Introduction. The fracture resistance of interim restorations influences their integrity and service in the mouth until the definitive restoration is delivered, they should demonstrate adequate strength, specially, when used for longer periods of time. The strength of interim restorations is influenced by the fabrication method and material.
Objective. The aim of this study was to investigate the influence of fabrication technique on fracture resistance of 3-unit interim fixed dental prostheses made by conventional and computer-aided design and computer-aided manufacturing (CAD/CAM) techniques.
Material and methods. Thirty-two 3-unit interim fixed dental prostheses (FDPs) were fabricated on epoxy resin models using 2 different techniques; CAD/CAM milling (group MIL, n=16) (Ceramill A-Temp; AmannGirrbach, AG, Austria), manual fabrication using self-activated poly methyl-methacrylate PMMA (group MAN, n=16) (Unifast III; GC Corp., Tokyo, Japan). The restorations were cemented on their corresponding models, subjected to cyclic loading and were loaded in a universal testing machine until fracture. Normality was checked using Shapiro Wilk test and Q-Q plots. Comparisons of the fracture resistance between groups using independent t test. Significance was inferred at p value <0.05.
Results. All specimens survived cyclic loading, the mean fracture resistance of MIL group was (1141.10 ± 131.36 N), while that of MAN group was (516.93 ± 62.96 N). A significant difference was found between the 2 groups (p <0.0001).
Conclusions. CAD/CAM fabricated interim restorations offers better mechanical properties over manually fabricated ones and are more suitable to use as long-term temporary restorations.