Also see my critique on the study that "shows that kids lose weight by eating breakfast". More fodder.

But I think there's a lot more to it than just smoking. There could be other factors. Like stress levels of smokers versus non-smokers? Or diets? Or dental care coverage? When I worked in the restaurant industry, most of the people I worked with were smokers, and most were also uninsured. I could see how having dental insurance could help you keep your teeth longer.

People who smoke are going to be less healthy-living oriented in general. Ergo, it makes sense that they probably (in aggregate) brush & floss less, visit the dentist less, and consume more sugary food & drinks. Those things are all known to correlate with increased tooth loss, so it's probable THEY are the problems and not smoking itself. You could also probably extend the study and find that smokers tend to drink more alcohol as well and vice-versa. So what causes what? I'm not a fan of smoking, but its most zealous opponents only make themselves out to be kooks/biased/idiots when they publish such fundamentally flawed "research". Were there really PhDs involved in this??

did they study the dental records of these people before they started smoking? perhaps they had 10-12 cavities before they started smoking.

i can't stand this new sensationalistic reporting of scientific studies/research/whatever. focusing on a small amount of the data always means you're going to see some sort of pattern that doesn't jibe with the bigger picture.