Moulding element of a mould for moulding and vulcanizing a tyre tread, this tread comprising a tread surface intended to come into contact with the ground when the said tyre is rolling, this moulding element (1) comprising a moulding surface (3) intended to mould part of the tyre tread surface and a blade (5) of length and of height H intended to mould a sipe or a groove in the tread, this blade comprising a rounded end extending along the length of the blade in a direction of extension X. The moulding element comprises two cutting means (7) positioned on either side of the blade (5) at a certain distance from this blade, and each cutting means (7) comprises a cutting edge (8)extending in the direction of extension, this cutting edge making an acute angle ± in a sectional drawing perpendicular to this direction of extension X, the distance D between this cutting edge and the moulding surface (3) being lower than the height H of the blade(5).