How far in advance should one shadow a dentist before applying to DS? I suppose it doesn't really matter, but I've read in several threads about asking the dentist for a letter of recommendation. I won't be applying until 2012, but I have some time on my hands and figured I'd like to get started with shadowing now. Assuming I finish most of my shadowing in the next few months, would it be strange to ask for a letter of recommendation two years before I even apply to DS?
You need to start shadowing early and carry it through your entire undergrad career. If you break this out over 4 years, it's really not bad at all. I would recommend spending a day with a dentist every few months. Make sure to shadow different dentists in different specialties and in different situations (military vs civilian). You'll grow close relationships with a couple of these dentists through the years. If you keep the relationship going, it would be best to wait until you apply to ask for the letter. That way they can talk about how they've known you for X years and how you've grown and how they're sure you're going to be a great dentist, etc.