Successful long-term results of dental implants have led to an increase in their usage in many clinical situations. Since the introduction ofosseo-integrated implants for the rehabilitation of the partially edentulous patient, a tremendous awareness and subsequent demand have arisen in the field resulting in implant supported fixed prosthesis being widely accepted as an alternative to conventional removable prosthesis.However, some clinical studies have reported variable rates of failure.Biomechanical factors and stress distribution around implant supportedFPDs are some of the prime factors leading to failure of implant supportedThe current study evaluated the effect of different abutment materials titanium and zirconia with different bone density (D2 & D3) on the stress distribution and fracture resistance of implant supported FPD.The relative effect of the two different abutment materials were compared using mechanical loading test together with strain gauge analysis.The following materials were used in the current study:1. Zimmer Dental Implant fixture.2. Zimmer Dental Implant abutment.(titanium & zirconia)3. inCoris TZI medi block4. Provicol C temporary cement.5. Unsaturated Epoxy resin (cancellous bone).6. Saturated epoxy resin (compact bone).Summary & Conclusion7. Electrical resistance strain gauges.Eight implants were fixed in four anatomically correct D2 and D3 bone density models in order to stimulate restoring posterior missing second premolar, first molar and second molar. The eight implant abutments were fixed in place over their fixture and the twenty Full anatomical zirconia FPD were fabricated as follow:1. D2 bone density with titanium abutment2. D2 bone density with zirconia abutment3. D3 bone density with titanium abutment4. D3 bone density with zirconia abutmentStrain gauges were bonded on the buccal, lingual , mesial and distal for the both implant abutment ( 2nd premolar & 2nd molar )Full anatomical Zirconia FPDs were milled using CerecInlab system. A cementing device is used to cement the FPD to its corresponding abutment