Method for manufacturing a toothbrush and a bristle head thereof, toothbrush obtained by said method and mould for such method

1) Method for manufacturing a toothbrush of plastic material with resistant inner core, in particular a metal one, of the type wherein the following steps are provided

• manufacturing a resistant inner core,
• introducing said resistant inner core into a mould cavity defined by opposite footprints belonging to a lower half-mould (S1) and to an upper half-mould (S2) and, subsequently,
• injecting molten plastic material into said mould cavity to manufacture at least part of the toothbrush handle, characterised in that
• said resistant inner core (1) is arranged in a respective footprint (P) of a lower half-mould (S1) in contact with at least two support platforms (Q, R), apt to support said core (1) in the proximity of a central line of the mould cavity,
• and in that, before the injection of structural plastic material, said lower half-mould (S1) is coupled with an upper half-mould (S2) provided with at least one ribbing (L) apt to come in contact with said metal core at least in a position between said support platforms (Q, R) and in an opposite position thereto.