I personally think a page is a lot. Also, are we talking single spaced? Double spaced?
A single spaced page is a LOT. These adcoms have to read thousands of personal statements, and then read through your app, and then read through all of your letters, and then read through your supplemental if they have one, etc etc. That is a lot of material to read.
I was under the impression that brief and to the point was good. For example I wouldn't expect a professor's letter to say more than something like "this person did really well, I think they can handle dental school and I recommend you highly consider them, they were very nice and professional in class, their excellent grade in my class also equates to their good performance in their other classes" etc. Obviously it would be more fleshed out across a couple paragraphs, but I don't think we should expect these people to be writing essays on us.
If anyone disagrees, by all means I'm willing to hear what you think.