Effect of calcium hydroxide dressing on the long-term sealing ability of two different endodontic sealers: An in vitro study

Effect of calcium hydroxide dressing on the long-term sealing ability of two different endodontic sealers: An in vitro study

Vol. 110 No. 3 September 2010 ENDODONTOLOGY Editor: Larz S. W. Spångberg Effect of calcium hydroxide dressing on the long-term sealing ability of t...

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Vol. 110 No. 3 September 2010


Editor: Larz S. W. Spångberg

Effect of calcium hydroxide dressing on the long-term sealing ability of two different endodontic sealers: An in vitro study Daiana Elisabeth Böttcher, DDS,a Vinicio Hidemitsu Goto Hirai, MSc,b Ulisses Xavier Da Silva Neto, DDS, PhD,c and Fabiana Soares Grecca, DDS, PHD,a Porto Alegre and Curitiba, Brazil FEDERAL UNIVERSITY OF RIO GRANDE DO SUL AND PONTIFICAL CATHOLIC UNIVERSITY OF PARANÁ

Objective. The aim of this in vitro study was to evaluate the long-term sealing ability of Real Seal system and Endofill after calcium hydroxide (CH) dressing, by using a fluid filtration model. Study design. Four randomized groups of single-rooted teeth (N ⫽ 110) were prepared using a crown-down technique to a size 50 file. Two groups (1 and 2) received CH dressing before filling. Roots were filled with gutta-percha and Endofill (groups 2 and 4) or Resilon and Real Seal (groups 1 and 3). Leakage was measured by using the fluid filtration method after 90 days and determined as ␮L/min䡠10 psi. Results. Statistical analysis by Kruskal-Wallis and Mann-Whitney tests indicated that CH dressing groups showed higher leakage values than those where CH was not used (P ⫽ .001). Conclusion. It may be concluded that the use of CH as an intracanal dressing material affected the sealing ability of both Real Seal and Endofill sealers. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:386-389)

Calcium hydroxide (CH) dressing is best suited to different clinical situations, and it plays an important role in cases of pulp necrosis,1 being widely used in endodontic practice. However, some authors show that CH remains may affect the sealing efficiency of the endodontic sealer from a mechanical point of view, allowing reinfection.2 Margelos et al.3 investigated the existence of an interaction between CH with zinc oxide eugenol (ZnOeugenol) type sealer. Calcium hydroxide interacted preferentially with eugenol, inhibiting the ZnO-eugenol chelate formation. The CH-eugenol interaction was rapid and kinetically dependent, leading to residual


Department of Conservative Dentistry, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre. b PhD student, Clinical Department, Pontifical Catholic University of Paraná. c Professor of Endodontics, Pontifical Catholic University of Paraná. Received for publication Jan 25, 2009; returned for revision Apr 28, 2010; accepted for publication May 7, 2010. 1079-2104/$ - see front matter © 2010 Published by Mosby, Inc. doi:10.1016/j.tripleo.2010.05.007


eugenol in the set product. The set ZnO-eugenol cement and sealers, in contact with CH, were brittle in consistency and granular in structure.3 A dual-curable methacrylate resin sealer (Epiphany; Pentron Clinical Technologies, Wallingford, CT, USA) has been developed to be used with a self-etching primer and in association with a new thermoplastic synthetic polyester polymer– based root canal filling material (Resilon; Resilon Research, Madison, CT, USA) which replaces gutta-percha.4 Obturation using the Epiphany/Resilon system is claimed to create a tight seal with the dentinal tubules within the root canal system. In essence, it produces a “monoblock” effect, where the core material (Resilon), sealer (Epiphany), and dentinal tubules become a single solid structure.5 In a recent study, the bond strength was decreased when a CH dressing was used before root canal filling with Epiphany, which suggested that the residues of the paste left into the root canal space could have interfered with the adhesion of the Epiphany to the root dentin.6 The effect on leakage of the root canal system is an important consideration when placing an intracanal

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medication. In view of this, the present in vitro study was to evaluate the long-term sealing ability of Real Seal system and Endofill after CH dressing using a fluid filtration model. MATERIALS AND METHODS This study was sanctioned by the Institutional Review Board and by the Research Ethics Commitee of the School of Dentistry of the Federal University of Rio Grande do Sul. One hundred ten human single-root teeth with fully formed apex and straight root canal were selected for this study. The teeth were stored in saline solution until the moment of use. The coronal portion of all teeth was removed with diamond disks. A diamond bur (KG Sorensen, Rio de Janeiro, Brazil) was used to gain a straight-line access to the root canal. The canal was irrigated with 2.0 mL 2.5% sodium hypochlorite (NaOCl) solution by using a syringe and a 27-gauge needle. A #10 K-Flexofile (Dentsply Maillefer, Ballaigues, Switzerland) was used to remove the pulp tissue, and it was further introduced into the root canal until the tip was just visible at the apical foramen. The working length was determined by subtracting 1 mm from this length. Apical patency was confirmed by inserting a #10 file through the apical foramen before and after root-canal preparation. The cervical portion of each tooth was prepared using Gates-Glidden burs #1 and #2. It was instrumented using the crown-down technique, and the canals were prepared to size #50 K-Flexofile (Dentsply Maillefer) to the working length. A final rinse with 3 mL 17% ethylenediaminetetracetic acid (EDTA) (Biodinâmica, Ibiporã, Brazil) and 2 mL 2.5% NaOCl solutions was performed to remove the smear layer. The prepared roots were randomly assigned into 4 experimental groups of 25 roots each: Group I: CH dressing and filling with Resilon and Real Seal (SybronEndo; Sybron Dental Specialities, Orange, CA, USA), using thermomechanical technique.7 Group II: CH dressing and filling with gutta-percha and Endofill (Dentsply, Rio de Janeiro, Brazil), using the same technique. Group III: filling with Resilon and Real Seal, using the same technique. Group IV: filling with gutta-percha and Endofill, using the same technique. The root apices of the groups that received the dressing were sealed with wax (groups I and II). The CH paste (Calen; S. S. White, Rio de Janeiro, Brazil) was placed using a threaded ML endodontic syringe

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(S. S. White) with a 27-gauge needle (Terumo, Tokyo, Japan). Radiographs were taken to evaluate the quality of the CH filling. The access openings were sealed with a temporary filling material (Coltosol, Vigodent, Rio de Janeiro, Brazil). Teeth were stored in an incubator for 14 days at 37°C and 100% relative humidity. After this period, the CH paste was removed using 2 mL 2.5% NaOCl solution with a #50 Flexofile. During irrigation, the file was placed to the working length and used manually until the paste was totally removed. Afterward, the canal was irrigated with 3 mL 17% EDTA solution (Biodinâmica) for 3 minutes and then irrigated with 2 mL 2% chlorhexidine (Quinta Essência Cosméticos e Medicamentos, Porto Alegre, Brazil). The canal was then dried with paper points. The sealers were mixed in accordance to the manufacturers’ instructions. All obturated specimens were then checked radiographically to verify the quality of the canal obturation. Thereafter, the specimens were stored at 100% humidity and 37°C for 90 days. In addition, 5 teeth with the external surface and apex covered with nail polish were used as negative control samples and 5 nonobturated teeth were used as positive control samples. The roots were mounted in the fluid filtration device designed to measure leakage, as previously described.8 The fluid filtration volume was measured by observing the air bubble movement; the air bubble displacement was recorded as the fluid filtration result, expressed in L/min䡠10 psi. Fluid movement measurements were made at 2-minute intervals for 8 minutes and then averaged. Four samples from group III (Real Seal) and another 2 from group IV (EndoFill) were discarded owing to handling problems during fluid filtration. The data obtained were subjected to statistical analysis using Kruskal-Wallis and Mann-Whitney tests. The confidence level was preset at 5%. RESULTS In the fluid filtration test, the negative control samples presented no air bubble movement, whereas in the positive control samples the air bubble moved too fast to be measured. The use of CH dressing negatively influenced the sealing ability of Real Seal system and Endofill. This difference was significant when the groups with CH dressing were compared with the ones without it. There was significant statistical difference when the Endofill groups, with and without CH, were compared (P ⬍ .05) However, this difference was not significant in the Real Seal groups (P ⬎ .05). Group IV (Endofill without CH) presented the lowest leakage (Table I).


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Table I. Statistical analysis and comparisons of materials (␮L/min䡠10 psi) Group






Mean Rank

Real Seal/CH Endofill/CH Real Seal Endofill Total

25 25 21 23 94

1.17 1.14 .67 .54

1.204 1.142 .305 .270

.87 .91 .75 .54

.241 .228 .066 .056

56.94A,B 55.46C,B 43.02A,D 32.67D

CH, Calcium hydroxide. A-D Different letters indicate statistical differences.

DISCUSSION Calcium hydroxide is the most widely used and investigated intracanal dressing material in endodontics, because of its antibacterial and biologic properties.9 It is also effective in inactivating lipopolysaccharides10 and in inducing the formation of a mineralized tissue.11 However, several studies have showed that the presence of CH on dentin walls can affect the sealing ability.2,3 The best way to remove the CH from the radicular canal has been investigated, and so far the use of the association between EDTA and NaOCl complemented with the last apical file from instrumentation has shown the best results,12 although it does not promote the complete removal of the paste.13 Calcium hydroxide seemed to decrease the sealing quality of the sealers tested in the present study. The CH and ZnO-eugenol interaction has already been described.3 In addition, a significant decrease in bond strength was found when Epiphany was used after CH dressing.6 Different leakage tests have been used to evaluate the Epiphany System sealing ability.14-18 However, there are no studies considering the influence of CH on leakage. The fluid filtration method used in the present study offers several advantages over other techniques. It is more sensitive than dye penetration for detecting full-length voids along root canals and it is highly reproducible.8 Therefore, it is also possible to observe the tendency of the tested materials to increase or decrease leakage over a period of time. Some researchers observed a reduced long-term sealing ability with the Epiphany system.19,20 For this reason, the present evaluation was performed 90 days after the filling of the canals. The results show that Real Seal was not better than Endofill when leakage was considered. Different from ZnO-eugenol based sealers, when adhesive materials like Resilon/Real Seal are used a monoblock between the root canal dentin and the respective filling material is expected, resulting in a lower incidence of apical leakage.4,5 However, gap-free areas combined with interfacial gaps without resin tags have been associated with a

Resilon-based material.21 Those findings and the results of the present study suggest that Real Seal is not superior to other materials, even when CH is not used. Finally, the use of CH dressing decreases the sealing ability after filling. However, because of the good properties of CH, its use should not be contraindicated. The presence of in vitro leakage does not necessarily mean endodontic failure. Improved techniques for CH removal and filling materials with better sealing properties are required. REFERENCES 1. Foreman PC, Barnes IE. Review of calcium hydroxide. Int Endod J 1990;23:283-97. 2. Calt S, Serper A. Dentinal tubule penetration of root canal sealers after root canal dressing with calcium hydroxide. J Endod 1999;25:431-3. 3. Margelos J, Eliades G, Verdelis C, Palaghias G. Interaction of calcium hydroxide with zinc oxide-eugenol type sealers: a potential clinical problem. J Endod 1997;23:43-8. 4. Shipper G, Orstavik D, Teixeira FB, Trope M. An evaluation of microbial leakage in roots filled with a thermoplastic synthetic polymer-based root canal filling material (Resilon). J Endod 2004;30:342-7. 5. Teixeira FB, Teixeira EC, Thompson JY, Trope M. Fracture resistance of roots endodontically treated with a new resin filling material. J Am Dent Assoc 2004;135:646-52. 6. Barbizam JV, Trope M, Teixeira EC, Tanomaru-Filho M, Teixeira FB. Effect of calcium hydroxide intracanal dressing on the bond strength of a resin-based endodontic sealer. Braz Dent J 2008;19:224-7. 7. Tagger R. Use of thermo-mechanical compactors as an adjunct to lateral condensation. Quintessence Int 1984;15:27-30. 8. da Silva Neto UX, de Moraes IG, Westphalen VP, Menezes R, Carneiro E, Fariniuk LF. Leakage of 4 resin-based root-canal sealers used with a single-cone technique. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:e53-7. 9. Grecca FS, Leonardo MR, da Silva LA, Tanomaru Filho M, Borges MA. Radiographic evaluation of periradicular repair after endodontic treatment of dog’s teeth with induced periradicular periodontitis. J Endod 2001;27:610-2. 10. Safavi KE, Nichols FC. Effect of calcium hydroxide on bacterial lipopolysaccharide. J Endod 1993;19:76-8. 11. Holland R, de Mello W, Nery MJ, Bernabe PF, de Souza V. Reaction of human periapical tissue to pulp extirpation and immediate root canal filling with calcium hydroxide. J Endod 1977;3:63-7. 12. Salgado RJ, Moura-Netto C, Yamazaki AK, Cardoso LN, de Moura AA, Prokopowitsch I. Comparison of different irrigants

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on calcium hydroxide medication removal: microscopic cleanliness evaluation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107:580-4. Lambrianidis T, Margelos J, Beltes P. Removal efficiency of calcium hydroxide dressing from the root canal. J Endod 1999;25:85-8. Baumgartner G, Zehnder M, Paque F. Enterococcus faecalis type strain leakage through root canals filled with gutta-percha/AH Plus or Resilon/Epiphany. J Endod 2007;33:45-7. Biggs SG, Knowles KI, Ibarrola JL, Pashley DH. An in vitro assessment of the sealing ability of Resilon/Epiphany using fluid filtration. J Endod 2006;32:759-61. Bodrumlu E, Tunga U. Apical leakage of Resilon obturation material. J Contemp Dent Pract 2006;7:45-52. Fransen JN, He J, Glickman GN, Rios A, Shulman JD, Honeyman A. Comparative assessment of ActiV GP/glass ionomer sealer, Resilon/Epiphany, and gutta-percha/AH Plus obturation: a bacterial leakage study. J Endod 2008;34:725-7. Kaya BU, Kececi AD, Belli S. Evaluation of the sealing ability of gutta-percha and thermoplastic synthetic polymer-based sys-

Böttcher et al. 389 tems along the root canals through the glucose penetration model. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:e66-73. 19. Paque F, Sirtes G. Apical sealing ability of Resilon/Epiphany versus gutta-percha/AH Plus: immediate and 16-months leakage. Int Endod J 2007;40:722-9. 20. De-Deus G, Namen F, Galan J Jr. Reduced long-term sealing ability of adhesive root fillings after water-storage stress. J Endod 2008;34:322-5. 21. Perdigao J, Lopes MM, Gomes G. Interfacial adaptation of adhesive materials to root canal dentin. J Endod 2007;33: 259-63. Reprint requests: Daiana Elisabeth Böttcher Ramiro Barcelos, 2492 Porto Alegre—Rio Grande do Sul Brazil CEP 90035-003 [email protected]