Also, maybe ask your uni's for feedback. i know some don't give it, and some might. your grades seem really good, so it ight be worth knowing what other ascpects of your application need to be improved. As mentioned above, work experince, extra curricular activities, and a good eprsonal statement are really good aswell as your GCSE grades and A-levels.
Regarding the dental nursing course, i think you may be ebtter of doing a dental therapy/ hygiene course which is for 2years and about 4 months. You would get a diploma and it allows you to do alot of practical work.
when doing dental nursing and dentistry- you have to learn to be a dental nurse too in a way, and im ntos rue how much this would improve your application.
Reapply next year- making your application as strong as possible!
(sorry if i ve repeated what others have said- i havent reas everyones posts).