i think your only barrier to the dental school is the interview itself, I think take that one more gap year otherwise you will regret it, you wont regret a 2nd gap year even if u are unsuccessful because then you will know for sure u did everything you could. Apply strategically to unis w a high post interview success rate. Your ucat was very high and is why liverpool rejected u so be sure to do proper research. Also this year sheffield gave offers without interview to ppl who reapplied after being on waitlist so uts very likely that you will get a place without having to reinterview if u reapply to sheffield. Ask for interview feedback. I did manchester interview twice and was successful when i realised what they were looking for, they want someone who can have a conversation and is eager and interested in dentistry, they dont necessarily want you to know everything but they want someone who is genuinely interested and not robotic which is what i found - if you're enjoying the interview, it is going well i'd say. Also do research into what unis allow you to reapply for a third time. if there are any that you have applied to twice - dont waste an option if they clearly state they dont accept your circumstances. I underatand its difficult and you feel like you are wasting another year but i know plenty of people who start dental school at 20+ and some post grads who start the process as well. Many people do other courses but eventually they come back so its all about your mentality. Dont give up i hope it goes well. Also consider studying abroad as a final option.