Biomedical Engineering Reference
In-Depth Information
FIGURE 21.2
Periapical radiograph demonstrating a disarticulated file in the mesial canal of the first molar preventing
further apical cleaning and shaping and obturation.
intervention
[19]
. Therefore, to reduce instrument fatigue and failure, reports have suggested
changes in instrument design, instrumentation protocol, and more recently the use of nanomaterials
for surface modifications of the currently used rotary Ni
Ti instruments.
Recent studies have attempted to modify the instrument surface by coating the Ni
Ti surface
with different nanomaterials to overcome these characteristic shortcomings. Adini et al.
[20]
exam-
ined the effects of cobalt coatings with impregnated fullerene-like WS
2
nanoparticles on file fatigue
and failure of Ni
Ti files. The addition of these nanoparticles significantly improved the fatigue
resistance and time to breakage of the coated files as observed under dynamic X-ray diffraction.
The authors attributed the improvement to the reduced friction between the file and the surrounding
tissue with the nanoparticles coating
[20]
. In another study, the distal end of the file was modified
by selective coating of endodontic files. The selective coating of the files distributed the nanoparti-
cles nonuniformly along the surface of the file leaving only a part of the file coated and thereby
having a higher torque making it more resistant to fatigue and failure
[21]
. Thus the use of nano-
particles for surface coatings of the instruments may significantly enhance their performance with
less potential for fatigue and failure.
21.2.2
Enhancement of canal disinfection
A number of solutions and medications are used for disinfecting the root canal system and may
be broadly classified under irrigants and medicaments. While irrigants usually signify high vol-
ume with low contact time within the canal system, medicaments are relatively more passive but
rely on a longer contact time to exert their disinfecting properties. Both of these categories are
being investigated for nanoparticle enhancement to help improve disinfection and sealing of the
root canal system.
