Background: This study evaluated the clinical performance of 39 light and heat polymerized fixed partial bridges made with a substructure of preimpregnated, unidirectional fiber-reinforced composite, or FRC, veneered with a hybrid particu late composite.
Methods: The authors evaluated 22 extracoronal, full-coverage retainer prostheses and 17 intracoronal, partial-coverage retainer prostheses placed over a 37-month period. All substructures initially were fabricated with a low-volume FRC. The authors reevaluated this design after early failures occurred, leading to a substructure with a higher volume of FRC. All prostheses were assessed for surface integrity, anatomical contour, marginal integrity and structural integrity at several intervals.
Results: The data show that survival was associated primarily with substructure design volume. When patients with severe parafunctional habits were excluded, the survival rate was 95 percent for prostheses made with a high-volume substructure (survival range, 2.77 to 4.30 years; mean +/- standard deviation survival, 3.75 +/- 0.4 years). Retainer configuration did not have a statistically significant influence on clinical survival. For all surviving prostheses, the authors observed few changes in any clinical parameters from baseline to 48 months. A loss of surface luster was observed in the majority of cases. Repairable surface defects were detected on two prostheses at 24 months. Scanning electron microscopic analyses indicated no exposed fibers on the occlusal surface and minimal wear.
Conclusions: This study shows that a unidirectional, preimpregnated FRC can be used successfully to make bridges of variable retainer designs that last up to four or more years when a high-volume substructure is used.
Clinical implications: Short-span polymer prostheses made with particulate composite and unidirectional glass FRC can be used in certain clinical situations in which a metal substructure is not desired.