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Curved root canal preparation
Department of Conservative Dentistry and
Dental Radiology
Presented by
Dr. Md. Nafizuzzaman Bhuiyan
Dr.
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Introduction
A tooth with a straight root and a straight root
canal is an exception rather than being normal
because most teeth show some curvature of the
canal. Appropriate removal of pulpal tissues with
proper cleaning and shaping, followed by an
obturation system and coronal seal, will satisfy
both mechanical and biological objectives.
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Continues..
Clinicians regularly encounter curves of different
degrees and in various places all along the root
canal system.
These curves cause a host of problems, includingledge formation, perforation, apical
transportation, zip formation, and file separation.
So there are some techniques using in curvedcanal preparation.
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Techniques using in curved canal preparation
Apical to coronal approach
Balanced forcetechnique
Step back technique
Circumferential fillingtechnique
Coronal to apical approach
Step down technique
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Figure: Curved root canal
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Step back technique
Also known as telescopic canal preparation or serial
root canal preparation.
It emphasizes keeping the apical preparation small, in
its original position and producing a gradual tapercoronally.
It has two phase
Phase I - Preparation of apical constriction.
Phase II - Preparation of remaining canal.
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Phase I
i. Working length
established.
ii. Motion watch
winding.
iii.Apical preparation
upto the file no. 25
to full length.iv.Recaputulation using
prior size
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Phase II
i. Stepping backprocedure in 1
mm increments,
No 25 through
45.
ii. Recapitulation
with a no 25 file
in full workinglength.
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Refining Phase II-A
Gates Glidden
drills No. 2,3,4
used to prepare
coronal and mid
root portion.
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Refining Phase II-B
i. Return to 25 last
file.
ii. Short of working
length to smooththe step back with
vertical push pull
strikes
(circumferential
filling) by H- file.
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ompleted preparation
A continuous
flowing flared
preparation from
the C-E junction to
the crown.
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Step back technique
Advantages:
a) It is designed to overcome instrument transportation in the
apical 1/3 of the canal.
b) Avoid zipping.
c) It can be used for the preparation of straight canal.
d) Suitable for slight to moderate curved canal.
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Step back technique
Disadvantages:
a) Chances of pushing debris into peri-radicular tissues.
b) Difficult to irrigate apical region.c) Working length likely to changes as canal curvatures are
eliminated.
d) More chances of instrument fracture.
e) Time consuming.f) Not suitable for severely curved canal.
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Experimental study for the success rate of step
back technique
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Conclusion
Step-back process creates a flared, tapering
preparation while reducing procedural errors.
The step-back preparation is superior to
standardized serial filing and reaming techniquesin debridement and maintaining the canal shape.
This technique results in more pulpal walls being
planed when compared to reaming or filing.
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References
1. Ref:
http://dentistry.about.com/od/specializeddentistry/a/r
ootcanal
2. Ref : Ingles endodontics 5thedition,537 page
3. Ref : Ingles endodontics 5thedition,527 page
4. Ref : www.ijos.org.cn | International Journal of Oral
Science
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Thank you