Flexural properties of the bulk fiber-reinforced composite DC-tell used in fixed partial dentures

PURPOSE: The aim of this study was to measure the flexural properties of fiber-reinforced composite (FRC) used in frameworks of fixed partial dentures. In addition, the influence of water storage on the properties was determined. MATERIALS AND METHODS: Rhombic test specimens for four groups were milled from bulk FRC material DC-Tell. The test specimens of the first group were stored and tested dry. In the second group, the test specimens were water stored for 3 months at 37 +/- 1 degrees C and tested in water. The specimens of the third group were also water stored, but they were tested dry at room temperature. Water-stored test specimens of the fourth group were dehydrated and tested dry at room temperature. A three-point bending test was used to measure the flexural properties. The quantity of glass fibers in the test specimens was determined by combustion analysis. Water uptake was calculated after 3 months of water immersion. The direction and length of fibers were examined, and elemental composition was determined. RESULTS: Water storage decreased the flexural strength by 66% and flexural modulus by 60%. After dehydration, the flexural strength did not recover to the same level as the flexural strength of the dry-group specimens. The fiber content was 38% by volume. Water uptake was 3 wt%. The reinforcement of DC-Tell was short fibers in random orientation, and the elemental composition of fibers was similar to that of E-glass. CONCLUSION: Water storage decreases the flexural properties of the bulk fiber-reinforced composite DC-Tell. This may restrict the use of DC-Tell as a framework of crowns and bridges in the oral cavity in the long term.