For those of you with periodontal problems- this is the results of my experimentation with all the free samples from my dentist and a bunch of my own purchases-
This is the best product I have found to reach in between teeth and get in the pockets:
Butler Gum End-Tuft Tapered Trim Toothbrush
The small head and tapered bristles get in all kinds of hard to reach places.
The bottle-brushy type picks are much more difficult to use, leave debris in deep pockets, and they seem to poke and cause abrasions as much as they clean.