I just got introduced to this manga, having read the previous volume (7) and I am convinced that Ruby's "dentist" visit for "crowns" and etc. has nothing to do with "weightloss" and, like the giant Korean, was done out of pure vanity to have bright, straight, clean teeth for her announcement that she's moving up to "lightweight" after defending this title match. It's all been played at and hinted so much, it HAS to happen, imo. She's gonna take off her mouthguard after her win in the ring, smile as big as she can and everyone will be in huge awe... except the chairman who will be angry she did something so stupid like going to the dentist two days before a boxing match and her friends who will feel like they've been fooled (like all the readers) they've been empathizing and feeling extreme pity Ruby ripped out teeth just to meet weight regulations.
Why do I guess that? It fits perfectly with the "wrong reason/comical" writing pattern that been established, so far.
And it will be hysterical. I can't wait to see that.