This document discusses the shaping and cleaning of root canals. It defines root canal shaping as removing pulp tissues and debris from the canal while shaping it to receive obturation material. The objectives of root canal shaping are to create a continuously tapering, conical shape that is narrow apically and widest coronally. The document outlines the phases of root canal shaping including negotiation, coronal pre-enlargement, working length determination, and shaping techniques. It describes crown-down technique in detail, noting that it involves first instrumenting the coronal third before apical shaping to help remove debris and gauge the canal more accurately.

1. SHAPING AND
CLEANING
OF ROOT
CANALS…..
VIJAYARAGAVAN. P
CRRI

2. INTRODUCTION:
DEFINITIONS
Removing the pulp tissues and debris from the canal
and shaping the canal to receive an obturation material.
obturation of an improperly cleaned canal would still
lead to an endodontic failure irrespective of the
obturation.
OBJECTIVES

3. MECHANICAL OBJECTIVES:
1. CONTINUOUS TAPERING CONICAL SHAPE
2. NARROW APICALLY AND WIDEST
CORONALLY
3. CONCEPT OF FLOW (MULTIPLE PLANES)
4. APICAL FORAMEN AS NARROW AS
POSSIBLE
5. AVOID TRANSPORTATION OF APICAL
FORAMEN

4. BIOLOGICAL OBJECTIVES:
 CONFINEMENT OF INSTRUMENT TO THE ROOTS
 NECROTIC DEBRIS NOT FORCED PERIAPICALLY
 COMPLETE REMOVAL OF TISSUE FROM THE
CANAL SPACE
 CREATION OF SUFFICIENT SPACE FOR
OBTURATING MATERIAL

5. GOALS OF THE RADICULAR
SPACE
 To eliminate microorganisms on
root canal
 To completely remove pulp tissue
 To increase the capacity of the
root canal to permit irrigation
solution to reach apical third
 To shape root canal to receive
obturation material.

6. PRINCIPLES OF CANAL
INSTRUMENTATION
 STRAIGHT LINE ACCESS
 PRECURVING
 RETAINING ITS ORIGINAL FORM & SHAPE
 IRRIGATION
 RESTRICTING INSTRUMENTS WITHIN THE CANAL
 RECAPITULATION
 REMOVAL OF DENTINAL DEBRIS

7. PHASES IN SHAPING OF ROOT CANAL
I. NEGOTIATION (PATENCY FILING)
II. CORONAL PRE-ENLARGEMENT
III. WORKING LENGTH DETERMINATION
IV. SHAPING TECHNIQUES
V. WORKING WIDTH

8. PATENCY FILING
 the concept of creating a path up to the working
length without altering the original root canal
anatomy.
 It is usually performed with a size 10 or smaller k file
which used in reaming motion.

9. CORONAL PRE-ENLARGEMENT
 Concept of enlarging the coronal third of the root
canal prior to the estimation of working length.
 Working length of the tooth should determined only
after coronal pre-enlargement of the canal is
completed.
 Coronal pre-enlargement achieved with orifice
enlargers or gates glidden drills.
ADVANTAGES
 Prevents premature binding of the shaping
instruments to the canal walls.
 Removes coronal third debris before apical third
shaping
 Allow operator to gauge the apical third of the
canal more accurately.

10. WORKING LENGTH
DETERMINATIOIN
 It defined as the distance from a coronal
reference point to the point at which the
canal preparation and Obturation should
terminate.
 Canal preparation is clinically
recommended to terminates
instrumentation and Obturation within
0.5mm to 1.0mm short of radiographic
apex.

11. ROOT CANAL SHAPING TECHNIQUES
 The endodontic hand instrument can be employed in any one of the
techniques such as
STEP BACK TECHNIQUE CROWN DOWN TECHNIQUE
HYBRID TECHNIQUE

12. CROWN DOWN TECHNIQUE
CONCEPT
first instrumentation the coronal third of the
root canal before apical shaping.

13. patency of canal achieved with a size 8 or 10 k file
preparation of coronal two third of the canal using H-files size of 15,20,and 25 to
a working length of 16-18mm or to point where files starting
flaring the coronal segment of canal with GG drills Nos.2 and 3
apical instrumentation with a small size of 10 ,15 K file followed by working
length determination
placement of large file(K-file 60) to point of canal binding
process repeated with smaller files until working length is reached
Apical portion of canal is enlarged to the approriate master apical file size. final
canal taper is accomplished by master apical file

14. ADVANTAGES
 Easier than step back technique
 Removal of coronal obstructions allows removal of
bulk of tissues , debris ,microbes before apical
shaping.
 Minimizes extrusion of debris through apical
foramen
 Better access and control over apical enlarging
instrument
 Allows penetration of irrigants .
 Working length less likely to be change.

16. Reference
 TEXTBOOK OF ENDODONTICS-GROSSMAN’S