The simple answer to that is to work hard, keep up your grades, so that when 3rd year dental school rolls around, you are in a position to specialize in whatever field you want. If you have a lower class ranking, then it will be more of an uphill battle to match into the more competitive specialties, or match into your desired location.
I have just completed my 5 months of anesthesia, and am starting general surgery tomorrow. Anesthesia schedule is dependent on the hospital you train at, but here at Shreveport, we have a pretty good deal. You don't work on weekends, you don't work on holidays, and you don't take call. You come to work around 6 AM and you'll be finished around 3 PM every day. Sometimes there are not enough people to cover you, so you end up staying later than 3, but everyone leaves by 5 PM. This happens about once every 2-3 weeks.
For general surgery, the schedule is tougher, but due to the 80 hour work week implemented by ACGME, life has been better for the residents in general surgery as compared to residents that worked 20-30 years ago, who have pulled over 100 hour work weeks. I'm on my Surgical Intensive Care Unit (SICU) rotation in March, and I'm going to be working ~6 AM-5 PM from Sunday to Friday, taking Saturday off.