applying to university

say if i take four alevels. If i got an A/A* in biology, chemistry and sociology, and a grade less than an A in physics, would universities still accept me in for dentistry. For dentistry I only really need biology and chemistry. I don't really need physics but im taking it anyway, and also sociology. say if my physics grade turns out bad, but my sociology grade is good (like A or above), would universities look at the subjects i get the best grades in? please let me know

Generally speaking, universities will pay no attention whatsoever to your fourth A level. They will set offer conditions based upon three A levels only. You could get an E in the fourth A level and they wouldn't bat an eyelid.
This is why, for most people, it's absolutely pointless to take four A levels. I realise that many schools insist on it, but it actually harms your chances, as you have less time to dedicate to the other three subjects, thus risking the grades in those three being adversely impacted by doing the fourth.

i just feel like i won't a grade good enough for physics alevel to get into uni, and since im well into year 12, its too late to drop it or replace it with something else. so i was just thinking that if i did an easier alevel privately, such as sociology alevel or ICT alevel or whatever over the course of the summer holidays, and achieve an A/A* in that,, as well as an A in bio and chem, wouldnt it increase my chance of getting into a good uni? im just scared of physics dragging me down and being the reason i can't apply for dentistry/medicine