STATEMENT OF PROBLEM: Challenges persist with conventional polymethyl methacrylate (PMMA) prosthetic materials and conversion protocols for immediate implant-supported interim restorations. Advances, such as the use of fiber-reinforced composites (FRCs), and novel conversion protocols, such as the Smart Denture Conversion (SDC), may mitigate existing prosthetic complications, yet their impact on flexural strength and mode of failure remains unclear. PURPOSE: The purpose of this in vitro study was to better understand the effect of the conversion method and to characterize the relevance of reinforcing interim implant-supported fixed prosthetics with FRCs. The effect of SDC, compared with a conventional conversion (CC) protocol, and the influence of FRC polymer was assessed on prosthesis flexural strength and mode of failure. MATERIAL AND METHODS: A total of 100 computer-aided design and computer-aided manufacturing (CAD-CAM) conversion matrices were divided into 4 groups: CC, SDC, SDC with FRC arch bar reinforcement (SDC-FRC bar), and SDC with FRC framework reinforcement (SDC-FRC framework). Flexural strength testing was conducted with a universal testing machine. Modes of failure were qualitatively analyzed. Statistical analysis was performed with 1-way ANOVA and the Tukey multiple comparison test (α=.05). RESULTS: SDC and SDC-FRC bar specimens demonstrated flexural strength comparable with that of CC (P=.995 and P=.907, respectively), while FRC framework reinforcement significantly increased strength (P<
.001). The SDC-FRC framework specimens exhibited the highest flexural strength (144.7 MPa). CONCLUSIONS: SDC offers a clinically convenient conversion technique with flexural strength comparable with that of conventional conversion methods. FRC framework reinforcement significantly enhances strength and reduces catastrophic prosthetic failure risk. These findings underscore the positive impact of reinforcement materials in interim implant-supported prosthesis fabrication.