Ahmed Sami Abd El Ghaffar Ismail*, B.D.S, Mustafa El Sayad B.D.S,M.D. Ph D Ahmad Khalifa, B.D.S. M.D, Ph D * Degree students, Faculty of Dentistry Mansoura University ahmed.samy1987@gmail.com Abstract: Purpose: to evaluate the masticatory efficiency between fixed and hybrid mandibular overdenture carried in four implants with  All-on-four concept. Material and Method: Ten edentulous patients had received four implants by All-on-four concept. After three months an impression was created. Patients subdivided to a group received fixed mandibular restoration with milled bar and the rest received hybrid prosthesis. After insertion and follow up masticatory efficiency was evaluated by chewing gum technique. The chewed samples was analysed by Photoshop®. Results: the results shows improvement in mastication more in the fixed restoration (mean = 0.43 ±0.09 )followed by  hybrid restoration (mean = 0.48 ±0.2 ) and at the end the conventional complete denture (mean = 0.56 ±0.06 ). Conclusion: restoring edentulous mandible with fixed restoration carried on All-on-Four concept is proper to restore masticatoryefficiency.