Research is always a plus.. but don't let it interfere with your DAT preparation!! Research means nothing if you don't have a good DAT score.
That being said, I did quite a bit of research, and feel it really boosted my application. But I didn't do any research the 3 months before the DAT. If you can manage to do both, it's a huge plus. I got into two schools, and one of the schools I am certain was because I had a strong research background and it was a heavy research school. Also, it really doesn't matter what research you do. I mean, I did a Micro/Organic project where we used essential oils from plants to kill mosquitos and then bacteria.... lol, totally irrelevant to dental school but I worked hard on it and they liked it. So I would recommend you go for it!