A combination of a dental implant and an insertion tool for inserting the dental implant into a bone of a patient, the dental implant comprising an anti-rotation means having a non-circular cross-sectional contour which comprises at least one planar force transmission surface in the form of an anti-rotation surface (7a, 7b, 7c, 7d), and the insertion tool comprising an anti-rotation means having a non-circular cross-sectional contour which comprises at least one planar force transmission surface in the form of a torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d") one of said anti-rotation means forming a recess, and the other of said anti-rotation means forming a bolt having a rotational axis and designed to be received in the direction of the rotational axis in the recess, such that the at least one anti-rotation surface and at least one torque transmission surface can cooperate to transmit torque between the parts, the anti-rotation surface (7a, 7b, 7c, 7d) and the torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d") being arranged such that, while the bolt is received in the recess, said anti-rotation surface (7a, 7b, 7c, 7d) and said torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d") can be rotated relative to one another between a first, non-torque transmission position, in which said anti-rotation surface (7a, 7b, 7c, 7d) and said torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d") have little or no contact, and a second, torque transmission position, in which said anti-rotation surface (7a, 7b, 7c, 7d) and said torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d") are in maximum contact with each other, wherein the angle between the anti-rotation surface (7a, 7b, 7c, 7d) and the torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d") is less in the second position than in the first position, the implant and/or insertion tool comprising at least two force transmission surfaces (7a, 7b, 7c, 7d), one of the anti-rotation means comprising at least one force transmission surface and the other anti-rotation means comprising at least two force transmission surfaces, said surfaces being arranged such that, while the bolt is received in the recess, relative rotation in either direction results in at least one anti-rotation surface and at least one torque transmission surface being brought into maximum contact with each other, the angle between said anti-rotation surface (7a, 7b, 7c, 7d) and torque transmission surface (11a', 11a"; 11b', 11b"; 11c', 11c"; 11d', 11d",) being less in this position than a first, non-torque transmission position, and one of the anti-rotation means comprising paired planar force transmission surfaces for co-operation with each planar force transmission surface of the other anti-rotation means, characterised in that the anti-rotation means of one of the implant and insertion tool is non-polygonal while comprising a functional cross-section defining a regular polygon and the anti-rotation means of the other of the implant and insertion tool is non-polygonal while comprising a functional cross section defining an irregular polygon.