My experience is interdental toothpicks (the wooden triangular ones) made the biggest difference of all:

- no flossing -> gums bleed regularly, getting worse as time since last dental hygienist visit approach six months.

- semi-regular flossing -> gum bleeding mostly stops, still need to visit hygienist every six months.

- daily flossing plus wooden interdental toothpicks -> no gum bleeding, even though my last dental hygienist visit was now 18 months ago.

What prompted the behaviour change to adding toothpicks:- switching to a dental practice whose hygienist was (a) very expensive; and (b) charged by the minute. There was a direct correlation between how I cared for my teeth and the cost!

What sustains the behaviour change:- Each time I use the toothpicks, I can feel the food particles they dislodge, even if I have just cleaned my teeth.