[Studies on heat generation by drills of various abrasion grade]

By means of our own measuring method, drilling tests were performed at a test block made of silicate cement using rose-head and fissure burs as well as diamond-stones with different feed. The temperature increases only within a limited range of wear and tear, it does not increase rectilinearly but stepwise, mainly influenced by two heat values, the shearing and the friction heat. Having reached the temperature maximum, further drilling or further wear and tear only prolong drilling time. The danger of damaging the pulp is primarily dependent on the feed and less on wear and tear, as was shown by the tests with the rose head burs. Only when the feed is rising, the worn-out driller further increases a rise in temperature.