Changes in Surface Roughness on Several Stages from Preparation to Casting

the original, the stone model and the casting with one another. Metal blocks having uniform V-shaped grooves on the tapered axial surface were made to simulate the abutment teeth, The grooves on block A, B and C were 16.80, 28.00 and 38.10 gm in depth respectively. These values were treated as the roughness of the blocks. A glass plate was also employed as the control surface having no grooves. When a silicone rubber or a polysulfide rubber impression material was used, the smooth surface of the glass plate and the grooved surface of block A were reproduced with a few micrometer larger roughness on the stone model. Judging from the fairly