Abstract.This study investigated the immediate effect of partial pulpotomy in monkey teeth using different rotary instruments. The rotary instruments used were a diamond bur at 300,000 rpm, a tungsten carbide bur at 300,000 rpm and a steel round bur at 6,000 rpm. The pulps were examined half‐an‐hour after the operative procedure. Both high speed techniques were shown to cause minimal damage to the pulp. The results also suggested that steel round burs produced a satisfactory alternative where the bur could be supported on dent