Emre Nagas

Hacettepe University, Engüri, Ankara, Turkey

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Publications (28)43.94 Total impact

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    ABSTRACT: The purpose of this in vitro study was to evaluate the effect of various chelating solutions on the radicular push-out bond strength of calcium silicate-based and resin-based root canal sealers. Root canals of freshly-extracted single-rooted teeth (n = 80) were instrumented by using rotary instruments. The specimens were randomly divided into 4 groups according to the chelating solutions being tested: (1) 17% ethylenediaminetetraacetic acid (EDTA); (2) 9% etidronic acid; (3) 1% peracetic acid (PAA); and (4) distilled water (control). In each group, the roots were further assigned into 2 subgroups according to the sealer used: (1) an epoxy resin-based sealer (AH Plus) and (2) a calcium silicate-based sealer (iRoot SP). Four 1 mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength test was performed at a crosshead speed of 1 mm/min., and the bond strength data were analyzed statistically with two-way analysis of variance (ANOVA) with Bonferroni's post hoc test (p < 0.05). Failure modes were assessed quantitatively under a stereomicroscope. Irrespective of the irrigation regimens, iRoot SP exhibited significantly higher push-out bond strength values than AH Plus (p < 0.05). For both the sealers, the use of chelating solutions increased the bond strength, but to levels that were not significantly greater than their respective controls (p > 0.05). iRoot SP showed higher resistance to dislocation than AH Plus. Final irrigation with 17% EDTA, 9% Etidronic acid, and 1% PAA did not improve the bond strength of AH Plus and iRoot SP to radicular dentin.
    Full-text · Article · May 2015 · Brazilian oral research
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    ABSTRACT: Objectives: This study evaluated the effect of different root canal sealers on the push-out bond strength of tooth-colored posts to root dentin. Material and methods: Eighty human mandibular premolar teeth with single roots were decoronated and randomly divided into two groups according to post material: G1–G5: Cytec blanco; G6–G10: Cosmopost. In each group, the specimens were further subgrouped according to the filling material plus sealer (n = 8): G1, G6: Gutta-percha + AH Plus; G2, G7: Resilon + Epiphany SE; G3, G8: Gutta-percha + Sealite; G4, G9: Gutta-percha + iRoot SP; and G5, G10: control (unobturated). Cytec blanco and Cosmopost of 1.4 mm diameter were adhesively luted to samples using Variolink II. Push-out test was performed in a universal testing machine, and failure modes were examined under stereomicroscope. Data were analyzed with the two-way ANOVA and post hoc Tukey’s tests. Statistical significance was set to 0.05. Results: Roots obturated with AH Plus (3.48 ± 1.41 MPa), Sealite (3.47 ± 0.65 MPa), and Resilon (3.36 ± 1.23 MPa) had the lowest bond strength (p p p Conclusions: When the resin cement Variolink II was used, the types of root canal filling materials and sealers could affect the retentions of the fiber/zirconium posts; the fiber post revealed the higher bond values than the zirconium post; and the calcium silicate-based sealer (iRoot SP) revealed the highest bond strengths.
    No preview · Article · May 2015 · Journal of Adhesion Science and Technology
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    ABSTRACT: This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator. Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software. The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of ± 1.0 mm (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for ± 0.5 mm; r = -0.940 for ± 1.0 mm). The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.
    Full-text · Article · Feb 2015
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    ABSTRACT: AimTo evaluate the effect of prior application of several intracanal medicaments on the push-out bond strength of ProRoot MTA and Biodentine.MethodologySixty freshly-extracted maxillary anterior teeth were sectioned below the cementoenamel junction, and the root canals instrumented using rotary files. Thereafter, a parallel post drill was used to obtain a standardized root canal dimension. The roots were randomly assigned into one of the following groups with respect to the intracanal medicament applied: Group 1. Calcium hydroxide (CH) powder (Merck, Darmstadt, Germany) mixed with distilled water; Group 2. A mixture of metronidazole, ciprofloxacin, and minocycline (Triple Antibiotic Paste); Group 3. A combination of amoxicillin and clavulanic acid (Augmentin, Champs Pharmacy, San Antonio, TX, USA); Group 4. An antibiotic-corticoid compound paste (Ledermix Riemser, Greifswald, Germany); and Group 5. No medicament (Control). Following removal of medicaments with instrumentation and irrigation, the roots were cut into 1-mm-thick parallel transverse sections in a coronal-to-apical direction (5 slices/tooth). Thereafter, the specimens were divided into two subgroups according to the calcium silicate cement applied (n=30/group): 1. ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK, USA) and 2. Biodentine (Septodont, Saint-Maur-des-Fosses, France). A push-out test was performed and the data were analyzed statistically using two-way ANOVA and Tukey's post-hoc test.ResultsRegardless of the type of intracanal medicament used, Biodentine had significantly higher bond strength than MTA (p <0.05). The highest push-out bond strength results were obtained in CH-treated dentine. Compared with other medicaments, this value was only significantly higher than that of Ledermix (p<0.05). In both the MTA and Biodentine groups, pairwise comparisons between other medicaments showed similar debonding values (p>0.05).Conclusions Biodentine had a higher bond strength to root canal dentine than ProRoot MTA. Prior CH in distilled water intracanal placement increased the dislodgment resistance of both calcium silicate cements.This article is protected by copyright. All rights reserved.
    Full-text · Article · Jan 2015 · International Endodontic Journal
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    E. Uzunoglu · M. Gorduysus · E. Nagas
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    ABSTRACT: Objectives: The aim of this in vitro study was to compare the removal efficiency of calcium hydroxide (CH) medicament from the root canal walls with various devices. Materials and Methods: The root canals of 85 extracted human maxillary incisors were prepared with ProTaper NiTi rotary files and randomly divided into five experimental groups (n = 15), whilst the remaining teeth (n = 10) served as positive and negative controls. In each experimental group, CH was placed into the canals by using a lentulo spiral. The negative control did not receive CH placement, and the positive control received the CH, but no subsequent removal. After 7 days, the CH was removed using five different techniques: Group (G) I, Master apical file (MAF) + manual needle irrigation (MNI); GII, CanalBrush (CB) +MNI; GIII, RinsEndo (RE); GIV, Self-adjusting file (SAF) + Vatea; GV, CB+MNI, followed by SAF+Vatea. Irrigants, total irrigant volumes and total irrigation time were kept constant throughout the study for all the experimental groups. The roots were grooved longitudinally and split into halves. Images of each half of the canal were acquired by a digital camera. A scoring system of 1 to 4 was used to assess the amount of residue on the cervical, middle and apical third of the canal. Randomly selected three specimens from each group also evaluated with SEM. The data were subjected to statistical analysis using Kruskal-Wallis and Mann-Whitney tests, with Bonferroni correction, at 95% confidence level (P < 0.05). Results: Remnants of CH were found in all experimental teeth regardless of the device used. When examining the root canal as a whole, there was no significant difference between the groups. When examining the efficacy of CH removal from the apical, middle and cervical third of the canal separately between groups there was a statistically significant difference between the middle (p=0.003) and cervical (p=0.006) thirds. Conclusion: None of the techniques removed the CH medicament completely; the use of the RE and SAF facilitated removal of CH especially from the cervical third.
    Full-text · Article · Jan 2015
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    ABSTRACT: The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a calcium silicate-based sealer + gutta-percha; (3) a calcium silicate-based sealer + Resilon; (4) a methacrylate resin-based sealer (RealSeal SE) + Resilon; (5) an epoxy resin-based sealer (AH Plus) + gutta-percha, and (6) a mineral trioxide aggregate-based endodontic sealer (MTA Fillapex) + gutta-percha. Four 1-mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength testing was performed at a cross-head speed of 1 mm/min, and the bond strength data were analyzed statistically by one-way analysis of variance and Tukey tests (p < 0.05). The highest and lowest debonding values were obtained for the calcium silicate-based sealer bulk-fill and mineral trioxide aggregate-based endodontic sealer + gutta-percha groups, respectively (p < 0.05). It was concluded that the calcium silicate-based sealer showed higher resistance to dislocation in the bulk-filled form than in conjunction with the tested core filling materials. When the calcium silicate-based sealer was placed in bulk, its dislocation resistance was similar to that of commonly used sealer + core root filling systems. Thus, the concept of using a calcium silicate-based sealer in bulk can be more easily advocated in clinical practice.
    Full-text · Article · Sep 2014 · Brazilian oral research
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    ABSTRACT: The aim of the study was to evaluate the regional push-out bond strength of mineral trioxide aggregate (MTA) after exposure to sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), and peracetic acid (PAA) irrigation solutions. 1-mm-thick longitudinal slabs of root dentin were obtained from freshly extracted human canine teeth (n = 80). Simulated root perforation defects, 1 mm in diameter, were prepared in the coronal, middle, and apical thirds of radicular dentin. Mineral trioxide aggregate was placed into the cavities, and the specimens were stored for 1 week at 37°C. Thereafter, the specimens were randomly divided into four groups (n = 20) according to the irrigation solution applied over the repair sites: Group 1-10 ml of 5.25% NaOCl for 10 min; Group 2-10 ml of 5.25% NaOCl for 10 min, followed by 5 ml 17% EDTA for 5 min; Group 3-10 ml of 5.25% NaOCl for 10 min, followed by application of 5 ml 1% PAA for 5 min; and Group 4-no irrigation. Push-out test was performed at a crosshead speed of 1 mm/min. Debonding values were compared statistically using two-way analysis of variance and Tukey tests (P < 0.05). The push-out bond strength of MTA was not affected by the type of irrigation solution or location of the perforation defects (both P < 0.05). Stereomicroscopic inspection of the samples showed that the bond failure was predominantly adhesive. Exposure of repaired root perforations to 5.25% NaOCl, 17% EDTA, or 1% PAA does not alter the dislocation resistance of MTA at different locations of root dentin.
    Full-text · Article · Sep 2013 · Dental Traumatology
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    ABSTRACT: Objective: To compare the smear layer removal efficacy and erosive effects of different irrigation protocols under clinical and laboratory conditions. Materials and methods: Mandibular third molars (n = 32) of 30-45 year-old patients were instrumented with rotary files and were randomly assigned to one of the following groups for final irrigation: (1) 5.25% NaOCl; (2) 17% EDTA; and (3) BioPure MTAD. Thereafter, the teeth were immediately extracted and processed for micromorphological investigation. In vitro specimen pairs were prepared by repeating the clinical experiments on freshly-extracted mandibular third molars. To compare open and closed systems, laboratory experiments were repeated on 32 additional teeth with enlarged apical foramen. The cleanliness of the root canals and the extent of erosion were assessed by environmental scanning electron microscopy. Results: Specimens prepared under clinical and laboratory conditions had similar cleanliness and erosion scores (p > 0.05). Under both conditions, the tested solutions were more effective in removing the smear layer in the coronal and middle regions than in the apical one. Comparison of closed and open systems showed similar levels of cleanliness and erosion in all regions (p > 0.05), with the exception of 17% EDTA showing significantly higher levels of cleanliness and erosion in the apical third of open-end specimens. Conclusions: Based on clinical correlates of in vitro root canal cleanliness and erosion, laboratory testing of root canal irrigants on extracted teeth with closed apices can serve as a reliable method to simulate the clinical condition. EDTA was the most effective final irrigation solution in removing the smear layer at the expense of yielding the greatest erosive effect.
    Full-text · Article · Feb 2013 · Acta odontologica Scandinavica
  • S. KKKAYA · M. GRDUYSUS · E. NAGAS · I. TATAR · H. ELIK
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    ABSTRACT: Objectives: The purpose of this study was to investigate the presence and the incidence of a third canal in the mesial root of the permanent mandibular first molars using micro-computed tomography (micro-CT) and to describe the morphology of mandibular first molar's root canal anatomy. Methods: A total of 100 extracted mandibular first molars were randomly collected. Teeth were scanned by using micro-computed tomography device (SkyScan 1074, Aartselaar, Belgium). These images were reconstructed three-dimensionally by using software NRecon (SkyScan 1074, Kontich, Belgium). After constructing, three-dimensional images exhibiting the shape of the roots were analyzed by using 3D-Doctor software programme (v.3.5 Able Software Corp, Lexington,MA). Thereafter, the number of the middle mesial canals were evaluated. Results: The results of this study indicate that a middle mesial canal present in 12 % of mandibular first molars. In this study, the middle mesial canals merged with the mesiobuccal or mesiolingual canals. Conclusions: 12% of mandibular first molars had a middle mesial canal which is significantly important from a clinical point of view. The possibility of additional canal in the mesial root should be anticipated in mandibular first molars. Micro-CT is an effective tool for the detection such extra canals in teeth.
    No preview · Conference Paper · Sep 2012
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    E. UZUNOGLU · A. EYMIRLI · O. UYANIK · E. NAGAS
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    ABSTRACT: Objectives: To evaluate the effect of calcium hydroxide (Ca(OH)2) removal techniques on the accuracy of Root ZX in enlarged root canals and compare the efficiency of these techniques for the removal of Ca(OH)2from root canals. Methods: 90 freshly extracted human maxillary incisors were prepared with ProTaper rotary system to an apical size F3. During the preparation, root canals were irrigated with 2mL of 2.5% NaOCl solution between each file and then filled with injectable Ca(OH)2 paste. Specimens were stored for 1 week at 37°C in 100% relative humidity. 6 teeth assigned randomly as control group (G) and six groups (n=14) arranged as follows: G1: only irrigation with 10mL 0,9% saline, G2: same manner as G1 and instrumentation with master apical file (MAF), G3: 10mL 17% EDTA, G4: G3 and MAF, G5: 10mL 5,25% NaOCl, G6: G5 and MAF. All specimens were mounted in an experimental apparatus for measuring root lengths via Root-ZX. Electronic measurements compared with actual canal lengths that were determined at beginning of study by inserting #10 file until the tip was visualized (12.8× magnification) just within the apical foramina. After all roots sectioned longitudinally along the length of the instrumented canals, each half was examined with a stereomicroscope at 500× magnification and photographed digitally. Residual Ca(OH)2 in root canals were measured via COMEF 4.3 software. The measurements of residual Ca(OH)2was analyzed with oneway ANOVA with post-hoc LSD test, and lengths measurements was analyzed with Kruskal-Wallis with post-hoc Dunn’s test. Results: Significantly less residual material was obtained in G4 and G6 than the other groups (p< 0.05). Root ZX was highly accurate in G4 and G6. Conclusions: None of the techniques removed the Ca(OH)2 dressing completely. Remaining Ca(OH)2 influenced the accuracy of RootZX.
    Full-text · Conference Paper · Sep 2012
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    ABSTRACT: The objective of this study was to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) on root fracture with respect to various concentrations at different time exposures. A total of 48 mandibular incisors were selected. Eight nonprepared roots were selected as a negative control. The remaining 40 specimens were instrumented with rotary files and randomly assigned to one of the following groups for final irrigation: (1) 10 mL distilled water for 10 minutes (positive control); (2) 10 mL of 17% EDTA for 1 minute + 10 mL of 1% NaOCl for 1 minute; (3) 10 mL of 5% EDTA for 1 minute + 10 mL of 1% NaOCl for 1 minute; (4) 10 mL of 17% EDTA for 10 minutes + 10 mL of 1% NaOCl for 1 minute; (5) 10 mL of 5% EDTA for 10 minutes + 10 mL of 1% NaOCl for 1 minute. Thereafter, the root canals were filled by using AH26 root canal sealer with a single-cone technique. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with 1-way analysis of variance and Student's t test. Statistically significant differences were detected among the groups (P < .05). The highest mean fracture resistance was obtained from the group treated with 5% EDTA for 10 minutes. This is about 2 times more than the weakest mean fracture resistance, which was obtained from the 17% EDTA-10 minute group. The fracture resistances of endodontically treated roots were found to be differently affected by the various concentrations of EDTA at different time exposures.
    Full-text · Article · Aug 2012 · Journal of endodontics
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    ABSTRACT: To prepare the post apace, some of the root-canal filling material has to be removed, which can affect the apical seal. The aim of this study was to compare the effect of immediate post space preparation to that of delayed post space preparation on apical sealing using three different endodontic sealers and obturation techniques.Materials and methodsIn total, 90 decrowned single-rooted human teeth were studied. After root canals were prepared with 0.06 tapered nickel–titanium rotary files to size 30, the roots were categorized randomly into three experimental groups according to the obturation material: (1) AH plus/gutta-percha; (2) Sealite Ultra/gutta-percha; and (3) Epiphany/Resilon. Furthermore in all groups, specimens were categorized randomly into three subgroups according to the obturation technique (n = 10): (1) single cone; (2) cold lateral compaction; and (3) System B + Obtura. After root-canal filling, post space preparation was immediately performed in Group 1, after 24 hours in Group 2, and after 7 days in Group 3. Apical leakage was measured using the fluid-filtration method. Statistical analysis was performed using the Kruskal–Wallis test and Wilcoxon signed ranks test at P < 0.001.ResultsRegardless of the obturation technique and sealers used, significantly better (P < 0.001) sealing was achieved at the apical ends using delayed post space preparation than with immediate post preparation. The obturation techniques tested did not significantly affect leakage values. The following statistical ranking of fluid filtration values was obtained for the obturation materials: Epiphany/Resilon > Sealite Ultra/gutta-percha > AH plus/gutta-percha (P < 0.001).Conclusion To reduce apical leakage, clinicians should use AH plus together with any of the obturation techniques after 7 days of obturation.
    No preview · Article · Jul 2012 · Journal of dental sciences
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    ABSTRACT: The purpose of this study was to evaluate the effects of intraradicular moisture conditions on the push-out bond strength of root canal sealers. Eighty root canals were prepared using rotary instruments and, thereafter, were assigned to 4 groups with respect to the moisture condition tested: (1) ethanol (dry): excess distilled water was removed with paper points followed by dehydration with 95% ethanol, (2) paper points: the canals were blot dried with paper points with the last one appearing dry, (3) moist: the canals were dried with low vacuum by using a Luer adapter for 5 seconds followed by 1 paper point for 1 second, and (4) wet: the canals remained totally flooded. The roots were further divided into 4 subgroups according to the sealer used: (1) AH Plus (Dentsply-Tulsa Dental, Tulsa, OK), (2) iRoot SP (Innovative BioCeramix Inc, Vancouver, Canada), (3) MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, Brasil), and (4) Epiphany (Pentron Clinical Technologies, Wallingford, CT). Five 1-mm-thick slices were obtained from each root sample (n = 25 slices/group). Bond strengths of the test materials to root canal dentin were measured using a push-out test setup at a cross-head speed of 1 mm/min. The data were analyzed statistically by two-way analysis of variance and Tukey tests at P = .05. Irrespective of the moisture conditions, iRoot SP displayed the highest bond strength to root dentin. Statistical ranking of bond strength values was as follows: iRoot SP > AH Plus > Epiphany ≥ MTA Fillapex. The sealers displayed their highest and lowest bond strengths under moist (3) and wet (4) conditions, respectively. The degree of residual moisture significantly affects the adhesion of root canal sealers to radicular dentin. For the tested sealers, it may be advantageous to leave canals slightly moist before filling.
    Full-text · Article · Feb 2012 · Journal of endodontics
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    ABSTRACT: To evaluate the translucency characteristics of new flowable bulk-filling resin composites at various thicknesses. Experimental short fibre-reinforced composite was also tested. Two new brands of flowable bulk composites (Venus Bulk Fill and SureFil SDR Flow), experimental short fibre-reinforced resin composite (FC) and, as control, conventional flow (Filtek Supreme Flow XT A3) and universal (Filtek Universal Supreme XTE A3B) resin composites were investigated. Translucency parameter was calculated for various thicknesses of composite (1, 2, 3, 4, 5 and 6 mm) over white and black backgrounds using spectrophotometry to determine the CIELAB values of each specimen. Data were statistically analysed with analysis of variance. Translucency values significantly correlated with thickness of resin composite specimens (P < 0.05). For the new types of flowable bulk-filling material, translucency was observed for thicknesses up to 5 to 6 mm, whereas for experimental FC composite, the effect was observed up to 4 to 5 mm, and for control flow and universal filling composites, up to 2 to 3 mm. New flowable bulk-filling resin composites have less masking ability than conventional universal filling resin composite materials, which should be taken into account when optimum colour match and aesthetic results are to be achieved.
    No preview · Article · Jan 2012 · The Chinese journal of dental research: the official journal of the Scientific Section of the Chinese Stomatological Association (CSA)
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    ABSTRACT: The aim of this study was to compare the in vitro reduction of a bacterial population in a root canal by mechanical instrumentation using three rotary systems and hand instrumentation technique. The root canals contaminated with a suspension of Enterococcus faecalis were instrumented using ProTaper, K3, HeroShaper and K-file hand instrumentation technique. Later the root canals were sampled. After serial dilutions, samples were incubated in culture media for 24 h. Bacterial colonies were counted and the results were given as number of colony-forming units per millilitre. The results showed that all the canal instrumentation systems reduced the number of bacterial cells in the root canals. Statistically, ProTaper instruments were more effective in reducing the number of bacteria than the other rotary files or hand instruments.
    No preview · Article · Dec 2011 · Australian Endodontic Journal
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    ABSTRACT: The purpose of this study was to compare the amount of apically extruded irrigant using 2 Ni-Ti rotary systems. Forty mandibular premolars with single canals were randomly assigned into 4 groups. Flower arrangement foam cubes were weighed with a precision balance before being attached to the apical portions of all teeth. In group 1, preparation was completed with ProTaper files. In group 2 canals were prepared with RaCe files. In groups 1 and 2, the irrigant was delivered with a 30-gauge conventional dental needle. In groups 3 and 4, teeth were prepared as in groups 1 and 2 with the exception that the irrigant was delivered with a side-vented irrigation needle. The weight of the extruded material (irrigant and debris) for each group was calculated by comparing the pre- and postinstrumentation weights of the foams used for periapical modeling. Obtained data were analyzed by Kruskal-Wallis and Mann-Whitney U tests, with P equals .05 as the level for statistical significance. ProTaper files used with regular needle irrigation had the highest fluid extrusion. The lowest irrigant extrusion was observed with the RaCe system combined with a side-vented irrigation needle. Within the limitations of this study, it can be concluded that irrigation needle and rotary instruments have an effect on the amount of extruded root canal irrigant.
    No preview · Article · Jul 2011 · Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology
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    E Nagas · O Uyanik · V Durmaz · Z C Cehreli
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    ABSTRACT: To evaluate the effect of plunger diameter on the push-out bond strength of different root filling materials to root canal dentine. Freshly extracted human incisors (n=90) were decoronated, and the root canals were enlarged with post drills. Prepared roots were placed into a custom alignment apparatus to embed the roots vertically within self-curing acrylic resin. The specimens were randomly assigned into three groups according to the root filling system used: gutta-percha/AH Plus; Resilon/Epiphany; and fibre-reinforced composite (FRC)/Duolink resin cement. After filling, the specimens were further subdivided according to the diameter of the plunger used to employ the debonding force: 0.75, 1 and 1.25 mm. Intra-radicular bond strength was measured using the push-out test at a cross-head speed of 1 mm min(-1) . The data were analysed statistically using Kruskal-Wallis test with Bonferroni correction at P = 0.05. Regardless of the plunger diameter, FRC yielded the highest bond strength, followed by gutta-percha and Resilon, respectively (P<0.001). In all groups, greater plunger diameter resulted in an apparent increased bond strength, but the differences were only significant in the FRC group, with the 1.25-mm plunger generating higher debonding values compared with that of its 0.75- and 1-mm versions (P<0.001). In the gutta-percha and Resilon groups, the majority of specimens had adhesive failures. Roots filled with FRC exhibited more cohesive failures than those of the other test groups. Different plunger diameters are associated with significantly different intra-radicular push-out bond strengths of root filling systems.
    Full-text · Article · Jul 2011 · International Endodontic Journal
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    Emre Nagas · Zafer C Cehreli · Veli Durmaz
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    ABSTRACT: The objective of this study was to investigate and compare the effect of different light-emitting diode (LED) polymerization modes on the bond strength of a methacrylate-based sealer used with Resilon or gutta-percha. Forty extracted single-rooted teeth were sectioned off below the cementoenamel junction, and the root canals were instrumented by using rotary instruments to ISO #30/0.06 taper. The roots were randomly assigned into 1 of the following groups for root canal obturation: (1) RealSeal + Resilon and (2) RealSeal + gutta-percha. In each group, specimens were further subgrouped according to the LED polymerization mode used to cure RealSeal: (1) standard (20 seconds of maximum intensity) and (2) exponential (5 seconds of exponential power increase, followed by 15 seconds of maximum intensity). Specimens were stored in 100% humidity for 1 week at 37 °C. Push-out test was performed at a crosshead speed of 1 mm/min on 2-mm-thick root slices obtained from coronal to apical direction. Multivariate analysis of variance and Tukey tests were used for statistical analysis of the data (P=.05). Failure modes were examined under the scanning electron microscope. The tested polymerization modes had no significant effect on the bond strength values (P > .05). RealSeal + gutta-percha yielded significantly greater bond strength than RealSeal + Resilon (P < .05). In all groups, the bond strength values decreased significantly from coronal to apical direction (P < .05). Adhesive failure at the sealer-dentin interface was the predominant fracture mode. The exponential photopolymerization mode had no significant advantage over the standard regimen in terms of dentin bond strength.
    Full-text · Article · Jun 2011 · Journal of endodontics
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    ABSTRACT: This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon. Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests. Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P < .05), but not by the type of obturation system used (P > .05). The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier.
    Full-text · Article · Jun 2010 · Journal of endodontics
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    ABSTRACT: The objective of this study was to investigate the surface porosity of hand-mixed, syringe-mixed and encapsulated set endodontic sealers using image analysis. Eight different root canal sealers (AD Seal/Meta Biomed; AH Plus/Dentsply; MM Seal/Micromega; AH Plus Jet/Dentsply; EndoREZ/Ultradent; Epiphany/Pentron; GuttaFlow/Coltène; RealSeal/Sybron Endo) were prepared in accordance with the manufacturer's recommendations and dispensed into plastic rings (n = 10/group). Following set of the specimens, scanning electron photomicrographs of the sealer surfaces were taken at standard magnification. The area fraction and the minimum-maximum diameters of surface pores were calculated on the micrographs using ImageJ open-source image analysis software. Statistical comparisons were made between the sealers with respect to the area fractions and number of pores (Kruskal-Wallis test, P < .05). The endodontic sealers differed significantly in both the percentage of area fraction and pore count (P < .001). The surface porosity of the methacrylate-based sealers Epiphany and RealSeal were significantly lower than those of resin- and silicone-based sealers. With the exception of AD Seal, hand-mixed sealers displayed significantly higher surface porosity than those of syringe-mixed ones (P < .001). The encapsulated sealer GuttaFlow exhibited the highest surface area fraction of pores. The mixing method influences the surface porosity of set endodontic sealers.
    Full-text · Article · Jun 2010 · Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology