I'm 42 and I've never had a cavity. I have had my wisdom teeth pulled, and I have 2 crowns on my molars (!!??). I don't know what I did to crack my teeth, since I don't do anything weird or reckless. I highly recommend the sonic toothbrushes. My husband bought me a fancy one recently, and my teeth feel as clean as they do after a dentist's cleaning on a daily basis. The hygienist spent noticeably less time using the awful scraper on my teeth than in times past. Totally worth it!