A tooth for attachment to a cutter head arm. The tooth has a front wear part and a rear coupling part, the rear coupling part having a main body with a rear free end and a forward end. The main body has a first upper surface, a first lower surface and two side surfaces joining both upper and lower surfaces, with the distance between the first upper surface and first lower surface decreasing towards the rear free end, side projections, and upper and lower segments. Each side surface has a side projection with a second upper surface parallel to a second lower surface, the second upper surface approximately parallel to a lower segment, and the second lower surface approximately parallel to an upper segment. The distance between the second upper surface and the second lower surfaces is smaller than the distance between the upper segment and the lower segment.