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Objective: This study examined whether 4-methacryloxyethyl trimellitate anhydride/methylmethacrylate-tri-n-butyl borane (4-META/MMA-TBB) resin can be used with mineral trioxide aggregate (MTA) to overcome MTA's shortcomings. The biologic reactions of the mixture of MTA powder and 4-META/MMA-TBB resin (MTA/4-META) and its potential in clinical applications were also investigated., Study Design: MTA powder was mixed with 4-META/MMA-TBB resin instead of water at the appropriate proportions determined by a series of studies prior to this experiment. MTA powder mixed with sterile water was used as control. The setting time, compressive strength, pH, and dye leakage of MTA/4-META and MTA were assessed by Gilmore apparatus, universal mechanical testing machine, pH meter, and methylene blue penetration method, respectively. Cytotoxicity also was evaluated by MTT assay with MC3T3-E1 cells., Results: The setting time of MTA/4-META was significantly lower than that of MTA: 11.2 ± 0.8 minutes versus 318 ± 56.0 minutes, respectively (P < .05). The mean compressive strength of MTA/4-META after 24 hours was significantly higher than that of MTA: 57.4 ± 11.6 MPa versus 18.7 ± 3.0 MPa, respectively (P < .05). MTA/4-META showed significantly less leakage than MTA (P < .05). The initial pHs for MTA and MTA/4-META at 2 hours were 10.73 ± 0.95 and 10.08 ± 0.13, respectively, and reached plateaus of 10.92 ± 0.31 and 10.54 ± 0.39 at 24 hours, respectively. The pH of MTA was higher than that of MTA/4-META in the entire period, but the differences were only significant up to 48 hours (P < .05). MTA and MTA/4-META both showed no cytotoxicity., Conclusions: 4-META/MMA-TBB resin as a mixing vehicle of MTA powder can improve the setting and handling properties of MTA and may maintain or improve its other biophysical properties., (Copyright © 2011 Mosby, Inc. All rights reserved.)

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 microL/min.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., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Objective: The objective of this study was to evaluate the apical sealing ability of Hybrid Root SEAL (MetaSEAL) in conjunction with different obturation techniques., Methodology: Sixty-eight extracted human mandibular straight single-rooted teeth with mature apices were prepared using a step-back technique and divided into 4 experimental groups (n = 15). An additional 8 teeth were prepared for controls (3 for positive, 3 for negative control, and 2 more for calculating 100% leakage). The experimental groups were obturated with Hybrid Root SEAL (MetaSEAL) using cold lateral condensation, vertical condensation, Thermafil, and Ultrafil techniques. Fluid movement along the filled canals was measured using a fluid filtration method. Measurements were made at 2-minute intervals for 8 minutes. The data were calculated as microL/min and statistically analyzed using 1-way ANOVA and Duncan Test., Results: Cold lateral and vertical condensation had significantly less fluid movement than the Thermafil and Ultrafil groups. Thermafil group had the highest fluid movement values when compared with the other groups (P < .01)., Conclusion: Hybrid Root SEAL (MetaSEAL) had less fluid movement with cold lateral and vertical condensation techniques when compared with Thermafil and Ultrafil techniques., (Copyright 2010 Mosby, Inc. All rights reserved.)

Objective: The aim of this study was to evaluate the microleakage of Resilon + Epiphany, EndoRez, Activ GP, and conventional AH Plus + gutta-percha technique using the glucose filtration model., Study Design: One hundred twenty maxillary incisors were divided into 5 experimental and 2 control groups. After root canal shaping, the experimental groups were filled with AH Plus + gutta-percha (lateral compaction), Resilon + Epiphany (lateral compaction), AH Plus + Protaper's proprietory cone, EndoRez + sealer, or Activ GP + sealer). The specimens were mounted on a glucose model and samples were taken for 3 weeks for leakage measurement., Results: No statistically significant difference was observed between the leakage of all groups at the 3 testing periods (P > .05)., Conclusion: The filling materials with the monoblock concept do not seem to be superior to the conventional AH Plus + gutta-percha system regarding microleakage., (Copyright 2010 Mosby, Inc. All rights reserved.)

Direct pulp capping is treatment of an exposed vital pulp with a dental material to facilitate the formation of reparative dentin and maintenance of vital pulp. It has been studied as an alternate way to avoid vital pulp extirpation. However, the success rate of pulp capping is much lower than that of vital pulp extirpation. Therefore, direct pulp capping is currently considered controversial by many clinicians. To increase the success rate, a critical need exists to develop new biologically based therapeutics that reduce pulp inflammation, promote the continued formation of new dentin-pulp complex, and restore vitality by stimulating the regrowth of pulpal tissue. Bioengineered anti-inflammatory direct pulp-capping materials, together with adhesive materials for leakage prevention, have great potential to improve the condition of the existing pulp from an inflamed to a noninflamed status and lead to a high rate of long-term success., (Published by Mosby, Inc.)

Objective: The aim of the study was to evaluate the postobturation apical seal following irrigation with 7% maleic acid (MA) or 17% EDTA using dye leakage under vacuum method., Study Design: Seventy single-rooted human anterior teeth were subjected to root canal instrumentation. Based on the final irrigating solution used, samples were divided into 3 groups: (1) 17% EDTA + 2.5% NaOCl, (2) 7% MA + 2.5% NaOCl, (3) 0.9% saline. Then samples were obturated and placed in 2% rhodamine B dye solution under vacuum pressure for 30 minutes and allowed to remain in the dye for 7 days. Samples were then longitudinally split and examined for dye leakage under stereomicroscope. Data were analyzed using the Kruskal-Wallis test., Results: MA showed the least apical leakage compared with EDTA and saline. Saline showed maximum leakage., Conclusion: Final irrigation with 7% MA improved the postobturation apical seal compared with 17% EDTA., (Copyright 2010 Mosby, Inc. All rights reserved.)

Objective: The aim of this study was to compare the leakage of root canal fillings of gutta-percha or Resilon cones in association with AH Plus or Epiphany sealer., Study Design: Four groups of premolars (n = 64) were instrumented to size 45/.04 ProFile and filled with laterally compacted gutta-percha cones or Resilon cones in association with AH Plus or Epiphany sealer. The specimens were stored for 2 weeks at 37 degrees C and 100% humidity. After that, leakage was measured using the fluid filtration method and determined as microL/min.10 psi., Results: Homogeneity of variance and multiple comparisons tests were performed and indicated that root fillings with the combination of gutta-percha cones and AH Plus sealer showed lower leakage values (P < .05) than the other groups., Conclusion: Considering the experimental conditions and the results obtained, it was concluded that fillings made with gutta-percha cones in combination with AH Plus sealer had the best performance., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Objective: The objective of this study was to determine the influence of smear layer removal on through-and-through fluid movement along root canal fillings obturated using 3 different root canal sealers, namely AH26, Pulp Canal Sealer, and Gutta-Flow, and 3 different obturation techniques., Study Design: The fluid transport model was used for detection of through-and-through fluid movement. Root canals of 230 human extracted teeth were mechanically instrumented using the step-back technique. The canals where the smear layer was not removed were irrigated with NaOCl 2.4%, whereas canals where the smear layer was removed were irrigated with EDTA 17% plus NaOCl 2.4%. The teeth were randomly divided into 10 experimental groups (n = 20) and 3 control groups (n = 10) and treated as follows. In group A, where no attempt was made for smear layer removal, the canals were obturated with lateral compaction of gutta-percha and AH26 as a sealer. In group B, the smear layer was removed, and canals were obturated as in group A. In group C (no attempt to remove the smear layer), the canals were obturated with System B plus Obtura II technique and AH26, whereas in group D, the smear layer was removed, and canals were obturated as in group C. The other 4 experimental groups were treated and obturated in the same way as in previous groups, respectively. The sealer that was used in those groups was the Pulp Canal Sealer. Finally, the latter 2 groups were obturated with Gutta-Flow technique. Fluid movement was measured at 24 hours and 30 days and 6 months., Results: In lateral compaction groups (with and without the smear layer), no significant differences were found regarding the ability of the same materials (AH26 and Pulp Canal Sealer) to prevent the fluid movement (P > .05). In warm obturation technique, no significant difference was found between the 2 groups (with and without the smear layer) of AH26 (P > .05). On the contrary, in groups of Pulp Canal sealer, fluid transport values were significantly less when the smear layer was removed (P < .05). Finally, no significant difference was observed between the groups of Gutta-Flow (with and without the smear layer) (P > .05)., Conclusions: Under these in vitro conditions, it seems that smear layer removal improves the ability of the filling materials to prevent the fluid movement, at least after the use of warm obturation techniques. On the contrary, smear layer removal does not seem to improve the same ability after the use of cold lateral compaction technique. Further laboratory and also clinical studies are needed in the future to compose a clear view concerning the improvement of sealing ability following smear layer removal., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Objective: The aim of this study was to investigate the effect of the cavity thickness and smear layer on apical sealing ability of mineral trioxide aggregate (MTA) as a root-end filling material., Study Design: Seventy single-rooted maxillary central teeth were used in this study. All teeth were instrumented to size 50 using a step-back technique. The selected teeth were randomly divided into 4 groups, each containing 15 experimental samples and 5 positive and 5 negative control samples. In the first and second groups (smear+), the teeth were irrigated with only 5.25% NaOCl. In the third and fourth groups (smear-), the teeth were irrigated with 17% EDTA and 5.25% NaOCl to remove the smear layer. Also, in the first and third groups, cavities were prepared as 3 mm. In the second and fourth groups, cavities were prepared as 5 mm. All the root-end cavities were then filled with MTA. Nail varnish was applied to all external root surfaces to the level of the resected root-ends to prevent lateral microleakage. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 4 weeks. The data obtained were analyzed using a chi-squared test, with alpha = .05 as the level for statistical significance., Results: There were no statistically significant differences in rate of bacterial leakage among the experimental groups at 1-4 weeks (P > .05). Also, there was no difference between the groups when the 2 thickness groups were combined (P > .05). However, there was statistically significant differences when the 2 smear groups were combined for 4-week observation periods (P < .05). Removal of the smear layer caused significantly more apical microleakage than when the smear layer was left intact for 4 weeks., Conclusion: The thickness of root-end cavity (3 or 5 mm) had no influence in the bacterial leakage of the root end filled with MTA. Removing the smear layer may not be necessary in root-end cavities filled with MTA., (Copyright 2010 Mosby, Inc. All rights reserved.)

Objective: The objective of this study was to evaluate the sealing ability of AH Plus, Epiphany, Acroseal, Endofill, and Polifil after active lateral condensation technique, by using a bacterial test, during 64 days., Study Design: One hundred bovine incisors were cleaned and shaped; then they were filled with the endodontic sealers and adapted into a microcentrifuge tube. The setup root/microcentrifuge tube was added to glass flasks containing Brain Heart Infusion broth. A culture of Enterococcus faecalis was inserted into the upper chamber of each assembly. Daily leakage was evaluated through the broth turbidity., Results: The results were submitted to statistical analysis (Kaplan-Meier method, Kruskal-Wallis and Dunn tests)., Conclusions: AH Plus and Endofill had the worst sealing ability when compared with Polifil, which showed the least leakage. Acroseal and Epiphany showed a tendency toward having an intermediate behavior; however, there was no significant difference among Acroseal, Epiphany, and the other sealers.

Objective: The aim of this study was to evaluate the percentage of sealer penetration in root canals filled with the Thermafil or RealSeal-1 systems analyzed by confocal laser scanning microscopy (CLSM)., Study Design: Twenty canals in 10 mesial roots of mandibular molars were cleaned and shaped using ProTaper and ProFile instruments to a size 35 and .04 taper at the apex and filled using RealSeal-1 or Thermafil systems in the mesial canal of each root. Horizontal sections were made at the 3 and 5 mm levels from the apex, and the percentage of sealer penetration in the root canal walls was analyzed using CLSM., Results: Thin layers of sealer (2-30 microm) and sealer tags into dentinal tubules were found in the root canal walls in a high percentage using both techniques at both evaluated levels, with no statistical differences between the techniques (Student t test: P > .05)., Conclusion: The percentage of sealer penetration in the root canal walls was similar using both thermoplastic carriers based systems.

Objective: The objective of this study was to investigate the sealing properties of 2 warm vertical compaction techniques (BeeFill 2in1, System B/Obtura II) in comparison with single-cone and cold laterally compacted gutta-percha., Study Design: The root canals of single-rooted human teeth were prepared by using Mtwo rotary files and divided into 4 groups (n = 10/group) with respect to the filling technique tested: Group 1, cold laterally compacted gutta-percha + AH-26; Group 2, single-cone tapered Mtwo gutta-percha + AH-26; Group 3, System B/ObturaII + AH-26; Group 4, BeeFill 2in1 + 2seal. The leakage of specimens was measured using a fluid-filtration method after 1 and 2 weeks. The data were analyzed statistically with 2-way repeated measures ANOVA (P = .05)., Results: After 1 week, the System B/Obtura II group showed the greatest amount of leakage(P < .05) compared with the other test groups that had similar levels of fluid conductance(P < .05). By the end of the second week, the BeeFill group yielded the greatest amount of leakage (P < .05). Compared with their 1-week values, the fluid conductance of all test groups decreased significantly (P < .05)., Conclusion: The apical sealing efficiency of System B/Obtura II and BeeFill were inferior to the other obturation techniques after 2-week fluid conductance testing in vitro.

Objective: The aim of this study was to examine the quality of root fillings in small and curved root canals using bidirectional radiographs and fluid transport (FT) measurements., Study Design: Root canals in eighty 38 degrees -curved mesial roots of mandibular molars were prepared using a balanced force technique. Samples were divided into 4 groups of 20 each and obturated by either the cold lateral compaction (LC) or the single cone (SC) technique, using either epoxy resin-based or zinc oxide-eugenol sealers. Bidirectional (buccolingual and mesiodistal) radiographs were acquired from each root. The voids along the root filling were assessed. The FT along the root filling was measured using an FT monitoring device. The differences between the groups regarding FT and the bidirectional radiographic score were analyzed by means of a Kruskal-Wallis test. The correlation between the FT values and the radiographic scores were analyzed using a Spearman test., Results: Three groups of LC or SC fillings containing epoxy resin-based sealers exhibited similar radiographic scores and FT values (P > .05). The group of SC fillings that contained zinc oxide-eugenol sealer had worse radiographic scores than the other groups (P = .047). The bidirectional radiographic scores and the FT values for the 80 filled roots were strongly correlated (r(2) = 0.519; P = .00001)., Conclusion: Root fillings of similar quality were confirmed in small and curved root canals filled using either a single cone or laterally compacted gutta-percha and epoxy resin-based sealers.

Objective: This study evaluated the ability of a resin-based system (Resilon/Epiphany) and gutta-percha/sealer with warm vertical or cold lateral compaction to prevent coronal leakage., Study Design: A polymicrobial suspension in a dual-chamber model was used. Seventy extracted maxillary incisors were prepared, divided into 4 groups, and obturated: Group 1, lateral compaction/gutta-percha/AH Plus; Group 2, lateral compaction/Resilon; Group 3, continuous wave compaction/gutta-percha/AH Plus; Group 4, continuous wave compaction/Resilon. Upper chambers held a mixed suspension of endodontic pathogens. Apices were suspended in the lower chambers. Leakage was determined daily for 40 days and evaluated for turbidity. Data were analyzed using survival analysis; log-rank test was used to analyze differences in time to leakage., Results: Median time to leakage: 16, 15, 11, and 25 days for Groups 1 to 4 respectively (P = .93, log-rank test)., Conclusion: No difference in time to leakage among the 4 treatment groups existed.

Objective: The objective of this study was to compare the short-term sealing abilities of recently introduced polymeric endodontic filling systems., Study Design: Root canals of 120 extracted and decoronated human single-rooted teeth were instrumented using crown-down technique with HERO Shaper rotary instruments. The roots were divided randomly into 8 groups (6 experimental and 2 control groups of 15 roots each) and filled with different combinations of core and sealer as follows: group 1, RealSeal/Resilon; group 2, RealSeal/Herofill; group 3, Hybrid Root Seal/Resilon; group 4, Hybrid Root Seal/Herofill; group 5, MM-Seal/Resilon; group 6, MM-Seal/Herofill; group 7, positive controls (Herofill only); group 8, negative controls. Apical leakage quantity was evaluated after 1 week by using a fluid filtration model. For each sample, measurements of fluid movement were recorded at 2-minute intervals for a total of 8 minutes, and then averaged. The data were calculated and analyzed using the Kolmogorov-Smirnov test, 1-way analysis of variance (ANOVA), and the Tukey test. Significance was set at P less than .05., Results: Multiple paired comparisons (Tukey test) showed that, of all the groups, MM-Seal/Herofill combination exhibited the least microleakage, and RealSeal/Herofill combination ranked second in this regard. The mean leakage values for the RealSeal/Resilon and MM-Seal/Resilon combinations were both significantly higher than the means for the other 4 experimental groups (P < .01). Hybrid Root Seal combined with Resilon resulted in significantly less microleakage than Hybrid Root Seal combined with Herofill (P = .001)., Conclusion: The results suggest that the sealing properties of epoxy-resin-based sealer (MM-Seal) combined with gutta-percha (Herofill) are superior to those of methacrylate-based sealers (Hybrid Root Seal and Realseal) combined with Resilon.

Objective: The aim of this study was to investigate the apical sealing ability of a newly introduced root canal sealer: iRoot SP Root Canal Sealer., Study Design: Sixty-eight extracted human anterior single-root teeth were used. The coronal part of each tooth was removed and the root canals were prepared with ProTaper files. The specimens were divided into 3 groups of 20 teeth each. Group A specimens were filled with iRoot SP using the continuous wave condensation technique; Group B specimens were obturated with iRoot SP using a single cone technique; Group C specimens were filled with AH plus by means of the continuous wave condensation technique. Evaluation of the apical leakage was performed with a fluid filtration method at 24 hours and 1, 4, and 8 weeks. Scanning electron microscopy (SEM) was used to qualitatively assess what mechanisms might be responsible for leakage of the different groups., Results: There was no significant difference in fluid leakage among the groups, as well as no time effect on leakage (P > .05). SEM revealed both gap-free regions and gap-containing regions in canals filled with both materials., Conclusion: iRoot SP was equivalent to AH Plus sealer in apical sealing ability.

Objective: The purpose of this study was to compare the sealing ability of an ultrasonically placed orthograde mineral trioxide aggregate (MTA) apical plug in open apices., Study Design: Thirty extracted human maxillary incisors were used. Experimental teeth were instrumented up to #100 file at the apex, and the 5 mm MTA apical barrier was placed with (group A; n = 11) or without (group B; n = 11) ultrasonic activation. Eight teeth served as control group. Bacterial leakage was assessed daily for 180 days using a double-chamber bacterial leakage model with Enterococcus faecalis. The results were analyzed with Fisher exact test., Results: After 60 days, the ratio of leaked samples showed significant difference between groups A (2 out of 10) and B (8 out of 11) (P < .05). The mean time elapsed before leakage showed significant difference between groups A (158 days) and B (23 days) (P < .05)., Conclusions: Ultrasonically placed orthograde MTA apical plugs were effective at delaying bacterial leakage.

Objective: The aim of this study was to compare the bond strength and apical sealing ability of master gutta-percha points with different tapers, as used in conjunction with different root canal sealers., Study Design: Roots of extracted human maxillary incisors (n = 135) were prepared with 0.06-taper nickel-titanium rotary files to final size 30. The roots were then randomly divided into 3 groups according to the root canal sealer used: 1) AH Plus; 2) Ketac-Endo; and 3) EndoREZ. Each sealer was combined with 1 of the following obturation techniques: 0.02-tapered gutta-percha master cone using lateral condensation, 0.04-tapered gutta-percha master cone using lateral condensation, or 0.06-tapered gutta-percha as a single cone. The bond strength and apical sealing ability were measured with the push-out test and dye penetration test, respectively. The data were statistically analyzed by using Kruskal-Wallis test with Bonferroni correction at P = .05., Results: Both the taper of the gutta-percha point and root canal sealers had significant effects on push-out bond strength (P < .001). According to the microleakage data, AH Plus exhibited significantly lower overall leakage, whereas no difference was found between master cone points (P = .093)., Conclusions: The use of matched-taper gutta-percha points in canals prepared with tapered rotary instruments may be advocated to improve bond strength ability of root canal filling material. Furthermore, AH Plus may be preferable to EndoRez and Ketac-Endo in terms of improved sealing and bonding quality of filling material.

Objective: To assess the long-term sealing ability of a new dual-curable, self-etching, 4-META containing resin-based sealer: Hybrid Root SEAL (MetaSEAL in the United States) and compare with RealSeal and AH Plus sealers., Methodology: Root canals of 44 extracted and decoronated single-rooted human teeth were instrumented using a crown-down technique with ProFile 0.04 tapered NiTi rotary instruments to ISO size 30 and then to size 45 with K-hand files. Four roots were selected and used as positive and negative controls (n = 2), the rest were randomly divided into 4 groups (n = 10) and filled using 0.04 tapered size 45 cones as follows: Group 1: AH Plus with gutta-percha; Group 2: Hybrid Root SEAL (MetaSEAL) with gutta-percha; Group 3: Hybrid Root SEAL (MetaSEAL) with Resilon point; and Group 4: RealSeal with Resilon point. The quality of seal of each specimen was measured after 1, 4, 12, and 24 weeks using a fluid transport model. Measurements were made at 2-minute intervals for 8 minutes. The data were calculated as Lp and statistically analyzed using 2-way repeated measures of ANOVA and Bonferroni pairwise comparison tests (alpha = 0.05)., Results: There were no significant differences among test materials in terms of fluid microleakage values (P = .126). There were statistically significant differences among the time periods (P = .009) and observed between 1- and 24-week test periods. There was significant interaction between root canal filling materials and time of testing (P = .048)., Conclusion: Within the limitations of this in vitro study, it was concluded that recently introduced Hybrid Root SEAL (MetaSEAL) showed similar sealing performance with RealSeal and AH Plus sealers when used either with gutta-percha or Resilon at 24 weeks.

Objective: To compare the root-end sealing of the different dentin-bonding adhesives (DBAs) in root-end cavities using a bacterial leakage system., Study Design: One hundred extracted single-rooted teeth were instrumented, and root-ends were resected and ultrasonically prepared. All teeth were then randomly assigned to 6 experimental groups (n = 15) and 2 control groups (positive and negative control; n = 5) for root-end filling with iBond (Heraeus Kulzer, Hanau, Germany), G-bond (GC Co., Tokyo, Japan), Xeno III Bond (Dentsply/Caulk, Milford, DE), AdheSe Bond (Ivoclar Vivadent, Schaa, Liechenstein), Clearfil Protect Bond (Kuraray, Osaka, Japan), or Clearfil Tri-S Bond (Kuraray). All preparations were further restored with a hybrid resin composite (Renew; Bisco, Schaumburg, IL). Nail varnish was applied to all external root surfaces to the level of the resected root-ends to prevent lateral microleakage. Samples were sterilized in an ethylene oxide sterilizer for 12 h. The apical 3-4 mm of the roots were immersed in brain-heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 h with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 h for 4 weeks. The data obtained were analyzed using a chi-squared test, with alpha = .05 as the level for statistical significance., Results: All positive controls leaked within 24 h; none of the negative controls leaked. Under the conditions of the study, despite some variations, there were no statistically significant differences in rate of bacterial leakage among the experimental test materials at 1-4 weeks (P > .05)., Conclusions: The type of DBA had no influence in the bacterial leakage of the root-end fillings.

Objective: To evaluate the effect of matrix on mineral trioxide aggregate (MTA) when used to repair furcal perforations., Study Design: Forty-five human molars with furcal perforations were randomly divided into 3 groups and repaired with MTA either alone or over a barrier (calcium sulfate or Collaplug). Eight teeth without perforations provided negative control samples. After assessing repair quality, 1 mol/L glucose solution was used as the tracer to detect the leakage. The concentration of leaked glucose was measured after 1, 2, 4, 7, 15, and 20 days using a glucose oxidase method., Results: No significant difference in either leakage or overfilling was found between the groups with Collaplug and MTA alone (P > .05). Although no overfilling was detected in the group with calcium sulfate, that group had the most leakage (P < .05)., Conclusions: Neither of the 2 internal matrices improved the sealing ability and reduced the incidence of overfilling simultaneously.

Few studies have compared Cavit thickness and access design as factors in microbial leakage. The present study used an acrylic tooth model to measure leakage of Streptococcus mutans. Pilot studies confirming the sterility of Cavit showed it will inhibit microbial growth for 2 days. The experiments compared class I preparations where Cavit thickness was 4 mm with class II preparations where thickness was 2-3 mm. Accesses sealed with cotton pellets were compared with those without cotton. Results of the study showed no bacterial contamination in any of the class I samples (up to 14 days). Some class II samples showed contamination at day 1 (3 out of 14), with all contaminated at day 7 (14 of 14), yet only 1 contaminated at day 14 (1 out of 14). The results suggest that a 4-mm thickness of Cavit should prevent bacterial ingress for at least 2 weeks, but microbial leakage may occur if temporary thickness is less than 3 mm or in a complex access preparation.

Objective: The aim of this study was to evaluate the sealing ability of Resilon after retreatment., Study Design: Sixty-six single-rooted mandibular premolars were enlarged to apical size 45 and then obturated with Resilon. The roots were randomly divided into 3 groups (n = 22/group). In group 1 no further treatment was done. Groups 2 and 3 were reinstrumented to apical size 60 using K-files and ProFile, respectively. In each group, 4 samples were kept for environmental scanning electron microscopy (ESEM) analysis. The remaining roots from groups 2 and 3 were refilled with Resilon. Sixteen roots from each group were then evaluated for microleakage; two roots served as controls. Data were analyzed statistically by Kruskall-Wallis test., Results: There were no significant differences between the experimental groups (P > .05). The ESEM showed new attachment of resin tags on the dentin surface of retreated roots., Conclusion: Resilon can be used for retreatment, but it still allowed microleakage.

Objective: The present study systematically compared the sealing ability of oval-shaped canals filled using the System B heat source with either gutta-percha/sealer or Resilon/Epiphany., Study Design: Eighty mandibular incisors with oval-shaped canals were selected after buccolingual and mesiodistal radiographs and divided into 3 experimental groups (n = 20). The teeth were obturated as follows: G1: gutta-percha/Pulp Canal Sealer EWT using cold lateral condensation; G2: gutta-percha/Pulp Canal Sealer EWT using the System B heat source; and G3: Resilon tips and Epiphany sealer using the System B heat source. The roots were mounted in a bacterial leakage model and the system was checked daily during the following 9 weeks. The log rank test was used to analyze the leakage data at intervals of 3, 6, and 9 weeks. The level of significance was set at P < .05., Results: Seven samples of G1 (35%) and 5 samples (20%) each of G2 and G3 were fully contaminated after 9 weeks. Data showed no significant difference between traditional gutta-percha/sealer and Resilon/Epiphany (P > .05). However, both materials showed significant difference to cold lateral condensation when System B heat source was used (P < .05)., Conclusions: The results demonstrated that Resilon/Epiphany combination do not improve the bacterial leakage resistance compared with traditional gutta-percha/sealer fillings.

Objective: The aim of this study was to measure leakage of 4 resin-based sealers., Study Design: Four groups of premolars (n = 60) were prepared using GT Rotary files and the crown-down technique and filled by the single-cone technique with AH26, AHPlus, EndoREZ, and an experimental MBP as sealer. Leakage was measured using the fluid filtration method after 15, 30, and 60 days and determined as microL/min(-1) x 10 psi., Results: Statistical analysis by ANOVA and Tukey HSD test indicated that root fillings with AH Plus and the MBP showed lower leakage values after 15 days (P < .05). At 30 days, AH26 presented higher leakage values when compared to other sealers (P < .05). At 60 days, MBP and AH Plus presented the lower leakage values, differing significantly from EndoREZ (P < .05)., Conclusion: It was observed that AH Plus and the experimental MBP showed lower leakage after 60 days than AH 26 and EndoREZ.

Objective: This study was performed to determine in vitro the short- and long-term sealing ability of a recently developed silicon-based root canal filling material (Gutta-Flow)., Study Design: Sixty human upper central incisors were divided into 3 groups (n = 20). The root canals were instrumented and obturated with laterally compacted gutta-percha and AH26 sealer (group 1), continuous-wave thermal compaction (System B technique) and AH26 sealer (group 2), and Gutta-Flow technique (group 3). Leakage along entire root canal fillings was measured by the movement of an air bubble in a micropipette connected to the experimental root using a fluid-transport model. Short-term leakage measurements were carried out for 3 hours after 24 hours of equilibrium establishment. Leakage was measured again and at 3, 6, and 12 months after the initial measurement., Results: At the 3-hour measurement, no significant differences were found among the 3 experimental groups. Long-term leakage measurements showed that at 3 and 6 months no significant differences were existed between Gutta-Flow and the other 2 techniques. However, at 12 months, root canal fillings with Gutta-Flow leaked significantly less than fillings of lateral compaction and System B technique., Conclusions: Gutta-Flow technique showed a similar sealing ability to either lateral compaction or System B technique. This comparison improved significantly over time. These findings may be related to the possible expanding capacity of the material and the partial dissolution of the sealer over time in the other 2 groups.

Objective: The purpose of this study was to evaluate the effect of immediate and delayed post space preparation on the sealing ability of a new root canal filling material., Study Design: Seventy-two extracted teeth were prepared and obturated with gutta-percha/AH-Plus and Resilon/Epiphany sealer by the lateral compaction technique. The teeth were divided randomly into 4 groups, and the post space was prepared either immediately after filling or after the obturated teeth had been stored in saline at 37 degrees C for a week. Leakage was determined by a fluid-transport device., Results: The results showed that immediate post space preparation of the Resilon/Epiphany-filled group had a mean leakage value of 0.81 microL/h, whereas the delayed preparation had a mean leakage value of 0.75 microL/h. No difference (P > .05) in microleakage was found between gutta-percha/AH-Plus and Resilon/Epiphany-filled groups after immediate preparation. There was significant difference between gutta-percha/AH-Plus and Resilon/Epiphany groups in the delayed post space preparation (P < .05)., Conclusion: Epiphany/Resilon obturation achieved better sealing than gutta-percha/AH-Plus at the apical end, especially in delayed post space preparation when mechanical techniques were used.

Objective: The capacities of bioactive glass S53P4 and calcium hydroxide suspensions to prevent microbial leakage through instrumented root canals were compared., Study Design: Root canals of caries-free extracted human mandibular premolars were instrumented and randomly filled with calcium hydroxide or S53P4 (n = 14 each). Crowns were exposed to Enterococcus faecalis ATCC 29212 suspensions in a test setup with 2 broth chambers, and leakage was checked daily. Event times were compared using log rank test. After 50 days, teeth were fractured and inspected in a scanning electron microscope (SEM)., Results: Calcium hydroxide prevented leakage significantly better than S53P4 (P < .05). Estimated mean days to leakage were 26 for calcium hydroxide and 4 days for S53P4. The SEM observations revealed substantial calcification of the glass material in the root canal but also gaps containing clusters of coccoidal bacteria., Conclusion: The bioactive glass material under investigation could not prevent contamination of instrumented root canals.

Objectives: The aim of this study was to compare bacterial penetration following obturation with 5 different techniques., Study Design: This study was performed on 120 teeth including negative control (n = 10), positive control (n = 10), and experimental groups (n = 100). One hundred teeth were randomly divided into 5 groups of 20 teeth each and obturated with System B (Sb), Lateral Compaction (Lc), Thermafil (T), Single ProTaper Gutta-percha (P), and laterally compacted ProTaper Gutta-percha (PLc). Enterococcus faecalis was used for determination of the bacterial penetration. Evaluation was carried out for 60 days., Results: At 30 days, the chi2 test showed that the slowest penetration was observed in Group Sb and Group PLc, which were not significantly different from each other. The fastest penetration in the all experimental groups was observed in Group T and Group P, which were not significantly different from one another. Also, there was no statistically significance difference (P > .05) among all groups at 60 days., Conclusion: It may be concluded that under the conditions of this study System B and laterally compacted ProTaper Gutta-percha prevent bacterial penetration of the root canal at 30 days. Furthermore, there was no difference among obturation techniques at 60 days.

Objective: Evaluate intraorifice sealing materials Cavit, Vitremer, and Flow-It for the prevention of coronal microleakage in root-canal treatment., Study Design: Root-canal treatment was performed on 80 extracted human molars. Three millimeters of coronal gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the 3 filling materials. After thermocycling (5 degrees C to 55 degrees C) and 5 days of immersion in dye, the teeth were cleared for stereomicroscope evaluation for evidence of dye penetration into the sealing material and along canal walls., Results: All groups showed dye penetration into the root canal. Cavit sealed significantly better than the other groups (P < .01), preventing the coronal leakage in 90% of the specimens. Flow-It exhibited the highest leakage (65% of specimens) and did not differ significantly from the Vitremer group, which showed dye penetration in 55% of specimens., Conclusion: Cavit sealed significantly better than Vitremer and Flow-It when used as intraorifice filling materials.

Objective: The aim of this study was to measure long-term leakage along single cone (SC) fillings., Study Design: Two groups of canines (n = 30) were prepared and a size 55 file was the apical master file. Step-back was performed using files of sizes 60, 70, and 80. The canals were filled by the single cone technique using RoekoRSA as sealer. To place sealer into each canal, a bidirectional spiral was used in 1 group, whereas a gutta-percha cone was used in the other group. Immediately after root filling, the coronal portion of root filling was removed by postspace preparation. Leakage along the 4 mm remaining apical root filling was measured after 1 week and again after 1 year using a fluid transport model. Ten additional canine roots were prepared and filled with gutta-percha cones without sealer, serving as positive controls. Occurrence of apical extrusion of materials was recorded., Results: The apical root filling in all 60 canine roots did not show leakage either at 1 week or at 1 year. All 10 positive controls showed gross leakage (>20 muL/h). In no case gutta-percha extruded through the apical foramen. Sealer extruded apically in 88% of the roots where a gutta-percha cone was used to introduce sealer, whereas in 28% of the roots where a bidirectional spiral was used to introduce sealer (by chi-square test, P < .05)., Conclusion: In wide and straight canals, SC fillings with RoekoRSA sealer prevented fluid transport for 1 year. Using bidirectional spiral to place sealer reduced sealer extrusion under the conditions of this experiment.

Objective: Outcome of pulpectomy in 2 treatment sessions with calcium hydroxide as an intracanal dressing was compared to a procedure comprising instrumentation and root-filling in 1 session., Study Design: Subjects with a vital pulp condition (N = 256) were recruited to a randomized clinical trial. Outcome parameters included radiographic signs of apical periodontitis and painful symptoms at clinical follow-ups 1 week and 1-3 years after treatment., Results: Of 244 subjects available for final recall, 17 presented with periapical radiolucency. Lesions were evenly distributed among the 2 treatment groups. Postoperative pain recorded 1 week after permanent filling was significantly associated with overfilling (P = .001), with no difference between treatment groups. There was no association with presence of overfilling and radiographic lesion at end point of recall., Conclusions: Study confirms that pulpectomy may be carried out at a high rate of success if due attention is given to aseptic operating procedures, proper instrumentation and filling. Under these conditions an interappointment dressing with calcium hydroxide does not seem to influence outcome.

Objective: The aim of this study was to make a quantitative assessment of the sealing ability of Super-EBA, IRM, and Pro Root MTA root-end fillings subjected to 3 different finishing techniques., Study Design: Eighty-one ultrasonically prepared root-end cavities in human canines were separated randomly into 3 test groups of 27 roots each. The cavities were filled with Super-EBA, IRM, or Pro Root MTA and finished by ball burnishing. Sequentially, 18 roots from each group received a final smoothing with either a 30-fluted tungsten carbide finishing bur or a Zekrya carbide 28-mm bur. Samples were prepared and immersed in 2% methylene blue dye neutral solution for 12 hours. Roots were ground into a powder and prepared for analysis in an absorbency spectrophotometer., Results: The results revealed that Pro Root MTA displayed significantly less mean dye microleakage ( P < .05) than Super-EBA and IRM root-end fillings. The Super-EBA root-end fillings, although presenting a greater mean dye microleakage, did not differ significantly from IRM ( P > .05). The finishing technique did not significantly ( P > .05) affect the incidence of microleakage among the materials tested., Conclusions: The favorable results obtained with MTA in leakage studies may be related to its good marginal adaptation. Spectrophotometric analysis may provide valuable information about the sealing capacity of root-end fillings. None of the procedures tested were able to avoid leakage, a finding that stresses the importance of the eradication of irritants within the root canal system.

The purpose of this study was to compare the ability of different thicknesses of mineral trioxide aggregate (MTA) to prevent apical leakage through the use of a protein-dye complex with Coomassie Brilliant Blue G. Sixty-four teeth were divided into 4 groups, then filled with MTA to depths of 1, 2, 3, or 4 mm. Two teeth served as the positive controls. Another 2 teeth served as the negative controls. Root-filled teeth were mounted in an apparatus and then challenged with protein solution. The evaluation was conduced at 24-hour intervals for 60 days. The 1-mm-thick MTA was the least effective in preventing apical leakage (P <.05). No significance difference was found between 2- and 3-mm-thick MTA (P >.05). Four-millimeter-thick MTA was significantly more effective than the other thicknesses tested (P <.05). The results of this study suggest that the thickness of 4 mm is most adequate for the use of MTA as a root-end filling material.

Objectives: In this in vitro study, the core-to-sealer ratios were calculated for 6 different gutta-percha techniques: Thermafil, JS Quick-Fill, Soft Core, Microseal, System B, and lateral condensation. The core consisted of gutta-percha or gutta-percha and carrier., Study Design: The sealer-to-core ratios for the Thermafil, JS Quick-Fill, System B, and lateral condensation techniques were published previously. In this study, the sealer-to-core ratio for Microseal and Soft Core techniques was investigated. For this purpose, 20 teeth filled by using the Soft Core or the Microseal technique were embedded in resin and sectioned horizontally at 1, 2, 3, and 4 mm from the anatomic apex. Photographs were taken of each section, and the total area of the canals filled with core material or sealer was calculated., Results: Once all results were compiled, it became clear that core techniques (Thermafil, JS Quick-Fill, and Soft Core) produced higher gutta-percha content than the Microseal, System B, and lateral condensation techniques (P <.05). The lateral condensation technique produced the least gutta-percha content (P <.05)., Conclusion: Thermafil, JS Quick-Fill, and Soft Core were found to be superior to the Microseal, System B, and lateral condensation techniques in terms of the gutta-percha-to-sealer ratio.

It has been recognized for many years that root canal instrumentation produces a smear layer that covers the surfaces of prepared canal walls. This layer contains inorganic and organic substances such as fragments of odontoblastic processes and necrotic debris. There is a lack of agreement regarding the effect of the smear layer on the quality of instrumentation and obturation, but the smear layer itself may be infected and may protect the bacteria within the dentinal tubules. Various methods have been used to remove the smear layer. Conflicting results have been obtained from numerous in vitro studies regarding the significance of the presence or the removal of the smear layer.

Objective: The objective of this clinical report was to evaluate the effectiveness of a microbrush as a carrier of priming-adhesive solution in formation of resin tags, adhesive lateral branches, and resin-dentin interdiffusion zone (RDIZ) when the brush was used to bond fiber posts under clinical conditions., Study Design: Twenty endodontically treated teeth, already scheduled for extraction for endodontic or periodontal reasons, were selected for this study. The patients were informed, and their written consent was obtained. The samples were randomly divided into 2 groups of 10 samples each. In group 1, One-Step (Bisco, Schaumburg, Ill) was applied with a brush with Duo-Link resin cement (Bisco). In group 2, One-Step was applied with a microbrush with Duo-Link resin cement (Bisco). Use of the adhesive systems and resin cements was strictly according to manufacturers' instructions. The priming-adhesive solution was light-cured before the dual resin cement and the post were placed. Twenty Aestheti-Plus posts (white quartz fiber posts; RTD, St. Egreve, France) were used. A week after application, the root samples were extracted and processed for SEM observations., Results: Both adhesive systems showed RDIZ and resin tag and adhesive lateral branch formation. In Group 2 samples, RDIZ morphology was easily detectable and uniform along root canals. Also, resin tag formation was well represented in all thirds. In group 1 samples, resin tag formation at the apical third and RDIZ formation was less evident. Statistically significant differences were found among the two groups at the apical third., Conclusion: The microbrush permitted a more uniform RDIZ and resin tag formation along the entire length of the canal than did the standard brush. The microbrush can be routinely used for bonding fiber posts into root canal preparations.

Objective: The purpose of this in vitro study was to evaluate the coronal microleakage in endodontic access cavities restored with Kalzinol (zinc oxide eugenol, De Trey, Dentsply Dental Products of India Ltd) and a zinc oxide eugenol (ZOE) intermediate restorative material at different intervals., Study Design: Restored access cavities were immersed in 2% freshly prepared methylene blue dye, and dye penetration was evaluated at 1-, 2-, 4-, and 7-day intervals., Results: ZOE cement displayed dye penetration throughout the complete depth of the restoration, reaching the pulp chamber by the second day, whereas Kalzinol produced leakage reaching the pulp chamber on the fourth day., Conclusion: Results indicated that none of the ZOE formulations tested could predictably produce a fluid-tight seal even up to the fourth day. We therefore recommend early replacement of these restorations during and after endodontic treatment to produce a better prognosis.

Objectives: In this in vitro study, the core (gutta-percha or gutta-percha and carrier)/sealer ratio and the sealing ability were calculated for 4 different gutta-percha techniques: Thermafil, JS Quick-Fill, System B, and lateral condensation., Study Design: One hundred single-rooted teeth were instrumented and obturated. Forty of the teeth were embedded in resin and sectioned horizontally at 1, 2,3, and 4 mm from the anatomic apex. Photographs were taken of each section, and the total area of the canal filled with core material or sealer was calculated. Sixty of the teeth were kept in wet storage for 90 days, after which the teeth were immersed in 2% methylene blue for 48 hours. The length of dye penetration was measured., Results: Roots obturated with Thermafil and JS Quick-Fill contained significantly more core material than did those obturated with System B or with lateral condensation. The lateral condensation technique had the lowest core/sealer ratio (P < .05). Roots using Thermafil and Quick-Fill showed significantly less dye leakage than did the lateral condensation technique., Conclusions: Through use of these techniques in vitro, Thermafil and JS Quick-Fill with carrier and System B were found to be superior to the lateral condensation technique in terms of core/sealer ratio. Thermafil and Quick-Fill were superior to lateral condensation in terms of dye leakage.

Objective: A common approach to creating an apical matrix (apical stop) in the apical dentin is to enlarge the root canal to 3 sizes greater than that of the first file that binds at the working length. The aim of this study was to test the hypothesis that this procedure will reduce the amount of material extruded and the leakage along the apical root fillings., Study Design: The canals of half of 120 maxillary and mandibular canines were prepared to the apical foramen through use of the serial shaping technique; the apical matrix creation procedure was not used. Each of the other 60 canals was prepared to 1 mm short of the apical foramen, and the canal was enlarged to at least 3 sizes greater than that of the first binding file to create an apical matrix. All the canals prepared with and all the canals prepared without the apical matrix creation procedure were obturated with laterally or vertically compacted cold or warm gutta-percha. In the leakage test, after post space preparation, the amount of fluid transport along the apical root fillings was measured. In the material extrusion test, the number of teeth with gutta-percha extrusion was recorded and the weight of the apically extruded materials was measured., Results: In both the leakage and the extrusion tests, no significant difference was found between canals prepared with and canals prepared without the apical matrix creation procedure., Conclusion: The hypothesis that a procedure to enlarge root canals to 3 sizes greater than that of the first binding file will reduce the amount of filling materials extruded and the leakage was not proved, as our results show.

Objective: The purpose of this in vitro study was to evaluate the coronal leakage of microorganisms from saliva into root canals filled by 3 obturation techniques., Study Design: Obturated canals were mounted in an apparatus and then exposed to human saliva. The number of days required for the entire contamination of the root canal was recorded. Evaluation was carried out for 60 days., Results: Regardless of the technique used, a significant number of specimens were contaminated after 30 and 60 days. No significant differences were detected among the techniques (P >.05)., Conclusions: Results indicated that none of the techniques tested could predictably produce a coronal bacteria-tight seal of the root canal after direct saliva challenge.

In light of the in vitro S. sanguis bacterial migration observed deep into root dentin, an in vitro system was developed to determine the viability of these bacteria at the end of migration. Also of interest is whether the smear layer formed during root canal instrumentation modifies migration into root dentinal tubules. Forty-eight bovine root dentin samples were randomly split into two groups. Group 1 dentin blocks were not instrumented and were treated with 17% ethylenediamine tetraacetic acid and 2.5% sodium hypochlorite for 4 minutes in an ultrasonic bath Group 2 root canals were conventionally instrumented. The smear layer formed was not removed. Dentin blocks were inoculated with a S. sanguis National Collection of Type Culture 7863 suspension. Each sample was immersed in a receiver broth, incubated at 37 degrees C, and checked daily for 14 days. After a 14-day incubation period, group 1 S. sanguis cells remained viable and capable of inoculating the receiver medium after migration through the tubules. Group 2 cells, where the smear layer was intact, revealed an absence of S. sanguis migration in 88% of the cases. It is therefore plausible that smear layer on canal walls limits S. sanguis penetration of dentinal tubules in vitro.

The purpose of this study was to examine the effect of smear layer on coronal microleakage. Fifty-two single-rooted extracted human teeth with a straight root canal were chemomechanically prepared and equally divided into experimental groups A and B. The teeth in group B were treated with ethylenediamine tetraacetic acid and sodium hypochlorite to remove the smear layer. All teeth in the experimental groups were next obturated with gutta-percha and sealer. Finally they were tested for dye leakage with methylene blue. Linear and volumetric measurement of dye penetration was used to assess leakage. The results of this study suggest that the removal of smear layer significantly improves the tightness of the sealing in the coronal area.