Instrumentation of Root Canal System Flashcards
1
Q
What is instrumentation?
A
- removal of infected soft and hard tissue
- providing disinfecting irrigants access to the apical canal space
- creating space for the delivery of medicaments and subsequent obturation
- retaining the integrity of radicular structures
2
Q
What is the estimated working length?
A
- length at which instrumentation should be limited
- measure pre-operative radiograph
- determine distance between coronal reference point and radiographic apex
- subtract 1mm
3
Q
What is the corrected working length?
A
- length at which instrumentation should be limited
- also subsequent obturation
- obtained through use of apex locator/radiograph
4
Q
What is a master apical file?
A
- largest diameter file taken to working length
- represents final prepared prepared size of apical part of canal
5
Q
What are the different types of motion that can be used for instrumentation?
A
- filing
- reaming
- watch winding
- balanced force motion
- envelope of motion
6
Q
What is watch winding movement?
A
- backwards and forwards oscillation of 30-60 degrees
- light apical pressure
- effective with K files
- useful for passing small files through canals
7
Q
What is balanced force motion?
A
- file rotated 1/4 diameter clockwise
- continued pressure applied
- file rotated 1/2 diameter anti-clockwise
- repeated 1-3 times then file removed to remove debris
7
Q
What are the different types of techniques used for instrumentation?
A
- modified double flare
- balanced force
- step-back
- hand proper
- NiTi
- reciproc
- modified reciprocation
- reciproc blue
- modified reciprocation
8
Q
What shape is the cross section of a K file?
A
- square
8
Q
What shape is the cross section of a K file?
A
- square
9
Q
What are the guidelines for rotary instrumentation?
A
- straight-line access
- reduce risk of preferential cutting
- perforation and thinning of root resulting in fracture
- cross-sectional diameter
- sufficient space to guide non-cutting tup of instrument
- ISO 15 before instrumentation
- root canal system anatomy
- determine number of canals
- use scouter file
- speed and sequencing
- speed recommend by manufacturer
- crown down to reduce torsion stress
- lubrication and light touch
- NaOCl
10
Q
How is a glide path created?
A
- introduce ISO 10-25 until resistance
- create coronal flare
- watch winding with ISO 10 to establish apex
- irrigate and repeat
- ISO 15 watch winding
- ISO 20 balanced force
11
Q
What can cause instrument separation?
A
- torsional stress
- extensive instrument surface encounters
- excessive friction on canal walls
- instrument tip larger than canal section being shaped
- flexural stress
- repeated cyclic metal fatigue
12
Q
What is patency filing?
A
- passing a small hand file through the apical constriction and apical foramen to contact apical tissues
13
Q
What is filing?
A
- dynamic movement of a hand file to optimally effect canal debridement
- predominantly push-pull (rasping), rotational (reaming)
- engine driven can be rotary, reciprocating or oscillating
