Objective To compare the fracture strength of six kinds reinforced epoxy resin dies. Methods Six kinds of epoxy resin dies were prepared: Epoxy resin EP-400（dieⅠ）, epoxy resin EP-400+20% 120 grit quartz sand（dieⅡ）, epoxy resin EP-400+glass fiber（5 dipping bundles, die Ⅲ）, epoxy resin EP-400+graphite carbon fiber（2 dipping bundles, die Ⅳ）, epoxy resin EP-400+graphite carbon fiber（5 dipping bundles, die Ⅴ）, epoxy resin EP-400+graphite carbon fiber（5 dry bundles, die Ⅵ）. All dies were loaded until failure using the WD-5A universal testing machine. Any difference among groups was tested for significance with One-Way ANOVA. Results It was ascendent for the fracture strength of die and Ⅱ, die Ⅲ and Ⅳ, die Ⅴand Ⅵ（P＜0.001）. There were statistical differences（P＜0.05） between any two kinds dies except for dieⅠ and Ⅱ, die Ⅲ and Ⅳ, die Ⅴand Ⅵ（P＞0.05）. Die Ⅴ showed best properties in six kinds dies by scanning electron microscope. Conclusion The epoxy resin die reinforced with graphite carbon fiber（5 dipping bundles） has excellent properties of fracture resistance and it can meet the needs of fracture testing of various crowns and fixed partial denture in vitro study.
