Actually in terms of preventing infection in any wound would be irrigation (washing) of the wound with losts of water.And frequently. Whether the dressing has iodine or is plain doesn't really make much of a difference in most wounds in normal people with adequate immune systems. But if you are diabetic or have a poorer wound healing ablility or poorer immunity, the antiseptic in the bandage MAY make a difference to you.
OTOH, if you have a wound which you cannot clean out or irrigate with clean water, no amount of antiseptic bandages are going to make a difference to you......it WILL get infected.