You have a valid question. We are currently taking Oral Surgery as thirds year students. This semester we are focusing on the reconstruction aspect and there is a lot out there for oral surgeons to do. If putting faces back together is your thing, you can definitely make a career out of it doing trauma stuff at a hospital. Our oral surgery professors explained to us that often the oral surgeon is most qualified to do the facial reconstructions after a car accident, fight victim, gun shot wound, etc because they have a clear understanding of how the teeth relate to each other. Many times the plastic/ENT/Head&Neck can put the face back together but they don't know how the teeth come together so the patient doesn't have normal functioning when it comes to chewing and this really bothers the patient.
You are on the right track with shadowing an oral surgeon this spring. Try to talk to a few to get different opinions b/c office oral surgery (wisdom teeth, implants) is very different from hospital oral surgery (trauma, reconstruction, medically complex patients). Although they get training in both, surgeons might choose to focus on one aspect or another in practice.
There are 4-yr (non-MD) and 6-yr (MD included) OMS residency programs. The scope of practice as an oral surgeon is the same for both, the only difference is one give you an MD. So the training period to get to do facial reconstructions is less time involved than the plastic surgeon routes logistical99 described. Especially if you didn't get into a categorical surgical year after med school - you are looking at 10+ years before you can do any facial reconstruction!
Dental school does have something like the "preliminary residency" for OMS. If a student (in reasonably good standing) didn't get into OMS straight out of school but was determined to apply, they could do a few things. Do a general practice residency (GPR) at a hospital where the GPRs do a ton of oral surgery (this isn't hard to find, OMS is a HUGE component of many GPRs). Or there are some OMS programs that offer a one-year residency/fellowship geared specifically for the student who is interested in oral surgery to gain more experience prior to applying to OMS. Louisiana and Nebraska have these, I have seen letters to our OMS department hanging up at school asking if we have any students interested in these one-year things.
The great thing about dentistry is you can practice a little bit of all specialties (or even heavily focus on one) with the DDS. Worst case scenario if OMS doesn't work out immediately after the things I described above, you can do general part-time and work under an OMS willing to take you on and teach you while you build even more experience and credentials to try and apply again. I don't think you can do this in medicine - as in work under a surgeon although you only did a residency in family medicine. You would be remain pretty low on the medical totem pole if you follow what logistical99 said about those who don't get into plastics the traditional way. As a DDS, you'd be earning a very good living during that same time while gaining your OMS experience.
"Don't apply to dental if you're not interested in general dentistry" - that is a very true statement. As much as you want to be an oral surgeon, you are a dentist first. You have to like doing dentistry because you'll have to do a lot of it the pre-clinic courses and in the clinics for 4 years in dental school. It will be hard to do well if you aren't into dentistry and have your mind on something else all the time. Also, the qualifications to ensure acceptance to OMS are pretty tough - 90+ on the part I boards, a good class rank, experience & interest in OMS, school involvement, and even research. Dental school is not easy to coast through to attain these credentials. However, if you know what you want, work your hardest for it - just look at Yah-E and his experience at Nova!
Check out
www.aaoms.org. This is a great website with info on the specialty, its residency programs, and summer externship programs (2 - 4 week summer programs where you get hands on experience as a second or third year dental student).
Not having dental shadowing experience will hurt your chance at ANY dental school, not just the "good" ones. Word of caution, I wouldn't rule out any dental school just because you haven't heard its "name" - dental school "reputations" work very differently than other professions (med, law, business). Qualified candidates get accepted to OMS every year regardless of the school they attended.
Ask, ask, ask! THis is a difficult decision for you to make, but try to talk several people in these fields, especially young graduates and young practitioners, about your situation. Good luck!