| Purpose:The purpose of this study was to develope a new zirconia abutment and assess its mechanical properties.Methods:The zirconia abutments were made from nano zirconia powder by cold isostatic pressing and two-step sintering. (1) 10 zirconia abutments and 10 titanium abutments were chosen and detemined their surface roughness. Ra and Rz values were gathered. (2) 10 zirconia abutments and 10 titanium abutments were attached to Osstem USⅡSystem implants. Divided them into Zirconia Abutment Group(Zr-Group) and Titanium Abutment Group(Ti-Group). Then the microgaps at abutment-implant interface were measured by scanning electron microscope. (3) 5 zirconia abutments and 5 titanium abutments were chosen and divided into Zirconia Abutment Group(Zr-Group) and Titanium Abutment Group(Ti-Group). All abutments were attached to Osstem USⅡSystem implants which fixed in stainless steel specimen holders. Afterwards, the fracture resistance of the specimens were tested by force perpendicular with their long axes (CHS=0.5mm/min).Results:The prepared zirconia abutments had good shape. (1) Ra and Rz values of the zirconia abutments were:0.108±0.026μm,1.058±0.227μm, the titanium abutments were 0.131±0.037μm,1.157±0.268μm; No statistical difference was observed in the two groups (P>0.05). (2) Zr-Group:the marginal microgaps and internal microgaps were 3.01±0.64μm,28.5±1.6μm, Ti-Group:the marginal microgaps was 2.71±0.42μm and the internal microgaps was 23.9±1.4μm; There was statistical differences between the Zr-Group and Ti-Group (P<0.05). (3) There were statistically significant differences (P <0.05) among different abutment groups with a mean fracture load of 537.6±90.0N for the Zr-Group,753.9±160.8N for the Ti-Group.Conclusions:Within the limitations of this study, the surface roughness,fitness of abutment-implant interface,and fracture resistance of the abutments made from nano zirconia powder using cold isostatic pressing and two-step sintering can meet the requirements of clinical applications.
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