The following guidelines must be considered in the maximum length for cantilever design of fixed prosthesis in dental implants.
1. A rigid cantilever on a single fixture is contraindicated.
2. The maximum cantilever length design for a linear fixture arrangement using two to three fixtures is approximately equal to the length of the implant fixture arrangement.
3. The maximum length cantilever design for a curved arrangement using four to six fixtures is almost twice the anteroposterior length of fixture arrangement.
For more info about Cantilever in Dental Implants, please read this informative article:
Dental Implants Occlusal Overload – http://costofdentalimplant.com/dental-implants-occlusal-overload/
For more information on the best possible Prosthodontic and Dental Implant Treatment for your case, please consult your Dentist. “There is no online material nor website that can substitute for professional advice.”
 Hobo S, Ichida E, Garcia L T: Osseointegration and Occlusal Rehabilitation, Quintessence Publishing Co., Ltd. 1989
Affordable Dental Implants – http://affordabledentalimplants.org/