title: Short fiber reinforced composite: a new alternative for direct onlay restorations.
abstract: OBJECTIVE
  To determine the static load-bearing capacity of direct composite onlay restorations made of novel filling composite resin system which combines short fiber-reinforced composite resin (FC) and conventional particulate filler composite resin (PFC).
  
  
  METHODS
  Three groups of onlay restorations were fabricated (n = 8/group); Group A: made from conventional particulate filler composite resin (Z250, 3M-ESPE, USA, control), Group B: made from short fiber-reinforced composite resin (EverX posterior, StickTeck Ltd, member of GC group, Turku, Finland) as substructure with 1 mm surface layer of PFC, Group C: made from FC composite resin. The specimens were incrementally polymerized with a hand-light curing unit for 80 s before they were statically loaded with two different sizes (3 & 6 mm) of steel ball until fracture. Failure modes were visually examined. Data were analyzed using ANOVA (p = 0.05).
  
  
  RESULTS
  ANOVA revealed that onlay restorations made from FC composite resin had statistically significantly higher load-bearing capacity (1733 N) ( p < 0.05) than the control PFC composite resin (1081 N). Onlays made of FC composite resin with a surface layer of PFC gave force values of 1405 N which was statistically higher than control group ( p < 0.05). No statistically significant difference was found in the load-bearing capacity between groups loaded by different ball sizes.
  
  
  CONCLUSIONS
  Onlay restorations combining base of short fiber reinforced composite resin as substructure and surface layer of conventional composite resin displayed promising performance in high load bearing areas.
authors: Department of Restorative Dentistry & Periodontology, Institute of Dentistry, Libyan International Medical University, Benghazi, Libya ; Department of Biomaterials Science and BioCity Turku Biomaterials Research Program, Institute of Dentistry, University of Turku, Turku, Finland.
authors: Sufyan
authors: S
authors: Garoushi
authors: Department of Biomaterials Science and BioCity Turku Biomaterials Research Program, Institute of Dentistry, University of Turku, Turku, Finland.
authors: Enas
authors: E
authors: Mangoush
authors: Department of Biomaterials Science and BioCity Turku Biomaterials Research Program, Institute of Dentistry, University of Turku, Turku, Finland.
authors: Mangoush
authors: M
authors: Vallittu
authors: Department of Biomaterials Science and BioCity Turku Biomaterials Research Program, Institute of Dentistry, University of Turku, Turku, Finland.
authors: Lippo
authors: L
authors: Lassila
keywords: Short fiber composite; load bearing capacity.; onlay restoration