A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Mechanical and structural characterization of discontinuous fiber-reinforced dental resin composite.
Tekijät: Bijelic-Donova J, Garoushi S, Lassila LV, Keulemans F, Vallittu PK.
Kustantaja: Elsevier
Julkaisuvuosi: 2016
Journal: Journal of Dentistry
Lehden akronyymi: J Dent
Vuosikerta: 52
Aloitussivu: 70
Lopetussivu: 78
Sivujen määrä: 9
ISSN: 0300-5712
DOI: https://doi.org/10.1016/j.jdent.2016.07.009
Rinnakkaistallenteen osoite: https://www-ncbi-nlm-nih-gov.ezproxy.utu.fi/pubmed/27449703
OBJECTIVES: This study evaluated
several fiber- and matrix related factors and investigated different mechanical
properties of discontinuous i.e. short fiber-reinforced composite (SFRC) (everX
Posterior, eXP). These were compared with three conventional composites, microfilled
G-ænial Anterior (GA), nanofilled Supreme XTE (SXTE) and bulk-fill Filtek
Bulk-Fill (FBF).
METHODS:
Fracture toughness (KIC), flexural strength (FS), flexural modulus (FM),
compressive strength (CS), diametral tensile strength (DTS), apparent horizontal
shear strength (AHSS) and fracture work (Wf) were determined for each composite
(n=8) stored dry or in water. SEM analysis of the fiber diameter (df) (n=6) and
orientation (n=6) were performed. The theoretical critical fiber length (lfc)
and the aspect ratio (l/d) of SFRC were calculated and the volume fraction of
discontinuous fibers (Vf%) and the fiber length (lf) of SFRC were evaluated.
The results were statistically analyzed with two-way ANOVA (α=0.05).
RESULTS:
The mechanical properties of SFRC (eXP) were generally superior
(p<0.05) compared with conventional composites. GA had the highest FM
(p>0.05), whereas FBF had the highest AHSS (p<0.05). The fiber related
properties Vf%, l/d, lf, lfc and df of eXP were 7.2%, 18-112, 0.3-1.9mm, 0.85-1.09mm
and 17μm respectively. SEM results suggested an explanation to several
toughening mechanisms provided by the discontinuous fibers, which were shown to
arrest crack propagation and enable a ductile fracture. Water exposure weakened
the mechanical properties regardless of material type. Wf was unaffected by the
water storage.
CONCLUSION:
The properties of this high aspect ratio SFRC were dependent on the
fiber geometry (length and orientation) and matrix ductility.
CLINICAL
SIGNIFICANCE: The simultaneous actions of the toughening
mechanisms provided by the short fibers accounted for the enhanced toughness of
this SFRC, which toughness value matched the toughness of dentin. Hence, it
could yield an inherently uniform distribution of stresses to the hard biological
tissues.
