Hiya and welcome Ali,
I don't see anything on the long term skill shortage list for dentistry, lots of stuff for health care though, so im sure you would be able to find a job. Here are a few links that might help you answer some questions.
New Zealand opportunties - FAQs
Skilled Migrant Category
You might want to try and contact NZQA (NZ qualifications authority) in regards to your degree; and whatever the IELTS is... sounds like a test/qualifaction of some sort? Here is a link to for you to contact NZQA....
Contacts [ NZQA ]
Hope that helps
Carl