![]() Five cylindrical specimens for each hand-mixed and extrusion mixed group investigated were employed for elastic recovery and strain in compression testing. A penetrometer assembly was used to measure the working time (n=5). Additionally specimens were also made from an extrusion-mixed polyether impression material and compared with the optimum hand-mixed base:catalyst ratio. The polyether was hand-mixed at the optimum (manufacturers recommended) base:catalyst ratios (7:1) and further groups were made by increasing or decreasing the catalyst length by 25%. The hypotheses tested were two-fold (a) whether altering the base:catalyst ratio influences working time, elastic recovery and strain in compression properties of a hand-mixed polyether impression material and (b) whether an extrusion-mixed polyether impression material would have a significant advantage over a hand-mixed polyether impression material mixed to the optimum base:catalyst ratio. McMahon, Caroline Kinsella, Daniel Fleming, Garry J P In very scarce cases, positive allergic reactions to polyether impression materials are possible.Įxtrusion-mixing compared with hand-mixing of polyether impression materials? In consideration of the widespread use of this impression material (millions of applications per year) and in comparison to the number of adverse reactions from other dental materials, the number of such allergic reactions is very low. The causative agent was a component of the base paste. Polyether impression materials may evoke type IV allergic reactions. The patient with the atypical clinical symptoms did not show any positive patch test reactions. In the patch tests, all eight patients with typical clinical symptoms showed positive reactions to the mixed polyether impression materials, to the base paste or to a base paste component. The prick tests showed no immediate reactions in the two patients tested. A further patient with atypical symptoms of an allergy (nausea and vomiting after contact with a polyether impression material in the oral cavity) but with a history of other allergic reaction was also patch tested. Eight patients with clinical symptoms of a contact allergy (swelling, redness or blisters) after exposure to a polyether impression material were subjected to patch tests, two of them additionally to a prick test. Here, we report on the results of allergy testing with polyether impression materials as well as with its components. Very recently, however, patients have started to report symptoms that suggest a new allergic reaction from polyether impression materials. ![]() Allergic reactions to these materials such as reported in the 1970s ceased after replacement of a catalyst. Polyether impression materials have been used in dentistry for more than 40 years. Mittermüller, Pauline Szeimies, Rolf-Markus Landthaler, Michael Schmalz, Gottfried A rare allergy to a polyether dental impression material. ![]()
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