Our local MBCA dealer uses Dent Solutions. They gave our section a private demonstration at the dealership this year (April?) by repairing dents on a salesman's current body style C-class and a member's 1970 280SL, including a door panel. Worked great! I don't think there's any advanced science to the tools or methodologies, it's more of an art and the results depend on the talent of the artist.
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420