Endodontic Instruments Flashcards
What are the aims of root canal preparation?
To remove all contents of canal including organic and inorganic to prevent microorganisms from growing and producing toxins
To remove irregularities of canal wall including obstructions such as calcifications
To prepare the canal for its disinfection and to develop a shape that permits a simple and effective root canal filling to be placed
What are the biological objectives of canal preparation?
Remove all tissue and other debris
Avoid periapical irritation
Create sufficient space within the canal for intracanal medication
How can periapical irritation be avoided?
Confine instruments to the canals
Do not force debris through the apical foramen (measure and prepare the canals at the same visit
What are the mechanical objectives of canal preparation?
Leave the apical foramen in its original place
Keep the apical foramen as small as practical
Create a continuously tapering conical shape
Create a shape that is easy to fill
What preparation tools are used for filing canals?
Hand files (stainless steel files)
Rotary files (Nickel titanium)
What determines the type of preparation technique used?
Instruments used (Design of the cutting blade)
Root filling technique used (Lateral compaction, vertical compaction, etc)
Operator (preference, skill, experience)
How are hedstrom files used?
Based on the overall design of the file and its cutting edges.
3 actions are used simultaneously:
- Slight rotation to engage
- Push-pull
- Circumferential filing
What should be done to the file before placing it into the canal?
Pre-curve all filed prior to use as >95% of canals are curved. This can help by-pass obstruction.
What is the limitation to precurving the files?
This can cause problems if the files are rotated too much.
What action can files have in canals?
Canal transportation
Ledging of the canal
Shortening of working length
Acts like a plunger or piston pushing smear layer apically then push laterally forming a false canal or a perforation.
How can plunger/piston action of file be prevented from leading to perforation?
By irrigating between each file.
What are Gates-Glidden Burs?
Burs for a slow speed handpiece that is used in the canals. It is side cutting and comes in 6 sizes.
Should only be used passively and cutting on withdrawal stroke only.
Used as an orifice opener and to flare the coronal few millimeters of the canal
How are gates Glidden burs designed to be used?
Designed to break at the top of the shaft if too much pressure is used.
What should preparation techniques depend on?
Instruments used (Design of the cutting blade)
Root filling technique used (Lateral compaction, vertical compaction, etc)
Operator (skill, preference, experience)
