Looks like I'm one of the few people around that has first hand experience with this or at least is willing to admit to it.
I took multiple semesters of science pre reqs with lab in on online self paced program and got accepted into multiple dental schools, some of which stated they did not accept online courses. I called the schools individually before applying and asked them about the requirements and my situation which prevented me from taking my post bac classes in person. One school told me sure no problem. Most schools said it would not affect my application, but I would be expected to retake the classes in person before matriculation and to indicate my planned classes on my application. I planned these for the spring and summer before dental school started. Some of the schools at the bottom of my list I wasn't upfront about this and they never asked. I don't think many schools label classes as "online" so it is your responsibility to be forthcoming about this. I never ended up re-taking the classes.
Having been through this I would not recommend taking online classes to anyone if you have the ability to take them in person. I felt like I was taking a lot of chances applying to dental school with these on my transcript and in addition to a few online courses I had a good undergrad gpa and a very strong application overall. There are exceptions as another poster already pointed out, but for the most part ONLINE CLASSES ARE A JOKE. It is very likely you will have to put in a lot of extra time studying for the DATs because your course was easy, didn't require a lot of memorization, or didn't cover the material in sufficient depth.
You have the time and ability to take the classes in person and probably not a good reason (correct me if I'm wrong, but this is based on the minimal information you gave earlier) for not being able to take regular classes. My advice is to put in the extra effort now and not be worried about it down the road during the application process.
