Yes you can apply for Dentistry with a Biology degree. I know someone who started at Peninsula last September after completing a Biology degree.
Having done Biology and Chemistry will also help your application.
Have a look at the UCLAN admissions (on their site). They have a list of subjects they accept which even includes psychology. They do however also ask for a levels - not sure if they specify the grade.
In short though, yes. I think most grad courses will accept biology. Given that the academics are you'll really need to focus on the extra-curricular stuff though to get an offer.