I was wondering if it is true what advertisers say:
that after 6 months of use, a toothbrush should be thrown away, because the hairs become coarse at the end and damage the gums. And that "their" ultra-super-extra-newest toothbrush have hair ends "polished" so they will not scratch the gingival tissue.
If you lack subjects for photos, I wonder if you can take a shot or two at an old brush and at a newer brush.
Thanks!