Seems having only a dentist on hand for that "experiment" is akin to having a mechanic as your only expert for analyzing a car wreck? As the author even concedes, an abundance of anecdotes is not evidence.
Was it so hard to find a chemist way back in aught-9? (Go down to the nearest uni and find a chem major at least...)
The wide distribution of oversimplified, media-sanitized, pseudo-science is likely one of the affectations of Western culture that has kept it from progressing further for a solid 60 years--since television gave the ability for snake oil salesmen to multiply their effectiveness. The internet exponentially increased that ability.
If the dentist is being scientific, it's up to him to back up his claims about sugar and acid being the most (or only) important indicators for what's bad for teeth.
If you do some googling, it's commonly accepted that both sugar and acid are bad for your teeth, with plenty of justification. Some of the reasons are even covered in the article.
You're correct in that their classification of "worst" only applies if sugar and acidity are the most important factors. But they're clearly a large factor in tooth decay, so measuring the contents of various liquids and comparing them to each other is instructive.
> 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). 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.
I was just suggesting that the dentist might be familiar with the best science we have directly or indirectly, not even that he was acting scientifically per se.
Their function 10^(5.5-pH) * (mg/cl sugar + 1) does seem to imply that sugar and acidity have a synergistic effect, where the +1 in the sugar term is a hack to keep the result from being 0 if the sugar is 0. This doesn't make sense, as a modest increase in sugar, say from 0 to 1 would double the result regardless of the pH.
What the equation says to me is that acidity sets the stage for tooth damage, but as bad as that is, once you start feeding the bacteria in that set stage, you are in real trouble.
However, the entire article is a hypothesis. It is a best guess by somebody with scientific knowledge, but there is no reason to believe the real formula shouldn't be 10^(5.5-ph)+10(mg/cl sugar) or something completely different.
However, my son and daughter both need a science fair project soon. I wonder if there is a way to formalize this a little.
Their function also improves the results if the drink is more basic. A drink with a pH of 13 would have an amazing score on here.
If you normalize the pH above 5.5 since it has "little to no effect" things on the lower end of the results are better, with milk being worse than water, and chocolate milk being worse than milk.
This shows how bogus it is - you can put lots of sugar in a basic drink and it would score well.
The key point for me is why is concentration of sugar in mg/cl? Why not mg/l, or g/l, or oz/gallon? Each one would give a different answer, and all are equally justifiable. (There is also the weird idea that a decrease in pH of 1, which is 10 times the concentration of H+, would therefore be 10 times as bad.)
