Personal experience isn't science. What about those people who brush their teeth, floss, etc and still have teeth problems? Do their personal experiences matter

Personal experience isn't science. What about those people who brush their teeth, floss, etc and still have teeth problems? Do their personal experiences matter? Also, in addition to brushing and flossing, did you change your lifestyle? Did you start eating better, working out or changing your diet? Were you stressed when you were younger but have less stress now? You can't even rule out the placebo effect. Does going to a hygienist make you think your teeth/gums are healthy and therefore boosts your immune system and the health of your gums/teeth? If something works for you, that's great, but that isn't science.