Too large, too thick, too hard - these are the main characteristics of most toothbrushes. This also applies to the frequently recommended medium-hard toothbrushes as well as to many children's toothbrushes.
Make sure you check the bristles (soft) and, in particular, the bristle area (small). Use an ultra soft toothbrush with a small head of 2 cm length and/or a soft single-tuft toothbrush.
The job of a toothbrush
The main task of the toothbrush is to remove plaque, i.e. to destroy the biofilm that has formed. One hundred per cent removal of plaque is not possible or desirable because a sterile mouth would be extremely unhealthy. Only relatively thick and old layers of bacteria cause caries and gum inflammations.