Simply put; Yes.
There's less dental schools in the UK, and it seems the number of dentistry applicants is growing each year.
However, the same applies for medicine applicants.
Dentistry schools seem, to me, a lot more clear-cut than medical schools. They tend to have clearer requirements e.g. UCAT cutoff scores which seem to be consistent across many of the universities.
I'm assuming you're torn between the two, and I would advise that you shouldn't decide on which degree to do out of how easy it is to get in, or settle less for medicine because you want to do dentistry but think it's too hard.
With dedication and drive, you are able to achieve this.
I can either put down your sixth form statistic to be because; not many people applied in the first place, your sixth form has a small student population, or they just don't offer enough support.
I'm happy to help if you have any questions about the application process or are looking for support (ex-medicine applicant, just finished second year A-Level student)