[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. The time saved by choosing the super-coarse grit for preparation is largely compensated because finishing of rough cavity walls will take longer. No constant effect of the rotating speeds on the depth of roughness of cavity walls was observed.