Commercial Short Fiber-Reinforced Composites: a Comparative Study

Objectives: Short fiber-reinforced composites (SFRCs) are restorative materials for large cavities claimed to effectively resist crack propagation. This study aimed to measure and compare definitive physical characteristics of seven available SFRCs (Alert, NovaPro-Flow, NovaPro-Fill, Fibrafill Flow, Fibrafill Dentin, everX Flow, and everX Posterior) on the market.
Methods:
The following characteristics were evaluated in accordance with ISO standards: flexural strength and modulus, and fracture toughness. The degree of monomer conversion (DC%) was determined by FTIR-spectrometry. A two-body wear test was performed in a ball-on-flat configuration using a chewing simulator with 15000 cycles. A three-dimensional (3D) non-contact optical profilometer was used to measure the wear depth. Polymerization shrinkage-stress was measured using a tensilometer. Posterior composite crowns (n=8) were made and quasi-statically loaded until fracture. The microstructure of the SFRCs was assessed using scanning electron microscopy. ANOVA was used to statistically analyze the results, and then the post hoc Tukey's test was performed.
Results:
Among the evaluated SFRCs, everX Flow showed the highest fracture toughness (2.8 MPa m^1/2) and the lowest wear depth (20.4 µm) values (p<0.05). Fibrafill Flow (92 MPa) and Fibrafill Dentin (98 MPa) showed the lowest flexural strength values (p<0.05). The used SFRCs exhibited comparable values (p>0.05) of shrinkage stress, except for everX Flow, which had the highest value (5.3 MPa). everX Flow composite crowns presented significantly greater fracture resistance (3866 ±263 N) (p<0.05) than that of the other SFRCs tested.
Conclusions:
The use of SFRCs in dentistry may provide enhanced clinical performance, however, a careful material selection is key.