Toothpicks- love ’em? Use ’em?
Toothpicks have been studied to reduce plaque significantly. Neanderthals were the first to use them (before they were called “toothpicks,” of course). That was over 1 million years ago, which might be one of the most primitive (and still useful) interdental device.
And round is scientifically proven to be more effective than triangular!