Apical sealing ability of a new glass ionomer root canal sealer

Apical sealing ability of a new glass ionomer root canal sealer

0099-2399/95/2110-0498503.00/0 JOURNALOF ENDODONTICS Copyright © 1995 by The American Association of Endodontists Printed in U.S.A. VOL. 21, NO. 10,...

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0099-2399/95/2110-0498503.00/0 JOURNALOF ENDODONTICS Copyright © 1995 by The American Association of Endodontists

Printed in U.S.A.

VOL. 21, NO. 10, OCTOBER1995

Apical Sealing Ability of a New Glass Ionomer Root Canal Sealer Fernando Goldberg, DDS, Liliana Patricia Artaza, and Ana De Silvio

This study compared the sealing ability of Ketac Endo with and without smear layer and Tubli Seal. Thirty upper central incisors and canines with straight canals were instrumented and randomly divided into three equal groups of 10. All teeth were obturated with laterally condensed gutta-percha. An additional group of five teeth with unobturated root canals served as positive controls. The sealers were Tubli Seal (group A), Ketac Endo (group B), and Ketac Endo preceded by the removal of the smear layer (group C). The teeth were immersed in India ink for 7 days, centrifuged for 5 min at 3000 rpm, cleared, and then examined under a light microscope at x 5 0 magnification. The mean value of ink penetration for group A was 0.14 mm, for group B 0.24 mm, and for group C 0.48 mm. No statistically significant differences were observed among groups (p > 0.05).

M A T E R I A L S AND M E T H O D S Thirty-five upper central incisors and canines with straight root canals were selected for this study. The crowns were removed with carborundum disks at the cementoenamel junction to facilitate instrumentation and obturation. The canal length was visually established by placing a #15 file into each root canal until the tip was visible at the apical foramen. The working length was established 1 mm short of the apex. All teeth were instrumented at the working length to a #45 file. The coronal and middle portions were flared to a gradual taper using #2 and #3 Gates Glidden drills. The apical patency was checked by passing a #15 file through the apical foramen. After every change of a file size and at the completion of the instrumentation, the canals were irrigated with 3 ml of 2.5% sodium hypochlorite solution. The canals were dried with paper points, and standardized gutta-percha points that fit with tugback at the working length were selected as master points. The teeth were randomly divided into three equal groups of 10. An additional five teeth with unobturated canals served as positive controls. Group A: The teeth were obturated with Tubli Seal (Kerr/ Sybron, Romulus, MI) in conjunction with laterally condensed gutta-percha. The sealer was introduced into the canal using a Lentulo spiral instrument. The master gutta-percha point was coated with the sealer and placed in the canal to the working length. Lateral condensation was performed using a size B finger spreader (Maillefer, Ballaigues, Switzerland) and fine-fine accessory gutta-percha points. Group B: The teeth were obturated with Ketac Endo and guttapercha lateral condensation technique. The sealer was mixed following the manufacturer's instructions. It was then placed on a clean glass slab and introduced into the canal using a Lentulo spiral instrument. The master gutta-percha point was coated with the sealer and seated in the canal to the working length. Lateral condensation was performed in the same manner as in group A. Group C." Before filling, the root canals were treated using 10% polyacrylic acid (Dentin Conditioner, Voco Chemic, Cuxhaven, Germany) activated for 10 s using a sonic device (MM1500, Micro Mega, Geneva, Switzerland) and a smooth instrument, in an attempt to remove the smear layer. The teeth were then obturated with Ketac Endo, exactly as in group B. In all groups, the excess gutta-percha was removed from the access cavity with a heated ball burnisher and vertically condensed using an amalgam plugger. The coronal access cavities were sealed with amalgam, and final radiographs were taken in the mesiodistal and buccolingual directions. The teeth were stored for 7 days at

The complete sealing of the entire root canal system is considered to be a major objective of root canal obturation (1, 2). Therefore, the evaluation of the sealing capacity of new endodontic sealers using leakage tests is still relevant (3). Different endodontic filling materials and techniques have been introduced in an attempt to improve apical sealing. Recently, a new glass ionomer root canal sealer, Ketac Endo (ESPE GMBH & Co., KG, Seefeld/Oberbay, Germany), became commercially available. The manufacturer states that Ketac Endo penetrates and seals dentinal tubules, as well as sealing the apex. Pitt Ford (4) reported that the glass ionomer cement may be used as a root canal sealer because it allows minimal leakage. Ray and Seltzer (5) found that glass ionomer shows a close dentinal adhesion and produces a tight sealer-dentine interface. Tubli Seal is a widely used zinc oxide-eugenol-based sealer. Its sealing capacity is comparable to other zinc oxide-eugenol-based sealers (6-8). The purpose of this study was to compare the sealing ability of Tubli Seal, Ketac Endo, and Ketac Endo after the removal of the smear layer in teeth obturated with the lateral condensation technique.

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FIG 1. Tooth filled with Tubli Seal and laterally condensed guttapercha (group A). Representative specimen of no ink penetration, A lateral canal in the apical third can be seen.

37°C and 100% humidity to ensure setting of the sealer. The root surface, except the apical 2 mm, was coated with two layers of nail varnish. The teeth were immersed in India ink (Pelikan, Argentina) for 7 days at 37°C, and then centrifuged for 5 min at 3000 rpm. Afterward, the teeth were rinsed under tap water to remove ink on the external root surface. The specimens were decalcified in 5% nitric acid, followed by washing for 2 h and dehydrated in ascending concentrations of alcohol (80%, 90%, and 100%). The roots were subsequently cleared using methyl salicylate. The cleared specimens were examined under a light microscope (×50), and a grid calibrated in microns was used to determine the extent of leakage. Each cleared root was rotated, and the greatest depth of ink penetration was measured for each specimen. Data were analyzed statistically using the Kruskal-Wallis test. RESULTS The five unobturated control teeth showed complete ink penetration throughout the canal. In group A, the values of dye penetration ranged from a minimum of 0.00 mm to a maximum of 0.94 mm, with a mean value of 0.14 mm (Fig. 1). The values of group B ranged from 0.00 to 1.05 mm, with a mean value of 0.24 mm. In group C, the values ranged from 0.00 to 1.26 mm, with a mean value of 0.48 mm (Fig. 2) (Table 1). No statistically significant differences were seen among groups (p > 0.05). In some specimens, there was no correlation between the radiographic quality of the endodontic filling and the degree of apical leakage.

Apical Sealing of Ketac Endo

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FIG 2. Tooth filled with Ketac Endo and laterally condensed guttapercha (group C). Representative specimen of deep ink penetration in the apical third. Dye leakage extended 1.26 mm into the root canal.

TABLE 1. Mean leakage values Apical Leakage (mm) Group A B C

Samples

Minimum Leakage

Maximum Leakage

Mean Leakage

SD

10 10 10

0.00 0.00 0.00

0.94 1.05 1.26

0.14 0.24 0.48

0.32 0.41 0.50

The results of this study indicate that the use of 10% polyacrylic acid in an attempt to remove the smear layer does not improve the sealing ability of Ketac Endo. Ray and Seltzer (5) also found similar results using a combination of NaOCl-citric acid to remove the smear layer. In this study, the teeth were submitted to passive immersion followed by centrifugation to force the dye through the filling defects in the root canal (10). Despite this, in some teeth there was no correlation between the radiographic quality of the root canal filling and the degree of leakage. The relationship of in vitro leakage measurements to the in vivo situation has not been established (11). Therefore, in vitro leakage results should be cautiously extrapolated to the clinical situation (3, 11). The authors thank Dr. G. Jaim Etcheverry for his help in manuscript preparation and Dr. R. L. Macehi for his statistical assistance. Drs. Goldberg, Artaza, and De Silvio are currently practicing in Buenos Aires, Argentina. Address requests for reprints to Dr. Fernando Goldberg, Viamonte 1620 1D, 1055 Buenos Aires, Argentina.

DISCUSSION Numerous investigations have compared the sealing capacity of different root canal sealers, showing conflicting results (3, 9). The present study showed no significant difference in the apical leakage when Tubli Seal or Ketac Endo was used. Pitt Ford (4) found similar results comparing the sealing capacity of a zinc oxide-eugenol sealer (Kerr's pulp canal sealer) with that of a glass ionomer cement (ASPA IV). Tubli Seal is a zinc oxide-eugenolbased sealer, and its sealing capacity is comparable to other zinc oxide-eugenol sealers (6-8).

References 1. Nguyen NT. Obturation ofthe root canal system. In: Cohen S, Burns RC, eds. Pathways of the pulp. 4th ed. St. Louis: CV Mosby Co., 1987:183. 2. Walton RE, Torabinejad M. Principles and practice of endodontics. Philadelphia: WB Saunders, 1989:224. 3. Wu MK, Wesselink PR. Endodontic leakage studies reconsidered. Part I. Methodology, application and relevance. Int Endod J 1993;26:37-43. 4. Pitt Ford TR. The leakage of root fillings using glass ionomer cement and other materials. Br Dent J 1979;146:273-8. 5. Ray H, Seltzer S. A new glass ionomer root canal sealer. J Endodon 1991 ;17:598- 603.

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6. Crane DL, Heuer MA, Kaminski EJ, Moser JB. Biological and physical properties of an experimental root canal sealer without eugenol. J Endodon 1980;6:438 -45. 7. Goldberg F, Frajlich S. Analisis de la capacidad de sellado. Diferentes materiales y tecnicas de obturaciOn de conductos. Rev Asoc Odontol Argent 1980;68:13-6. 8. Hovland EJ, Dumsha TC. Leakage evaluation in vitro of root canal sealer cement Sealapex. Int Endod J 1985;18:179-82.

Journal of EndodonUcs 9. Branstetter J, von Fraunhofer JA. The physical properties and sealing action of endodontic sealer cements: a review of the literature. J Endodon 1962;8:312-6. 10. Kersten HW, Ten Cate JM, Exterkate RAM, Moorer WR, Thoden Van Velzen SK. A standardized leakage test with curved root canals in artificial dentine. Int Endod J 1988;21:191-9. 11. Goldman M, Simmonds S, Rush R. The usefulness of dye-penetration studies reexamined. Oral Surg 1989;67:327-32.

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