Objective: To evaluate the static-load-bearing capacity of severely damaged endodontically-treated incisors restored with short fiber composite (SFC) as a direct post-core-crown complex and to investigate the effect of SFC on the failure mode of the restorations.
Materials and methods: The clinical crowns of 40 maxillary incisors were prepared by cutting 2/3 parts of the crown horizontally. Five groups were fabricated (n = 8) using the direct technique; Group A: Crown restorations from conventional composite (CC); Group B: FRC-posts with core-crown restorations from CC; Group C: Crown restorations from SFC; Group D: FRC-posts and core-crown restorations from SFC; Group E: Post-core-crown restorations from SFC. The posts were cemented with dual-cure resin cement. The restorations were polymerized with a hand-light curing unit. All restored teeth were stored in distilled water at 37°C for 5 days before they were statically loaded. Initial fracture (IF) and final fracture (FF) were recorded. Failure modes were visually examined.
Results: ANOVA revealed that SFC restorations had greater IF (469.8 N) and FF load values (515.8 N) (p < 0.05) than the CC restorations (164.8 N). No significant difference for both IF and FF was observed among groups C, D and E. Group E revealed a more favorable fracture mode than any other material combination used.
Conclusion: The use of SFC as a restorative material for fabricating the direct composite post-core-crown restorations of severely damaged incisors provided improved load-bearing capacity than CC used alone or with FRC post reinforcement.