Have you addressed this with your current dentist? Sometimes a simple re-lining is all that is needed. A lot of people do have problems with ther lower dentures, but you don't have to. Sometimes they are loose due to lack of bone in the lower gums, or if you had your teeth pulled and then dentures put in right away, it may be that the swelling has now subsided and you need to be re-fitted. Before spending more money to see another dentist, I would ask your current one to do another impression to obtain a better fit.
Fabrication of full denture requires masterful skill. Well fabricated full denture can give you comfortable chewing, swallowing, adequate retention, effortless pronunciation, and satisfactory esthetics.Seeing a prosthodontist is advised.