International), The Total 14 15 2 31 eavity was restored with provisional IRM reinforced zinc oxide-eugenol cement (De Trey/Dentsply Inter- national), After 1 week, the gutta-percha was removed with a Mortenson No, 2 condenser, to 1 mm below bleaching techniques had been unsuccessful. The eval- the dentinoenamel junction. Radiographs were made uation involved assessment of changes in the color of for future comparison. The gutta-pereha was filled the teeth 4 years after the bleaching procedure, deter- with a glass-ionomer cement liner. The cavity was in- mination of the clinical success of endodontic treat- ternally etched with 37% orthophosphoric acid gel for ment, and determination of the presence or absence 1 minute. Pure sodium perborate was ground until a of external root résorption. fine powder consistency was achieved. The powder was mixed with 110 vol oxygen-water, until a viscous consistency was reached. The mixture was introduced Method and materials into the pulp chamber with a pressure syringe and was condensed with a manual instrument. The cavity was The group consisted of 31 patients (mean age of 21 restored with fiber-eugenate. years). Distribution of the patients by age and sex is presented in Table 1, All patients suffered from severe The patients were reexamined every 10 to 15 days, discoloration of their teeth as a result of early and and the procedure was repeated until satisfactory re- profuse tetracycline ingestion. The patients all had sults were obtained. Once this was achieved, all been treated with conventional external bleaching bleaching agents within the pulpal chamber were re- methods with unsatisfactory results. moved, and permanent composite resin restorations The therapy included treatment of the four maxil- were placed (Figs 1 to 14). All treatments were per- lary incisors and two canines in all patients, treatment formed by two operators experienced in this tech- of the maxillary first premolar in some patients in a nique.

784 Quintessence Internalional Volume 21, Number )0/t990 Endodontics

Fig 3 Pretreatment appearance of a 17-year-old girl. Only Fig 4 The 4-year recall photograph reveals ttiat the treat- the maxillary central and lateral incisors and ttie canines ment resulted in disappearance of the transversal striping were treated. and also that the teeth still maintain their immediately post- treatment color uniformity.

Fig 5 Pretreatment appearance ot a 14-year-old girl who Fig 6 The results of endodontics and internai bieaching was the first patient with severe staining that the authors 4'/? years after the end of treatment are excelient and sta- treated. Initialiy, the maxillary central incisors were treated bie. in this type ot case, it is often more difficult to obtain with resin veneers and opaqeur. The result was deplorable. good resuits with porcelain veneers or externai bieactiing.

Fig 7 Pretreatment appearance of a 16-year-oid girl. She Fig 8 Four years atter the conciusion ot the internai was initially treated with four sessions of external bleach- bleaching, Ihe patient requested additionai treatment, in the ing, btjt 6 months atter treatment was not satisfied. The operator's opinion, the teeth were acceptable, but one ad- internal bieaching technique was employed on the maxil- ditionai session was performed, to the patient's satisfaction. lary central and lateral incisors, and the result was satisfactory.

Quintessence International Volume 21, Number 10/1990 785 Endodontics

Fig 9 Pretreatment appearance oí a 14-year-old boy witti Fig 10 An attempt to match the color of the two central a fractured and fistulized central incisor. The maxiliary cen- incisors wculd have been more compromising. The teeth tral and lateral incisors were bleached, and ttie fractured were bleached for one session oniy, because the patient tooth was restored witn a universal composite resin. did not want to have tne other teeth treated.

Fig 11 Pretreatment appearance ot a 21-year-oid woman. Fig 12 The maxillary anterior teeth immediately after ini- The teeth were treated in two sessions, wilh a 2-year in- tial internai bleaching. tervai.

Fig 13 After a 2-year intervai, the mandibular anterior teeth have been bleached. There is a slight difference in Fig 14 After 4 years, the esthetic resuit is optimal, and the tonality between the maxiliary and mandibular teeth as a color variation is not noticeable except to the operator. The resuit of the darkening eventualiy observed in ali patients. transversal striping has not reappeared.

786 Quintessence Internationai Voiume 21, Number '0/1990 Endodonties

The patietits underwent periodic recall to assess the and without structural defects in the clinical crown. following parameters: (1) change or relapse of col- Because complete-crown preparations are not re- oring; (2) success of the endodontic treattnent; and quired, structure is preserved and gingival irritation is (3) presence of external cervical résorption as revealed prevented, in addition, tooth preparations for com- hy radiographs. The data were collected 4 years after plete-erown restorations that are performed in lateral coneltision of treatment. incisors are sometimes followed by root canal treat- The results of treatment on tooth coloring have been ment. Complete-crown restorations can improve the evaltiated according to the operator's criteria and the color and appearance of the teeth, but the interface patient's opinion. For this purpose photographs were between the crown and the periodontal tissues has the made before and after treatinent. potenlial to develop gingival infiammation. The internal bleaching method has shown superior esthetic results in severely discolored teeth {Jordan Classes Iii and IV}, Vital bleaching methods are un- Results predietable in teeth with such severe discoloration. It Esthetics should be noted, however, that some patients desire an overwhite color that does not match the appear- The results achieved in the present study were consid- ance of normal teeth. ered to be excellent by both operators and patients, In all patients who,se teeth are bleached internally, Iti the first 3 years after treatment, the operators found over the course of several years, a slight darkening no color ehange in any of the 258 treated leeth. At the may be noticed by the operator, although the patient 4-year recall, the operators found only six of the treat- may not perceive a difference. Such darkening can be ed teeth to have a slight change in color. easily treated with another session of internal bleach- In the first 3 years after treatment, all of the patients ing. considered the esthetics to be satisfactory. Only one Selection of teeth should he restricted to teeth with- patient was not pleased with the color, 4 years after out coronal structural defects. This prevents the need the conclusion of the treatment. He believed that the for any other restoration, thus redueing the possibility teeth had darkened slightly, although the darkening of fractures and failures. There were no fractures in was not as evident to the operator who had carried any of these teeth over the 4-year study, out and controlled the course of treatment. However, A review of the literature on internal bleaching re- the internal bleaching technique was repeated, and the veals that all the previously reported cases present a patient was satisfied with the itnprovement, history of trauma.'"'^ No report of external radicular résorption in vital, tetracyclinc-stained teeth that were treated with inten- Endodonties tional endodonties and internal bleaching was found One maxillary lateral incisor was symptomatic of fail- in the literature, ure on percussion 2 years after initiation of treatment. Traumatie factors result in the appearance of small The root canal was re-treated, and at present the tooth fractures in the radicular cementum. The persistant is asymptomatic and functional. The original endo- microbiotie irritation and chemical stimulation via dontic treatment of the other 257 teeth was successful, dentinai tubuh caused by the bleaching agent cause and those teeth remain functional, the periodontal attachment apparatus to invade the radicular denlinal tissue, creating external cervical ré- sorption.'*"" For this reason, a good pulpal pressure Exiernal cervical résorption syringe and root canal sealing with glass-ionomer ce- No evidence of external cervical résorption has been ment are required, Finn use of the pressure syringe found in the radiographs taken periodically during the and meticulous radicular seahng are of the utmost 4 years of followup. importance. The application of orthophosphorie or polyacrylic acid is both logical and necessary to elear the dentinai Discussion tubuh from the crown or at least open them to facil- This treatment is an effective alternative to complete- itate the arrival of the bleaching agent. coverage restorations in teeth with severe discoloration Local anesthesia is not needed for this procedure.

Quintessence International Volume 2t, Number 10/1990 787 Endodontics once the root canal treatment has been performed. Goon W, Cohen S, Boner RF: External cerviciil root resorplion following bleaching. J Endod ]986;12:4I4. This procedure can be accomplished in a short time. Lado EA, Stanley HR, Weisman M: Ceri-ical résorption in The technique is not suitable when the patient's bleached teeth. Orul Surg Oral Med Oral Piiiln'l 1983:55:78-80. teetb have been restored with composite resin or when Montgomery S: Exiernal cervical resorplion iifter bleaching a the enamel shows severe defects. In such cases alter- pulpless looth. Oral Surg Drat Med Oral Puihol 1984:57:203- 206. native treatment (eg, porcelain laminate veeners) is Lindskog S, Blomlöf L, Hammarstrom L: Cellular colonization recommended.""'^ of denuded root surfaces in vivo: cell morphology in dentin This treatment is indicated only in tbose patients rcsorption and cementum repair ./ Clin Peñodomol I9S7; with teeth that are severeiy discolored.""' but tbat have 14:390-395. complete enamel integrity and an adequate anatomic Gartner AH, Mack T, Somerlüti RG, et al: Differential diag- shape, and in whom conventional external bleaching nosis of internal and external résorption J Endod Í976;2:3?9- 334. tecbniques bave failed or can be anticipated lo fail Wedenberg C, Lindskog S: Experimental internal résorption in because of the severity of the stain. This treatment is monkey ieeth. Endod Denl Traumulo! 1985:1 221. a vahd alternative to porcelain laminate veneers be- Cwyk h, SainL-Pierre F, Tronstad L: Endodontic implicalions cause of the difficulty in masking severe discoloration. oforthodontic tooth movement, y De'if Re.s 1984:63:XXX (abstr No. 1039). Pierce A, Heithersay G, Lindskog S: Evidence for direct inhi- bition of denlinoclasts by corticosteroid/antibiotic endodontk paste. Endod Dem Traumaiol 1988:4:44-^5. HammarströmL. Blomlöf LB, Feiglin B, et al: Effect of calcium References hydroxide treatment on periodontal repair and root resorplion. Endod Dem Traumaiol 1986:2:184-189 1. Faunce F: Managenienl of discolored teeth. Dem Clin Norlh Am 198Í;27:657-67Ü. Cvek M: Endodonlic treatment of traumatized teeth, in An- 3. Pearson H: Bleaching of the discolored pulpiess toolh. J Am dreasen JO (ed): Traumatic Injuries of the Teeih. ed 2. Copen- hagen, Munksgaard, 1981. Dent Assoe l95S;5S:56-64. 3. Nutting EB, Poe GS; A new combination of bleaching leeth. Makkes PG, Thoden Van Velzen SK: Cervical external rool Dem Clin North Am 1970; 15:655-662. résorption. / Dent Res 1975:54:217-222. 4. Seale NS, Thrash WJ: Systematic assessment of color removal Frank AL: External and internal progressive résorption and its following vital bleaching of intrinsically stained teeth. / Dem nonsurgical correction. J Endod 1981:7:473^76. Res 1985:64:457-^61. Frank AL, Bakland L: Nonendodontic therapy for supraos- 5. Dean HI: A summary of Ihe epidenjiology of chronic endemic seous extracanal invasive résorption. J Endod 1987:13:348-355. dental fluorosis. Te\ Dem J t973,60:S6. Andreasen JO (ed¡: Tmumatie Injuries of the Teelh. ed 2. Co- 6. Griffin RE. Grower MF: Effects of solution used to treat denial penhagen, Munksgaard, 1981. fluorosis on permeability of teeth J Endod 1989;15:135-143. Bellizzi R, Cias WL: Endodontic management of extensive root 7. Haywood VB, Heymann HO: Nightguard vilai bleaching. Quin- résorption. Oral Surg Oral Med Oral Paihol 1980:49:165. tessence ¡m 1989:20:173-176. Gotiltschin J, Nitgan D, Azaz B: Root resorption—review and 8. McEvoy SA: Chemical agents for removing intrinsic stains from discussion. Oral Surg Oral Med Oral Paihol 1982:54:586. vital teeth. I. Technique development. Quimessence ¡nl 1989: Kaife I, et al: A radiographie survey of apical root résorption 20:323-328. in pulpless pertnanent teeth. Oral Surg Oral Med Oral Paihol 9 McEvoy SA: Chemical agents for removing intrinsic stains from 1984^58.109-112. vilal teeth. II. Current techniques and their clinical application. Quimessenee Int 1989:20:379-384. Latchman NL: Postbleaching cervical re.sorption. J Endod 1986:12:262. 10. Bowles WH, Thompson LR: Vital bleaching: the effects of heat and hydrogen peroxide on pulpal enzymes / Endod 1986: Tamse A, Littncr MM. Kaffc 1: Roentogenographic features of 12:108-112. external root résorption in Ihe permanent dentition. Quint- t.t.5É«iL' Im 1982;13:51-54. 11. Davies AK: Photo-oxidalion of letracycline absorbed on hy- droxyapatite in relation to the light induced staining of teeth. / Stewart H, Goerig A: An in vitro comparison of different Dent Res 1985:64:936-939. bleaching agents in the discolored tooth. J Endod 1989;15:1O6- 12. Torres V: Bleaching of vital teeth: technique. Estomodeo 111. 1984:9:7-30. Horn HR: Porcelain laminate veneers bonded to etched enamel. 13. Abou-Rass M: The discoloration problem. An endodontic so- Dem Clin North Am 1983:27:671-684. luüon. Alpha Omegan 1982;75:57-87. McLaughlin G: Porcelain fused to tooth—a new esthetic and 14. Abou-Rass M: The elimination of tetracycline discoloration by reconstructive modality. Compend Comin Edue DetH 1985; intentional endodontics and internal bleaching. / Endod 5:430^35. 1982;8:10i. Christiansen GJ: Veneering of teeth. State of the art. Dem Clin 15. Lado EA: Bleaching of endodontically treated teeth An update Norlh Am 1985:29:373-391. on cervical résorption. 1988:36:500-502. 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