I did 3 weeks of shadowing in dentistry a few years ago. 1 week was cosmetic dentistry and the other 2 were at a general dentistry clinic. All I did was go into the clinics in person with my dad and he basically asked the receptionists if I could shadow the dentist!! Lol. You could also go in by yourself but at that time in my life I was quite timid so it helped having my dad there. Btw we didnt know these dentists previously, they just happened to be near our home. Got turned down by 1 other one we asked.
Idk how this would work now because of covid. Which method are you using to ask them if you can shadow?
And yeah, all you need to do it watch the procedures and if you want (or if they let you) you can ask the dentist questions.
In the end I decided dentistry wasnt for me and am now studying medicine but it was a great experience!
Good luck!!