Our Bass toothbrush bristles are medium firmness. You see, bristles with medium firmness are more effective at disrupting bad bugs in the mouth than bristles that are too soft (soft bristles tend to just mash against the teeth and gums).
Of course, brushing too hard can hurt the delicate tissue in the mouth, so any tool we use in the mouth can help or harm depending on our technique and whether or not we are using it with conscious awareness.
Our article Electric vs Manual Brushing, Which is Better? – Part 1 explains the importance of conscious brushing, and our article and video How to Brush Your Teeth to Reduce Gum Disease demonstrates how to do the Bass Brushing Technique.