JOURNAL OF ENDODONTICS Copyright © 2002 by The American Association of Endodontists
Printed in U.S.A. VOL. 28, NO. 6, JUNE 2002
Apical Leakage of Five Root Canal Sealers After One Year of Storage Ivana Miletic´, DDS, PhD, Sonja-Pezelj Ribaric´, DDS, PhD, Zoran Karlovic´, DDS, MS, Silvana Jukic´, DDS, MS, Andrija Bosˇnjak, DDS, MS, and Ivica Anic´, DDS, PhD
MATERIALS AND METHODS
A fluid transport model study was used to compare the sealing ability of five root canal sealers (AH26, AH Plus, Apexit, Diaket, and Ketac-Endo) on 60 single-rooted teeth after 1 yr of storage. The root canals were prepared with Gates Glidden drills by using a step-back technique before lateral condensation of gutta-percha with the tested sealers. The specimens were stored in saline solution for 1 yr at 37°C. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. Apexit (0.490 l) leaked significantly more than AH Plus (0.378 l) and Ketac-Endo (0.357 l), whereas AH26 (0.390 l) and Diaket (0.429 l) showed no significant difference from either Apexit or from AH Plus and Keto-Endo.
The tested sealers were AH26 silver-free, AH Plus (Dentsply, DeTrey), Diaket, Apexit, and Ketac-Endo. In a previously published experiment (7), canals of 60 human teeth were enlarged at the apical opening with a Gates Glidden bur (ISO size 70). The canals were flared with Gates Glidden burs up to ISO size 150 by using the step-back technique. The teeth were divided into 5 experimental subsamples, each consisting of 10 specimens, and 2 control groups. After the smear layer was removed, the root section was filled with the tested materials and gutta-percha points by using a cold lateral condensation technique. The first measurement was performed 2 weeks after sealing (7), and the specimens were afterward stored in saline solution at 37°C for a full yr. Before remeasurement, all specimens were examined under stereomicroscope at ⫻52 magnification to exclude the existence of major cracks in the dentine. The remeasurement was performed blindly by one author. Sealing ability was measured by the movement of an air bubble in a capillary tube for 5-min intervals under the pressure of 120 kPa (1.2 atm), using the method described by Wu et al. (8). Each specimen was tested four times, and the mean value was calculated. The difference in leakage between sealers was statistically analyzed by using the Student’s t test and analysis of variance.
Leakage studies on the sealing properties of endodontic materials are still important and necessary. There are many materials in use today, and current endodontic therapy uses a combination of guttapercha cones and a sealer, which is frequently based on resin, calcium hydroxide, or glass ionomer. Among resin-based sealers, the best known products are AH26 (Dentsply, DeTrey, Konstanz, Germany) and Diaket (ESPE GmbH, Seefeld, Germany). Dentsply/DeTrey also introduced an epoxy-resin sealer named AH Plus, which is said to have the good physical properties of AH26 without the undesirable biological properties that the old material has been shown to have (1–3). Apexit (Vivadent, Schaan, Liechenstein) is a calcium hydroxidetype sealer, which may have good sealing ability and biocompatibility with the surrounding tissues (4). A glass-ionomer root canal sealer, Ketac-Endo (ESPE GmbH), has been introduced and has the ability to bond chemically to the canal wall (5), which is an important quality, because the majority of leakage occurs between the sealer and the wall of the root canal (6). Also, it is reported that Ketac-Endo is highly resistant to resorption by tissue fluids (6). The purpose of this study was to compare the sealing quality of five root canal sealers (AH26, AH Plus, Apexit, Diaket, and Ketac-Endo) after the specimens were stored in saline solution for 1 yr.
RESULTS The microleakage data for the different experimental groups are presented in Table 1. Apexit showed significantly more leakage than AH Plus and Ketac-Endo. Leakage of AH26 and Diaket sealers was not significantly different from that of AH Plus and Ketac-Endo, which showed the least leakage, nor from that of Apexit, which showed the most.
TABLE 1. Mean leakage values and standard deviation for each tested sealer
Mean ⫾ SD Value (L)
Ketac-Endo AH Plus AH26 Diaket Apexit
0.357 ⫾ 0.082 0.378 ⫾ 0.076 0.390 ⫾ 0.071 0.429 ⫾ 0.152 0.490 ⫾ 0.137
Miletic´ et al.
Journal of Endodontics
In the negative controls, no fluid transport was recorded, whereas in the positive controls the air bubble moved too fast to be measured.
DISCUSSION This study sought to asses the sealing property of five root canal sealers after storage in saline solution for 1 yr with the fluid transport model proposed by Wu et al. (8). This method offers several advantages over more commonly used techniques of assessing leakage. It has been suggested that the fluid transport model is both more sensitive than dye penetration for the detection of full-length voids along root canal and at the same time highly reproducible (8, 9). Also, this method does not destroy the samples; therefore, it is possible to obtain measurement of microleakage of the same specimens at intervals over extended periods (10). It is very important to assess leakage not only immediately after sealing but also after some time, because sealing needs to be long lasting to be clinically effective. The results of this study showed that after 1 yr, AH Plus and Ketac-Endo show significantly better sealing ability than Apexit, whereas AH26 and Diaket show no statistical differences with either sealer. Georgopoulou et al. (11) stated that the sealing quality of Ketac-Endo in thick layers does not justify its use with single-cone, gutta-percha techniques as advocated by its manufacturers. Also Wu et al. (10) stated that the thickness of the sealer layer is of primary importance for the sealing. They showed, using a fluid transport, that there were no significant differences between Ketac-Endo, AH26, and Tubuliseal, used in thin layers, either immediately after setting or after being stored in water for 1 yr. Our results are in accordance with theirs. The results confirm the good dimensional stability and great adhesive strength that AH26 is known to have (12). AH Plus and Diaket showed satisfactory sealing ability, just as in the previous study (7). Apexit produced the greatest leakage after storage in saline solution for 1 yr. This was contrary to the results obtained in an earlier study (7), in which the measurements were taken after a 2-week period, and there were no statistically significant differences between these materials. This discrepancy can probably be explained by the fact that the decomposition of Apexit during 1 yr
of storage may have destroyed the seal. A similar effect was reported by Wu et al. (10), who found the greatest leakage through Sealapex, a Ca(OH)2-containing sealer by the same method. It is well known that calcium hydroxide-based sealers are soluble and that quality could probably cause a deficiency in their sealing ability over an extended period of time. This study demonstrated the need to repeat microleakage measurement after long periods, because the relative differences between the materials change over time, and this change has a clinical relevance. Drs. Miletic´, Karlovic´, Jukic´, and Anic´ are affiliated with the Department of Dental Pathology, and Dr. Bosˇnjak is affiliated with the Department of Periodontology, School of Dentistry, University of Zagreb, Zagreb, Croatia. Dr. Ribaric´ is affiliated with the Department of Dental Pathology, Department of Stomatology, Medical School, University of Rijeka, Rijeka, Croatia. Address requests for reprints to Ivica Anic´, Department of Dental Pathology, School of Dentistry, University of Zagreb, Gundulic´eva 5, 10000 Zagreb, Croatia.
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