Hi!.
If just that the filling has come off and you have no pain/ sensitivity, then it would be the simple procedure of filling the cement as would have been done 8 years back.
But any other complains might change the mode of action.
An x- ray mostly will be taken.
Next Steps
Visit a Dentist at the earliest.
Health Tips
Don't postpone open cavities. The earliest you visit the simple will be the procedure for both you and your dentist. Take care.