[Quantitative profilometric surface analyses to verify the accuracy of reproduction of elastic impression material].

The optical fine scanner RM 600 Laser Stylus (Rodenstock) allows in combination with the perthometer S 8P (mechanical scanner, Feinprüf/Perthen) a direct quantitative analysis of elastic impression materials. We verified with this apparatus the accuracy of surface reproduction of thirty-three various impression materials. The mean roughness values (Rz) of the originals and the reproductions showed no significant differences.

[The effect of diamond grinding instrument of different grit on dental hard tissue].

Under practice-related conditions 100 human molars and premolars were prepared with diamond grinding instruments of different grit. We obtained the smoothest surfaces by using the extra-fine grit at 250,000 rpm, thus indicating the suitability of these instruments for finishing cavity walls especially at high rotating speeds. Only slight differences were found between medium and coarse grit.