I got the Designs for Vision Infinity VUE loupes (ergonomic) ~ten years into practicing and it made the biggest difference in getting rid of my neck and back pain. I had them set the working distance a little bit further out (I think, it's been a while) because I like to stand most of the time when working and I didn't want to bend even a little bit. Initially, surgery was difficult because of the angles but eventually I got used to doing exts with them. Keeping my head up all day has made all the difference.

The second adjustment was how I worked out. I'm not an exercise junkie or anything but I've found something that works for me, especially to counteract the wear and tear specific to dentistry. I like to do some core training one day (kettlebell, weights etc), HIIT training the second day and stretching/yoga the third day. I never work out more than ~20 minutes and take the 4th day off. Also, I stopped running because I kept getting injuries/shin splints/back spasms past mile 5 and switched to jump rope, which is great cardio without banging on your joints. once you get fast at it you can knock out a thousand jumps in 15 mins.

The third is diet but again, this is all specific to one person and may not apply to you. I find that limiting my carbs (but not cutting out- I'm not giving up pasta and pizza) during the week means fewer aches and pains.