A screw (100) comprising a head (105) and a shank (110) extending from said head (105) according to a pre-set longitudinal axis (X), characterised in that said shank (110) comprises at least two axial portions, of which a first portion (130), proximal to the head (105), which has an outer thread (140) adapted to make it self-threading or self-tapping, and a second portion (135), distal to the head (105), which has smooth outer surface and diameter (D2) between the outer diameter (D1') and the inner diameter (D1") of the first portion (130) is disclosed.