Would an MDS (Master of Dental Surgery) from India be adequate for a research position in Australia?
Generally, research assistant is not a regulatory job in Australia (I work with many!). I've seen RA coming from all different background. As long as your boss is happy, there's nothing stopping you working as an RA. However, I have never seen an RA without a university degree, it's hard to convince anyone for your research potential if you don't even have a degree.

Of course, you won't be able to work as a dentist in Australia as dentist is regulatory job.