Mechanical Properties Of Wollastonite Resin Composites

Objective:This paper is to research the reinforcement efficacy of wollastonite in bis-GMA-based dental resin composites and the mechanical properties such as compressive strength test,fracture toughness test and flexture strength test.Five different kinds of wollastonite powders were mixed in various proportions with bis-phenol-A-diglycidyldimethacrylate(bis-GMA)-based polymer matrix.Method:The polymer matrix was made of 48wt% bis-GMA,25wt% TEGDMA,25wt% HEMA,1wt% CEMA and 1wt% CQ.There were five types of wolastonite from Fibertec Inc.The types were 520 U,915U,1515 U,800U and 905 U.For 520 U,915U and 1515 U,30vol%,40vol%,50vol%,and 60vol% experimental resin component were prepared.In addition,for 800 U and 905 U,40vol%,50vol%,60vol%,and 70vol% were prepared.After having been mixed completely,the composite needed to be stored in a refrigerator(4-8°)to stabilize for at least 48 h.For fracture toughness test using a notchless triangular prism(NTP),six specimens(n=6)were prepared: for hardness test also six specimens were measured by using Vickers hardness;for compressive strength,eight specimens(n=8)were tested by preparing cylinder samples,and for flexure strength eight beam specimens(n=8)were prepared.The samples were prepared in these measures,stored at room temperature and then tested after 24 hours storage for initial stability.The data were analyzed by statistical methods using one-way ANOVA.Results:Reinforcing efficacy was significantly dependent on filler morphology.Wollastonite had good wettability and dispersibility with bis-GMA-based matrix.Wollastonite promoted better mechanical properties in bis-GMA-based composites.Conclusion:1.From the EDX analysis,it could be seen that there was no different in the major element composition in the four types of wollastonite.2.The most difficult experimental resin composite to compress was based on 905 U in 40vol%.3.In the fracture toughness test,wollastonite 1515 U in 60vol% exhibited the highest value.4.In the flexural strength test,wollastonite 915 U in 40vol% showed the highest in mean.