Fiber-reinforced Composite Fixed Dental Prostheses with Various Pontics

Purpose: To evaluate the load-bearing capacities of fiber-reinforced composite (FRC) fixed dental prostheses (FDP) with pontics of various materials and thicknesses. Materials and Methods: Inlay preparations for retaining FDPs were made in a polymer phantom model. Seventytwo FDPs with frameworks made of continuous unidirectional glass fibers (everStick C&B) were fabricated. Three different pontic materials were used: glass ceramics, polymer denture teeth, and composite resin. The FDPs were divided into 3 categories based on the occlusal thicknesses of the pontics (2.5 mm, 3.2 mm, and 4.0 mm). The framework's vertical positioning varied respectively. Each pontic material category contained 3 groups (n = 8/group). In group 1, pontics were fabricated conventionally with composite resin (G-ӕnial, GC) with one additional transversal fiber reinforcement. In group 2, the pontics were polymer denture teeth (Heraeus- Kulzer). Group 3 had an IPS-Empress CAD pontic (Ivoclar Vivadent) milled using a Cerec CAD/CAM unit. Groups 1 and 2 served as controls. Each FDP was statically loaded from the pontic until initial fracture (IF) and final fracture (FF). Initial-fracture data were collected from the load-deflection graph. Results: ANOVA indicated statistically significant differences between the materials and occlusal thicknesses (p 0.001). Quadratic analysis demonstrated the highest correlation between the thickness of the pontic and IF and FF values with ceramic pontics (IF: p 0.001; R2 = 0.880; FF: p 0.001; R2 = 0.953). Conclusion: By increasing the occlusal thickness of the pontic, the load-bearing capacity of the FRC FDPs may be increased. The highest load-bearing capacity was obtained with 4.0 mm thickness in the ceramic pontic. However, with thinner pontics, polymer denture teeth and composite pontics resulted in higher load-bearing values. Keywords: fixed dental prostheses, fiber-reinforced composites, prosthodontics, inlay bridges, CAD/CAM