Practice, practice, practice!!!!! Don't worry, there are alot of diamond ground mesial walls of teeth out there that you weren't planning on prepping, even in actual real world private practice settings😱 😀
One of the things, aside from cutting alot of practice teeth, is finding a routine, and then sticking to it each and every time. The repitition will help alot in your comfort level after a while. For example, my routine for a prepping a crown is
1. Occlussal/Incisal depth cuts (yes, I still make them even after having cut over 1000 crowns
😀 )
2. Occlussal/Incisal reduction (This I really find helps with the mesial and distal reductions since you've eliminated that 2 or so mm's of tooth that was blocking your view of the interproximal surfaces)
3. Rough buccal wall prepping
4. Rough lingual wall prepping
5. Rough mesial wall prepping
6. Rough distal wall prepping
7. Verify occussal/Lingual and/or Incisal reduction/clearance
8. Refine all walls/margins
That's my pattern for every crown that I've prepped for the last 6 years, and it's a pattern that one of my mentors started me on. I'm not saying follow it exactly, but find a patern that works for you, and keep repeating it, that will really help alot in the long run.
Also, once you leave the hallowed halls of dental school and enter private practice, you'll find that you'll be able to get whatever bur shape that/size/grit that YOU want, not what works best in your prof's hands. This I also found helped alot for my interproximal preps. I really like a extra coarse narrow diameter (0.8mm) falt end 90 degree, short shanked, short diamond grit length(5mm of diamond grit) cylinder for my interproximals, it works in my hands, but then when my partner tries to use it, he likes to say "how the hell can you use that little dinky tooth eater??" My reply, "to each and every there own!"😀
