ABSTRACT
Objective To compare the different accuracy of implant model made by the two types of silicone impressions.Methods Fifteen impressions of standard abutment were made separately by machine-mixed and hand-mixed,then made into super-stone models and the accuracy of the different impressions was compared.Results The two types of silicone impressions showed significant difference of the margin precision,while differences on the height,diameter and the width of abutment shoulder were not found.Conclusions The two methods both have ideal accuracy,but porcelain-fused-to-metal restorations require high accuracy of the model shoulder,which is not suitable to use machine-mixed silicone impression technology,and hand-mixed method can be used in fixed restoration,removable denture and implant level impression.