The conscious dental thing varies a lot depending on location. I'm in Ontario, Canada, and no vet is trained in conscious dentals in my area (I have looked.) My vet gives them a gas anesthesia, which is supposedly the safest for small animals. Both of my pigs have had gas anesthesia without side effects (my younger one has been put out at least four or five times due to dental/abscess issues and has recovered quite well each time.) One of my previous pigs had gas anesthesia twice in the last weeks of her life when she was extremely ill and recovered well from the anesthesia, though she eventually passed away to osteomyelitis and sepsis. So although there is always a risk to anesthesia, my experience thus far is that my pigs have all done well with it even when ill or deconditioned.
One suggestion that I have when dealing with dental issues when nothing seems to be wrong with the teeth is that there may be an abscess brewing that is not yet apparent. I went through this with Sundae, one of my pigs. She had obvious dental symptoms (weight loss, being interested in food but not eating it, chewing slowly, pulling faces when chewing, coughing/gagging while eating, etc.) She had one dental which found a molar spur and filed it down, but continued to intermittently show symptoms. She had two more dentals where the vet filed her teeth slightly, but didn't really find anything that looked like it needed fixing. This went on for a period of five or six months (with a dental filing every 6 weeks or so, followed by recovery and then a gradual return of symptoms while led to another dental filing.) After about 6 months, almost overnight, the side of her jaw puffed up in a huge abscess. The vet lanced and drained it, and apparently it was very deep, all the way down under her jaw muscle, and was probably very painful for her. Once the abscess was under control, she resumed eating normally for the first time in 6 months, regained all the weight she had lost, and required no more dentals (it's now been about 6 months since the surgery; she was previous going for a dental at least every 1.5 months.) I now think that she probably had a deep abscess that was uncomfortable when chewing and her dental issues were due to her favouring the opposite side, but that there was no way to detect it until it became big enough to swell externally. So I would keep a close eye on his face, and keep feeling along the jawline for lumps/bumps that weren't there before. Abscesses can pop up very suddenly, Sundae went from having no lump to a lump so large that she could no longer open her mouth literally overnight.
Lots of luck, I know dental problems are stressful and wish you and your piggy all the best!
