Search the hospitals and dental schools around you , call them regarding this if they have an opening they will provide you with fee and duration details.
You could also meet and ask dentists practicing near you , they don't charge any fee for shadowing.
If you are looking for short term clinical training programs search from preceptorships , they can range from 1 month to 1 year , you can apply in your desired speciality and fee structure is given for each program on program websites.