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Dye Leakage (dye + leakage)
Selected AbstractsAn in vitro comparison of three thermal gutta percha systemsINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2001M. P. Horrocks Aim,The aim of this study was to compare the ability of three contemporary obturation techniques to resist microleakage, using root canals prepared in extracted single rooted teeth by a standardized method. Methodology,The shaping technique involved the use of tapered nickel titanium rotary files to create a uniform 0.08-mm/mm taper. Six groups were compared, two representing control groups, a third group being obturated with a warm vertical condensation technique, a fourth group by an injection thermoplasticized system, a fifth group with a thermomechanical compaction method and a sixth group using cold lateral condensation. A zinc oxide/eugenol sealer was used as the sealant in all the obturation procedures. Forty-six extracted teeth were used in the study, three teeth in each control group and 10 teeth in each of the remaining four groups. Microleakage was compared using dye leakage with Indian ink. Penetration of the dye at the gutta percha/dentine interface was visualized after the root had been rendered transparent. Dye leakage was then measured from four aspects with the use of a stereomicroscope and export of a digital image to a software package, to facilitate accurate assessment of dye penetration. Two parameters were measured for each sample, the mean dye penetration and maximum dye penetration. Results,The mean values for linear dye leakage in the thermomechanical compaction group was 0.53 mm, the warm vertical condensation group was 0.73 mm, the injection thermoplasticized group was 0.15 mm and the cold lateral condensation group was 0.53 mm. There was no statistical difference between the means of the different groups (P > 0.05). The mean of the maximum values for dye leakage in the thermomechanical compaction group was 0.65 mm, the warm vertical condensation group was 1.02 mm, the injection-thermoplasticized group was 0.28 mm and the cold lateral condensation group was 0.74 mm. There was no statistical difference between the means of the different groups (P > 0.05). Conclusions,Within the conditions of this study, there was no statistical difference between the different groups with respect to either mean or maximum dye leakage. [source] Simultaneous Optical Mapping of Transmembrane Potential and Intracellular Calcium in Myocyte CulturesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2000VLADIMIR G. FAST Ph.D. Simultaneous Mapping of Vm and Cai2+. Introduction: Fast spatially resolved measurements of transmembrane potential (Vm) and intracellular calcium (Cai2+) are important for studying mechanisms of arrhythmias and defibrillation. The goals of this work were (1) to develop an optical technique for simultaneous multisite optical recordings of Vm and Cai2+, and (2) to determine the relationship between Vm and Cai2+ during normal impulse propagation in myocyte cultures. Methods and Results: Monolayers of neonatal rat myocytes were stained with fluorescent dye RH-237 (Vm) and Fluo-3AM (Cai2+). Both dyes were excited at the same wavelength range. The emitted fluorescent was optically separated into components corresponding to changes in Vm, and Cai2+ and measured using two 16 × 16 photodiode arrays at a spatial resolution of up to 27.5 ,m per diode and sampling rate of 2.5 kHz. The optical setup was adjusted so that there was no optical cross-talk between the two types of measurements, which was validated in experiments involving staining with either RH-237 or Fluo-3. The amplitude of Fluo-3 signals rapidly decreased during experiments due to dye leakage. Dye leakage was substantially reduced by application of 1 mM probenecid, a blocker of organic anion transport, which had no effect on action potential duration and only minor effect on conduction velocity. In double-stained preparations, during regular pacing Cai2+ transients had a rise time of 14.2 ± 2 msec, and they followed Vm upstrokes with a delay of 5.3 ± 1 msec (n = 9). Durations of Vm, and Cai2+ transients determined at 50% level of signal recovery were 54.6 ± 10 msec and 136 ± 8 msec, respectively. Application of 2 ,M nifedipine reduced the amplitude and duration of Cai2+ transients without significantly affecting conduction velocity. Conclusion: The results demonstrate feasibility of simultaneous optical recordings of Vm and Cai2+ transients with high spatial and temporal resolution. [source] Microleakage of composite resin restorations in cervical cavities prepared by Er,Cr:YSGG laser radiationAUSTRALIAN DENTAL JOURNAL, Issue 2 2008S Shahabi Abstract Background:, Evaluation of microleakage is important for assessing the success of new methods for surface preparation and new adhesive restorative materials. The aim of this laboratory study was to assess microleakage at the margins of composite restorations in Er,Cr:YSGG laser prepared cavities on the cervical aspects of teeth by means of dye penetration, and compare this with conventionally prepared and conditioned cavities. Methods:, Class V cavities were produced on sound extracted human teeth, which had been assigned randomly to one of three groups (N = 10 each), as follows: Group 1 , prepared using a diamond cylindrical bur and then treated with 37% phosphoric acid; Group 2 , irradiated with an Er,Cr:YSGG laser (Biolase Waterlase) and then treated with 37% phosphoric acid; Group 3 , irradiated only with the laser. After application of bonding agent (Excite, Ivoclar Vivadent), all cavities were restored with composite resin (Heliomolar). After polishing the restorations, the teeth were thermocycled from 5,50°C for 500 cycles. Dye leakage was assessed after immersion in methylene blue, by examining longitudinal sections in a stereomicroscope at ×30 magnification. Results:, The extent of dye penetration was lowest in the laser only group (Group 3). Penetration of dye to dentine and axial walls occurred in 80 per cent of conventionally prepared (bur + acid) specimens, but in the laser group, dye penetration to the axial wall occurred in only 30 per cent of cases. There was a strong statistical association between treatment group and the distribution of microleakage scores (Chi-square, P = 0.0023). Conclusions:, For Class V cavities, with the adhesive materials employed, higher microleakage occurs with phosphoric acid etching of bur- or laser-cut surfaces, than with the surface created by use of the laser alone without additional conditioning. [source] Sealing ability of occlusal resin composite restoration using four restorative proceduresEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2008Danuchit Banomyong The purpose of this work was to investigate fluid flow after restoration using four restorative procedures. Micro-gap, internal dye leakage, and micropermeability of bonded interfaces were also investigated. Each tooth was mounted, connected to a fluid flow-measuring device, and an occlusal cavity was prepared. Fluid flow after cavity preparation was recorded as the baseline measurement, and the cavity was restored using one of four restorative procedures: bonding with total-etch (Single Bond 2) or self-etch (Clearfil SE Bond) adhesives without lining; or lining with resin-modified glass-ionomer cement (GIC) (Fuji Lining LC) or conventional GIC (Fuji IX) and then bonding with the total-etch adhesive. Fluid flow was recorded after restoration and at specific time-points up to 6 months thereafter and recorded as a percentage. Micro-gap formation was analyzed using resin replicas and scanning electron microscopy. Internal leakage of 2% methylene blue dye was observed under a light microscope. In micro-permeability testing, fluorescent-dye penetration was investigated using confocal laser microscopy. None of the restorative procedures provided a perfectly sealed restoration. Glass-ionomer lining did not reduce fluid flow after restoration, and micro-gaps were frequently detected. The self-etch adhesive failed to provide a better seal than the total-etch adhesive, and even initial gap formation was rarely observed for the former. Penetration of methylene blue and fluorescent dyes was detected in most restorations. [source] Sealing capacity of a photochromatic flowable composite as protective base in nonvital dental bleachingINTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2006C. Llena Abstract Aim, To evaluate microleakage of a flowable composite used as a protective isolating base, applied with different adhesive systems. Methodology, Seventy root-filled teeth were divided into seven groups. A flowable composite base (Tetric Flow Chroma) was used with three adhesive techniques (Syntac, Excite, Excite DCS; in the three cases with and without acid etching) and in a control group without dentine conditioning or adhesive placement. A 30% hydrogen peroxide solution was applied for 24 h in the pulp chambers, followed by the placement of a dye (silver nitrate) for 4 h. Each tooth was sectioned longitudinally, and examined under 4× magnification to assess the tooth/restoration dye leakage following a four-degree scale. Percentage of dye penetration was registered. Statistical analysis was made through the Tukey and Mann,Whitney U -tests. Results, Maximum leakage (100% of specimens) was recorded in the control group without an adhesive system. In the groups subjected to acid etching, the percentage of leakage corresponded to Excite DSC (10%), followed by Syntac (20%) and Excite (30%). In the groups in which only an adhesive system was used, 50% of the teeth demonstrated dye leakage. Statistically significant differences in terms of leakage were observed between the control group and the experimental groups (P < 0.05). There were no significant differences among the experimental groups, but comparing the leakage percentages obtained between the groups in which the teeth were subjected to prior acid etching, and those in which no etching was carried out, observed differences were significant (P = 0.04). Conclusions, There were no significant differences between the adhesive systems in terms of leakage. Acid etching significantly reduced leakage. [source] An in vitro comparison of three thermal gutta percha systemsINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2001M. P. Horrocks Aim,The aim of this study was to compare the ability of three contemporary obturation techniques to resist microleakage, using root canals prepared in extracted single rooted teeth by a standardized method. Methodology,The shaping technique involved the use of tapered nickel titanium rotary files to create a uniform 0.08-mm/mm taper. Six groups were compared, two representing control groups, a third group being obturated with a warm vertical condensation technique, a fourth group by an injection thermoplasticized system, a fifth group with a thermomechanical compaction method and a sixth group using cold lateral condensation. A zinc oxide/eugenol sealer was used as the sealant in all the obturation procedures. Forty-six extracted teeth were used in the study, three teeth in each control group and 10 teeth in each of the remaining four groups. Microleakage was compared using dye leakage with Indian ink. Penetration of the dye at the gutta percha/dentine interface was visualized after the root had been rendered transparent. Dye leakage was then measured from four aspects with the use of a stereomicroscope and export of a digital image to a software package, to facilitate accurate assessment of dye penetration. Two parameters were measured for each sample, the mean dye penetration and maximum dye penetration. Results,The mean values for linear dye leakage in the thermomechanical compaction group was 0.53 mm, the warm vertical condensation group was 0.73 mm, the injection thermoplasticized group was 0.15 mm and the cold lateral condensation group was 0.53 mm. There was no statistical difference between the means of the different groups (P > 0.05). The mean of the maximum values for dye leakage in the thermomechanical compaction group was 0.65 mm, the warm vertical condensation group was 1.02 mm, the injection-thermoplasticized group was 0.28 mm and the cold lateral condensation group was 0.74 mm. There was no statistical difference between the means of the different groups (P > 0.05). Conclusions,Within the conditions of this study, there was no statistical difference between the different groups with respect to either mean or maximum dye leakage. [source] An in vitro investigation of the bulk flow of fluid through apical foramina during simulated tooth extraction: a potential confounder in microbiological studies?INTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2001A. Kapalas Aim,The ,pumping action' induced during tooth extraction may cause bacteria suspended in tissue fluids to be transposed from one anatomical compartment to another. Apart from causing bacteraemia, this may lead to inaccuracies in studies evaluating the presence and distribution of bacteria in and around tooth apices. The aim was to investigate the bulk flow of fluid through apical foramina during simulated extraction of teeth in an in vitro model. The influence of the presence or absence of a coronal restoration was also evaluated. Methodology,Twenty extracted single-rooted, human, mature, permanent teeth were used. Standard access cavities were prepared and the root canals located. Standardized micrographs of the apical foramina were obtained and their area (µm2) was calculated by image analysis software. The teeth were then set and sealed into polyvinylsiloxane (rubber base) impression material. Crystal violet dye was inoculated into the coronal half of the root canal system. Tooth extraction movements were simulated in the impression matrix and the leakage of dyes with and without the presence of a coronal restoration was examined. The procedure was repeated, following application of safranin dye in a coronal trough within the simulated rubber base gingival margin at the CEJ. The results were analysed statistically with the independent-samples t -test and the McNemar test. Results,In the absence of a coronal restoration crystal violet leaked out of the apical foramina in 18/20 teeth; conversely safranin leaked into the teeth through the apical foramina in 11/20 cases when applied to the external root surface. In the presence of an intact coronal restoration crystal violet dye leaked out in 6/20 teeth and conversely safranin leaked into 7/20 teeth. The presence of a coronal restoration significantly reduced (P = 0.002) dye leakage out of the root canal system. No associations were found for leakage of dye into the root canal system when applied externally. In addition, the amount of dye leakage was positively correlated with the area of the apical foramen in the presence of a coronal restoration (P = 0.009). Conclusion,The presence of a coronal restoration significantly reduced leakage of dye out of the apical foramen. Microbiological studies on root canals and periapical lesions using extracted teeth should take potential contamination from this source into account. [source] Simultaneous Optical Mapping of Transmembrane Potential and Intracellular Calcium in Myocyte CulturesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2000VLADIMIR G. FAST Ph.D. Simultaneous Mapping of Vm and Cai2+. Introduction: Fast spatially resolved measurements of transmembrane potential (Vm) and intracellular calcium (Cai2+) are important for studying mechanisms of arrhythmias and defibrillation. The goals of this work were (1) to develop an optical technique for simultaneous multisite optical recordings of Vm and Cai2+, and (2) to determine the relationship between Vm and Cai2+ during normal impulse propagation in myocyte cultures. Methods and Results: Monolayers of neonatal rat myocytes were stained with fluorescent dye RH-237 (Vm) and Fluo-3AM (Cai2+). Both dyes were excited at the same wavelength range. The emitted fluorescent was optically separated into components corresponding to changes in Vm, and Cai2+ and measured using two 16 × 16 photodiode arrays at a spatial resolution of up to 27.5 ,m per diode and sampling rate of 2.5 kHz. The optical setup was adjusted so that there was no optical cross-talk between the two types of measurements, which was validated in experiments involving staining with either RH-237 or Fluo-3. The amplitude of Fluo-3 signals rapidly decreased during experiments due to dye leakage. Dye leakage was substantially reduced by application of 1 mM probenecid, a blocker of organic anion transport, which had no effect on action potential duration and only minor effect on conduction velocity. In double-stained preparations, during regular pacing Cai2+ transients had a rise time of 14.2 ± 2 msec, and they followed Vm upstrokes with a delay of 5.3 ± 1 msec (n = 9). Durations of Vm, and Cai2+ transients determined at 50% level of signal recovery were 54.6 ± 10 msec and 136 ± 8 msec, respectively. Application of 2 ,M nifedipine reduced the amplitude and duration of Cai2+ transients without significantly affecting conduction velocity. Conclusion: The results demonstrate feasibility of simultaneous optical recordings of Vm and Cai2+ transients with high spatial and temporal resolution. [source] Effects of dimerization of the cell-penetrating peptide Tat analog on antimicrobial activity and mechanism of bactericidal actionJOURNAL OF PEPTIDE SCIENCE, Issue 5 2009Wan Long Zhu Abstract The cell-penetrating peptide Tat (48,60) (GRKKRRQRRRPPQ) derived from HIV-1 Tat protein showed potent antibacterial activity (MIC: 2,8 µM). To investigate the effect of dimerization of Tat (48,60) analog, [Tat(W): GRKKRRQRRRPWQ-NH2], on antimicrobial activity and mechanism of bactericidal action, its dimeric peptides, di-Tat(W)-C and di-Tat(W)-K, were synthesized by a disulfide bond linkage and lysine linkage of monomeric Tat(W), respectively. From the viewpoint of a weight basis and the monomer concentration, these dimeric peptides displayed almost similar antimicrobial activity against six bacterial strains tested but acted more rapidly against Staphylococcus aureus on kinetics of bactericidal activity, compared with monomeric Tat(W). Unlike monomeric Tat(W), these dimeric peptides significantly depolarized the cytoplasmic membrane of intact S. aureus cells at MIC and induced dye leakage from bacterial-membrane-mimicking egg yolk L -,-phosphatidylethanolamine/egg yolk L -,-phosphatidyl- DL -glycerol (7:3, w/w) vesicles. Furthermore, these dimeric peptides were less effective to translocate across lipid bilayers than monomeric Tat(W). These results indicated that the dimerization of Tat analog induces a partial change in the mode of its bactericidal action from intracellular target mechanism to membrane-targeting mechanism. Collectively, our designed dimeric Tat peptides with high antimicrobial activity and rapid bactericidal activity appear to be excellent candidates for future development as novel antimicrobial agents. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] | ||||||||||