The
aim of this study was to compare bonding of composite resin luting
cement to a fiber-reinforced composite (FRC) root canal post with either
a cross-linked or a semi-interpenetrating polymer network (IPN) polymer
matrix.

Four different types of
prefabricated FRC posts with a cross-linked polymer matrix and two types
of FRC posts with a semi-IPN polymer matrix which were individually
formed were tested. Serrated titanium posts served as the reference. An
auto-polymerizing resin luting cement was used for cementing the posts
into the holes of composite resin disks. The pull-out force was measured
using a universal testing machine after the post/cement/disk system had
been stored dry or thermocycled (5 degrees C/55 degrees C, 6000x) in
water. The bonding sites of the posts were examined with SEM.

The
FRC posts with a semi-IPN polymer matrix gave significantly higher
pull-out force values than the prefabricated FRC posts with a smooth
surface and a cross-linked polymer matrix (p < 0.004). The highest
pull-out force was obtained with serrated titanium posts. Both the type
of FRC post and thermocycling had a significant effect on the pull-out
force (n = 8, ANOVA p < 0.001 and p < 0.007, respectively). SEM
photomicrographs confirmed the results.

This
study showed that FRC posts with a semi-IPN polymer matrix bonded better
to composite resin luting cement than did prefabricated FRC posts with a
cross-linked polymer matrix, although their pull-out force was not as
high as that of the mechanically interlocked serrated titanium posts.