A tooth for being connected to an adaptor by means of a retaining system, said adaptor being intended to be attached to the propeller of a dredging machine, said tooth having a front wear part intended for being in contact with dirt and stones, and a rear coupling part in the form of a projection or nose, said rear coupling part comprising: - a lower base body having a section with at least four sides with rounded vertices and with an upper surface and a lower surface, - an upper appendage arranged on the lower base body, the upper appendage having an upper surface and a lower surface, whereby the upper surface and the lower surface of the upper appendage form a trapezoidal cross section, the lower surface of the appendage being narrower than the upper surface of the lower base body and being centered with respect to the upper surface of the lower base body, the rear coupling part having: - a free end opposite to the front wear part or tip, and - an end opposite to said free end and being attached to the front wear part of the tooth, characterized in that the upper surface and lower surface of the lower base body progressively separate from one another from a point close to the free end of the rear coupling part to the front wear part of the tooth thereby increasing a first height of the rear coupling part, the section of said base body therefore increasing in the direction from the free end to the front wear part of the tooth until defining a first maximum gap corresponding with a first maximum height of the lower base body, and the upper surface and lower surface of the appendage progressively separate from one another from a point close to the free end of the rear coupling part to the front wear part of the tooth thereby increasing a second height of the rear coupling part, the section of said appendage therefore increasing in the direction from the free end to the front wear part of the tooth until determining a second maximum gap defining a second maximum height of the upper appendage, whereby the location of the first and second maximum heights (H1, H2) of the lower base body and of the appendage respectively are located at a third maximum height of the rear coupling part or nose of the tooth, such that after said location of the third maximum height the upper surface of the upper appendage and the lower surface of the lower base body begin to converge towards the front wear part of the tooth until these surfaces (153, 123) meet, the location where both surfaces meet being located towards the side of the front wear part of the tooth and in front of the location of the third maximum height. - a lower base body having a section with at least four sides with rounded vertices and with an upper surface and a lower surface, - an upper appendage arranged on the lower base body, the upper appendage having an upper surface and a lower surface, whereby the upper surface and the lower surface of the upper appendage form a trapezoidal cross section, the lower surface of the appendage being narrower than the upper surface of the lower base body and being centered with respect to the upper surface of the lower base body, - a free end opposite to the front wear part or tip, and - an end opposite to said free end and being attached to the front wear part of the tooth,