Clinical Evaluation of Fiber-reinforced Composite Bridges: Two-year Report

Objectives: To assess the clinical performance of 3-unit fixed bridges made with glass-fiber reinforced composite frameworks (Vectris) under an experimental veneering composite (Trend). Methods: In one group 30 bridges were made with Trend over Vectris. In the other group 30 bridges were made with Trend over gold alloy (Academy Gold-XH). Manufacturer's instructions were followed in all clinical procedures. Trend/Vectris bridges were luted with ExciteDSC/VariolinkII and Trend/Gold bridges with zinc-phosphate cement. Evaluation criteria used were: “shade match”, “surface texture”, “marginal shoulder”, “marginal gap”, “fracture”, “secondary caries”, “retention” and “abutment tooth hypersensitivity”. The bridges were rated as: “R” (ideal), “S” (acceptable), “T” or “V” (both unacceptable). Results: Comparison between Baseline and 2-Year in the Trend/Gold group showed no statistically significant degradation (p>0.05) in “shade match”, “secondary caries”, “retention”, and “hypersensitivity”. All changes were minor from “R” to “S” except in the criteria “marginal gap” where 1 bridge was rated “T/V”, and “fracture” with 7 “T/V” ratings. In Trend/Vectris group the majority of the criteria didn't show significant degradation. Only degradation of “surface texture” and “fracture” were statistically significant (p=0.001 and p=0.011, respectively). Comparing the results for the two groups in each period, statistically significant differences were found on “hypersensitivity” at Baseline (p<0.001) and on “surface texture” at 2-Year (p=0.009). At the 2-Year recall 7 (25.9%) Trend/Gold bridges were considered unacceptable because of “fracture” (n=6) or both “marginal gap” and “fracture” (n=1). Seven (29.2%) Trend/Vectris bridges were also considered unacceptable because of “fracture” (n=5) or “retention” (n=2). Seven of the “fractured” bridges remained in service because only small parts of veneering composite were lost and 7 were replaced. Conclusion: After 24 months, the overall performance was acceptable, but revealed some deficiencies that were corrected in the marketed material (SR Adoro). (This study was supported by Ivoclar/Vivadent).