hi,
I am not very sure but as far as my knowledge goes u can do reasearch in dentistry if u have any kind of MS degree here in US and which is 3-yr course. Other way is I guess to be exceptinally good, why I am saying this is once while searching some information I got to BU website where there was one guy working with the research faculty of BU with a BDS (some indian guy). I dont remember the site. But will pm u if find it.