So my WHOLE LIFE I have just been using the standard toothbrushes sold everywhere, found in hotels, etc. The kind that look like this
The other day after a dentist visit the dentist's office gave me a toothbrush with smaller bristles -- looks something like this.
Omg. Total game changer. It is so much easier to clean my teeth using this size of toothbrush, and I can tell I can reach more places on my teeth as well.
I know basically everything is formulated for, and tested by, men, leading to things always being slightly too large for women(medication dosages, airbags, etc). I now suspect toothbrushes are in this category as well.
I would suggest trying a toothbrush with a smaller head/bristles if you can!
Note: I am not a dentist, this is just anecdotal