Effects of Zeolite Filler in Surfactant-Containing Silicone Rubber Impression Materials

Objectives: This study was purposed to evaluate the effects of replacing some parts of crystalline quartz filler (Qu) with zeolite in surfactant-containing addition polymerization silicone rubber impression materials (AS). Methods: The experimental AS were mainly composed of vinyl-terminated silicone polymers (VS series, Hanse Chemie) and reinforcing fillers (Qu + fumed silica). To improve the wettability, non-ionic surfactant (Igepal CO-520, Aldrich) was added with the variation of its content. Cross-linker (CR101, Hanse Chemie) and inhibitor were incorporated in base paste. Organoplatinum complex and PDMS plasticizer were incorporated in catalyst paste. The groups of Surf0, Surf2, Surf4, Surf6, Surf8 were designed by adding surfactant (Surf) with 0, 2, 4, 6, 8 parts per 200 parts of silicone polymer, respectively. By replacing 20% of Qu with zeolite (Zeo; Colite-AB, Cosmofine), Zeo-Surf2, Zeo-Surf4, Zeo-Surf6, Zeo-Surf8 groups were designed. The water contact angle, tensile strength, working & setting times were measured. One-way ANOVA followed by multiple range test was performed. Results: The surfactant-containing groups showed significantly lower contact angles compared with Surf0 group (92.60±1.82°)(p<0.05). Zeo-Surf groups showed significantly lower contact angles (ex; 31.93±1.96° for Zeo-Surf4 group) compared with those of corresponding Surf groups containing same amounts of surfactant (p<0.05). Surfactant-containing groups showed delayed working and setting times. The tensile strengths (kgf/cm²) of surfactant-containing groups (ex; 13.98±1.63 for Surf2 group) were significantly lower compared with that of Surf0 group (28.00±2.56) (p<0.05). However, the Zeo-Surf groups showed faster setting time and significantly higher tensile strengths compared with corresponding Surf groups (p<0.05). Porosities were produced by surfactant incorporation, and those were reduced by replacing parts of Qu with zeolite. Conclusion: The pore production and delayed setting phenomena accompanying to the incorporation of large amount of surfactant were resolved by replacing parts of Qu with zeolite, by which increased tensile strengths were obtained. Supported by KITECH Grant (in 2004-2005).