Dental schools are looking for passion. If they cannot sense that you are passionate about your research, it will mean absolutely nothing to them. I had absolutely no research, but put all of my effort into something I was passionate about. Only had about 10 experiences listen on my app, but the passion was shown through the way I talked about each of them and the hours listed. I got into some top notch schools - UCSF, UNC, Columbia, etc (ALL as an OOS). Do things that truly mean something to you and be able to explain it throughout your application and interview.
Additionally, don't think you HAVE to have dental experience besides shadowing. It's nice if you enjoy it and if it reminds you of why you want to be a dentist, but I truly think you shouldn't do it to "look good."
If you like it, do it. If you don't like it, find something that means something to you and figure out how to make something out of it.