اندودنتیک

1. CLEANING AND SHAPING OF
THE ROOT CANAL SYSTEM
DR SHABNAM SABERI

2. CLEANING AND SHAPING OF THE ROOT
CANAL SYSTEM
• Endodontic treatment mainly consists of three steps:
• 1. Cleaning and shaping of the root canal system
• 2. Disinfection
• 3. Obturation

3. CLEANING AND SHAPING OF THE CANALS MEANS:
• To remove all the contents from root canal which may cause growth of
microorganisms
• to develop a shape that permits a three-dimensional sealing of the canal.
• To remove all the irregularities, obstructions and old fillings from the canals.

4. CLEANING OF CANALS CAN BE ASSESSED BY:
• presence of clean dentinal shavings.
• color of the irrigant
• Properly shaped canal should feel smooth in all dimensions
when tip of file is pushed against the canal walls

5. CONT…
• Any communication from root canal system to periodontal
space acts as portal of exit which can lead to formation of
lesions of endodontic origin

6. MECHANICAL OBJECTIVES OF ROOT
CANAL PREPARATION
1. Root canal preparation should develop a continuously tapering cone
2. Making the preparation in multiple planes which
introduces the concept of “flow”:
3. Making the canal narrower apically and widest coronally:
4. Avoid transportation of the foramen:
5. Keep the apical opening as small as possible:

8. Biologic Objectives of Root Canal Preparation
‰
. Procedure should be confined to the root canal space
‰
. All infected pulp tissue, bacteria and their by-products
should be removed from the root canal
‰
. Necrotic debris should not be forced periapically
‰
. Sufficient space for intracanal medicaments and irrigants
should be created

9. Clinical Objectives of Biomechanical Preparation
• The clinician should evaluate the tooth to be treated
• straight-line access to canal orifice
• performing cleaning and shaping
• shaping facilitates cleaning
• This creates a smooth tapered opening
to the apical terminus
• complete sealing of the pulp chamber / to prevent microleakage
• restored with permanent restoration
• recalled on regular basis

10. DIFFERENT MOVEMENTS OF
INSTRUMENTS
Reaming
‰
. To ream means use of sharp-edged tool for enlarging
holes
‰
. It involves clockwise rotation of an instrument
filing
 result in iatrogenic errors like ledge formation

12. Patency:
• Patency means that apical foramen has been cleared of any debris in its path.
• Patency keeps the clear passage to apical foramen by removing debris from apical
area.
• It is performed with files or reamers.

13. ‰
. In this, first instrument is moved apically by rotating it
right and left through an arc
‰
. When the instrument feels any resistance, it is taken out
 used with Headstorm (H-files)
WATCH-WINDING AND PULL MOTION

14. BASIC PRINCIPLES OF CANAL
INSTRUMENTATION
• straight-line access to the canal orifices
• Establish the apical patency by passing a #10 file across the
apex (0.5 mm) so as to make minor constriction patent.
• Copious irrigation
• Preparation of canal should be completed while retaining
its original form and the shape
• Canal instrumentation without skipping file sizes

15. CONT…
• working instruments should be kept in confines of the root canal
• File flutes should be cleaned and inspected
• Fine instruments should be used extravagantly.
• Recapitulation is regularly done to loosen debris by returning to working length
(WL).
Canal walls should not be enlarged during recapitulation
• Never force the instrument in the canal, it may cause instrument separation, ledge
formation, etc.

16. APICAL GAUGING
• Apical gauging is a mechanical term which clinically indicates
the measuring of the apical diameter prior to obturation
• final instrument size must be large enough to touch all walls.
• Because most canals are oval in their cross-sectional shape.

17. Apical gauging helps in
1. Choosing the best master cone that closely matches canal length and taper
2. Achieving true tug back—as opposed to false tug back!
3. Minimizing gutta-percha (GP) extrusions during obturation, especially with warm
vertical compaction.

19. How to measure apical gauging?
1. Establish the position of apical constriction and keep working length (WL) 0.5 mm –
1mm short of this
2. After cleaning and shaping, passively insert 02 taper hand files, starting from #15. If the
file goes past the apical constriction, then choose the next largest file and repeat.
3. When a file passively binds short of the apical constriction that will be the upper limit of
the apical constriction diameter.
The smaller file before that would be the lower limit.

22. STEP BACK