title: In vitro repair of fractured fiber-reinforced cusp-replacing composite restorations.
abstract: Objective. To assess fracture resistance and failure mode of repaired fiber-reinforced composite (FRC) cusp-replacing restorations. Methods. Sixteen extracted human premolars with fractured cusp-replacing woven (Group (A)) or unidirectional (Group (B)) FRC restorations from a previous loading experiment were repaired with resin composite and loaded to fracture. Results. Differences in fracture loads between groups were not statistically significant (P = 0.34). Fracture loads of repaired specimens were significantly lower than those of original specimens (P = 0.02 for Group (A) and P < 0.001 for Group (B)). Majority of specimens showed failure along the repaired surface. In Group (B) 89% of specimens showed intact tooth substrate after restoration fracture, while this was 28% in Group (A) (P = 0.04). Conclusion. Fractured cusp-replacing FRC restorations that are repaired with resin composite show about half of fracture resistance of original restorations. Mode of failure with a base of unidirectional fibers is predominantly adhesive.
authors.affiliation: Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Willem M M
authors.initials: WM
authors.lastname: Fennis
authors.forename: Cees M
authors.initials: CM
authors.lastname: Kreulen
authors.forename: Arzu
authors.initials: A
authors.lastname: Tezvergil
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: Nico H J
authors.initials: NH
authors.lastname: Creugers