Comparison of ProTaper Next and HyFlex instruments on apical debris extrusion in curved canals.

AIM: To evaluate the amount of apically extruded debris after root canal instrumentation with ProTaper Next and HyFlex instruments in curved root canals. METHODOLOGY: Forty extracted mandibular first molar teeth with curved mesial roots and of similar lengths were instrumented using ProTaper Next or HyFlex instruments. The extruded debris was collected into pre-weighed Eppendorf tubes. The tubes were stored in an incubator at 68 °C for 5 days. The tubes were weighed to obtain the final dry weight of the extruded debris. The weight of the extruded debris was determined by subtracting the initial weight from the final weight. Distribution of data was determined by Shapiro-Wilk test. Continuous variables were compared with the Independent Sample t-test or Mann-Whitney U-test. The significance level was set at P = 0.05. RESULTS: Both instruments were associated with apical debris extrusion. The HyFlex group had significantly less debris extrusion than the ProTaper Next group (P = 0.014). CONCLUSION: HyFlex CM was associated with significantly less apical extrusion than ProTaper Next.

Apical extrusion of debris using ProTaper Universal and ProTaper Next rotary systems.

AIM: To assess and compare the amount of extruded debris after canal preparation using ProTaper Universal and ProTaper Next files. METHODOLOGY: Forty extracted mandibular premolars with single canals and of similar lengths were instrumented using the ProTaper Universal F3 or the ProTaper Next X3. The extruded debris during instrumentation was collected into pre-weighed Eppendorf tubes. The tubes were stored in an incubator for 5 days. The tubes were weighed to obtain the final dry weight of the extruded debris. The amount of apically extruded debris was calculated by subtracting the initial weight of the tube from the final weight. The distribution of the data was examined using the Shapiro-Wilks test. Continuous variables were compared with an independent-samples t-test for two groups. RESULTS: All specimens were associated with apical debris extrusion. The ProTaper Universal group produced a significantly greater amount of debris extrusion (P < 0.001). The lowest and highest amounts of debris for PTU and PTN groups were recorded as 0.00117-0.00165 g and 0.00017-0.00067 g, respectively. CONCLUSION: ProTaper Next files was associated with significantly less extruded apical debris when compared to ProTaper Universal files.

The effects of calcium hydroxide removal methods on bond strength of Epiphany SE with two irrigation protocols.

OBJECTIVE: The purpose of this study was to compare the effects of five calcium hydroxide removal methods on the bond strength of Epiphany SE sealer after canal irrigation with NaOCl+EDTA or NaOCl+MTAD. MATERIALS AND METHODS: The 120 roots were instrumented by using the ProTaper rotary system under irrigation with 2.5% sodium hypochlorite and randomly divided into two major groups according to the final irrigation: 1.3% NaOCl + MTAD and 5% NaOCl + 17% EDTA. For controls, 10 roots from each of the final irrigations with NaOCl + MTAD and NaOCl + EDTA (20 roots) were not filled with Ca(OH)2. The intra-canal paste, Ca(OH)2 was applied to each of the 100 remaining roots and stored at 37°C for 7 days. Each group was sub-divided into five sub-groups (n = 10) according to the removal technique for the intra-canal dressing: Group-1: recapitulation with size 30 K file + 3 ml of saline solution, Group-2: recapitulation with size 30 K file + 3 ml of 5% NaOCl, Group-3: using 5% NaOCl + 17% EDTA, Group-4: using 5%NaOCl + 15% citric acid, and Group-5: using 1.3% NaOCl + 5 ml MTAD. The root canals were filled with Resilon and Epiphany SE sealer. The bond strength was measured. RESULTS: The mean bond strength of Epiphany SE to root dentine irrigated with NaOCl + MTAD was lower than that of NaOCl + EDTA. The highest bond strengths were 3.31 ± 0.057 and 2.60 ± 0.054 in the NaOCl + citric acid group when Ca(OH)2 was applied to roots treated with NaOCl + EDTA and NaOCl + MTAD, respectively (p < 0.05). CONCLUSION: For root canals treated with NaOCl + EDTA or NaOCl + MTAD, the use of NaOCl + chelating agent for Ca(OH)2 removal does not adversely affect the bond strength of Epiphany SE to dentin.

Bacterial survival in the radiographic processes.

AIM: The purpose of this study was to investigate the microbial contamination in hand-operated and automatic radiographic solutions and on contact surfaces during radiographic procedures such as X-ray cone and button and surface of hand-operated and automatic radiographic solution tanks in dental clinics. METHODS: A 10 mL liquid solution was taken with syringe at 5, 10, 24, and 48 hour time intervals from freshly prepared hand-operated and automatic processing solution. The swab samples were taken from the surfaces of radiographic solution tanks, X-ray cone and its button. The specimens were inoculated into blood agar and Eosin Methylene-Blue (EMB) agar. The plates were incubated in an incubator for 48 hours at 37 °C. Becton Dickinson Phoenix Automated Microbiology System was used for determining the microorganisms. RESULTS: Although the microbiologic analyses of the samples revealed no microbial growth in the hand-operated and automatic radiographic solutions in all observation periods, the microbial growth on the contact surfaces was observed. Staphylococcus epidermidis, metisillin resistant from the surface of radiographic solution tanks, X-ray cone and switch. Streptococcus mitis was found on the X-ray switch. CONCLUSION: Radiographic procedures can cause cross contamination; clinicians should therefore apply disinfection protocols in all radiographic procedures.

The magnetic resonance imaging assessment of optic nerve sheath diameter in pediatric acute liver failure patients.

OBJECTIVE: To evaluate the diagnostic value of optic nerve sheath diameter (ONSD) using brain MRI in the pretransplantation period in the pediatric acute liver failure patients, and correlate the ONSD with clinical grade of hepatic encephalopathy (HE) and MRI findings. PATIENTS AND METHODS: Forty acute liver failure patients and 40 control group patients were retrospectively analyzed. The high signal intensities in T2W (T2-weighted image), FLAIR (Fluid Attenuated Inversion Recovery) and DWI (diffusion-weighted imaging) sequences were evaluated and ONSD was measured. The patients were grouped first into 5 according to their West Haven score, and HE grade 0 and grade 1 were accepted as low grade HE, HE grade 2, 3 and 4 were accepted as high grade HE. The patients were grouped to 2 according to the MRI findings as low grade and high grade MRI group. RESULTS: The mean value of ONSD was 6.0 ± 1.80 and 4.94 ± 1.27 in the all patients and in the control group, respectively. There was statistically significant difference between both the ONSD and the low grade-high grade HE groups (p=0.01), and between the ONSD and the low grade-high grade MRI groups (p<0.001). CONCLUSIONS: Although high ONSD values do not make the diagnosis of cerebral edema, it may cause suspicion in the early period. MRI can be helpful in the diagnoses of increased intracranial pressure like ultrasound. Our study is the first study to compare ONSD and MRI findings in addition to HE grades. The widespread use of MRI in children in recent years may help determine the normal range of ONSD values.

Metal concentrations in two bioindicator fish species, Merlangius merlangus, Mullus Barbatus, captured from the West Black Sea coasts (Bartin) of Turkey.

The Black Sea is very vulnerable to originating from land based human activities and its health is equally dependent on the coastal and non-coastal states of its basin. Total concentrations of cadmium, copper, zinc, lead, nickel, aluminum, iron, manganese, boron and chromium concentrations were determined in Merlangius merlangus (whiting) and Mullus barbatus found in Amasra in the West Coast of the Black Sea (Turkey). The metal contents that were measured in head and muscle was expressed in µg g(-1) wet weight. On average, while the highest Fe (344.25 µg g(-1)), Mn (10.35 µg g(-1)), Cr (0.96 µg g(-1)) and Al (76.77 µg g(-1)) concentrations were measured in the heads of M. merlangus and the highest Zn (77.99 µg g(-1)), Cu(8.53 µg g(-1)), B (44.83 µg g(-1)), Ni (1.96 µg g(-1)), Cd (0.40 µg g(-1)) and Pb (6.80 µg g(-1)) concentrations were detected in the muscles of M. merlangus. There were significant differences between metal levels of muscles in these two species. In terms of permissible levels reported by WHO FAO and TSE, there is not any risk for human consumption for both M. merlangus and M. barbatus, for Pb.

The effects of 201Tl myocardial perfusion scintigraphy studies on oxidative damage in patients.

The aim of this study was to investigate gamma radiation-induced oxidative damage in erythrocytes after 201Tl myocardial perfusion scintigraphy. Twenty patients (8 women and 12 men) who performed 201Tl myocardial perfusion scintigraphy were included in this study. The blood samples were taken from patients just before, 1 hour after and three hours after injection of the radiopharmaceutical. Malondialdehyde (MDA) and antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) levels were measured to evaluate the gamma radiation induced oxidative damage. The enzyme activities of SOD, GPX and CAT were decreased 1 hour after (p = 0.042, p = 0.697 and p = 0.653 respectively) and 3 hours after (p = 0.003, p = 0.573 and p = 0.002 respectively) injection of the radiopharmaceutical. Malondialdehyde levels were increased 1 hour after (p = 0.10) and 3 hours after (p = 0.47) injection of the radiopharmaceutical. In this study, we found that radiation due to 201Tl myocardial perfusion scintigraphy decreased the erythrocyte antioxidant levels and increased MDA levels.

Vitamin C attenuates methotrexate-induced oxidative stress in kidney and liver of rats.

Like several other anticancer drugs, methotrexate (MTX) causes side effects, such as neuropathic pain, hepatotoxicity, and nephrotoxicity. Abnormal production of reactive oxygen species has been suspected in the pathophysiology of MTX-induced hepatorenal toxicity. Therefore, the aim of this study was to investigate the probable protective role of vitamin C (Vit C) on oxidative stress induced by MTX in the liver and kidney tissues of rats. A total of 32 rats were randomly and equally divided into four groups. The first group served as the control group. The second group received a single dose of 20 mg/kg of MTX intraperitoneally. To demonstrate our hypothesis, the third and the fourth groups received 250 mg/kg of Vit C for 3 days by oral gavage, with or without MTX treatment. At the end of the study, the liver and kidney tissues of the rats were collected and examined using histology. Both the tissues were assayed for malondialdehyde concentration and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities. In hepatic and renal tissues, lipid peroxidation levels were increased, whereas SOD, CAT, and GSH-Px levels were decreased by MTX. All parameters, including CAT levels in hepatic tissue, were significantly restored after the administration of Vit C for 3 days. Similar to the biochemical findings, evidence of oxidative damage was examined in both types of tissues by histopathological examination. From the results of this study, we were able to observe that Vit C administration modulates the antioxidant redox system and reduces the renal and hepatic oxidative stress induced by MTX. Vit C can ameliorate the toxic effect of MTX in liver and kidney tissues of rat.

Histopathologic changes in liver and renal tissues induced by Ochratoxin A and melatonin in rats.

Nephrotoxicity and hepatotoxicity induced by Ochratoxin A (OTA) and ameliorating effects of melatonin were investigated in rats exposed to OTA. Experimental groups were as follows: control; OTA-treated; and OTA plus melatonin (MEL)-treated (OTA+MEL). The rats in the control group were administered with only a daily oral administration of 0.5 M NaHCO3. OTA was administered with a dose of 289 microg/kg in the same way. OTA and MEL were administered orally with OTA (289 microg/kg) and melatonin (10 mg/kg) in two different periods of time during the same day. The histopathologic changes in the liver and kidney tissues of control, OTA and OTA+MEL-treated rats were examined. There were no significant changes in the kidney and liver tissues of the control rats. Significant histopathologic changes were found in the kidney and liver tissue of rats treated with OTA. These were granular or vacuolated degeneration and necrosis of the liver cells, sinusoidal and central vein dilatation, bile duct proliferation, enlargement of periportal areas with mononuclear cell inflammatory infiltration and mild degree fibrous tissue proliferation, tubular epithelial cells degeneration, necrosis, proliferation and karyomegaly in the epithelial cells nuclei and peritubular and periglomerular lymphocyte infiltration, stromal fibrous tissue proliferation, hyperemic vessels. The severity of the lesions was significantly reduced by administration of melatonin. These results revealed that OTA induced significant histopathologic changes in liver and kidney tissue advocating OTA toxicity (P < 0.001), and administration of MEL+OTA significantly reduced the toxic effect of OTA on kidney and liver tissue of rats (P > 0.05).

Impairment of endothelium-dependent vasorelaxation in cadmium-hypertensive rats.

Abnormalities in the production and/or release of relaxing factors from the endothelium have been implicated in the development of hypertension in several animal models. Endothelium-dependent relaxation has been reported to be impaired in thoracic aorta in experimentally induced and genetically hypertensive rats. Present study has extented these observations to thoracic aorta of cadmium-hypertensive rats. The possible role of alterations in oxidant status was also studied. Hypertension was induced by the intraperitoneal administration of 1 mg/kg/day cadmium for 15 days. Mechanical responses produced by acetylcholine (ACh, 10(-9)-10(-4) M) and sodium nitroprusside (SNP, 10(-10)-10(-5) M) were studied on phenylephrine-precontracted thoracic aorta rings from control and cadmium-hypertensive rats. Serum nitric oxide (NO) and aortic malondialdehyde (MDA) levels were measured. ACh-induced relaxation was attenuated in aorta from cadmium-hypertensive rats, whereas relaxation responses to SNP did not differ significantly between the groups. Exposure of aortic rings to N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) resulted in a significantly greater inhibition of relaxation response to ACh in aortic rings of cadmium-hypertensive rats as compared with control rats. Incubation with L-arginine (L-Arg, 10(-3) M) caused a similar reversal of the inhibition of ACh-induced relaxation by L-NAME in both groups. Serum NO levels were decreased and aortic MDA levels were increased in cadmium-treated rats as compared with control rats. However, the differences between the groups did not reach a statistical significance. These findings suggested that the reduction in endothelium-dependent relaxation may play a role in cadmium-induced hypertension as it was in many other hypertension models.

Protective role of caffeic acid phenethyl ester and erdosteine on activities of purine-catabolizing enzymes and level of nitric oxide in red blood cells of isoniazid-administered rats.

The aim of this experimental study was to investigate the possible role of nitric oxide (NO) and the activities of adenosine deaminase (ADA) and xanthine oxidase (XO) in the pathogenesis of isoniazid (INH)-induced oxidative damage in red blood cells (RBCs), and also to show the effect of caffeic acid phenethyl ester (CAPE) and erdosteine, antioxidants, in decreasing this toxicity. A total of 25 adult male rats were divided into four experimental groups as follows: control group (n = 7), INH-treated group (n = 6), INH + CAPE-treated group (n = 6), and INH + erdosteine-treated group (n = 6). INH, INH-CAPE, and INH-erdosteine-treated groups were treated orally with INH 50 mg/kg daily and with the tap water for 15 days. Control group was given only tap water. CAPE was intraperitoneally injected for 15 days at a dose of 10 micromol/kg. Erdosteine was treated orally for 15 days at a dose of 10 mg/kg/day. The injection of INH led to a significant increase in the activities of ADA, XO, and NO levels in RBCs of rats. Co-treatment with CAPE caused a significant decrease in the activities of ADA and XO and the levels of NO in RBCs. In addition, co-treatment with erdosteine caused a significant decrease in the activities of ADA and XO and the levels of NO in RBCs. The results of this study showed that ADA, XO, and NO may play an important role in the pathogenesis of INH-induced oxidative stress in RBCs. CAPE and erdosteine may have protective potential in this process and they may become a promising drug in the prevention of this undesired side effect of INH.

The effects of thyroid scintigraphy studies on oxidative damage in patients.

The majority of radiation injury in cells depends on oxidative stress. Irradiation and absorbed doses, duration of the irradiation and the susceptibility of the tissue against radiation are the factors that cause variations on living cells. The aim of this study was to investigate gamma radiation-induced oxidative damage in erythrocytes after thyroid scintigraphy with Tc-99m pertechnetate. Fifteen patients (8 women and 7 men) who performed thyroid scintigraphy with Tc-99m pertechnetate were included in this study. The median age was 52 +/- 8 years (range 33-65). The blood samples were taken from patients just before, 1 hour after and three hours after injection of radiopharmaceutical. Malondialdehyde (MDA) and antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) levels were measured to evaluate the gamma radiation induced oxidative damage. No difference was detected in any final measurement activities of erythrocyte antioxidant enzyme such as SOD and GPX in the direct comparison between the before and after injection of the radiopharmaceutical groups, except erythrocyte CAT activities measured 1 hour after and 3 hours after injection of the radiopharmaceutical (p < 0.05). MDA levels were decreased 1 hour after and 3 hours after injection of the radiopharmaceutical.

Comparison of ephedrine and ketamine in prevention of injection pain and hypotension due to propofol induction.

BACKGROUND AND OBJECTIVE: This prospective, double-blind, randomized, placebo-controlled study compares the effects of ephedrine and ketamine on injection pain, and hypotension from propofol. METHODS: After obtaining the approval of the Ethics Committee, 75 patients (ASA I-II) scheduled for elective operations with general anaesthesia were divided into three groups. Saline 2 mL (Group S, n = 25), ketamine 0.5 mg kg(-1) (Group K, n = 25) or ephedrine 70 microg kg(-1) (Group E, n = 25) were administered over 5 s after tourniquet application. After releasing the tourniquet, propofol 2 mg kg(-1) was injected in 30 s. Pain was evaluated on a numerical scale (0-10) where 0 represented no pain and 10 the most severe pain possible. Systolic, diastolic blood pressures and heart rates were recorded preoperatively, 1 min after propofol injection, before intubation and 1, 2 and 3 min after intubation in all patients. RESULTS: The incidences of pain in Groups S, E and K were similar (84%, 80% and 72%, respectively). The mean pain score in Group K (2.1, SD 3.1) was significantly lower than those of Groups S and E (4.9, SD 2.6 and 4.6, SD, 3.3, respectively) (P < 0.05). The systolic and diastolic blood pressure values in Group K (120 +/- 27 mmHg) and Group E (123 +/- 21 mmHg) before intubation were significantly higher than that of Group S (104 +/- 25 mmHg) (P < 0.05). There was no significant difference between the mean heart rate values of the groups. CONCLUSIONS: Low dose ketamine or ephedrine pretreatment may prevent hypotension due to propofol induction. Despite the reduction in injection pain intensity after ketamine, the study drugs were found to be ineffective in lowering the injection pain incidence.

The effects of 201Tl myocardial perfusion scintigraphy studies on oxidative damage in patients / Efectos de los estudios de escintigrafía de perfusión miocárdica 201Tl sobre el daño oxidativo en los pacientes

The aim of this study was to investigate gamma radiation-induced oxidative damage in erythrocytes after 201Tl myocardial perfusion scintigraphy. Twenty patients (8 women and 12 men) who performed 201Tl myocardial perfusion scintigraphy were included in this study. The blood samples were taken from patients just before, 1 hour after and three hours after injection of the radiopharmaceutical. Malon-dialdehyde (MDA) and antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) levels were measured to evaluate the gamma radiation induced oxidative damage. The enzyme activities of SOD, GPX and CAT were decreased 1 hour after (p = 0.042, p = 0. 697 and p = 0.653 respectively) and 3 hours after (p = 0.003, p = 0. 573 and p = 0.002 respectively) injection of the radiopharmaceutical. Malondialdehyde levels were increased 1 hour after (p = 0.10) and 3 hours after (p = 0.47) injection of the radiopharmaceutical. In this study, we found that radiation due to 201Tl myocardial perfusion scintigraphy decreased the erythrocyte antioxidant levels and increased MDA levels.

El objetivo de este estudio fue investigar el daño oxidativo inducido por radiaciones gamma, sobre los eritrocitos luego de realizada una escintigrafía de perfusión miocárdica 201Tl. Veinte pacientes (8 mujeres y 12 hombres) a quienes se les realizó escintigrafía por perfusión miocárdica 201Tl, fueron incluidos en este estudio. Las muestras de sangre fueron tomadas de los pacientes antes, 1 hora más tarde, y tres horas después de inyectar el radiofármaco. Se midieron los niveles del malondialdehido (MDA) y las enzimas antioxidantes tales como la glutationa peroxidasa (GPX), superóxido dismutasa (SOD), y la catalasa (CAT), a fin de evaluar el daño oxidativo inducido por la radiación gamma. Las actividades de las enzimas SOD, GPX y CAT fueron disminuidas 1 horas después (p = 0.042, p = 0. 697 y p = 0.653 respectivamente) y tres horas (p = 0.003, p = 0. 573 y p = 0.002 respectivamente) tras la inyección del radiofármaco. Los niveles de malondialdehido fueron aumentados 1 hora después (p = 0.10) y tres horas después (p = 0.47) de la inyección del radiofármaco. En este estudio, hallamos que la radiación a causa de la escintigrafía de perfusión miocárdica 201Tl disminuyó los niveles antioxidantes del eritrocito y aumentó los niveles de MDA.

5-Hydroxytryptamine-induced contraction of human isolated umbilical artery and its dependence on cellular and extracellular Ca++.

The contribution of intra- and extracellular Ca++ during KCl- and 5-hydroxytryptamine-induced contractions was investigated in human isolated umbilical arteries obtained from cords of normal full-term deliveries. In normal solution, nifedipine caused dose-dependent relaxations of the arteries contracted by high K+ (80 mM) and 5-hydroxytryptamine. The IC50 value of nifedipine on KCl-induced contractions was about 9 times lower than that on 5-hydroxytryptamine-induced contractions. In Ca(++)-free medium, KCl failed to induce contractions of the artery. However, 5-hydroxytryptamine caused contractions amounting to 52% of the maximum response obtained by re-addition of Ca++, and this response was abolished by 10(-6) M of nifedipine. In the presence of either KCl or 5-hydroxytryptamine, subsequent addition of Ca++ caused reproducible contractions which were also inhibited by nifedipine. These results indicate that the KCl-induced contraction of human isolated umbilical artery is mainly dependent on extracellular Ca++, whereas that induced by 5-hydroxytryptamine involves both intra- and extracellular Ca++. It is also suggested that nifedipine does not only inhibit the influx of extracellular Ca++ during the contraction by 5-hydroxytryptamine but that it may also have intracellular effects.