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Microleakage between endodontic temporary restorative materials placed at different times.

Occlusal endodontic access preparations are occasionally made in teeth without removing the original restoration. However, microleakage between restorative materials that are placed at different times has not been extensively studied. Therefore, our objective was to compare microleakage at three areas: between an access opening restorative material and the cavity wall; between an additional material placed later to patch a secondary opening in the first restorative material and the original restorative material itself; and between the secondarily placed material and the cavity wall. Standard endodontic access preparations were made in 120 noncarious, nonrestored crowns of extracted human molars. These teeth were divided into six experimental groups. Another four molars were controls. The endodontic access cavities were restored with either IRM or amalgam as the primary restorative material. After 14 days, half of the primary restorations was removed, and this defect was filled with a secondary restorative material: IRM, Caviton, or a double seal of Caviton and IRM. Microleakage was measured linearly as the extent of basic fuchsin dye penetration under a stereomicroscope after thermal cycling (5 degrees and 55 degrees C for 100 cycles) and tooth sectioning. Wilcoxon signed-rank test was used for statistical analysis. Results indicated significantly less microleakage between primary and secondary restorative materials placed at different times than microleakage between primary temporary restorative materials and the access cavity wall, regardless of the type of primary restorative material used (IRM or amalgam).

Calcium Sulfate↗

The permeability of dental procedure and examination gloves by an alcohol based disinfectant.

OBJECTIVES: The usage of gloves in dentistry has increased greatly over the last 10 years and this has highlighted certain problems when gloves are being worn extensively. While skin irritations and allergies caused by latex proteins and accelerators have been the main focus of attention, dental materials such as disinfectants have also become known as a source of skin reactions. This study was performed to evaluate the permeability of various gloves by ethanol. METHODS: The tip of the middle finger of 13 glove brands (natural latex gloves (NLG) powdered or unpowdered, powdered vinyl, nitrile and synthetic elastomer) was exposed to 5 ml of a hand disinfectant (Desderman). After a penetration time ranging from 2 min to 8 h the permeation of Desderman was detected with a gas chromatograph. RESULTS: Only one component of the disinfectant (ethanol) could be detected to have gone through the gloves. After only 2 min the vinyl and one nitrile glove and after 10 min all glove types were permeated. Powder seemed to have no real influence on the penetration of ethanol. Some natural latex gloves showed a low rate of leakage, while vinyl and nitrile gloves were penetrated quickly and to a great extent. The synthetic elastomer (Biogel Neotech) was the only one with a significantly lower penetration even after 2-8 h. SIGNIFICANCE: While there are reports of adverse skin reactions to alcohol the amount of ethanol (up to 40 microliters after 2 h) detected in this study is much too low to cause irritations and certainly not toxicity, but it could possibly initiate allergic reactions.

Analysis of Variance↗

Portal hypertension in vinyl-chloride production workers.

Portal hypertension was seen in seven patients who had been involved in the production of vinyl-chloride monomer for 4-15 years. Four presented with bleeding oesophageal varices. In liver biopsy specimens non-cirrhotic portal fibrosis was inconspicuous and was seen more clearly on wedge rather than needle biopsy specimens. The intrahepatic venous pattern was hardly distrubed. Three patients have done well following shunt surgery. In one patient an angiosarcoma developed, but fibrosis was a more common lesion and was probably not pre-malignant.

Adult↗

Genetic risks of vinyl chloride.

A study of pregnancy outcome among wives of workers exposed to vinyl-chloride monomer (V.C.M.) indicated that, in comparison with controls, there was a significant excess fetal loss in the group whose husbands had a primary exposure to V.C.M., whereas no differences between the groups were observed before the husband's exposures. The difference in fetal death-rates for the post-exposure comparisons was a reflection of a greater fetal loss associated with the wives younger-aged husbands. The significant excess did not seem to be the result of bias from interviewers, respondents, nor from women who had experienced chronic abortions weighting the results. These findings, in conjunction with the demonstration of a mutagenic response via microbial test systems and with observations of significant excesses of chromosomal aberrations among workers exposed to V.C.M., raise scientific and public-health concern for the possible genetic risks of V.C.M. to man.

Age Factors↗

Genetic susceptibility to scleroderma-like syndrome induced by vinyl chloride.

Vinyl chloride (VC) monomer can induce a scleroderma-like syndrome in a proportion of workers exposed to it during production of polyvinyl chloride. As part of a 5-year follow-up study HLA A, B, and DR antigens and anti-centromere and anti-scleroderma-70 antibodies were determined in 44 such workers. 21 of these had severe and 23 mild forms of vinyl-chloride disease. 50 patients with "classical" scleroderma and 148 healthy hospital workers acted as controls. 11 of the 21 patients classified as having severe VC disease were DR3 positive, and 8 of these had both B8 and DR3 antigens. None of the 23 patients with mild disease carried either antigen. The HLA-antigen frequencies in VC disease mirrored those found in scleroderma (raised DR5 frequency and increased linkage disequilibrium between B8 and DR3). There were, however, significant differences in the frequency of autoantibodies in the two conditions.

Autoantibodies↗