Case Report/Clinical Techniques

Tooth Discoloration of Immature Permanent IncisorAssociated with Triple Antibiotic Therapy: A Case ReportJong-Hyun Kim, DDS, MS, Yuran Kim, DDS, Su-Jung Shin, DDS, MS, Jeong-Won Park, DDS, MS,PhD, and Il-Young Jung, DDS, MS, PhD

Abstract

Introduction: A triple antibiotic mixture of ciprofloxa-cin, metronidazole, and minocycline was used as an in-tracanal medicament in an attempt to disinfect the rootcanal system for revascularization of a tooth witha necrotic pulp. However, discoloration developed afterapplying the triple antibiotic mixture. Methods: Sixweeks after a triple antibiotic paste had been appliedto the root canal of tooth #8 of a 7-year-old girl, thetooth showed a dark discoloration. An in vitro experi-ment with human extracted teeth was performed todetermine which of the 3 antibiotics caused the toothdiscoloration. Another experiment was then carriedout to examine whether a currently used dentin bondingagent would prevent or reduce such discoloration. Thedegree of discoloration was assessed by using a colorim-eter. Results: Among the components of the triple anti-biotic paste, only minocycline caused the toothdiscoloration. Moreover, the dentin bonding agentreduced the intensity of the discoloration but did notprevent it. Conclusions: The possible esthetic problemswith the tooth color should be considered when usingminocycline as a canal medication. (J Endod2010;36:1086–1091)

Key WordsDiscoloration, immature teeth, minocycline, regenera-tive endodontics, revascularization, triple antibioticpaste

From the Department of Conservative Dentistry, College ofDentistry, Yonsei University, Seoul, Korea.

Address requests for reprints to Dr Il-Young Jung, Depart-ment of Conservative Dentistry, College of Dentistry, YonseiUniversity, Sinchon-dong, Seodaemun-gu, Seoul, Korea 120-752. E-mail address: juen@yuhs.ac.0099-2399/$0 - see front matter

Copyright ª 2010 American Association of Endodontists.doi:10.1016/j.joen.2010.03.031

1086 Kim et al.

Although the precise mechanisms and outcomes are unknown, there have been anincreasing number of reports showing that the regeneration/revascularization of

nonvital immature permanent teeth might be another treatment option for restoringroot development and apical closure (1–6). Disinfection of the root canal system isconsidered to be one of the very important procedures of this type of treatment.Several authors have used a triple antibiotic mixture (1, 2, 4), which has beenextensively investigated by Japanese researchers for disinfection (7, 8). This tripleantibiotic mixture consists of ciprofloxacin, metronidazole, and minocycline. Thiscombination’s effectiveness was also proven in the animal study (9). However, thedisadvantages of this mixture are not well-known. Among the components of themixture, minocycline, a derivative of tetracycline, can induce tooth discoloration afterlong-term oral use (10–13). Kim et al (14) suggested that Ledermix (Haupt PharmaGmbH, Wolfratshausen, Germany) paste introduced in the canal might cause discolor-ation of teeth, and that such effects might be due to the demeclocycline in the Ledermixpaste. However, there has been little concern about the effects of intracanal antibiotictherapy, including minocycline, causing tooth discoloration. The aim of this article wasto present a coronal discoloration after triple antibiotic therapy in an immature tooth.Additional objectives were to (1) investigate the possible cause of the discolorationand (2) assess the performance of a dentin bonding agent in the prevention of toothdiscoloration.

Case ReportA 7-year-old girl was referred to the Department of Conservative Dentistry of Gang-

nam Severance Hospital for an evaluation of the right maxillary central incisor. Thepatient had experienced a traumatic injury as a result of falling down the stairs 1 dayprior. Clinical examination revealed that tooth #8 was fractured in the dentin withoutpulpal exposure. The tooth was sensitive to percussion but reacted normally to coldstimulation. On the day of the visit, the fractured tooth was restored with a light-curing resin-modified glass ionomer (Fig. 1). At the 3-month recall, the patient wasasymptomatic and had no abnormal clinical manifestations. The glass ionomer fillingwas replaced with composite resin by using an etch-and-rinse dentin bonding system.

The patient returned 8 months later, reporting a history of spontaneous pain intooth #8. Tooth #8 had no response to a pulpal vitality test and was sensitive to percus-sion and palpation. Periradicular radiographic examination revealed that tooth #8 hada periradicular radiolucency (Fig. 2). A diagnosis of pulp necrosis with symptomaticapical periodontitis was made for tooth #8. The tooth was isolated with a rubberdam. The access cavity was prepared without local anesthesia because we thoughtthe tooth was nonvital. The patient did not report any painful sensation until the filereached the apex. Pus and necrotic tissue stump were obtained from the file. A revas-cularization technique was attempted to expect further root development and apicalclosure of tooth #8, as described elsewhere (4).

Copious canal irrigation with 3% sodium hypochlorite was performed. Ciproflox-acin (Cycin; Ildong Pharmaceutical Co, Ansan, Korea), metronidazole (Flasinyl; CJCheilJedang, Hwaseong, Korea), and minocycline (Minocin; SK Chemicals, Osan, Ko-rea) were ground into a powder and mixed with distilled water to a creamy consistency.This antibiotic mixture was applied to the canal by using a lentulo spiral. The accesscavity was sealed with Caviton (GC, Aichi, Japan). The patient did not show up at thenext appointment and then returned in 6 weeks, complaining of a dark discoloration

JOE — Volume 36, Number 6, June 2010

Figure 1. Radiographic image showing an incompletely developed apex of thecentral incisors. The fractured tooth (tooth #8) was restored with light-curingresin-modified glass ionomer.

Figure 2. Radiographic image showing periapical radiolucency associatedwith the apex of tooth #8 at the 11-month follow-up.

Figure 3. Photograph of the right maxillary central incisor showing discolor-ation.

Case Report/Clinical Techniques

JOE — Volume 36, Number 6, June 2010 Tooth Discoloration

of tooth #8 (Fig. 3). The tooth was asymptomatic to percussion andpalpation. Blue-grayish discoloration of coronal tooth structure wasnoted. Walking bleaching was planned to improve the esthetic problemafter the root filling was completed. After removing the antibioticmixture from the tooth, the root canal was flushed with sterile salineand 3% sodium hypochlorite. Paper points were used to evoke freshbleeding within the canal, and bleeding was left for 10 minutes to allowclotting. Mineral trioxide aggregate (MTA) was mixed with distilledwater and filled over the blood clot to a thickness of 4 mm (Fig. 4).

Figure 4. Radiograph presenting the placement of MTA.

of Immature Permanent Incisor Associated with Triple Antibiotic Therapy 1087

Figure 5. Appearance after 3 consecutive walking bleach treatments illus-trating the considerable whitening. The bluish-white tooth shade is still shownin tooth #8 compared with the adjacent teeth

Figure 6. Radiographic image and clinical picture at the 8-month recall.Continued root development was observed.

Case Report/Clinical Techniques

Most procedures were performed under a dental operating micro-scope. One week later, the patient returned as asymptomatic, and settingof the MTA was confirmed. After obtaining a cervical seal with a resin-modified glass ionomer base, a bleaching agent, sodium perboratemixed with distilled water, was set in place and changed twice witha 7-day interval. Because the cervical dark shade had not improved afterthe first trial of bleaching, a cervical seal was re-prepared for the place-ment of a bleaching agent more apically by using a microscope. After 3walking bleaching procedures, the cervical shade had improved.However, the tooth did not return to its original shade; it appeared

Figure 7. Photographs of the tooth sections at the time intervals after antibiotics application. Only triple antibiotic pastes and minocycline discolored the sections.(A) Mixture of triple antibiotic pastes (B) ciprofloxacin (Cycin), (C) metronidazole (Flasinyl), and (D) minocycline (Minocin).

1088 Kim et al. JOE — Volume 36, Number 6, June 2010

TABLE 1. Mean Change in the CIE Lab Parameters between Baseline Examination and 14 Days after Introduction of Minocycline (mean � standard deviation)

Group N DL* Da* Db* DE*

1 (no adhesive) 10 �19.9 � 6.3a �2.8 � 1.2d 1.9 � 2.9f 20.4 � 6.3h

2 (adhesive) 10 �13.3 � 3.2b �0.3 � 0.9e 2.6 � 2.4f 13.7 � 3.4i

3 (control) 8 �0.4 � 2.4c �0.3 � 0.6e �1.3 � 2.6g 2.9 � 2.4j

Different superscripts denote statistical significance (P < .05).

Case Report/Clinical Techniques

bluish-white compared with the adjacent teeth, although the patient wassatisfied with the tooth whitening (Fig. 5). Two weeks later, the accesscavity was filled with a bonded composite resin restoration.

The patient was recalled 8 months later. She was asymptomatic,and the tooth was clinically normal. The radiograph showed the reso-lution of the radiolucency, with the evidence of continued apical closure(Fig. 6).

Experimental StudyDetermination of Cause of the Discoloration

This experiment examined which antibiotics cause tooth discol-oration. Freshly extracted human maxillary and mandibular anteriorteeth were collected without any information of the donors. The teethwere sectioned 3 mm above and 5 mm below the cementoenameljunction by using water-cooled diamond points. Endodontic accesscavities were prepared, and the root canals of the tooth sectionswere enlarged by using an Endo-Z bur and Gates-Glidden burs, fol-lowed by copious canal irrigation with 17% ethylenediaminetetraace-tic acid and 6.0% NaOCl to remove the smear layer. The specimenswere divided randomly into 4 groups. In group 1, triple antibioticmixtures were applied to the root canals of 5 specimens by usinga lentulo spiral, mimicking the clinical procedure. In groups 2, 3,and 4, ciprofloxacin, metronidazole, and minocycline pastes werefilled in 5 canals, respectively. The specimens were then stored inthe dark.

Effect of Dentin Sealing with Dentin Bonding AgentThis experiment examined whether a current dentin bonding

agent would prevent or reduce the discoloration. Twenty-eight extractedhuman maxillary or mandibular incisors were used. The canal of eachtooth was enlarged as in the first experiment and then divided randomlyinto 3 groups as follows: group 1 (10 teeth), minocyclin paste wasapplied directly in the root canal as in the first experiment (no adhe-sive); group 2 (10 teeth), dentin bonding adhesive (AdheSE; Ivoclar Vi-vadent, Schaan, Liechtenstein) was applied into the root canal beforethe introduction of the antibiotic (adhesive); and group 3 (8 teeth,

Figure 8. Mean change in L* values at each time interval (DL*).

JOE — Volume 36, Number 6, June 2010 Tooth Discoloration

control group), the canals were empty (no antibiotics). In group 2,the bonding layers were polymerized for 20 seconds by using a halogencuring light, and minocycline pastes were applied to the canals 10minutes later. A 3-mm-diameter spot was made at the center of thecrown surface in each sample. The specimens were then stored inthe dark for 2 weeks.

The color changes were measured with a colorimeter, Chroma-meter CR-321 (Konica Minolta Sensing Inc, Tokyo, Japan), and thesamples were mounted on a specific sample positioning system forconsistent assessments. The colorimeter was calibrated at each timeinterval, and the tooth colors were measured before the endodontictreatment (baseline) and then once a day for 14 days. The recordsby the colorimeter were reported in terms of the CIE L*a*b* system.

These 3 parameters for measuring the color changes (DL, Da,Db) were calculated by substracting the baseline values from the valuestaken at each time. In addition, the DE* values, which are used to assessthe color differences between 2 samples, were obtained by using thefollowing equation:

DE� ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiðL �2 �L�1Þ2þða �2 �a�1Þ2þðb �2 �b�1Þ2

q:

One-way analysis of variance was used to analyze the change in theCIE Lab parameters by using SPSS 12.0 analytic software (SPSS Inc, Chi-cago, IL), which confirmed a normal data distribution. Scheffe testswere used for a post hoc comparison. A P value <.05 was consideredsignificant.

ResultsDetermination of Cause of the Discoloration

One day after applying the triple antibiotic mixture, a dark green-brown shade began to appear in the samples. The discoloration becamedarker with time (Fig. 7A). The discoloration was similar to the darkshade in our clinical case. Among groups 2, 3, and 4, only the group4 (minocycline) specimens showed discoloration in the same manneras the triple antibiotic specimens (Fig. 7).

of Immature Permanent Incisor Associated with Triple Antibiotic Therapy 1089

Figure 9. Mean change in a* values at each time interval (Da*).Figure 11. Mean change in E* values at each time interval (DE*).

Case Report/Clinical Techniques

Effect of Dentin Sealing with Dentin Bonding AgentTable 1 lists the changes in the CIE Lab parameters before applying

the medication and 14 days after medication. The mean changes foreach parameter in the different experimental periods are depicted inFigs. 8–11. The changes in brightness DL* were significantly differentin the 3 groups (P < .05). Group 1 showed the greatest change,followed by group 2. Significant color changes along the red-greenaxis Da* were observed in group 1 (P < .05). The dentin bonding agentprevented the color change along this axis significantly (P < .05). Thecolor changes Db*, which determine the degree of yellowness and blue-ness, in the medicated groups were also significantly different fromthose of the control group (P < .05). All medicated teeth showed signif-icant color differences (DE*) compared with the control teeth (P <.05). However, the dentin bonding agent reduced the discolorationsignificantly (P < .05).

DiscussionThese results showed that among the 3 antibiotics, minocycline

was the only cause of tooth discoloration. Minocycline is a semisyntheticderivative of tetracycline and is effective against gram-positive andgram-negative bacteria (9). It binds to calcium ions via chelation toform an insoluble complex. Hence, the minocycline incorporatedinto the tooth matrix causes the discoloration (15). Therefore, mino-cycline cannot stain the tooth matrix unless it comes in contact withthe coronal dentin. On the basis of this hypothesis, Reynolds et al(16) recommended the use of a special device during the introductionof triple antibiotic pastes to prevent coronal discoloration. However,this procedure requires special appliance such as a Root CanalProjector. Dentin bonding systems are more familiar to dentists and

Figure 10. Mean change in b* values at each time interval (Db*).

1090 Kim et al.

are easy to apply and remove. Accordingly, this study examined theperformance of a dentin bonding agent in the prevention of toothdiscoloration. An assessment of the color change by the naked eye ina pilot study showed that the bonding agent was effective in preventingdiscoloration (Fig. 12). Therefore, the color changes were evaluatedmore precisely and objectively by using a colorimeter. However, theresults were somewhat disappointing. The L* value stands for bright-ness (17). Groups 1 and 2 had a negative DL* value (Table 1), whichmeans that the teeth became darker. The results showed that the dentinbonding agent can reduce the change in darkness of the teeth butcannot prevent it. The a* value indicates red on the positive axis andgreen on the negative (17–19). Therefore, the negative Da* valuesin group 1 (Table 1) indicate that the samples showed a greenishhue, and the dentin bonding agent was effective in preventing thiskind of color change. The b* value represents yellow on the positiveaxis and blue on the negative (17–19). The positive Db* values ingroups 1 and 2 (Table 1) indicate that the samples had becameyellowish. These changes might be due to the color of minocycline itself(yellow). If this were true, it is unlikely that a transparent bonding agentwill block the yellowish color emitted from the antibiotics completely.The overall changes in these 3 color coordinates can be expressed interms of DE. DE* is used to determine whether the changes in the over-all shade are perceptible by a human observer (18). The resultsshowed that the dentin bonding agent reduced the overall color changebut did not prevent it. Because only 1 product among the many dentinbonding agents available was used, we could conclude that AdheSE,

Figure 12. Photographs of the tooth sections at the time intervals after theapplication of minocycline (Minocin). (A) Positive control (no adhesive);(B) the dentin bonding adhesive (AdheSE) was applied into the root canalbefore antibiotic introduction. The bonding agent seems to be very effectivein preventing the discoloration. However, the assessment by the colorimetershowed that the dentin bonding agent reduced the overall color change butdid not prevent it.

JOE — Volume 36, Number 6, June 2010

Case Report/Clinical Techniques

which is a light-curing, self-etching, 2-component adhesive dentinbonding system, cannot prevent minocycline-induced discoloration.

Reducing the application time of the pastes might also preventdiscoloration associated with use of minocycline. Experimental studiesof triple antibiotic therapy reported that 24- to 48-hour application issufficient for effective disinfection of infected root dentin (7, 8).However, it is not likely that this short application period is enoughto prevent the discoloration on the basis of the results of the presentstudy, wherein discoloration began to appear 24 hours afterapplication (Fig. 7).

It is well-known that the discoloration by the tetracycline family isthought to be a photoinitiated reaction (20). Kim et al (14) also sug-gested that the effect of sunlight was important in the discoloration ofthe teeth by the Ledermix paste. However, the tooth samples in ourexperiment became dark after minocycline treatment despite a lackof sunlight. Therefore, further investigations are needed to clarify theeffect of sunlight on minocycline-induced discoloration.

Sato et al (7) suggested that minocycline should be used only forlimited periods and attempted to find substitutes for minocycline in thetriple antibiotic paste as a result of the risk of tooth discoloration. Theyreported that cefaclor and fosfomycin are possible alternatives for min-ocycline in terms of their antibiotic effectiveness. Further clinical studiesshould be carried out to demonstrate the efficacy of these medicationsin the root canal.

Another issue is whether discoloration caused by minocycline hasthe same prognosis after bleaching as trauma- or necrosis-induceddiscoloration. There are few rigorous scientifically based studies onthe prognosis of tooth whitening, despite the many clinical reports.Brown (21) suggested that the discoloration caused by root canal medi-cation has a dubious prognosis. In our case, the cervical shade was unsat-isfactory, despite 3 consecutive walking bleach treatments. However, thisdoes not mean that the discoloration caused by minocycline has a poorprognosis because the cervical barrier might prevent the bleaching pastefrom entering the cervical dentinal tubules in our case.

In conclusion, minocycline should be limited to the root canalbecause of the potential risk of tooth discoloration, despite the biologicsuccess. Suitable techniques for preventing contact with the coronaldentin can be investigated and suggested for the safe use of minocycline.

AcknowledgmentsThe authors thank Dr Sin Yeon Cho for statistical analysis

support.

JOE — Volume 36, Number 6, June 2010 Tooth Discoloration

References1. Iwaya SI, Ikawa M, Kubota M. Revascularization of an immature permanent tooth

with apical periodontitis and sinus tract. Dent Traumatol 2001;17:185–7.2. Banchs F, Trope M. Revascularization of immature permanent teeth with apical pe-

riodontitis: new treatment protocol? J Endod 2004;30:196–200.3. Chueh LH, Huang GT. Immature teeth with periradicular periodontitis or abscess

undergoing apexogenesis: a paradigm shift. J Endod 2006;32:1205–13.4. Jung IY, Lee SJ, Hargreaves KM. Biologically based treatment of immature perma-

nent teeth with pulpal necrosis: a case series. J Endod 2008;34:876–87.5. Bose R, Nummikoski P, Hargreaves K. A retrospective evaluation of radiographic

outcomes in immature teeth with necrotic root canal systems treated with regener-ative endodontic procedures. J Endod 2009;35:1343–9.

6. Chueh LH, Ho YC, Kuo TC, Lai WH, Chen YH, Chiang CP. Regenerative endodontictreatment for necrotic immature permanent teeth. J Endod 2009;35:160–4.

7. Sato I, Ando-Kurihara N, Kota K, Iwaku M, Hoshino E. Sterilization of infected root-canal dentine by topical application of a mixture of ciprofloxacin, metronidazoleand minocycline in situ. Int Endod J 1996;29:118–24.

8. Hoshino E, Kurihara-Ando N, Sato I, et al. In-vitro antibacterial susceptibility ofbacteria taken from infected root dentine to a mixture of ciprofloxacin, metronida-zole and minocycline. Int Endod J 1996;29:125–30.

9. Windley W 3rd, Teixeira F, Levin L, Sigurdsson A, Trope M. Disinfection of immatureteeth with a triple antibiotic paste. J Endod 2005;31:439–43.

10. Cheek CC, Heymann HO. Dental and oral discolorations associated with minocyclineand other tetracycline analogs. J Esthet Dent 1999;11:43–8.

11. Dodd MA, Dole EJ, Troutman WG, Bennahum DA. Minocycline-associated toothstaining. Ann Pharmacother 1998;32:887–9.

12. McKenna BE, Lamey PJ, Kennedy JG, Bateson J. Minocycline-induced staining of theadult permanent dentition: a review of the literature and report of a case. DentUpdate 1999;26:160–2.

13. Tredwin CJ, Scully C, Bagan-Sebastian JV. Drug-induced disorders of teeth. J DentRes 2005;84:596–602.

14. Kim ST, Abbott PV, McGinley P. The effects of Ledermix paste on discolouration ofmature teeth. Int Endod J 2000;33:227–32.

15. Tanase S, Tsuchiya H, Yao J, Ohmoto S, Takagi N, Yoshida S. Reversed-phase ion-pair chromatographic analysis of tetracycline antibiotics: application to discoloredteeth. J Chromatogr B Biomed Sci Appl 1998;706:279–85.

16. Reynolds K, Johnson JD, Cohenca N. Pulp revascularization of necrotic bilateralbicuspids using a modified novel technique to eliminate potential coronal discolou-ration: a case report. Int Endod J 2009;42:84–92.

17. Bizhang M, Chun YH, Damerau K, Singh P, Raab WH, Zimmer S. Comparative clinicalstudy of the effectiveness of three different bleaching methods. Oper Dent 2009;34:635–41.

18. Karaagaclioglu L, Yilmaz B. Influence of cement shade and water storage on the finalcolor of leucite-reinforced ceramics. Oper Dent 2008;33:386–91.

19. Martin-Biedma B, Gonzalez-Gonzalez T, Lopes M, et al. Colorimeter and scanningelectron microscopy analysis of teeth submitted to internal bleaching. J Endod2010;36:334–7.

20. Sheets CG, Paquette JM. Tooth-whitening modalities for pulpless and discolored teeth.In: Cohen S, Burns RC, eds. Pathways of the pulp. 8th ed. St Louis: Mosby; 2002:749–64.

21. Brown G. Factors influencing successful bleaching of the discolored root-filledtooth. Oral Surg Oral Med Oral Pathol 1965;20:238–44.

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