From Manchester Uni Dentistry entry req.
A level: Grades AAB. This must include Chemistry and Biology at grade A and one AS-level at grade B or above. Alternatively, two A-levels at grades AB and three AS-levels at grades AAB, including Chemistry and Biology. If only one of Biology and Chemistry is studied to A-level the other must be studied to AS-level and one other science, from Physics, Mathematics or Computer Science, must be studied to A-level. General Studies is excluded.
GCSE: We normally require five of your GCSEs to be at a minimum of Grade A (including either Integrated Double Award Science or Physics, Chemistry and Biology) and Grade B or above in GCSE English Language and Mathematics.
But they do a 6 year course of which you dont need any science background. So you should be fine, assuming other universities have similar entry requirements.