The aim of this study was to evaluate the glass ionomer cement Ketac-Endo (K) compared with Endofill (E), N-Rickert (N), and Sealer 26 (S) in terms of disintegration, solubility, and dimensional alteration properties, based on ADA Specification No 57. For dimensional alterations, 12-mm high cylindric specimens measuring 6 mm in diameter were prepared and left to stand for a period corresponding to three times the setting time. These specimens were immersed in 30 ml of deionized distilled water after measuring their length with a caliper. Thirty days later, the sample was removed from the container, dried and measured again for length to determine the percent of dimensional alteration. For solubility and disintegration, 1.5-mm thick cement samples measuring 20 mm in diameter were prepared and left to stand for a period corresponding to three times the setting time. The samples were weighed and immersed in 50 ml of deionized distilled water. After seven days, the samples were removed, dried and weighed again to determine the mass loss of each sample, expressed as percentage of original mass. This was considered to correspond to solubility and disintegration of cement. The results were: dimensional alteration: E (+0.14), K (-0.24), N (+0.23), S (+3.26); for disintegration and solubility: E (3.90), K (9.90), N (3.00), S (0.25). We concluded that the dimensional alteration of all cements conformed to ADA standards; Endofill and Ketac-Endo sealers presented higher values for disintegration and solubility than ADA recommendations. Obturating a root canal with a sealer that presents low disintegration and low contraction could minimize the penetration of fluids into the root canal system, thus sealing the space hermetically.
The calcium hydroxide ionization of four root canal sealers (Sealapex, CRCS, Sealer 26, and Apexit) was studied by measuring conductivity and pH and by conducting atomic absorption spectrophotometry. Samples 6 mm in diameter and 15 mm long were prepared from these sealers. After setting and 48 h storage in a desiccator, five samples of each material were placed in 50 mL distilled water and analysed after 0,1,2,4,6 and 24 h and 5, 15 and 30 days. The results showed that Sealapex was the root canal sealer showing the highest pH, ionic calcium and total calcium values (P < 0.05) throughout the experimental period, followed by CRCS, Apexit and Sealer 26.
The aim of this work was to evaluate the hematological changes induced by Tityus serrulatus venom (TsV). Blood of Wistar rats was collected 0.5, 2, 6 and 24 h after i.p. injection of TsV (0.5 mg/kg) or saline (controls). Two additional groups were injected with 0.67 mg/kg and 0.25 mg/kg of TsV and the blood was collected after 0.5 and 2 h, respectively. The results showed an increase on hematocrit (Ht), red blood cells (RBC) count, hemoglobin concentration (Hb), albumin and total protein, mainly 2-6 h after envenoming. Increase in serum activities of amylase, creatine kinase and aspartate aminotransferase were also observed, indicating tecidual damages. Hyperglycemia was observed at all times analyzed, as a consequence of catecholamine release. No significant changes were detected in the urea, [Na(+)] and [Ca(2+)], but an increase of [Mg(2+)], [K(+)] and conductivity was observed. TsV induced a reduction of erythrocytes osmotic fragility as consequence of dehydration and increase in plasma electrolytes concentration, as evidenced by its higher conductivity. This study demonstrated that TsV is able to induce severe hematological changes, that appear within the first hours after envenoming, justifying the seeking of medical attention as soon as possible to avoid worsening of clinical symptoms.
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