Effect of fiber incorporation on the contraction stress of composite materials.

OBJECTIVES

This study aimed to assess the effects of fiber incorporation on the contraction stress (CS), time to gelation (TG), and temperature rise (TR) features of two experimental resin-based composites (RBCs) in comparison to those of bulk-fill RBCs and conventional RBCs in simulated, clinically relevant cavities.

MATERIALS AND METHODS

CS over 300 s, TG and TR were assessed by a stress-strain analyzer (SSA T80) in two cavity configurations (2 × 4 × 4 mm/4 × 4 × 4 mm/configuration value [Formula: see text] and [Formula: see text]) for two experimental RBCs, eight bulk-fill RBCs (EverX Posterior, Filtek Bulk Fill, SDR, SonicFill, Tetric EvoCeram Bulk Fill, Venus Bulk Fill, X-tra base, and X-tra Fill) and one RBC (Filtek Supreme XTE) by light curing (1200 mW/cm) (n = 10). The experimental materials used were based on EverX Posterior with modifications made to the fiber and filler content. Statistical analyses were performed via ANOVA; multiple pair-wise comparisons were performed via Tukey's test, and homogeneous subsets were identified ("multcomp" package, R).

RESULTS

CS values ranged from 1.00 to 4.07 MPa (2 × 4 × 4 mm) and from 0.97 to 2.49 MPa (4 × 4 × 4 mm); TG values ranged from 1.31 to 4.05 s (2 × 4 × 4 mm) and from 1.39 to 3.84 s (4 × 4 × 4 mm). SDR values showed lowest stress values in both cavity configurations. The experimental composite with fibers presented significantly higher stress values than did the experimental composite without fibers.

CONCLUSION

Bulk-fill RBCs showed lower levels of stress than did conventional RBCs. The incorporation of fibers had no positive impact on the CS and TG.

CLINICAL RELEVANCE

Appropriate material selection may be essential to clinical success because certain RBCs exhibit higher CS, TG, and TR values.