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Journal of Applied Oral Science :... 2009During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation... (Comparative Study)
Comparative Study Randomized Controlled Trial
UNLABELLED
During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation technique and quality of filling.
OBJECTIVE
The purpose of this study was to investigate the effect of immediate and delayed post space preparation on the integrity of the apical seal.
MATERIAL AND METHODS
Sixty-four extracted human incisors were biomechanically prepared using the step-back technique. Sixty roots were randomly assigned to 6 experimental groups of 10 teeth each and the remaining 4 roots served as positive and negative controls (n=2). The root canals in the different groups were obturated with cold lateral and warm vertical condensation of gutta-percha and one of two sealers (Sealapex and Diaket). Post space was prepared either individually or simultaneously. An insulated copper wire was cut into 10-cm-long pieces. In each canal, one piece was inserted to maintain contact with gutta-percha and extended to the outside as one of two working electrodes. A stainless steel wire with the same dimensions of those of the copper wire, used as the other working electrode, was immersed into the background electrolyte from the center of the bottle. The electrical current between standard and experimental electrodes in canals was measured over a period of 10 days applying a conductivity meter. The Kruskal-Wallis test (p=0.05) determined whether there was a significant difference in microleakage among the groups and the Mann-Whitney U test (p=0.01) was used for multiple comparison grouping variables.
RESULTS
The results suggest that only the differences between the root canal filling techniques were statistically significant (p<0.01). There were no statistically significant difference in the sealers and the times of filling removal for post space preparation (p>0.01).
CONCLUSION
The quality of the root canal filling is important for the integrity of the apical seal.
Topics: Bismuth; Calcium Hydroxide; Conductometry; Dental Bonding; Dental Leakage; Dental Pulp Cavity; Drug Combinations; Electrodes; Gutta-Percha; Humans; Incisor; Materials Testing; Polyvinyls; Post and Core Technique; Root Canal Filling Materials; Root Canal Obturation; Root Canal Preparation; Salicylates; Time Factors; Zinc Oxide
PubMed: 20027435
DOI: 10.1590/s1678-77572009000600013 -
Chemosphere Oct 2009The transformation of organic halogenated pesticides by laccase-mediator system has been investigated. Twelve pesticides were assayed in the presence of nine different...
The transformation of organic halogenated pesticides by laccase-mediator system has been investigated. Twelve pesticides were assayed in the presence of nine different mediators. Acetosyringone and syringaldehyde showed to be the best mediators. The halogenated pesticides bromoxynil, niclosamide, bromofenoxim and dichlorophen were transformed by the laccase-syringaldehyde system showing catalytic activities of 48.8, 142.0, 166.2 and 1257.6nmolmin(-1)U(-1), respectively. The highest pesticide transformation rates were obtained with a mediator-substrate proportion of 5:1, one of the lowest reported so far for the laccase-mediator systems. The analysis of the main product from the dichlorophen transformation showed that an oxidative dehalogenation is involved in the catalytic mechanism. Adduct formation between the mediator syringaldehyde and the pesticides dichlorophen or bromoxynil was also found after enzymatic oxidation. The main goal of this work is to evaluate environmental-friendly mediators for the pesticide transformation, and the potential of laccase-mediator system to efficiently reduce the environmental impact of organic halogenated pesticides is discussed.
Topics: Benzaldehydes; Biotransformation; Dichlorophen; Fungi; Halogenation; Laccase; Niclosamide; Nitriles; Oxidation-Reduction; Oximes; Pesticides; Trametes
PubMed: 19695672
DOI: 10.1016/j.chemosphere.2009.07.039 -
Oral Surgery, Oral Medicine, Oral... Sep 2009The aims of this study were to compare the radiopacity of 8 root canal sealers relative to gutta-percha and dentin in standard discs and to evaluate the effect of these... (Comparative Study)
Comparative Study
OBJECTIVE
The aims of this study were to compare the radiopacity of 8 root canal sealers relative to gutta-percha and dentin in standard discs and to evaluate the effect of these sealers on the radiopacity of root canal fillings in simulated canals.
STUDY DESIGN
Radiographs were taken of 1-mm-thick specimens of 8 root canal sealers (Diaket, Endion, MTA, Endofil, Roeko Seal, Sealite, AH26, AH Plus) and gutta-percha, a 1-mm-thick human tooth slice, and aluminum stepwedge.Simulated canals were used to evaluate the effect of the sealer on radiopacity of the root fillings. After enlargement of the simulated canals with ProTaper instrument, root canals were filled with these 8 sealers alone and with single ProTaper gutta-percha cone. Radiographs of all filled simulated canals were taken with an aluminum stepwedge.
RESULTS
All the sealers demonstrated greater radiopacity than dentin (0.7940 mm Al) (P < .001). AH Plus showed the highest radiopacity in the standard disc group (Group 1) (8.9881 mm Al) (P < .001), and in the sealer group in simulated canals (Group 2) (9.2100 mm Al) (P < .001). In the sealer plus gutta-percha group in simulated canals (Group 3), Sealite plus gutta-percha showed greater radiopacity (8.4460 mm Al) (P < .001).
CONCLUSION
Whether the opacity of the sealers alone is more or less than 3 mm Al, their radiopacity is increased when they are used in combination with gutta-percha, because of its higher radiopacity. However, when sealers are used in conjunction with gutta-percha, they can affect the radiopacity of the root canal filling according to their type and thickness.
Topics: Aluminum; Aluminum Compounds; Bismuth; Calcium Compounds; Contrast Media; Dental Cements; Dental Pulp Cavity; Dentin; Drug Combinations; Epoxy Resins; Glass Ionomer Cements; Gutta-Percha; Humans; Materials Testing; Models, Anatomic; Oxides; Polyvinyls; Radiography, Dental; Root Canal Filling Materials; Root Canal Preparation; Silicates; Silver; Surface Properties; Titanium; Zinc Oxide; Zinc Oxide-Eugenol Cement
PubMed: 19577493
DOI: 10.1016/j.tripleo.2009.04.016 -
International Endodontic Journal Mar 2009To evaluate the effect of leakage on differences in genotoxicity of root canal sealers ex vivo according to their main components using two different cytogenetic assays.
AIM
To evaluate the effect of leakage on differences in genotoxicity of root canal sealers ex vivo according to their main components using two different cytogenetic assays.
METHODOLOGY
Six materials of different composition (GuttaFlow, Epiphany, Diaket, IRM, SuperEBA and Hermetic) were tested on human peripheral blood lymphocytes using the comet assay and chromosomal aberration analysis. Prepared materials were eluted in physiological solution for 1 h, 1 day, 5 and 30 days. Thereafter cultures were treated with 8 microg, 4 microg and 2 microg of each sealer. Frequencies of chromatide and chromosome breaks and accentric fragments were determined. Comet assay was used to evaluate primary DNA damage by measuring tail length and tail intensity. Chi-square, Fisher's PLSD (Protected Least Significant Difference) and Kruskall-Wallis non parametric tests were used for statistical analysis.
RESULTS
After 1-h elution only the highest dose of Diaket, Hermetic and SuperEBA significantly (P = 0.035, P = 0.048, P = 0.037 respectively) affected the measured cytogenetic parameters. The migration ability of DNA was more strongly affected than induction of chromosomal aberrations. After elutions longer than 24 h none of the tested sealers exhibited a genotoxic effect.
CONCLUSION
Under the conditions used in the study all sealers had acceptable biocompatibility in terms of genotoxicity.
Topics: Biocompatible Materials; Bismuth; Cell Survival; Cells, Cultured; Chromatids; Chromosome Aberrations; Coloring Agents; Comet Assay; Dental Leakage; Dentin-Bonding Agents; Dimethylpolysiloxanes; Drug Combinations; Gutta-Percha; Humans; Lymphocytes; Materials Testing; Methylmethacrylates; Mutagens; Polyvinyls; Root Canal Filling Materials; Time Factors; Trypan Blue; Zinc Oxide; Zinc Oxide-Eugenol Cement
PubMed: 19228216
DOI: 10.1111/j.1365-2591.2008.01510.x -
Acta Odontologica Latinoamericana : AOL 2008The aim of this study was to evaluate in vitro the duration of the antimicrobial effect of endodontic sealers by means of the Direct Contact Test. The sealers tested...
The aim of this study was to evaluate in vitro the duration of the antimicrobial effect of endodontic sealers by means of the Direct Contact Test. The sealers tested were: Endomethasone - Septodont, Endomethasone C-Septodont, Endion-Voco, Diaket-ESPE, Pulp Canal Sealer-SybronEndo, and AH26-Dentsply DeTrey. The endodontopathic microorganisms (MO) confronted were: Staphylococcus aureus (Sa), Candida albicans (Ca), Enterococcus faecalis (Ef), Prevotella intermedia (Pi), Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn). Test specimens of each sealer were prepared and placed on the surface of agar plates that had been inoculated with each MO, and after predetermined periods, transfers were made from the contact area between the test specimen and the cultured agar and from the area that had not been in contact with the test specimens (control). The results were read as presence/absence of microbial growth and analyzed statistically using the Kruskal-Wallis test. It was concluded that the structural features and virulence of endodontopathic microorganisms determine their response to the sealers, independently of the time during which sealers act and the mechanism by which the antiseptic reaches the microorganism, which in this case was by direct contact.
Topics: Anti-Infective Agents; Bismuth; Candida albicans; Colony Count, Microbial; Creosote; Dental Pulp Diseases; Dexamethasone; Drug Combinations; Enterococcus faecalis; Epoxy Resins; Formaldehyde; Formocresols; Fusobacterium nucleatum; Glass Ionomer Cements; Humans; Hydrocarbons, Iodinated; Hydrocortisone; Microbiological Techniques; Polyvinyls; Porphyromonas gingivalis; Prevotella intermedia; Root Canal Filling Materials; Silver; Staphylococcus aureus; Thymol; Time Factors; Titanium; Virulence; Zinc Oxide
PubMed: 19177855
DOI: No ID Found -
British Journal of Pharmacology Jan 2009The cardiovascular effects of cannabinoids can be influenced by anaesthesia and can differ in chronic hypertension, but the extent to which they are influenced by acute...
BACKGROUND AND PURPOSE
The cardiovascular effects of cannabinoids can be influenced by anaesthesia and can differ in chronic hypertension, but the extent to which they are influenced by acute hypertension in conscious animals has not been determined.
EXPERIMENTAL APPROACH
We examined cardiovascular responses to intravenous administration of anandamide and the synthetic cannabinoid, (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone (WIN55212-2), in conscious male Wistar rats made acutely hypertensive by infusion of angiotensin II (AII) and arginine vasopressin (AVP). Rats were chronically instrumented for measurement of arterial blood pressure and vascular conductances in the renal, mesenteric and hindquarters beds.
KEY RESULTS
Anandamide dose-dependently decreased the mean arterial blood pressure of rats made hypertensive by AII-AVP infusion, but not normotensive rats. Interestingly, acute hypertension also revealed a hypotensive response to WIN55212-2, which caused hypertension in normotensive animals. The enhanced depressor effects of the cannabinoids in acute hypertension were associated with increased vasodilatation in hindquarters, renal and mesenteric vascular beds. Treatment with URB597, which inhibits anandamide degradation by fatty acid amide hydrolase, potentiated the depressor and mesenteric vasodilator responses to anandamide. Furthermore, haemodynamic responses to WIN55212-2, but not to anandamide, were attenuated by the CB(1) receptor antagonist, AM251 [N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophen yl)-4-methyl-1H-pyrazole-3-carboxamide].
CONCLUSIONS AND IMPLICATIONS
These results broadly support the literature showing that the cardiovascular effects of cannabinoids can be exaggerated in hypertension, but highlight the involvement of non-CB(1) receptor-mediated mechanisms in the actions of anandamide.
Topics: Acute Disease; Amidohydrolases; Animals; Arachidonic Acids; Benzamides; Benzoxazines; Blood Pressure; Cannabinoids; Carbamates; Consciousness; Endocannabinoids; Hindlimb; Hypertension; Infusions, Intravenous; Injections, Intravenous; Male; Morpholines; Naphthalenes; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Renal Circulation; Splanchnic Circulation; Vascular Resistance; Vasodilation
PubMed: 19133994
DOI: 10.1111/j.1476-5381.2008.00034.x -
European Journal of Pharmacology Jan 2009The possible inhibition of kinin B(1) receptor up-regulation by arachidonoylethanolamide (anandamide) was evaluated in isolated human umbilical vein. Anandamide and its...
The possible inhibition of kinin B(1) receptor up-regulation by arachidonoylethanolamide (anandamide) was evaluated in isolated human umbilical vein. Anandamide and its metabolically stable analogue, R-N-(2-Hydroxy-1-methylethyl)-5Z,8Z,11Z,14Z-eicosatetraenamide (R-(+)-methanandamide), produced a selective and dose-dependent inhibition of kinin B(1) receptor-sensitized contractile responses. The inhibitory effect of anandamide on B(1) receptor-sensitized responses failed to be modified either by 5-biphenyl-4-ylmethyl-tetrazole-1-carboxylic acid dimethylamide (LY2183240), a selective anandamide uptake inhibitor, or 6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-y l](4-methoxyphenyl) methanone (AM630), selective cannabinoid CB(2) receptor antagonist. However, the cannabinoid CB(1) receptor antagonist, N-(Piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophen yl)-4-methyl-1H-pyrazole-3-carboxamide (AM251), abolished anandamide effects on kinin B(1) receptor sensitization. The present results provide strong pharmacological evidence indicating that endocannabinoid anandamide inhibits kinin B(1) receptor up-regulation through cannabinoid CB(1) receptor stimulation in human umbilical vein.
Topics: Arachidonic Acids; Bradykinin B1 Receptor Antagonists; Cannabinoid Receptor Modulators; Dose-Response Relationship, Drug; Endocannabinoids; Humans; Polyunsaturated Alkamides; Receptor, Bradykinin B1; Receptor, Cannabinoid, CB1; Umbilical Veins; Up-Regulation
PubMed: 19022239
DOI: 10.1016/j.ejphar.2008.10.058 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Jul 2008In order to obtain salt-tolerant calli of Dandelion (Taraxacum officinale Weber), calli were induced from leaf explants of Dandelion on Murashige and Skoog's medium...
In order to obtain salt-tolerant calli of Dandelion (Taraxacum officinale Weber), calli were induced from leaf explants of Dandelion on Murashige and Skoog's medium supplemented with 2.0 mg/L 6-benzyladenine and 0.5 mg/L 2,4-dichlorophen oxyacetic acid With 1.5% NaCl as selection pressure, most calli became brown and dead, whereas some new cell clusters appeared at the edge of the brown calli after 2 to 3 weeks. The survived cells were picked out and sub-cultured every 3 weeks onto the fresh selection medium and salt-tolerant calli were finally obtained through 4 continuous selections on the selection medium supplemented with 1.5% NaCl. Salt-tolerant calli increased steadily under a fixed NaCl stress though their relative growth rate decreased with increased NaCl concentration whereas the control calli which were sub-cultured by 4 continus selections on salt free medium ceased to grow under the same condition. This result indicated that the salt-tolerance of the selected calli is improved and this character is stable. Compared with the control, the SDS-PAGE pattern of the salt-tolerant calli had a unique 34 kD protein band. Its 30 kD and 18 kD protein bands were up-regulated. Further more, within the NaCl stress range up to 1.5%, the activities of antioxidant enzymes such as super oxidase dimutase, peroxidase and catalase, and the proline contents of the salt-tolerant calli were higher than those of the control. The results indicated that the selected calli with improved and stable salt tolerance were cell variants. The accumulation of the organic compatible solutes including proteins and the enhanced antioxidant capabilities in the salt tolerant calli are the two ways for them to regulate their osmotic homeostasis and alleviate the secondary reactive oxygen spexies damage respectively.
Topics: Adaptation, Physiological; Cell Culture Techniques; Drug Tolerance; Salt-Tolerant Plants; Sodium Chloride; Stress, Physiological; Taraxacum
PubMed: 18837396
DOI: No ID Found -
Journal of Hazardous Materials May 2009Palladium, ruthenium and silver were investigated as catalysts for the dechlorination of dichlorophen (DCP, 2,2'-methylenebis(4-chlorophenol)), an antimicrobial and...
Palladium, ruthenium and silver were investigated as catalysts for the dechlorination of dichlorophen (DCP, 2,2'-methylenebis(4-chlorophenol)), an antimicrobial and anthelmintic agent largely used as algicide, fungicide and bactericide. Experiments were undertaken under oxic and anoxic conditions for experimental durations up to 180 min (3h). The anoxic conditions were achieved by purging the solutions with nitrogen gas. Reactions were performed in a 12+/-0.5 mg L(-1) DCP solution (V=20 mL) using 0.8 g of Fe(0) (40 g L(-1)). Along with micrometric Fe(0), five Fe(0)-plated systems were investigated: Pd (1%), Ru (0.01%), Ru (0.1%), Ru (1%) and Ag (1%). Metal plating was controlled by atomic absorption spectroscopy. DCP degradation was monitored using: (i) two HPLC devices, (ii) ion chromatography, (iii) UV and fluorescence spectrophotometry. Results indicated: (i) total dechlorination with Fe/Pd, (ii) partial dechlorination (40%) with Fe/Ru, and no reaction with Fe/Ag. DCP is vanished completely after 90 min of contact with Fe/Pd following a first order kinetic. The observed degradation rate k(obs) was about (3.98+/-0.10)x10(-2)min(-1), the calculated half-life t(1/2) about 17.4+/-0.9 min and a t(50) about 10.1+/-0.5 min. A DCP degradation pathway map was also proposed.
Topics: Anti-Infective Agents; Catalysis; Dichlorophen; Environmental Restoration and Remediation; Halogenation; Kinetics; Metals; Palladium; Ruthenium; Silver; Water Pollutants, Chemical; Water Purification
PubMed: 18819749
DOI: 10.1016/j.jhazmat.2008.08.048 -
Journal of Neurophysiology Nov 2008Previous studies have demonstrated that locally administered cannabinoids attenuate allodynia and hyperalgesia through activation of peripheral cannabinoid receptors...
Previous studies have demonstrated that locally administered cannabinoids attenuate allodynia and hyperalgesia through activation of peripheral cannabinoid receptors (CB(1) and CB(2)). However, it is currently unknown if cannabinoids alter the response properties of nociceptors. In the present study, correlative behavioral and in vivo electrophysiological studies were conducted to determine if peripheral administration of the cannabinoid receptor agonists arachidonyl-2'-chloroethylamide (ACEA) or (R)-(+)-methanandamide (methAEA) could attenuate mechanical allodynia and hyperalgesia, and decrease mechanically evoked responses of Adelta nociceptors. Twenty-four hours after intraplantar injection of complete Freund's adjuvant (CFA), rats exhibited allodynia (decrease in paw withdrawal threshold) and hyperalgesia (increase in paw withdrawal frequency), which were attenuated by both ACEA and methAEA. The antinociceptive effects of these cannabinoids were blocked by co-administration with the CB(1) receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophen yl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) but not with the CB(2) receptor antagonist 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-y l](4-methoxyphenyl)methanone (AM630). ACEA and methAEA did not produce antinociception under control, non-inflamed conditions 24 h after intraplantar injection of saline. In parallel studies, recordings were made from cutaneous Adelta nociceptors from inflamed or control, non-inflamed skin. Both ACEA and methAEA decreased responses evoked by mechanical stimulation of Adelta nociceptors from inflamed skin but not from non-inflamed skin, and this decrease was blocked by administration of the CB(1) receptor antagonist AM251. These results suggest that attenuation of mechanically evoked responses of Adelta nociceptors contributes to the behavioral antinociception produced by activation of peripheral CB(1) receptors during inflammation.
Topics: Action Potentials; Analysis of Variance; Animals; Arachidonic Acids; Cannabinoids; Dose-Response Relationship, Drug; Drug Interactions; Freund's Adjuvant; Inflammation; Male; Nerve Fibers, Myelinated; Neural Conduction; Nociceptors; Pain Measurement; Pain Threshold; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Reaction Time; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Skin
PubMed: 18784270
DOI: 10.1152/jn.90809.2008