Some fails take decades. When I was 9, my dentist told me if I didn't start brushing a LOT more, he'd stop being my dentist. I got toothbrush religion. I always used a "soft" bristle bush, as directed. And I'd brush for several minutes, after every meal, while reading or watching TV. And decades later, the local dental school informed me I had brushed away most of my enamel. How? Calcium is a METAL! The bristles were SOFT PLASTIC! #LFMF