The work a dentist can do who does not specialize. Basically, they are trained to do everything, and can choose to do whatever they feel comfortable doing.
Ex: Tooth restorations, periotontal work, cosmetic work, work on children, braces (typically only easy cases), Tooth extractions... I'm sure you get the point. If there is something a general dentist is not comfortable doing, they can refer them to the proper specialist.