Transcript Document

Rationale for chemomechanical debridement
Dr LM Naidoo BDS, MSc Dent, M Dent Pros (Wits)
28/02/2011
Shilder 1974
“Unlike funnels of simple geometric
design, this root canal preparation should
occupy not only three planes, but as many
planes as are presented by the root canal
under treatment…”
Stace Linde
2003
Round files in root canals
Not All Canals Are Round
Stace Linde 2003
Round files in root canals
Grande et al. 2007
Objectives of chemo-mechanical
debridement
• Remove organic material and
inorganic debris
• Disinfect as much of the canal
system as possible
• Allow for ease of cleaning and
shaping of the canals in
preparation for obturation
Dentinal walls following instrumentation
Stace Linde 2003
Shilder 1974
“Unlike funnels of simple geometric
design, this root canal preparation should
occupy not only three planes, but as many
planes as are presented by the root canal
under treatment…”
Stace Linde
2003
Principles of Irrigation
• Only irrigate under usage of
rubber dam
• Irrigate following the use of each
file
• Canal access endeavours should
allow for the irrigation tip to lie at
two thirds of the radiographic
working length.
Principles of Irrigation
• The needle tip should not bind to
the walls of the canal
• Allow for adequate time in the
canal system for optimal action
• Always check for leakage around
the protected areas.
Types of Irrigants
Unknown source
Contemporary Irrigants
1.NaOCl (Sodium hypochlorite)
• Dissolves organic content
• Bacteriostatic and bactericidal
• Spectrum of action includes fungi
• Effective at low concentrations
• Able to penetrate up to 300
microns into the dentinal tubules
• Harmful to the periapical tissues if
extruded beyond the apex.
Contemporary Irrigants
2. Sterile water and or Distilled water
• Weak evidence that it is
bacteriostatic
• Does not adequately dissolve
organic contents
• Less harmful if extruded beyond
the apex.
Contemporary Irrigants
3. Local anaesthetic
• Weak evidence that it is
bacteriostatic
• Does not dissolve organic contents
• Penetration into dentinal tubules?
• Less harmful if extruded beyond
the apex.
Contemporary Irrigants
4. Hydrogen peroxide
• Bacteriostatic and bactericidal
• Weak action against fungi
• Dissolves organic contents?
• Penetration into dentinal tubules?
• Toxic if extruded beyond the apex
Contemporary Irrigants
5. Chlorhexidine
• Bacteriostatic and bactericidal
• Very weak action against fungi
• Dissolves organic contents?
• Penetration into dentinal tubules?
• Less toxic to periapical tissues
compared with NaOCl
International Standards
• American Association of Endodontists
(2004)- Not comprehensive with nonsurgical endodontics
• European Society of Endodontology
(1994)- Predated Rotary
Instrumentation.
(2006)- More comprehensive
• ISO- Standards based on evidencebased research
Irrigant choice amongst SA
clinicians
Irrigant Selection
-
Sodium hypochlorite
(NaOCl)
EDTA
Saline
Hydrogen peroxide
Other:
Chlorhexidine
Local anaesthetic
Water
Percentage of
respondents
91
40
6
14
6
6
2
The optimal irrigant
In terms of antimicrobial and tissuedissolving properties there is no
other current irrigant besides NaOCl
which can optimally achieve the
objectives of chemo-mechanical
debridement
The current available evidence is
suggestive that a concentration of >1%
NaOCl is not required
Dentinal walls following instrumentation
Stace Linde 2003
The effect of chelating agents..
Stace Linde 2003
NaOCl + EDTA
• No evidence to support any claims for the
antimicrobial action of EDTA
• Partial inhibition of the action of NaOCl
Grawehr et al. 2003; Zehnder et al. 2005
Stace Linde 2003
NaOCl + Chlorhexidine
The combination of 2% NaOCl and 0.2%
chlorhexidine digluconate produced better
antimicrobial results compared to their
separate use. (Kuruvilla and Kamanth 1998)
• A dense brown substance is the resultant
• A chemically unstable material produced
Marcheson et al. 2007; Cathro 2004
Designs of needle tips