KhairyIsmaiel AL-Azrag¹, Mohamed HamedGhazy², Mohamed Ibrahim El-Anwar ³, Lamia EL-Saeed Dawood⁴. ¹B.D.S. Faculty of Dentistry, Almergib University, Libya. ²Professor of Fixed Prosthodontics, Conservative Dentistry Department, Faculty of Dentistry Mansoura University. ³AssociateProfessor of Applied Mechanics, Mechanical Engineering Department,Engineering Researches Division, National Research Center. ⁴Assistant Professor of Fixed Prosthodontics, Conservative Dentistry Department Faculty of Dentistry Mansoura University. Abstract: Objectives: The purpose of current study was to estimate and compare the effect of implant-abutment angulation on fracture resistance over different all-ceramic superstructure. Methods:28 implant abutment angulations were used to represent the upper right central incisor. According to the abutment angulations (150 and 250) the specimens were divided into main groups I and II (n=14). Group I &II: Implant abutmentangulations 150 and 250 respectively, these groups were further subdivided into 2 sub-groups a&b receiving IPS e-max CAD crown and Zirconia crown respectively.Thecrowns were manufactured using the CAD-CAM technique. Allspecimens were cementedusing Rely X unicemAplicap 3M ESPE. The final restorations were prepared and stored in water path at temperature (37 0C) for 24 hours prior to testing. The specimen  was placed on the test device, then the force was applied at 450 until thefracture occurred. All the results obtained were statistically analyzed  by the student t test (level of significance p < 0.05). Results:Revealed that the highest mean value of fracture resistance was for implant abutment angulation 150 with zirconia crown. while the lowest value was for implant abutment angualtion  250 with  IPS emax CAD crown. Conclusions:Within the limitations of this in-Vitro study the following conclusions could be obtained; Zirconia crown is  recommended in cases of increase implant abutment angulation. Increasing the abutment angulations has an adverse effect on the fracture resistance of IPS e max CAD and zirconia crown. The screw played a role in the final strength of the restoration despite the different abutment angulations and crownmaterial used. Recommendations:The results of this study showed that the screw inside the abutment may play a considerable role in the final strength values. It may be repeat the experiments utilizing a stainless steel screw, whichwould resist bending forces better.That being said, it is important to realize that the screw of theabutment will play a role in-Vivo, and it is important to know at what level it will fail.   keywords:Dental implant, angled abutment , Fixed prosthesis, CAD/CAM, Zircoina,IPS e-max CAD, Fracturestrength.