I agree. Unless your excuse for the low GPA is also some sort of life-changing, dental-motivation event that is more than an excuse for a poor GPA, than I say steer clear of the GPA/low DAT discussion in the PS.
If you write a good personal statement it will stand out to admissions officers. The last thing you want is for you to be associated with your low GPA. When you walk into an interview you don't want the interviewer recalling your application and thinking "this is the girl/guy that had to make excuses for her/his poor performance".
In my interviews I was referred to as the "sausage-boy" because of a story I related in my PS. It was much better than being referred to as the "low science GPA boy."
It may help to draft a few different versions of a PS. Compose one including your GPA explanationn and another without. Take it to a writing center, friends, pre-dental advisor etc. and have them read both and have them tell you which one sounds better.