against the earth in the cutting advance direction 5 only the outer edge lying in the cutting direction of the cutter 2 has a cutting function fig1 and 2 show a first cutting tooth according to the invention having a step 10 running from the outside inward on the advance side 9 of the cutter support region 6 the step 10 is in this case directed approximately parallel to the at least one cutting edge 3 that partial area of the cutter support region 6 which adjoins it in the opposite direction to the cutting direction 4 being drawn down toward the tooth root in the opposite direction to the cutting direction as a result of the parallel profile the length of the active advance side 9 remains constant even as the level of wear increases therefore the active advance surface area does not change even when the width remains constant in an area next to the step the constant cross sectional area is achieved by the fact that as the active length of the active surface increases the width is reduced in accordance with a predetermined curve 20 in operation this surface area does not increase in size as a result of wear since the step 10 or the reduction in width prevents the abraded surface from growing the transition of the step 10 to the adjoining partial area of the advance side 9 is considerably rounded as.