curved root

8/10/2019 Curved Root

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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

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