Case Report/Clinical Techniques

Management of Cyst-like Periapical Lesionsby Orthograde Decompression and Long-termCalcium Hydroxide/Chlorhexidine IntracanalDressing: A Case Series

Suelleng Maria Cunha Santos Soares, PhD, MD, DDS,* Manoel Brito-J�unior, PhD, MD, DDS,†

Fl�avia Kelly de Souza,* Eduardo Von Zastrow,* Carla Oliveira da Cunha,*Frank Ferreira Silveira, PhD, MD, DDS,‡ Eduardo Nunes, PhD, MD, DDS,‡

Carlos Augusto Santos C�esar, PhD, MD, DDS,* Jos�e Cristiano Ramos Gl�oria, PhD, MD, DDS,*and Janir Alves Soares, PhD, MD, DDS*

Abstract

Significance

The control of root canal infection and periapicalexudation has pivotal importance in nonsurgicalmanagement of large cyst-like periapical lesions.The apical patency or periapical overinstrumenta-tion followedby intracanalpuncturepromotesperi-apical decompression. In addition, the use ofchlorhexidine/calcium hydroxide intracanal dres-sing after chemomechanical preparation providessupplementary antisepsis associated at stimula-tion of periapical repair. In this case series the peri-odic renewal of this intracanal dressing did provideprogressive clinical and radiographic resolution oflarge cyst-like periapical lesions.

Cyst-like periapical lesions should be treated initially withconservative nonsurgical procedures. In this case series,we describe the clinical and radiographic outcomes oflarge cyst-like lesions that were treated by orthogradedecompression and long-term intracanal use of calciumhydroxide [Ca(OH)2] mixed with 2% chlorhexidine digluc-onate. Ten cases of cyst-like periapical lesions involving15 teeth from 10 patients were selected. Maximal radio-graphic diameters of the lesions ranged from 11 to28 mm. Nonsurgical procedures were performed,including apical patency, orthograde puncture of cyst-like exudates, chemomechanical preparation, and place-ment of intracanal Ca(OH)2/CHX dressings, which wereperiodically replaced during 6–10months. The root canalswere then filled with gutta-percha and sealer. The follow-up periods ranged from 6 to 24 months, and the outcomewas classified as healed, healing, or failure. Nine lesionsdrained copious exudates after canal patency. One lesiononly drained bloody serous exudate after periapical over-instrumentation. In 9 patients, intracanal exudationceased in the first follow-up visit. At the 24-monthfollow-up, 6 lesions (60.0%) had healed, and 3 lesions(30.0%) were healing, with the corresponding patientsbeing without clinical signs or symptoms. The case oftreatment failure was submitted to surgical treatment.Microscopically, the lesion appeared to be an apicalcyst with exuberant extraradicular bacterial biofilmsattached to the sectioned root apex. This case series sup-ports the use of nonsurgical methods to resolve largercyst-like periapical lesions. (J Endod 2016;42:1135–1141)

From the *Department of Dentistry, Federal University of Waleysros, Montes Claros; and ‡Department of Dentistry, Pontificial Catho

Address requests for reprints to Dr Janir Alves Soares, Federal UMG, Brazil. E-mail address: janirsoares@msn.com0099-2399/$ - see front matter

Published by Elsevier Inc. on behalf of American Association ofhttp://dx.doi.org/10.1016/j.joen.2016.04.021

JOE — Volume 42, Number 7, July 2016

Key WordsCalcium hydroxide, large cyst-like periapical lesions, nonsurgical endodontic treatment,periapical healing, regression of apical cysts

Inflammatory cyst-likeperiapical lesions areoften associated with intra-radicular or extraradicularinfections (1). Such lesionsmay undergo slow asymp-tomatic evolution and attainremarkable radiographicdimensions (2–4). Epi-demiologically, apical cystsrepresent 6%–55% of allperiapical lesions (5–7),sometimes with prevalencesimilar to that ofperiapical granulomas (8,9). Elevated rates of apical

periodontitis healing (80%–95%) after conservative root canal treatment suggest thatan apical cyst does not require surgical intervention (1, 3).

In this scenario, nonsurgical resolution of cyst-like lesions can be achievedthrough orthograde lesion decompression and control of the intracanal exudation(2–4, 10, 11). Moreover, long-term calcium hydroxide [Ca(OH)2] therapy has beenrecommended (3, 4) because of antimicrobial, antiexudative, and reparativeproperties of this material (12, 13).

Ca(OH)2 can be mixed with inert vehicles or active substances such as chlorhex-idine (CHX) (12, 14), which has a broad spectrum of activity against several endodonticpathogens (14–16). Favorable periapical healing outcomes have been achieved fornecrotic teeth with apical periodontitis by using Ca(OH)2/CHX intracanal dressings(17, 18). Orthograde treatment of cyst-like lesions should aim to overcome the

Jequitinhonha and Mucuri, Diamantina; †Department of Dentistry, State University of Montes Cla-lic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.niversity of Waleys Jequitinhonha and Mucuri, Campi I, Rua da Gl�oria 187, 39100-00 Diamantina,

Endodontists.

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Case Report/Clinical Techniques

persistent intracanal exudation (3, 4), which is often caused byresistance infections (1, 19). Thus, intracanal use of Ca(OH)2/CHXcould be advantageous in these cases.

Nevertheless, limited clinical information is available regarding the useof intracanal Ca(OH)2/CHX as an adjunct to nonsurgical treatment of cyst-like lesions. In this case series study, we describe the clinical and radio-graphic outcomes of large cyst-like periapical lesions treated by orthogradedecompression and long-term Ca(OH)2/CHX intracanal dressings.

Materials and MethodsPatient Selection

This study was approved (protocol #036/155) by the EthicsResearch Committee of the Federal University of Waleys Jequitinhonhaand Mucuri, Brazil. Treatments were performed between February2009 and December 2013. We selected 10 cases of periapical lesionsshowing clinical and radiographic features compatible with large cyst-like lesions (3). Selected cases involved 15 teeth from 10 patients (6women, 4 men; mean patient age, 23.4 � 5.6 years) who had beenreferred to the endodontic clinic of our university. All patients gave theirwritten informed consent before participating. Patients’ medical and fam-ily histories were noncontributory. All teeth presented negative responsesto cold (Endo-Ice; The Hygenic Corp, Akron, OH) and electric (VitalityScanner; Analytic Technology, Glendora, CA) pulp sensibility tests.

Preoperative and postoperative radiographs were taken by usingthe paralleling cone technique with an intraoral radiographic film hold-er (Maquira Ind�ustria de Produtos Odontol�ogicos Ltda, Maring�a, PR,Brazil) and ultra-speed film (Eastman Kodak Co, Rochester, NY). Filmswere processed by the time-temperature method. The diameter of theapical radiolucency was measured on each preoperative radiographwith a digital caliper (Mitutoyo Corp, Tokyo, Japan) by using a light-box with variable illumination. Maximal radiographic diameters ofthe lesions ranged from11 to 28mm. Detailed clinical and radiographicdata are summarized in Table 1.

Nonsurgical Treatment ProtocolsDuring endodontic treatment, strict antiseptic conditions were

observed. Tooth, clamp, and surrounding parts of the rubber dam

TABLE 1. Clinical/Radiographic Aspects and Treatment Outcomes of Large Cyst-lik

Case/patient Tooth

Clinical andradiographic aspects

Maximal diameter oradiolucency

1 9 ‡, §, k, # 112 7 †, ‡, # 133 9 †, ‡, # 134 19 ‡, § 155 7 †, ‡, # 176 7 †, ‡, # 207 7, 8 †, ‡, k, ¶, # 218 22, 23, 24, 25 †, ‡, # 229 7 *, †, ‡, #, ** 2410 9, 10 *, †, ‡, ¶, #, †† 28

*Slight facial asymmetry.†Tooth crowding.‡Accentuated swelling of the cortical alveolar bone.§Sinus tract.kCalcification/pulp nodule.¶Previous endodontic treatment.#Exudation after apical patency.

**Exudation after periapical overinstrumentation.††Supplementary surgery.‡‡After surgery.

1136 Santos Soares et al.

were cleaned with 30% hydrogen peroxide, swabbed with 5% iodinetincture, and later swabbed with 5% sodium thiosulfate solution. Afterproper coronal access, the pulp chamber and root canals were irrigatedwith 5.25% sodium hypochlorite (NaOCl) solution (Lenza Farmaceu-tica Ltda, Belo Horizonte, MG, Brazil) through a syringe with 30-gauge needle (NaviTip; Ultradent, South Jordan, UT). Preflaring wasperformed by using #15 to #40 K-files followed by #2 to #5 Gates-Glidden drills (Dentsply Maillefer, Ballaigues, Switzerland).

After apical patency with small K-file sizes, lesion decompressionwas completed through intracanal puncture under gentle aspirationwith a Luer-Lock syringe and a 30/06 needle blocking the access cavitywith a wet cotton pellet. Periapical overinstrumentation with #20 K-filewas performed beyond the radiographic apex in a maximum extensionof 5 mm when no drainage was observed after canal patency. Once theexudation was controlled, the apical canal third was chemomechani-cally prepared by the step-back technique by using K files and 5.25%NaOCl. Master apical file sizes for maxillary incisors (#45 to #55),mandibular incisors (#35 to #45), and the mandibular molar (#30to #40) were set at 3 sizes larger than the first file binding at the workinglength. The smear layer was removed with 17% EDTA solution (LenzaFarmaceutica) for 3 minutes, and the root canal was dried with absor-bent paper points.

Ca(OH)2 was mixed with 2% CHX digluconate solution (FGM Pro-dutos Odontol�ogicos, Joinville, SC, Brazil) at a ratio of 0.9 g/mL toobtain a toothpaste-like consistency (4, 13, 15). Intracanal dressingswere placed by using a lentulo spiral. The access cavity was sealedwith a temporary restorative material (IRM; Dentsply, Petr�opolis, RJ,Brazil). Ca(OH)2 pastes were replaced every 2–4 weeks (17) for thenext 3–10 months (mean time interval, 6.2 months). Instrumentationby using the master apical and patency K-files with copious irrigationof 5.25% NaOCl was performed to remove intracanal dressings.

The tooth to be root-filled should be asymptomatic and without in-tracanal exudation. Thus, a 17% EDTA solution was used for 3 minutes,followed by 5.25% NaOCl. Root canals were dried with absorbent paperpoints. They were filled by thermomechanical compaction by using gutta-percha cones (Dentsply) and a zinc oxide–eugenol–based sealer (PulpCanal Sealer; Kerr Sybron Dental Specialties, Glendora, CA). Afterward,the coronal restoration was placed with a permanent material.

e Periapical Lesions

f periapical(mm)

Follow-up periods (mo)

OutcomeIntracanal dressing After root filling

4 18 Healed6 6 Healing8 12 Healed

10 24 Healed8 7 Healing

10 24 Healed6 12 Healing8 6 Healed6 12 Healed4 24 Healed‡‡

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Case Report/Clinical Techniques

Outcome AssessmentThe follow-up period ranged from 6 to 24 months. Two experi-

enced endodontists used clinical and radiographic criteria to categorizeeach tooth as healed (absence of periapical radiolucency and absenceof signs/symptoms), healing (advanced reduction of periapical radiolu-cency size and absence of signs/symptoms), or treatment failure (pres-ence of pain, swelling, a sinus tract, persistent intracanal exudation, andunchanged periapical radiolucency) (3, 20). Once identified as a casefailure, further surgical treatments including marsupialization,cystectomy, and apicoectomy were performed.

ResultsAnterior teeth comprised 93.3% of sample teeth. Traumatic in-

juries (70%) were the predominant etiologic factor of cyst-like lesions,followed by caries (20%) and restoration loss (10%). Nine lesionsdrained large amounts of yellow serous exudates after canal patency,with 1–6mL of exudates being recovered through orthograde puncture.In 1 case, the intracanal drainage of yellow or bloody serous exudateonly occurred after periapical overinstrumentation.

In 9 patients, exudation ceased in the first follow-up visit. Amongthese 9 lesions, 6 (60.0%) were categorized as healed and 3 (30.0%) ashealing (Table 1). These 9 patients were without clinical signs/symp-toms at 24-month follow-up. Figures 1 and 2 (healed teeth) andFigure 3 (healing tooth) show some representative cases.

One case was categorized as treatment failure. This case evidencedlarge maxillary radiolucencies associated with teeth #9 and #10

Figure 1. Case classified as healed. (A) Clinical aspects of accentuated swelling ofperiapical radiolucency associated with tooth #7. (C) K-file placed on apical patency(E) Healed periapical tissues at 12-month follow-up visit.

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(Fig. 4A). Endodontic retreatment of tooth #9 was performed, followedby endodontic treatment of tooth #10, in which continuous purulent in-tracanal drainage persisted during a 4-month period. Therefore, surgi-cal marsupialization was performed. After 6 months, the root canals ofteeth #9 and #10 were filled, followed by cystectomy (Fig. 4B) and api-coectomy of tooth #10. Histopathologic findings (hematoxylin-eosinstaining) of the lesion showed a continuous epithelial lining and fibrouscapsule containing chronic inflammatory infiltrate (Fig. 4C), withdisperse cholesterol crystals (Fig. 4D). Scanning electronic micro-scopic analysis of the 2-mm sectioned root apex revealed exuberantbacterial biofilms with cocci forms immersed in an amorphous material(Fig. 4E). Radiographically (Fig. 4F), the periapical tissues werecompletely healed at 24-month follow-up.

DiscussionSeveral decades ago,many pathologists andmaxillofacial surgeons

considered that apical cysts did not have a favorable response to con-servative endodontic treatment alone and that they required periapicalcurettage (5, 21). Nowadays, the endodontic community stronglybelieves that large cyst-like periapical lesions and apical true cystsare most likely not able to heal through conservative root canal treat-ment alone (5, 6, 21).

For many years, periapical radiolucencies with a size greater than10 mm were interpreted as probable cystic lesions (21), although thedefinitive diagnosis could only be confirmed by biopsy (6, 22). In 1study, histopathologic analysis found that 6% of serially sectioned

buccal cortical bone (arrow) and crowding of teeth #6, #7, and #8. (B) Largelength. (D) Orthograde puncture of cyst-like lesion resulted in exudate (6 mL).

Endodontic Treatment of Cyst-like Lesions 1137

Figure 2. Case classified as healed. (A) Large periapical radiolucency associated with tooth #19. (B) K-files placed on apical patency length. (C) Orthogradepuncture of lesion resulted in bloody serous exudate. (D) Healed periapical tissues at 24-month follow-up visit.

Case Report/Clinical Techniques

periapical lesions were apical pocket cysts and 9% were true cysts (6).The relative discontinuity between a true cyst and the apical foramenmade the cyst self-sustaining (6, 24, 25), thereby impairing a positiveresponse to root canal disinfection procedures (6, 7, 24, 25).However, apical pocket and true cysts are morphologically andimmunologically identical (26). Thus, if the intracanal infection wasto be controlled, the lesions might be able to heal (1, 3). This caseseries confirms the potential utility of nonsurgical treatmentprotocols for resolving large cyst-like periapical lesions.

In this study, the lesions drained yellow or blood serous exudatesduring apical patency or periapical overinstrumentation, approachesthat have been recommended previously for cyst-like lesions (3, 4,10, 22). Together with decompression, apical patency and periapical

Figure 3. Case classified as healing. (A) Large periapical cyst-like radiolucency asture of lesion resulted in bloody serous exudate. (D) Healing process of periapica

1138 Santos Soares et al.

overinstrumentation can be used to remove exudates, fluid, bacterialcolonies, and cholesterol crystals (1). Thus, intracanal puncture playsa pivotal role in the orthograde treatment protocol and promotescomfortable decompression of the lesion, in contrast to aspirationthrough the mucosa (27) or surgical procedures such as marsupializa-tion and enucleation (28). In addition, orthograde lesion decompres-sion may be facilitated by using the EndoVac System (Kerr Dental,Plymouth, MA) (11).

In most cases, teeth treated by intracanal puncture followed byroot canal preparation and intracanal dressings showed a progressivereduction in the amount of exudates. This result may be attributed to theantiseptic effect of the chemomechanical debridement, supplementedby the extended use of an intracanal Ca(OH)2-based paste (3, 4).

sociated with tooth #7. (B) K-file on the patency length. (C) Orthograde punc-l tissues at 6-month follow-up visit.

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Figure 4. Case classified as treatment failure, which was subsequently surgically resolved. (A) Occlusal radiograph showing large maxillary radiolucency. (B)Enucleation of remaining lesion 6 months after marsupialization procedure. (C) Histopathologic analysis showing cystic cavity and intense chronic inflammatoryinfiltrate. (D) Cystic structure containing cholesterol crystals. (E) Numerous cocci forms immersed in exuberant periapical biofilm. (F) Healed maxillary radio-lucency at 24-month follow-up visit (after surgery).

Case Report/Clinical Techniques

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This treatment approach differs from the conventional short-term use ofCa(OH)2 (29) for the endodontic management of apical periodontitis.Some studies found that the ex vivo long-term use of Ca(OH)2 was asso-ciated with weakening of the root canal dentin and increased tooth frac-ture risk (30, 31). However, in this study, we did not observe anyinstance of fracture among our cases at the end of the follow-up period.

During the intracanal dressing period, we found an evident reduc-tion in the radiolucency sizes of the cyst-like lesions in a mean time in-terval of approximately 6 months. This positive outcome was possiblydue to the alkaline pH of the intracanal Ca(OH)2 paste and the effectof the Ca++ and OH� ions on the periapical tissue and microorganisms(13). Prolonged Ca(OH)2 exposure maintains a high concentration ofOH� ions and inhibits bacterial enzymes, producing an antimicrobialeffect. The Ca++ ions, in turn, activate tissue enzymes such as alkalinephosphatase, thereby inducing a mineralizing action (12, 13, 29).In addition, Ca(OH)2 has been used to aid in the drying ofpersistently wet canals and neutralizing bacterial endotoxins (ie,lipopolysaccharides), thus reducing periapical inflammation (32, 33).

The rationale for the combined use of Ca(OH)2 and 2% CHX was toprovide an intracanal dressing that is more effective against drug-resistance microorganisms such as Enterococcus faecalis and Candidaalbicans (14, 34), which are often present in persistent periapicallesions of endodontic origin (19, 35). In vivo studies recommendedthat CHX can be used at a 2% concentration when applied as a rootcanal irrigant (36, 37). Replanted teeth whose root canals weredressed with CHX showed a significant reduction of inflammatoryresorption in the periodontal space by 4 weeks of treatment (38).

The broad antimicrobial activity of CHX is due to its cationic nature.CHX binds to negatively charged bacterial cell walls, leading to osmoticalterations that allow themolecule to penetrate the bacteria, causing toxiceffects and death (15, 16). Furthermore, CHX has substantivity, whichfavors its release and availability in the root canal dentin during anextended time (up to 90 days) (39, 40). The prolonged prevalence ofCHX ensures a residual bactericidal effect (15, 40) and preventsmicrobial colonization on the dentin surface (15, 16). Moreover, the2% CHX intracanal medication presents passive diffusion through theradicular dentin and reaches the outer surface, exerting antimicrobialaction in vitro (41). This evident diffusion could eliminate biofilmsattached to the radicular surface and indirectly control the periapicalexudation. When CHX is combined with Ca(OH)2, a precipitate of non-soluble CHX molecules is formed, which decreases the effectiveness ofthe CHX molecule (16). Conversely, CHX fragmentation producesdifferent by-products with antioxidant or pro-oxidant properties, whichhave high antimicrobial activity (15, 42). Despite the theoretical risk thatthese potentially cytotoxic by-products could cause periradicular tissuedamage (42, 43), no clinical evidence exists to support this adverseeffect. In this study, Ca(OH)2/CHX dressings confined to root canalspace were helpful in managing the exudative inflammatory cyst-like le-sions, as demonstrated by the reduction of clinical and radiographicpathologic signs in 90% of cases.

The refractory lesion (treatment failure case) continuouslydrained periapical inflammatory exudate, despite efforts to controlthe infection. Continuous exudation made the root canal debridementdifficult. Possible causes for treatment failure could include a resistantintracanal infection (19, 33, 35) or extraradicular infection (23), suchas bacterial biofilm formation (22, 44, 45). Scanning electronicmicroscopic images revealed an adhered and well-characterized extra-radicular biofilm with predominance of cocci forms. This observationsuggests that the bacterial microcolonies were related to the mainte-nance of the cyst-like lesion, as verified in previous reports (44, 45).

Poor patient compliance in terms of attending recall visits afterroot canal filling limited the follow-up of this study to 24 months. At

1140 Santos Soares et al.

this time, 60% of the cyst-like lesions had completely healed. Another30% of lesions evidenced advanced reduction of the periapical radio-lucency size, which is a predictive factor of successful endodontic out-comes up to a 1-year follow-up period (20). Thus, overall therapeuticoutcomes for large periapical cyst-like lesions were similar to those ofthe conventional endodontic treatments performed in teeth with apicalperiodontitis (17, 18, 46).

ConclusionLarge cyst-like periapical lesions had favorable clinical and radio-

graphic responses to nonsurgical endodontic treatment protocols.Although the treatment was extended for several months, the orthograderoot canal procedures presented in this case series may be a viable clin-ical alternative for solving cyst-like periapical lesions.

AcknowledgmentsThe authors are very grateful to Professors Maria Helena San-

tos and Flaviana Dornela Verli for carrying out the microscopicanalysis of case classified as failure treatment.

The authors deny any conflicts of interest related to this study.

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