Purpose: This research is conducted for better clinical test of Zirconia as we find out the fracture strength difference of Zirconia on cement gaps of full Crown that made use of Zirconia which is somewhat being used in recent dental technology.Methods: We produced each nine of Zirconia Crown of Zirconia fracture cement gaps A group(0.03 mm), B group(0.05 mm), C group(0.08 mm) on cement gaps by use of CAD/CAM, and compared the results. We could end up getting conclusions as following.Results: There was fracture strength difference per cement gaps but no impact(P<0.05). There was difference between 1.962 0.259 from group A and 2.005 0.367 from group B, but no impact(P<0.05). There was difference between 1.962 0.259 from group A and 2.478 0.331 from group C, but it s hard to be considered as an impact(P<0.05).Conclusion: Because of the hight pressure 0.08 mm is fractured and Margin has a lot of empty space due to gap for 0.08 mm. To identify the difference between 0.08 mm and 0.05 mm, 0.08 mm is selected as a gap. Therefore when it comes to using 0.05 mm authentically 0.05 mm is quite practical to use as a gap.[Abstract]접 수 일 수 정 일 확 정 일