Dentaltown May 2017 - 81

debridement achieved by the XP-3D Shaper's
adaptive discontinuous contact of the canal
walls. The desired minimally invasive shape
achieved with this instrument is shown in
Fig. 7b (p. 80).
The distinctions of greatest importance
between the XP-3D Shaper and conventional
NiTi instruments are: The Shaper does not
compact debris on the flutes, resulting in
increased frictional resistance, as it provides
substantial space in the lumen or the virtual
core; nor does it force the debris apically,
as evidenced in instruments used with
reciprocating motion.11
Because the points of contact on the
dentinal walls are discontinuous, less stress
is applied and thus less cyclic fatigue created
than with conventional instruments, which
can be readily demonstrated in photoelastic
testing models (Fig. 8a, p. 80).12
Fig. 8b demonstrates that efforts have
been made with other file systems to emulate
the uniqueness of the adaptive core design
of the XP-3D Shaper; however, regardless
of the design alterations, a solid round core
remains. The overall result is that this file
can create a #30 tip size with different
tapers, depending on the preference of the
practitioner, while adapting to the natural
anatomy of the canal.

disinfectants will work. This is analogous
to scaling and root planing in periodontal
therapy.
As referenced previously, most files produce a final round shape on any given canal
cross section, and as such the practitioner is
limited in the capacity to scrape the walls
of the nonround root canal space; at best,
a round file can "brush" the walls to facilitate an enhanced disinfection. Alternative
methods must be applied to remove toxins
unreachable by the traditional files.

Unfettered access
The XP-3D Finisher was designed to be
adjunctive to the XP-3D Shaper. The Finisher
has many properties that allow it to gain
access to and scrape untouched components
of the canal walls, and the turbulence it
produces in the canal irrigant enhances its
antimicrobial properties. The file is a #25
tip diameter with .00 taper. It is extremely
flexible and thus has tremendous resistance
to cyclic fatigue. Its primary action within
the root canal is to scrape the walls that it

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Effective disinfection
Inhibition or eradication of microflora
presence from the root canal spaces is a
multifactorial conundrum. The bulk of
the microbes reside in the primary canal
in a planktonic/loose form. However,
there is a vast network of labyrinthine
irregularities acting as a microbial reservoir
that communicates with the primary canal.
While irrigation with disinfectants may be
very effective against planktonic microbes,
it is not sufficiently effective when the
microbes are in biofi lm form or in canal
irregularities.
The ability of organisms within the
residual biofilms to create an adaptive
mechanism to the environmental changes
resulting from the treatment protocol can
result in recrudescence of the pathosis.13
The biofilm must be eliminated before the

Fig. 8b. Protaper Next was the first example of an attempt to migrate away from the auguring peck and
pull motion of most NiTi files. Its swaggering motion was an improvement in regard to emulating the
constricted envelope of motion. However, its foundation remained a round blank with all the attendant
issues related to cyclic fatigue and torsional failure.

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Table of Contents for the Digital Edition of Dentaltown May 2017