Effect of Movement Kinematics and Heat-Treated Alloys on the Apical Extrusion of Debris: An In Vitro Study.

BACKGROUND: Apically extruded debris can be affected by some features of the file systems such as kinematics or metallurgic properties. AIMS: This in vitro study aimed to evaluate the effect of movement kinematics (reciprocation or rotation) and heat-treated alloys (C.Wire) on the amount of debris extrusion. METHODS: Seventy-two mesiobuccal root canals were assigned into three experimental groups related to the single-file system used (n = 24): two rotational; One Shape (Conventional Ni-Ti), One Curve (C.Wire), and one reciprocating; and One Reci (C.Wire). The file systems were used according to the advisable speed and torque according to the manufacturers' suggestion. The weight of debris was calculated by subtracting the preweights from postweights of Eppendorf tubes. Kruskall-Wallis and Mann-Whitney U tests were used to analyze the data (P = 0.05). RESULTS: One Shape produced the greatest amount of extruded debris compared with One Curve (P < 0.001) and One Reci (P < 0.001), respectively. No statistical difference was found between One Curve and One Reci concerning amount of apical debris extrusion (P = 0.489). CONCLUSION: Metallurgical properties of files may affect apical debris extrusion. Alloy type is an important factor in the amount of debris extrusion. File kinematics does not affect apical debris extrusion.

Adaptive short-term plasticity in the typical reading network.

The left temporo-parietal cortex (TPC) is crucial for phonological decoding, i.e., for learning and retaining sound-letter mappings, and appears hypoactive in dyslexia. Here, we tested the causal contribution of this area for reading in typical readers with transcranial magnetic stimulation (TMS) and explored the reading network's response with fMRI. By investigating the underlying neural correlates of stimulation-induced modulations of the reading network, we can help improve targeted interventions for individuals with dyslexia. 28 typical adult readers overtly read simple and complex words and pseudowords during fMRI after effective and sham TMS over the left TPC. To explore differences in functional activation and effective connectivity within the reading network, we performed univariate and multivariate analyses, as well as dynamic causal modeling. While TMS-induced effects on reading performance and brain activation showed large individual variability, multivariate analyses revealed a shift in activation in the left inferior frontal cortex for pseudoword reading after effective TMS. Furthermore, TMS increased effective connectivity from the left ventral occipito-temporal cortex to the left TPC. In the absence of effects on reading performance, the observed changes in task-related activity and the increase in functional coupling between the two core reading nodes suggest successful short-term compensatory reorganization in the reading network following TMS-induced disruption. This study is the first to explore neurophysiological changes induced by TMS to a core reading node in typical readers while performing an overt reading task. We provide evidence for remote stimulation effects and emphasize the relevance of functional interactions in the reading network.

The effect of nebulised magnesium sulphate in the management of childhood moderate asthma exacerbations as adjuvant treatment.

BACKGROUND: After the bronchodilator effect of magnesium was shown, the use of magnesium in treatment of asthma exacerbations became common. With the results of recent studies, the use of intravenous magnesium in severe asthma exacerbations took its place. We aimed to examine the effects of adding isotonic magnesium sulphate instead of isotonic saline into nebulised salbutamol on the Modified Pulmonary Index Score (MPIS) and the hospitalisation rate in moderate asthma exacerbations. METHODS: Our study population included 100 children age between 3 and 15 years with asthma admitted to emergency department due to moderate asthma exacerbations. The patients were randomised to placebo or magnesium, with 50 patients in each arm. All patients received 1mg/kg of systemic methylprednisolone at the beginning of treatment and thereafter received either nebulised salbutamol (0.15mg/kg/dose) and 1ml magnesium sulphate (15%)+1.5ml isotonic saline on three occasions at roughly 20min intervals (Magnesium group) or nebulised salbutamol (0.15mg/kg/dose) and 2.5ml isotonic saline mixture on three occasions at roughly 20min intervals (Placebo group). The MPIS of patients on 0th min, 20th min, 40th and 120th min were calculated and compared. The primary outcome was to compare MPIS values at the end of 120th min. RESULTS: Both groups have similar demographic, allergic characteristics and baseline MPIS scores. When the MPIS scores in the 120th min and admission rates in the 200th min, there was no significant difference between the two groups. CONCLUSIONS: The use of nebulised magnesium sulphate in moderate asthma exacerbation as adjuvant treatment showed no benefit to standard treatment in our study.

Evaluation of the amount of apically extruded debris during retreatment of root canals filled by different obturation techniques.

OBJECTIVE: To evaluate the amount of apically extruded debris during retreatment (with or without solvent) of root canals filled by two obturation techniques. MATERIALS AND METHODS: Forty-eight root canals were prepared using ProTaper Universal F3 and filled with Gutta-percha and AH 26 sealer using single cone or lateral condensation techniques. The root canal fillings were removed using ProTaper Universal Retreatment system with or without solvent, and the canals were further prepared with ProTaper F4. The operating time was measured. The debris extruded was collected into preweighed Eppendorf tubes. The dry weight of the extruded debris was calculated by subtracting the weight of the empty tube from that of the tube containing debris. Statistical analysis was performed with two-way analysis of variance test, with Bonferroni correction at a 95% confidence level. RESULTS: There was no statistically significant difference in the amount of extruded debris between the two obturation techniques (P=0.332). The mean amount of debris was higher in the nonsolvent groups than the solvent groups, particularly with the single cone technique (P=0.013). There was a significant difference between groups with regard to the retreatment time (P<0.001). Gutta-percha removal took less time in the single cone group than in the lateral condensation group (P<0.001). Gutta-percha removal in the nonsolvent groups took significantly less time than that in the solvent groups (P<0.001). CONCLUSIONS: The amounts of apically extruded debris were similar in both obturation techniques. A greater amount of apically extruded debris was observed in the nonsolvent groups than the solvent groups.

Contamination of bovine carcasses and abattoir environment by Escherichia coli O157:H7 in Istanbul.

The aim of this study was to investigate contamination of carcasses and abattoir environment with Escherichia coli O157:H7. Five abattoirs in Istanbul were visited between January 2000 and April 2001. During visits, sampling was performed and a total of 330 cattle were selected. Cattle were examined for the presence of faeces on the hide (abdomen and legs) before slaughter. The swabs from the carcasses and environmental samples (abattoir floor, benches including conveyors, knives, aprons, saws, hooks, hands) were taken at the abattoir immediately after slaughter using sterile cotton swabs. A sample from the wash water of the abattoir was also taken. Preenrichment, immunomagnetic separation and CT-SMAC agar were used for the isolation. The reaction of the isolates with anti-O157 and H7 antisera were also analysed. Twelve strains (3.6%) of E. coli O157 were isolated from the cattle carcasses and eight (2.4%) of them gave positive reaction with anti-H:7. Six strains of E. coli O157 were isolated from the environmental samples and all strains were positive for H7. The number of E. coli O157H:7 strains isolated from the environmental samples was two from the knife, two from the hands, one from the apron and one from the floor. No E. coli O157 was isolated from the abattoir water.

The effect of bleaching agents on the microhardness of dental aesthetic restorative materials.

This study investigated the effects of three home bleaching agents on the microhardness of various dental aesthetic restorative materials. The restorative materials were: feldspatic porcelain, microfilled composite resin and light-cured modified glass-ionomer cement and the bleaching agents Nite-White (16% carbamide peroxide), Opalescence (10% carbamide peroxide and carbapol jel) and Rembrandt (10% carbamide peroxide jel). A total of 90 restorative material samples were prepared 1 cm diameter and 6 mm thick and kept in distilled water for 24 h before commencing bleaching which was carried out for 8 h day-1 for 4 weeks. Microhardness measurements were then made using a Tukon tester. Statistically significant differences with respect to unbleached controls were found only for the feldspatic porcelain and microfilled composite resins (P <0.05) for Nite-White and Opalescence. All the bleaching agents decreased the microhardness of the porcelain and increased that of the light cured modified glass-ionomer cement. For the composite resin, whereas Nite-White increased its microhardness, the other bleaching agents decreased it. There were no significant differences between the bleaching agents for any of the restorative materials.

p53 staining as a prognostic indicator in endometrial carcinoma.

OBJECTIVE: To investigate p53 expression in endometrial cancer and its significance as a prognostic indicator. METHODS: Thirty-five consecutively surgically treated patients with endometrial cancer had their p53 expression studied by immunoperoxidase staining and quantified by lighted microscopic evaluation of the staining pattern. The determination of mean percentage of p53 expression was compared to prognostic indicators of endometrial cancer. RESULTS: p53 staining was detected in 20 of the 35 cases of endometrial carcinoma. Eleven of the 21 endometrioid tumors stained positive, while 9 out of 14 tumors with more aggressive histology stained positive for p53. If the grade I and II patients were taken into account as a whole, there was a statistically significant correlation (p<0.001) between the grade I and II patients and the grade III patients. The difference was statistically significant between stage I and III (p<0.05). The difference between lymphovascular space invasion and no lymphovascular invasion and p53 positivity was statistically significant (p<0.05). CONCLUSION: p53 expression is more common in more aggressive histologic subtypes than in endometrioid adenocarcinomas. Strong expression of p53 correlates with advanced stage and high grade and is detected more frequently in endometrial cancers with lymphovascular invasion.

The use of a stent-resin-bonded splint combination to stabilize a free gingival autograft.

This article describes the use of a resin-bonded retainer in combination with an acrylic resin stent to stabilize a free gingival graft. This retainer also prevents migration of muscle attachment after surgery to deepen a section of the vestibule where the oral mucosa closely approached the gingival margin. The acrylic resin stent is attached to the resin-bonded retainer by means of an integrally cast metal framework. After surgery, the retainer is attached to the occlusal two thirds of the buccal surfaces of maxillary molar teeth by using the acid-etched resin bonding technique. The stent effectively retains the graft, is simple to fit, and does not cause any permanent damage to the enamel. It has none of the disadvantages of conventional removable acrylic resin stents.