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ABSTRACT: 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.
Acta odontologica Scandinavica 02/2013; · 1.41 Impact Factor
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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.
Journal of endodontics 08/2012; 38(8):1110-3. · 2.95 Impact Factor
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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.
Journal of endodontics 02/2012; 38(2):240-4. · 2.95 Impact Factor
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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.
The Chinese journal of dental research: the official journal of the Scientific Section of the Chinese Stomatological Association (CSA) 01/2012; 15(1):31-5.
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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.
Australian Endodontic Journal 12/2011; 37(3):128-33. · 0.96 Impact Factor
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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.
Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 07/2011; 112(4):e31-5. · 1.50 Impact Factor
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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.
Journal of endodontics 06/2011; 37(6):832-5. · 2.95 Impact Factor
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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.
Journal of endodontics 06/2010; 36(6):1061-3. · 2.95 Impact Factor
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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.
Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 06/2010; 109(6):e117-22. · 1.50 Impact Factor
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ABSTRACT: To investigate the effects of an interfacial fiber-reinforced resin-based material (FRRM) application and different light-curing modes on the bond strength of a thermoplastic synthetic polymer-based root canal filling material (Resilon) to a methacrylate-based sealer (Epiphany).
One hundred Resilon disks were prepared and divided into two experimental groups: 1. application of FRRM (EverStick Net) on the Resilon surface, and 2. Resilon alone (control). Following subsequent application of the Epiphany sealer, the specimens were randomly assigned into 3 subgroups according to the curing method employed: 1. chemical curing, 2. quartz-tungsten-halogen (QTH) light, and 3. light-emitting diode (LED). The latter two groups were further subdivided to test the effects of two different polymerization modes for each light-curing unit. Cured specimens were subjected to shear bond strength testing and the failure modes were examined. The data were analyzed with three-way analysis of variance (ANOVA).
Regardless of the curing method tested, application of FRRM at the interface significantly increased the bond strength of Resilon to Epiphany (p < 0.001). Bond strength values (MPa) were as follows (mean +/- SD): 1. chemical curing with FRRM= 3.0 +/- 0.4, without FRRM = 1.2 +/- 0.3; 2. QTH: a) standard mode with FRRM = 8.6 +/- 0.6, without FRRM = 5.5 +/- 0.9; b) ramp mode with FRRM = 8.0 +/- 1.0, without FRRM = 5.3 +/- 1.4; 3. LED: a) standard mode with FRRM = 8.8 +/- 1.1, without FRRM = 5.4 +/- 1.0; b) exponential mode with FRRM = 8.5 +/- 1.0, without FRRM = 4.6 +/- 0.6. Although light curing of specimens significantly increased the bond strength of Resilon to Epiphany (p < 0.001), the type of light-curing unit and different curing modes had no significant influence on bond strength (p = 0.852 and p = 0.776, respectively).
The highest bond strength values were obtained when the FRRM was used at the interface and the sealer was light cured.
The journal of adhesive dentistry 09/2009; 11(4):325-30. · 1.11 Impact Factor
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ABSTRACT: The pulp chamber is inevitably exposed to irrigants during endodontic therapy. This study aimed to investigate whether different irrigation regimens would alter the sealing ability of repaired furcal perforations.
Pulp chambers of 90 extracted human molars were accessed, after which standardized diamond bur-cut perforations were created in the center of the pulp chamber floor. The canal orifices and the apical end of roots were sealed with acid-etch composite resin. Eighty teeth were randomly divided into 2 groups (n = 40/group) according to the material used for repairing the perforation defects: (1) Mineral trioxide aggregate (MTA), (2) Super-EBA. The remaining teeth (n = 10) served as controls. The specimens were further subgrouped according to the irrigation regimens applied over the repair site (n = 10/group): (a) 5.25% NaOCl, (b) 5.25% NaOCl + EDTA, (c) 5.25% NaOCl + MTAD, and (d) No irrigation. Coronal leakage was measured by the fluid-filtration method at 1 day and 1 week.
Fluid conductance was not affected by the type of repair material (P = .964) or time (P = .726), but was affected significantly by the irrigation regimens in the following ranking: (P < .001): NaOCl < or = No Irrigation < NaOCl + MTAD < or = NaOCl + EDTA.
The sealing ability of furcal perforations repaired with MTA or Super-EBA were differentially affected by exposure to the tested irrigation regimens.
Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 01/2009; 107(3):e91-5. · 1.50 Impact Factor
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ABSTRACT: 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.
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.
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).
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.
Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 01/2009; 107(1):e61-4. · 1.50 Impact Factor
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ABSTRACT: The purpose of this study was to compare the sealing ability of a resin- and polymer-based root canal obturation system (Resilon; Resilon Research LLC, Madison, CT/Epiphany; Clinical Technologies, Wallingford, CT) used in conjunction with different light-curing units and obturation techniques. A total of 120 decrowned single-rooted human teeth were used. After preparation of the root canals with 0.06 taper nickel-titanium rotary files to size 30, the roots were randomly assigned into three experimental groups according to the obturation technique used: (1) single cone, (2) cold lateral compaction, and (3) System B + Obtura. In all groups, the specimens were randomly assigned into four subgroups according to the polymerization method that was used to cure Epiphany sealer from the coronal aspect: (1) quartz-tungsten-halogen (QTH), (2) light-emitting diode (LED), (3) plasma-arc curing (PAC), and (4) chemical cure (uncured). Leakage was measured by the fluid-filtration method at 1 day and 1 week. Statistical analysis was performed by using Kruskal-Wallis and Wilcoxon signed-rank tests at p < 0.001. Fluid conductance of all groups increased significantly within time (p < 0.001). The tested obturation techniques had no significant effect on the leakage values (p = 0.433). The following statistical ranking was obtained for fluid-filtration values: uncured > PAC > LED > QTH (p < 0.001).
Journal of endodontics 11/2008; 34(10):1230-2. · 2.95 Impact Factor
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ABSTRACT: In this study we compared the micropush-out (micro-PO) and microtensile (micro-TBS) test methods for resin composites on different levels and surfaces of dentin.
Thirty-four sound human molars were divided into two groups in accordance with the dentin surface used (occlusal (O) or mesio-distal (M)), then subdivided into a further two groups in accordance with the test method (micro-PO (P) or micro-TBS (T)). In groups OP and OT, teeth were ground occlusally perpendicular to their axis, and in groups MP and MT, mesio-distally parallel to their axis to expose dentin. Dentin disks were prepared from different regions of the teeth either in an occluso-cervical (group OP) (n=5) or mesio-distal direction (group MP) (n=5) (S, superficial; M, middle; D, deep). One-hundred-and-twenty standardized occlusal cavities were prepared in these dentin disks using a conical-shaped diamond rotary cutting instrument. The adhesive (Adper Scotchbond Multi-Purpose Dental Adhesive) and a composite material (Filtek Z250 Universal Restorative) were applied and polymerized with a LED light curing unit (Elipar FreeLight 2). The disks (n=20/per group) were tested in a universal testing machine and pushed out with a cross-head speed of 1.0 mm/min. In groups OT (n=12) and MT (n=12), the teeth were ground to expose superficial, middle, and deep dentin. Build-ups of resin composite were constructed with the same materials. The specimens were serially sectioned and trimmed to hour-glass shapes, then tested with the micro-TBS tester at a rate of 1 mm/min. Failure modes were examined using a stereomicroscope and scanning electron microscope.
ANOVA revealed significant differences among the groups (p<0.001). With the push-out test, no premature failure occurred, the variability of the data distribution was acceptable, and regional differences in bond strength among dentin levels could be assessed.
The micro-PO test method could be an alternative to the micro-TBS technique.
Acta odontologica Scandinavica 05/2008; 66(2):73-81. · 1.41 Impact Factor
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ABSTRACT: The purpose of this study was to assess the push-out bond strength and coronal microleakage of the Epiphany (Pentron Clinical Technologies, Wallingford, CT) + Resilon (Resilon Research LLC, Madison, CT) obturation system with respect to different photoactivation methods used. Roots of human maxillary central incisors (n = 60) were prepared with 0.06 taper nickel-titanum rotary files to size 30. After application of the Epiphany sealer, the roots were obturated with Resilon cones. The specimens were randomly assigned into three groups (n = 10/group) according to the light-curing unit (LCU) used from the coronal aspect: (1) quartz-tungsten-halogen/40 seconds, (2) light-emitting diode/20 seconds, and (3) plasma arc/6 seconds. Thereafter, 2-mm thick horizontal sections (n = 3) were obtained from each specimen from the coronal to apical direction and subjected to push-out test at a crosshead-speed of 1mm/min. Failure modes were assessed quantitatively under a stereomicroscope and morphologically under a scanning electron microscope. The remaining 30 roots were used for the dye-leakage assessments. Both the type of LCU and the level of sectioning had significant effects on bond strength. The following statistical ranking was obtained for bond strength values: quartz-tungsten-halogen > light-emitting diode > plasma arc. Coronal microleakage of specimens cured with the plasma arc was significantly greater than those of other groups (p < 0.05).
Journal of Endodontics 12/2007; 33(12):1464-8. · 2.88 Impact Factor
