Dentaltown November 2017 - 80

Bioceramics are ideal for use in
endodontics as they are not affected
by moisture or blood contamination
and, therefore, technique sensitivity
is not an issue unlike most other
sealers where moisture negates their
performance.
sealer. The leakage can be delayed for up
to 30 days with the use of sealer. Sealers
are the materials in root canal filling that
provide whatever resistance to leakage is
achieved. Traditional sealers generally shrink
on setting and wash out in the presence of
tissue fluids8-9(Fig. 3).
Results on the GuttaCore carrier-based
system in combination with root canal sealer
do not improve the microleakage resistance
compared with Thermafi l/Topseal fi lling
and the Continuous Wave compaction
technique.10
Gutta-percha, regardless of how it is
biochemically reconstituted or introduced
into the root canal space, is not an effective
barrier to microbes. Furthermore, the volume

E
X
P
A
N
S
I
O
N

Zinc Oxide-Based Sealers

Ca(OH)2-Based Sealers
Glass Ionomer-Based Sealers
Silicone-Based Sealers
Epoxy Resin-Based Sealers
Bioceramic Sealer
0.5

0.225 0 -0.225

-0.45 -0.665

-0.9

S
H
R
I
N
K
A
G
E

Fig 3. Table of expansion/shrinkage of popular sealers. Silicone and epoxy resin sealers expand slightly
before shrinking. Note that by contrast, bioceramic sealer expands slightly on setting but does not
shrink.

80

NOVEMBER 2017 // dentaltown.com

of sealer is the weak link in the chain of
success; volume must be minimized by
the density of the core/fi ller regardless of
the technique used. With the new array
of equipment for identifying, shaping and
cleaning of the root canal space, reliance
on ineffective materials and techniques
mandate a paradigm shift in root filling.

The Schilderian Epoch
Dr. Schilder's transgressive articles, "Vertical Compaction of Warm Gutta-Percha"
and "Filling Canals in Three Dimensions,"
addressed technical adjustments to traditional obturation techniques that enabled
gutta-percha to replicate the microstructural
anatomy of the root canal space to a demonstrably greater degree than any previous
technique.11-12
Despite the enhanced rheology, gutta-percha neither adhered to nor penetrated
the interfacial dentin and it was sealer that
was integral to achieving a positive treatment
outcome, albeit short-lived. Schilder and
Goodman13 established the hypothesis that a
warm vertical condensation technique pushed
a greater volume of filler material into the
apical space and theoretically the material
would not shrink on cooling; however,
regardless of enhanced gravitometrics, the
leakage studies on gutta-percha alone and
gutta-percha and sealer and their inability
to create an impervious apical seal are
repeatedly demonstrated in the literature.14
Microfractures are a complication of
any instrumentation technique that requires
significant preparation of the coronal portion
of the canal to place a plugger/condenser
(heated or otherwise) within 4mm of the
working length. Furthermore, thinning of
the root dentin by "imprinting a fi le size
to accommodate a fi lling technique" will
proportionally weaken the tooth, leaving
a root susceptible to fracture.15-16

The future of
bioceramic nanotechnology
Bioceramic materials include alumina,
zirconia, bioactive glass, hydroxyapatite and
resorbable calcium phosphates.17-19 They are
used as joint or tissue replacements in both
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Table of Contents for the Digital Edition of Dentaltown November 2017
