Sy-28 Sy-20 Series Of Complex Prosthetic Silicone Rubber Physical And Mechanical Properties Of The Measurement And Evaluation

Although numerous advances in maxillofacial materials have been made in the past several years, the need for improvement continues. Currently, the most widely used materials are the silicones. SY blending silicone elastomers are a series of maxillofacial prosthetic materials developed by the Fourth Military Medical University in order to meet all kinds of clinical demands in different types and parts of maxillofacial defect.In this study, two representative blending silicone elastomer materials, Shore-A hardness being 28 and 20, were selected to measure their mechanical, physical and aging properties in accordance with the National Standards, and compared with those of MDX4-4210 in the same condition. The main results are being shown below:1. This study compared the mechanical properties of SY-28 and SY-20 silicone elastomers with those of MDX4-4210. The properties tested were tensile strength,elongation at break, permanent deformation rate (3 minutes ) ,tear resistance and the hardness (Shore-A) .The results showed: elongation at break, tear resistance and hardness of SY-28 were better than those of MDX4-4210.The tensile strength and permanent deformation rate of SY-28 were similar to those of MDX4-4210. The hardness of SY-20 was superior to that of MDX4-4210.The tensile strength, elongation at break, permanent deformation rate and tear resistance were similar to those of MDX4-4210.2. In order to evaluate the effects of heat aging on the mechanical properties of SY-28 and SY-20 silicone elastomers, their mechanical properties before and after aging were tested. The results revealed that the elongation at break, permanent deformation rate and the hardness of SY-28 were superior to those of MDX4-4210. The tensile strength and tear resistance were similar to those of MDX4-4210. The tensile strength, permanent deformation rate and hardness of SY-20 were better than those of MDX4-4210. The elongation at break of SY-20was similar to that of MDX4-4210.While the tear resistance of SY-20 was inferior to that of MDX4-4210.3. In order to evaluate the effects of ozone aging on the mechanical properties of SY-28 and SY-20 silicone elastomers, their mechanical properties before and after aging were tested. The results revealed that the permanent deformation rate and the hardness of SY-28 were superior to those of MDX4-4210. The tensile strength and elongation at break were similar to those of MDX4-4210. The tear resistance of SY-28 was inferior to that of MDX4-4210.The tensile strength, permanent deformation rate and hardness of SY-20 were better than those of MDX4-4210. The elongation at break and tear resistance of SY-20 was similar to those of MDX4-4210.4. This combination of mechanical properties made SY-28 and SY-20 silicone elastomers, a better choice than the traditional MDX4-4210 for the fabrication of facial prostheses,and the integrative aging properties indicated that SY-28 and SY-20 exhibited excellent aging resistant properties and could be used as prostheses for the repair of maxillofacial soft tissue defects.5. This study was made to investigate the water sorption and solubility of SY-28 and SY-20 silicone elastomers for 1-8 weeks. The results showed that the means of percentage about water sorption at 8 weeks was 3.112% for SY-28, and 3.012% for MDX4-4210, which showed no significant differencesjthe solubility at 8 weeks was 0.4401% for SY-28, which showed higher than that of MDX4-4210 (0.3179%) . The means of percentage about the water sorption and solubility at 8 weeks were 3.501% and 0.4756% for SY-20,which were higher than those of MDX4-4210 (3.012%,0.3179%) .