I wouldn’t considering shadowing to be volunteer work (or anything done in a dental office for that matter, unless it’s a community health center or some dental nonprofit organization), sure you’re not getting paid but I would not consider it to be volunteer work. If I remember correctly when you fill out your AADSAS application you’ll be able to list your EC activities as either dental related/shadowing, volunteer work, or paid/compensated work (something along these lines). So shadowing is not the same as volunteering, volunteering at a hospital, food bank or other nonprofit organization would be things you could put down as volunteer work. In my experience schools like to see that you haven given back to your community, a lot of secondary and primary essay prompts ask about this kind of stuff.
Edit: This was already said earlier, but schools like to see commitment. So it’s a good idea to volunteer at a place for a long time (volunteering at a couple of places is even better). You also don’t necessarily need to volunteer at a dental clinical, although that would probably look really good. I volunteered at a bunch of different places, none of which had anything to do with dentistry. So don’t worry so much about where you’re volunteering (try food banks, homeless shelters, hospitals, blood banks, you can also tutor students that need help but can’t afford a traditional tutor).
