The Preparation And Analysis Of New Condensation Silicone Rubber Impression Material

Silicone rubber impression material,which is a man-made irreversible elastomeric high polymeric material, has fine reproduction of models,dimensional stability, favorable handling properties and so on. It was widely used in developed countries. But in China, silicone rubber impression material has high price so its popularity rate is low in clinical use. Research of its independence is quiet a few. In order to prepare the silicone rubber impression material which has the good properties,low cost and popularity, CSR-Ⅰcondensation silicone rubber impression material was developed by the research group cooperated with Department of Applied Chemistry, School of Science, Northwestern Polytechnical University. And , to evaluate its properties for reference of clinical use.Technological route of this study is below:First of all, usedα,ω-dihydroxypolydimethylsiloxane as found polymer, gained contents of catalyst and silica gel filler by technological formula test ect, then obtained the optimized formula and prepared silicone rubber impression material,named CSR-Ⅰsilicone rubber impression material. Next, compared with OranwashVL silicone rubber impression material,estimated mechanical properties of CSR-Ⅰsilicone rubber impression material with tensile strength, elongation at break, tear strength and elastic recovery test; estimated its biological safety with cytotoxicity test , acute systemic toxicity test and oral mucous membrane irritation test. In the last, estimated its feasibility of clicical use with precision text.The main results of this study are being show below:1.When contents of catalyst is 8wt%～10wt%, mixing time and setting time of silicone rubber impression material can be satisfied in clinical ues.2.When use silica gel filler which treated with dry process surface treatment and its content is 15wt%～30wt%, tear strength of silicone rubber impression material was effectively improved.3..The results of mechanical propeties texts showed that there were no significant difference of tensile strength, elongation at break between CSR -Ⅰsilicone rubber impression material and Oranwash VL silicone rubber impression material(P>0.05). The tear strength of CSR -Ⅰsilicone rubber impression material was superior to those of contrast materia(lP<0.05). Elastic recovery rate of CSR -Ⅰsilicone rubber impression material was fit the requestion of impression material.There were no significant difference of elastic recovery rate between two silicone rubber impression material(P>0.05).4.The results of biological safety texts showed CSR -Ⅰsilicone rubber impression material had no cytotoxicity, no acute systemic toxicity and no oral mucous membrane irritation.5. The results of precision text showed CSR -Ⅰsilicone rubber impression material had the smaller difference between the masters and casts . There were no significant difference of precision between CSR -Ⅰand Oranwash VL silicone rubber impression material(P>0.05).This study investigated the optimized formula and prepared the CSR -Ⅰsilicone rubber impression material.After estimating its mechanical properties, biological safety and precision,it was concluded that CSR -Ⅰsilicone rubber impression material had good tensile strength, elongation at break,tear strength , elastic recovery properties,good biological safety and suitable precision.