A lot of people have difficulty brushing their teeth and it can be frustrating, but don’t worry. There are a few things you should try before giving up on the whole process!
The first step would generally involve making sure that your bristles are polished enough for better cleaning; if this doesn’t work then I recommend using an old toothbrush or one with soft nylon instead—just make sure both pieces have been cleaned thoroughly beforehand so there isn’ t too much bacteria build-up under them.