2009;140;326-330 J Am Dent Assoc

Meydan and Nuray Tuloglu Emre Bodrumlu, Aysun Avsar, Ahmet Deniz

Ability of Resin-Based Root Canal Sealers?Can Radiotherapy Affect the Apical Sealing

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The goal of endodontictherapy is to cleanand disinfect the rootcanal system, as wellas to seal all portals

of entry to prevent reinfection.Consequently, root canal fillingmaterials should create a her-metic seal between the rootcanal system and the periapicaltissues. Apical leakage is acommon cause of clinical failureof root canal treatment.1,2 There-fore, microleakage studies of thesealing properties of endodonticmaterials are important.2

The number of patients withcancer has been increasingsteadily, and these patients mayrequire endodontic treatment.Radiotherapy can result in sideeffects on dental hard tissues.Researchers have observed asignificant reduction in dentinmicrohardness after irradia-tion.3,4 Moreover, irradiationmay affect the bond strengthbetween dental adhesives anddentin.5 Nevertheless, the effectsof radiotherapy on the sealingability of root canal fillingmaterials is not known.

Although a wide variety ofroot canal filling materials are

Dr. Bodrumlu is an assistant professor, Department of Operative Dentistry and Endodontics, Ondokuz Mayis University, Faculty of Dentistry, 55139 Kurupelit-Samsun, Turkey, e-mail “bodrumlu@omu.edu.tr”. Address reprint requests to Dr. Bodrumlu.Dr. Avsar is an assistant professor, Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayis University, Kurupelit-Samsun, Turkey.Dr. Meydan is an assistant professor, Department of Radiation Oncology, Ondokuz Mayis University, Kurupelit-Samsun, Turkey.Dr. Tuloglu is a research assistant, Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayis University, Kurupelit-Samsun, Turkey.

Can radiotherapy affect the apical sealingability of resin-based root canal sealers?Emre Bodrumlu, DDS, PhD; Aysun Avsar, DDS, PhD; Ahmet Deniz Meydan, DDS, PhD; Nuray Tuloglu, DDS

Background. The authors conducted a study to assess the influence of radio-therapy on the apical sealing ability of one recently introduced resin-basedroot canal sealer and two sealers that have been in use for several years. Methods. The authors divided 90 human maxillary anterior teeth into threegroups according to the type of root canal sealer used and, using lateral con-densation, obturated the roots with gutta-percha. They randomly divided allroots into two main groups according to the presence or absence of radio-therapy. For the groups that received irradiation, a dose of 60 gray was deliv-ered in fractions of 1.8 Gy per day, five days a week for seven weeks. Theauthors then performed the centrifuging dye penetration test to determineapical leakage for each specimen.Results. The authors compared the specimens in the groups that receivedradiotherapy after endodontic treatment with the specimens in the groupsthat did not undergo radiotherapy after endodontic treatment. They foundthat mean apical leakage was slightly higher in the radiotherapy groups, butthey did not observe any statistical difference between the groups (P > .05). Inthe groups that did not undergo radiotherapy, the mean apical leakage for thespecimens in the MM-Seal (MicroMega, Besançon, France [not marketed inthe United States]), AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany)and AH 26 (Dentsply DeTrey GmbH) groups was 2.52 ± 0.42 millimeters, 2.85 ± 0.52 mm and 3.73 ± 0.41 mm, respectively. In the groups that under-went radiotherapy, the mean apical leakage for the specimens in the MM-Seal, AH Plus and AH 26 groups was 2.72 ± 0.55 mm, 2.96 ± 0.47 mmand 3.93 ± 0.61 mm, respectively. Conclusion. The apical sealing ability of the resin-based root canal sealersdecreased slightly when radiotherapy was administered, although there wasno statistically significant difference.Clinical Implications. Clinicians can safely use a resin-based root canalsealer in patients receiving radiotherapy.Key Words. Resin-based root canal sealer; apical sealing ability; radiotherapy. JADA 2009;140(3):326-330.

A B S T R A C T

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available commercially, clinicians generallyprefer the resin-based root canal sealers. MM-Seal (MicroMega, Besançon, France [not mar-keted in the United States]) is a recently intro-duced resin-based root canal sealer. It iscomposed of epoxy polymer resin, ethylene glycolsalicylate, calcium phosphate, bismuth subcar-bonate and oxide components. However, to ourknowledge, no data are available concerning itssealing ability in comparison with that of othersealers. Moreover, no information has been pub-lished about the apical sealing ability of anysealer after radiotherapy.

The purpose of this study was to assess theinfluence of radiotherapy on the apical sealingability of one recently introduced resin-basedroot canal sealer and two resin-based root canalsealers that have been in use forseveral years: MM-Seal, AH 26(Dentsply DeTrey GmbH, Kon-stanz, Germany) and AH Plus(Dentsply DeTrey, GmbH).

MATERIALS AND METHODS

We selected 90 extracted humanmaxillary anterior teeth (plus sixteeth to be used as positive controlsand six teeth to be used as negativecontrols) with straight root canalsand fully mature root apexes,cleaned of extraneous soft tissueand calculus. We obtained ethical approval foruse of the extracted teeth from the ethical com-mittee at Ondokuz Mayis University, Kurupelit-Samsun, Turkey. One of us (N.T.) removed thecrowns at the cementoenamel junction with adiamond disk under water coolant. We stored theroots in deionized water until use.

Root canal preparation. Three of us (E.B.,A.A., N.T.) established the canal lengths visuallyby placing a size 15 K-file into each root canaluntil the tip of the file was visible at the tip ofthe apical foramen. We also measured theworking length radiographically and verified theapical patency. We established working lengths1.0 millimeter short of the apical foramen.

We instrumented the root canals to theworking length with a size 40 K-file by using astep-back technique. The coronal one-third of theroots were flared by using sizes 2, 3 and 4 Gates-Glidden burs and a slow-speed handpiece. Wethen irrigated the root canals with 10 millilitersof 5.25 percent sodium hypochlorite (NaOCl). We

removed the smear layer by washing the roots in10 mL of 17 percent ethylenediaminetetraaceticacid (Canal+, Septodont, Saint-Maur des Fossés,France) for five minutes, followed by 10 mL of5.25 percent NaOCl. Finally, we flushed the rootcanals with 3 mL of saline solution and driedthem with paper points.

Root canal obturation. We filled the rootswith gutta-percha by using the lateral condensa-tion technique with one of the following sealers (n = 30 per group): MM-Seal, AH 26 and AHPlus. We prepared the sealers according to themanufacturer’s instructions. After the obturationprocess, we removed excess gutta-percha andfilled the coronal access cavities with temporaryfilling material (Cavit G, 3M ESPE AG, Seefeld,Germany). We stored the specimens for three

weeks in 100 percent relativehumidity at 37°C to allow thesealers to set.

We randomly divided all 90 roots into two main groupsaccording to the presence orabsence of radiotherapy.

Radiotherapy. A radiationtherapist in the Department ofRadiation Oncology, Faculty ofMedicine, Ondokuz Mayis Univer-sity, delivered radiation to speci-mens. The therapist placed theroots, which were in resin blocks, in

a 25-square-centimeter plastic container duringirradiation. To administer a consistent radiationdose, the therapist replaced the saline solutiondaily to a level up to 0.5 cm above the resinblocks in the plastic container.3 The radiationtherapist administered radiation with Co-60 pho-tons (Theratron 780C, Theratronics Int., Car-rollton, Texas) by using a single anterior field.The source water surface distance was 80 cm.The therapist delivered a total dose of 60 gray infractions of 1.8 Gy/day (conventional fractiona-tion schedule) five days a week for seven weeks.After irradiation, we again stored both the irradi-ated and nonirradiated specimens in saline.

We then coated the roots completely with twolayers of nail varnish, except for the apical parts.In addition to the 90 roots, we used six roots asnegative controls (filled with gutta-percha andsealant) and six roots as positive controls (filledwith gutta-percha only). We removed the apexes

ABBREVIATION KEY. NaOCl: Sodium hypochlorite.

Although a widevariety of root canal

filling materials are available commercially,

clinicians generallyprefer the

resin-based rootcanal sealers.

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of the roots down to the root canal filling or, inthe case of the positive controls, to the point atwhich the canal lumen was visible. We coated thenegative controls completely withthe nail varnish. We immersed thespecimens in 5 percent methyleneblue dye and centrifuged them at30 gauss for four minutes. The finalstep was to wash the specimenswith water.

We grooved the roots longitudi-nally on both sides by using a dia-mond disk under water coolant. Wethen sectioned them carefully andexamined each half of each rootunder a stereomicroscope. Wemeasured the amount of leakagefrom each half, from the apex to the most coronalsection of the root canal to which the dye hadpenetrated. We then calculated the mean amountof leakage for each of the three sealers.

We used two-way analysis of variance to deter-mine statistically significant differences in apicalleakage between the groups. We performed mul-tiple comparisons by using the t test to isolateand compare statistically significant differences.We set the level of significance at α = .05.

RESULTS

The table shows the mean (± standard devia-tion) apical leakage values for specimens in allof the groups. The positive controls exhibiteddye penetration along the entire length of theroot canal, while the negative controls exhibitedno leakage.

When we compared the groups that receivedradiotherapy after root canal treatment with thegroups that did not receive radiotherapy afterroot canal treatment, the mean apical leakage

was slightly higher in the radiotherapygroups, but we did not observe any sta-tistical difference between the groups(P > .05).

For specimens that did not receiveradiotherapy, we found no statisticallysignificant differences between the AHPlus and MM-Seal groups (P > .05).However, the mean leakage values forthe AH Plus and MM-Seal groups weresignificantly different from the meanleakage value for the AH 26 group (P < .05).

For specimens that received radio-therapy, we found no statistically significant dif-ferences between the AH Plus and MM-Sealgroups (P > .05). However, the mean leakage

value for the AH 26 group was sta-tistically different from values forthe AH Plus and MM-Seal groups(P < .05).

DISCUSSION

Radiotherapy involves the deliveryof the correct radiation dose to thetumor mass. Absorbed radiationdoses are expressed in gray, thestandard unit.6 The wide range ofside effects of ionizing radiation tothe head and neck region are well-known, and they are related to

cumulative doses that vary from 50 to 70 Gydelivered across a five- to seven-week period.However, in our study, the specimens were irra-diated with 60 Gy delivered incrementally acrossseven weeks,3 which corresponds to a commonclinical procedure for adults receiving radiotherapy.

In this study, we stored the freshly extractedteeth in saline. This is a common procedure, as itdoes not influence the chemical and physicalproperties of human tooth structure.

Leakage studies. Leakage studies of thesealing properties of endodontic materials areimportant and relevant.7 Different methods havebeen used to evaluate the sealing efficacy ofendodontic cements. We used methylene blue asthe leakage marker because it has a low molec-ular weight and penetrates more deeply alongthe root canal filling.8,9

Air trapped in the root canal filling material orinside the root canal system may inhibit penetra-tion of the dye into the pores and gaps.10 Oliver

We used methyleneblue as the leakagemarker because it

has a low molecularweight and

penetrates moredeeply along the root

canal filling.

TABLE

Mean apical leakage for roots in experimental groups.SEALER MEAN (± SD*) APICAL LEAKAGE, mm† P VALUE

> .05

NonradiotherapyGroups

Radiotherapy Groups

MM-Seal‡ 2.52 ± 0.42 2.72 ± 0.55

AH Plus§ 2.85 ± 0.52 2.96 ± 0.47

AH 26§ 3.73 ± 0.41 3.93 ± 0.61

* SD: Standard deviation. † mm: Millimeters.‡ MM-Seal is manufactured by MicroMega, Besançon, France.§ AH Plus and AH 26 are manufactured by Dentsply DeTrey GmbH, Konstanz, Germany.

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and Abbott10 stated that after centrifugation at3,000 revolutions per minute for five minutes,dye penetration was 91.7 percent, while dye pen-etration via passive immersion was 20.7 percent.For this reason, these authors10 recommendeduse of active dye penetration tests, wherebytrapped air is removed under a vacuum or dyepenetration is performed under high pressure.We used centrifugation in this study.

A wide variety of root canal sealers are avail-able commercially. Among the resin-basedsealers, the sealing properties of AH Plus andAH 26 are well-known.11-13 Thus, we comparedtheir leakage values with those of MM-Seal. Inaddition, the sealing ability of these sealers inpatients undergoing radiotherapy had not beenassessed before our study.

Zmener and colleagues13 and Bodrumlu andTunga14 reported that the mean apical leakagevalue for specimens sealed with AH Plus waslower than that for specimens sealed with AH 26.Although we found similar results in this study,the mean apical leakage values for AH 26 andAH Plus were lower in the previous studies thanin this study, because they did not use centrifu-gation to perform the dye penetration tests (thus,less dye penetrated the roots).

The apical sealing ability of MM-Seal was sim-ilar to that of AH Plus. Because no study to datehas evaluated the sealing ability of MM-Seal, wecould not conduct any comparisons. In addition,regardless of whether the specimens were irradi-ated or not, MM-Seal and AH Plus were similarwith regard to mean leakage values; this mightbe explained by the sealers’ chemical components.

The failure of sealers may be the result oftheir physical properties (adhesiveness, dimen-sional stability, flow, solubility).13,15 Someauthors16,17 have suggested that the apical sealmay be improved by increasing the surface contact between the root canal walls and thesealer (these connections can be affected byradiotherapy).

Bond strength. al-Nawas and colleagues18

found that the mechanical properties of dentinseem to be much less affected by irradiation thanare those of enamel. According to these authors,irradiation has only a minor effect on themechanical properties of dentin. Gernhardt andcolleagues19,20 found no differences between irra-diated and nonirradiated dentin specimens.Changes in hardness, the crystalline structure

and the collagen matrix resulting from irradia-tion do not influence the bond strength of resin-based materials.19,20 For these reasons, thebonding ability of the sealers in this study wasnot affected by radiation therapy, and weobserved no difference in leakage between speci-mens in the irradiation and nonirradiationgroups.

CONCLUSION

Further studies are needed to assess the sealingability of the new root canal sealer, MM-Seal,and evaluate its clinical performance. In addi-tion, the results of our study show that the apicalsealing ability of the three resin-based root canalsealers was slightly lower in the groups thatreceived radiotherapy than in those that did not,although the differences between the groupswere not statistically significant. ■

Disclosure. None of the authors reported any disclosures.

1. Verissimo DM, do Vale MS. Methodologies for assessment ofapical and coronal leakage of endodontic filling materials: a criticalreview. J Oral Sci 2006;48(3):93-98.

2. Ruddle CJ. Nonsurgical endodontic retreatment. J Calif DentAssoc 2004;32(6):474-484.

3. Kielbassa AM, Beetz I, Schendera A, Hellwig E. Irradiation effectson microhardness of fluoridated and non-fluoridated bovine dentin.Eur J Oral Sci 1997;105(5 pt 1):444-447.

4. Kielbassa AM, Munz I, Bruggmoser G, Schulte-Mönting J. Effectof demineralization and remineralization on microhardness of irradi-ated dentin. J Clin Dent 2002;13(3):104-110.

5. Cheung DT, Perelman N, Tong D, Nimni ME. The effect ofgamma-irradiation on collagen molecules, isolated alpha-chains, andcrosslinked native fibers. J Biomed Mater Res 1990;24(5):581-589.

6. Howard H, Speizer FE. Specific environmental and occupationhazards. In: Braunwald E, Fausi AS, Kasper DL, et al, eds. Harrison’sPrinciples of Internal Medicine. 15th ed. Vol. 2, part 15, section 1.395.New York City: McGraw-Hill; 2001:2591-2592.

7. Miletic I, Ribaric SP, Karlovic Z, Jukic S, Bosnjak A, Anic I.Apical leakage of five root canal sealers after one year of storage. JEndod 2002;28(6):431-432.

8. Schafer E, Olthoff G. Effect of three different sealers on thesealing ability of both thermafil obturators and cold laterally com-pacted gutta-percha. J Endod 2002;28(9):638.

9. Ahlberg KM, Assavanop P, Tay WM. A comparison of the apicaldye penetration patterns shown by methylene blue and India ink inroot-filled teeth. Int Endod J 1995;28(1):30-34.

10. Oliver CM, Abbott PV. Entrapped air and its effects on dye pene-tration of voids. Endod Dent Traumatol 1991;7(3):135-138.

11. Pommel L, About I, Pashley D, Camps J. Apical leakage of fourendodontic sealers. J Endod 2003;29(3):208-210.

12. Adanir N, Cobankara FK, Belli S. Sealing properties of differentresin-based root canal sealers. J Biomed Mater Res B Appl Biomater2006;77(1):1-4.

13. Zmener O, Spielberg C, Lamberghini F, Rucci M. Sealing proper-ties of a new epoxy resin-based root canal sealer. Int Endod J 1997;30(5):332-334.

14. Bodrumlu E, Tunga U. Apical leakage of Resilon obturationmaterial. J Contemp Dent Pract 2006;7(4):45-52.

15. Miletic I, Anic I, Pezelj-Ribaric S, Jukic S. Leakage of five rootcanal sealers. Int Endod J 1999;32(5):415-418.

16. Sen BH, Piflkin B, Baran N. The effect of tubular penetration ofroot canal sealers on dye microleakage. Int Endod J 1996;29(1):23-28.

17. Cergneux M, Ciucchi B, Dietschi JM, Holz J. The influence of thesmear layer on the sealing ability of canal obturation. Int Endod J1987;20(5):228-232.

18. al-Nawas B, Grötz KA, Rose E, Duschner H, Kann P, Wagner W.

Copyright © 2009 American Dental Association. All rights reserved. Reprinted by permission.

on May 31, 2010

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Using ultrasound transmission velocity to analyse the mechanicalproperties of teeth after in vitro, in situ, and in vivo irradiation. ClinOral Investig 2000;4(3):168-172.

19. Gernhardt CR, Koravu T, Gerlach R, Schaller HG. The influenceof dentin adhesives on the demineralization of irradiated and non-

irradiated human root dentin. Oper Dent 2004;29(4):454-461. 20. Gernhardt CR, Kielbassa AM, Hahn P, Schaller HG. Tensile

bond strengths of four different dentin adhesives on irradiated andnon-irradiated human dentin in vitro. J Oral Rehabil 2001;28(9):814-820.

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