Purpose: The purpose of this study was `to appraise the fracture strength of provisional crown and fixed partial denture resins with an in vitro test system. Materials and Methods: Bar-type specimens were fabricated according to American National Standards Institute/American Dental Association specification number 27. Reinforcement materials; polyethylene fiber and glass fiber are compared.  Provisional crown-bridge materials are autopolymerising Poly Ethyl Metacrylate (PEMA), autopolymerising Poly Methyl Metacrylate (PMMA), bis-acryl composite resin and light cured composite resin). A total of 150 specimens are arranged for the flexural strength test. The specimens are divided into 5 groups according to the type of resin used (Dentalon Plus, Tetric Ceram, Charisma, Protemp 3, TAB 2000) and then every group was distributed into 3 subgroups rendering to the type of fiber reinforcement (Construct, Fiber-splint ML). Unreinforcement specimens functioned as the control. Specimens were fractured in a universal testing instrument until the point of rupture. Mean flexural strengths were calculated in MPa. Comparisons were completed with analysis of variance and then Duncan's multiple range tests. Results: Mean flexural strengths ranged from 63.45 to 397.8 MPa. There are statistical difference between the groups (Fiber-splint ML, Construct and control). Conclusion: Flexural strengths were material- rather than classification precise. Several, but not all, bis-acryl resins validated expressively superior flexural strength over traditional methacrylate resins. There was significant difference between Fiber-splint ML, Construct and control group.