The Experimental Study Of Modifying Artificial Tooth Via Nano-SiO₂ Treated By Coupling Agent KH-570

Objective:To discover an effective way to enhance the mechanical properties of the artificial tooth by filling the nano-SiO₂ particle treated by KH-570 into the MMA, using insitu polymerization method, preparing PMMA/ KH570-SiO₂ composite materials, testing some mechanical properties, comparing to the PMMA/SiO₂ composite materials as contrast group and the blank group, provide the reference and foundation for further study in denture materials.Methods:1. Filled nano-SiO₂ particle treated by the KH-570 into mono-MMA at different contents, and mixed it with PMMA powder, and then initiated polymerizing according to the preparation rule of clinic artificial tooth in order to get the experimental group of PMMA/ KH570-SiO₂.2. Filled the nano-SiO₂ particle into mono-MMA at different contents, and mixed it with PMMA powder, and then initiated polymerizing according to the preparation rule of clinic artificial tooth in order to get the PMMA/SiO₂ composite material.3. Mixed mono-MMA which was not been added any matter with PMMA powder, and then initiated polymerizing according to the preparation rule of clinic artificial tooth in order to get the blank group.4. Tested the mechanical properties of the three groups, which including the flexure strength, flexure modulus of elasticity, impact strength, tensile strength, rigidity and antiwear, etc. What's more, the microstructrue of the three kinds of materials was analyzed by Olympus optic microscopy. Treated the experimental data with statistics, evaluated the mechanical properties of the three different artificialtooth materials, and analyzed the mechanism of coupling agent with pertinent literatures. Results:1. The results of mechanical properties: When the content of nano-SiO2 particle was 0.5%, there were no significant differences between the three groups (P>0.05). When the contents of nano-SiO2 particle were 1%, 3%, 5%, there were significant differences between the three groups (P<0.05), and got to the top at the content of 3% with nano-SiC>2 particle, when the content of SiO2 was 5%, the mechanical properties began to decline. The mechanical properties of composite material increased firstly and then declined with the increasing of the content of nano-SiC^ particle. The best content is 3%.2. From the pictures of fracture pattern, which were obtained by Olympus optic microscopy could find that the morphology of PMMA/ KH570-SiO2 and PMMA/SiO2 composite materials at the content of 3% appeared silk-bundle cracking, its surface appeared unfairness. There were a lot yielding area on the resin matrix, but the fracture surface of the blank group appeared smooth, in addition, there were a lot platform on fracture section and it is likely conformed that the energy absorbed in fraction was very low.Conclusions:1. The mechanical properties of the artificial tooth materials can be improved by filling KH-570 treated nano-SiO2 particle. The strength toughness and rigidity of the PMMA/ KH570-SiO2 artificial tooth composite materials can be improved when the content of the nano-SiO2 particle is more than 0.5%.2. Coupling agent KH-570 is the appropriate bridge of nano-SiC>2 particle and resin, and it can be as treated agent of nano-SiC>2 particle, which is filled into PMMA.3. Dispersing nano-particle with ultrasonic wave is an effective way, which has a lot advantages such as time, energy and cost saving.