Comparison of six different fiber reinforced composite FPD framework designs

Objective: Many important properties and behaviors of a fiber reinforced composite fixed partial denture (FPD) depend on the internal stress distribution of the overall structure. The purpose of this study was to evaluate and compare six different fiber reinforced framework designs and determine if the framework design. Material and methods: Two-dimensional photoelastic simulation models (5 x life size) of posterior maxillary three-unit FPDs were fabricated using photoelastic material sheets. The fiber reinforced composite framework simulation was made with conventional fiberglass. The teeth simulation models were prepared cutting epoxy resin sheets representing the second maxillary premolar and second molar leaving a space of a missing first molar. One FPD model was the control model without an internal framework and other models were the FPD models with an internal structure of fiberglass designs. The FPDs were bonded with the teeth models. The complete models were loaded vertically with different points of the occlussal surface (in the junction, in the center of the pillars and in the center of all the FPD) and photographed in the transmission polariscope. The images were analyzed and interpreted to measure the number and closeness of the fringes to get the data. Results: Depending on the fiber reinforced composite framework design there was a variation on the results, but in fact, the stressed models with a fiberglass framework depending on the design displayed the lowest magnitude and concentration of stress, specially in the critical parts like the middle part of the pontic and the junction between the pontic and the pillar. Conclusion: This study suggests that, the fiber reinforced framework design influenced positively the stress distribution and the stress concentration in the overall the structure of the fiber reinforced composite FPD.