DentaltownUK August 2017 - 17

debris, in contrast to the 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.
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).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

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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 biofilm 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 DentaltownUK August 2017