> But they're clearly a large factor in tooth decay Maybe, maybe not. The in-vivo environment might have many significant differences than some in-vitro setup.

> But they're clearly a large factor in tooth decay Maybe, maybe not. The in-vivo environment might have many significant differences than some in-vitro setup. What's the role of saliva? of bacteria? of genetics? Don't underestimate the power of the telephone game (http://en.wikipedia.org/wiki/Chinese_whispers http://en.wikipedia.org/wiki/Chinese_whispers). You need to go back to primary sources. It's very common for papers in software engineering, for instance, to confuse qualitative statements from earlier papers with empirical results.