2. Objectives of root canal preparation
The root canal system must be:
• Cleaned of its organic remnants
• Shaped to receive a three
dimensional filling of the entire
root canal space
3. Objectives of root canal preparation
The canal is
• Cleansed primarily by irrigation
• Shaped primarily by instrumentation
4. Five Mechanical objectives
•Develop a continuously
tapering conical form in the
root canal preparation
•Make the canal narrower
apically, with the narrowest
cross-sectional diameter at
its terminus
•Make the preparation in
multiple planes
•Never transport the
foramen.
•Keep the apical foramen as
small as possible Herbert Schilder
The real key to
obturation is
Cleaning and Shaping
5. Cleansing of the root canal
Objectives
• Removal of organic and
inorganic debris
• Elimination of bacteria
16. METHODS OF DETERMINING
WORKING LENGTH
• Radiographic Methods
• Digital Tactile Sense
• Apical Periodontal Sensitivity
• Paper Point Measurement
• Electronics
20. Clinical Procedure
Actual WL determination
Preparation should terminate at
• Apical constriction
• 1 mm short of radiographic apex
21. Clinical Procedure
• Estimate working length
• Parallel radiograph
• Estimated working length is the distance from
the reference point to the radiographic apex
27. Master Apical File
• Take a radiograph with MAF in place.
This confirms:
– Length
– Placement
28. RECAPITULATION
Repeated reintroduction and reapplication
of instruments previously used
throughout the cleaning and shaping
process in order to create well-designed,
smooth, unclogged, evenly tapered root
canal preparations.
29. Apical Patency
Maintain a pathway
through the apical constriction
with a small K-file (#10 or #15)
during cleaning and shaping
31. Crown Down Technique
•Coronal third Orifice shapers
•Middle third 0.06 taper rotary Profiles
•Apical third 0.04 taper hand Profiles
32. Crown Down Technique
• The coronal portion is prepared before the apical
portion
• Reduces effect of canal curvature
• Improves tactile awareness during apical
preparation
• Allows more effective irrigation
• Removes majority of tissue and microbes before
apical third is approached
• Reduces change in working length during apical
preparation
35. • Sodium Hypochlorite:
• Lower concentrations (e.g., 0.5% or1%) dissolve mainly necrotic
tissue
• Chlorhexidine:
• A broad-spectrum antimicrobial agent effective against gram-
negative and gram-positive bacteria
• A cationic molecular
• binds to hydroxyapatite
Iodine Potassium Iodide:
• an oxidizing agent by reacting with free sulfhydryl groups of
bacterial enzymes
• MTAD
• EDTA
• Hydrogen peroxide
36. Cleaning---Irrigation
• Sodium Hypochlorite?
• Dissolves organic debris ✔
• Has a powerful anti-bacterial action ✔
• Lubricates the use of files ✔
• Disinfects & cleans where files don’t reach ✔
• The tissue-dissolving ability of 5.25-1%
What irrigant should we use?
