Pre-Op Sessions Flashcards
What are the design objectives?
- Create a continuously tapering funnel shape
- Maintain apical foramen in original position
- Keep apical opening as small as possible
What is the process of a root canal?
- Coronal access to RC system
- RC instrumentation and preparation
- Obturation of RC system
- Coronal seal
- Final restoration
Before treatment what must be done?
take a peri apical radiograph to show all root and 2/3 mm of surrounding tissue
What are the objectives of access cavity prep?
- Remove entire roof allowing complete removal of pulpal tissue
- Allow visulisation of RC entrance
- Produce smooth walled prep with no overhangs
- Allow unimpeded straight line access of instruments
What is the ISO colour codes?
file tip size
White = 15, 45
Yellow = 20, 50
Red = 25, 55
Blue = 30, 60
Green = 35, 70
Black = 40, 80
What are the 3 lengths of ISO instruments?
21, 25, 31mm
What are the files made from?
stainless steel
What length is the cutting flute?
16mm
What is d1?
diameter at the first rake angle
What is the taper of the file?
0.32mm over the 16mm, or 0.02mm per millimetre
What is d2?
tip of the file
What is the diameter of the file at d2?
apical size of the root canal plus 0.32mm.
What is a 02 ISO taper?
It has a diameter of 0.2mm at the D1 level.
Why is a flexible k file advantageous?
Cross-sectionalshapeallows greater flexibility
used in rotation or filing motion
What are the 4 file motions?
- Filing
- Reaming
- Watch-winding
- Balanced Forced Motion
What technique does the modified flare use?
Uses the balanced force technique
What is the balanced force technique used for
– to enlarge/flare the coronal part of root canal
– to negotiate the narrower apical part of canal
– to flare the apical part of canal by step-back technique
Why is coronal pre flaring done?
– Avoids hydrostatic pressure in canal
– Early removal of heavily contaminated contents
– Improved straight line access to apical 1/3
What is coronal pre flaring?
widen the coronal (top) portion of a root canal.
What tool is used for coronal pre flaring?
gates glidden bur (not 1)
Where should the working length be?
- WL should be as close as possible to CDJ
*This is usually the narrowest part of the
canal – apical constriction
How is the CWL determined?
- Radiographically
– Length should be 1mm from radiographic apex - EAL - electronic apex locator
- Paper point determination
What is the max distance in a radiograph for the CWL?
1mm from apex
What is the estimated working length and how is it obtained?
– Estimated length at which instrumentation should be limited. Obtained by measuring pre-operative radiograph to determine distance between coronal reference point and radiographic apex then subtracting 1mm.
What is the corrected working length and how is it obtained?
Length at which instrumentation and subsequent obturation should be limited. Obtained by the use of an electronic apex locator and/or working length radiograph.
What is the master apical file?
The largest diameter file taken to working length and therefore represents the final prepared size of the apical portion of the canal at the working length.
What sealer is used?
epoxy resin
What should happen with the master cone?
tug back with tweezers
apical portion must remain undistorted when at length
Where should accessories stop?
1-2mm short of WL
What is the law of symmetry 1?
Except for maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal direction through the pulp-chamber floor
What is the law of symmetry 2?
Except for the maxillary molars, the orifices of the canals lie on a line perpendicular to a line drawn in a mesial-distal direction across the center of the floor of the pulp chamber
What is the law of color change?
The color of the pulp-chamber floor is always darker than the walls
What is the law of orifice location 1?
The orifices of the root canals are always located at the junction of the walls and the floor
What is the law of orifice location 2?
The orifices of the root canals are located at the angles in the floor-wall junction
What is the law of orifice location 3?
The orifices of the root canals are located at the terminus of the root developmental fusion lines
How many laws are there?
6
2 symmetry
1 color
3 orifice
Maxillary 1st premolar
roots, canals
roots = 1/2/3
canals = mostly 2, rarely 1
Maxillary 2nd premolar
roots, canals
roots = 1/3
canals = mostly 1, sometimes 2
Maxillary 1st molar
roots, canals
roots = 3
canals = mostly 4, rarely 3
Maxillary 2nd molar
roots, canal
roots = 3
canals = mostly 3, somtimes 4
Mandibular 1st premolar
roots, canals
roots = 1
canals = mostly 1, sometimes 2
Mandibular 2nd premolar
roots, canals
roots = 1
canals = mostly 1, sometimes 2
Mandibular 1st molar
roots, canals
roots = 2/3
canals = mostly 3, sometimes 4
Mandibular 2nd molar
roots, canals
roots = 2
canals = mostly 3, sometimes 2 or 4
What are the angles of reciprocation?
150 degrees counterclockwise
30 degrees clockwise
What is the tip is reciproc?
non cutting
s-shaped cross section
What are the 3 sizes for the reciproc system?
R25 0.25
R40 0.4
R50 0.5
What is different in reciproc blue?
heat treatment on traditional NiTi alloy
better centering in the canal due to higher flexibility
suitable for strongly curved canals
can be pre bent for better accessibility or bypassing ledges
silver colored shaft
What is a glide path?
a smooth, patent passage from the coronal orifice of the canal to the radiographic terminus or electronically determined portal of exit
What’s the difference between glide path and patency?
Glide path
A smooth passageway that extends from the canal’s opening at the pulp chamber floor to the opening at the root’s apex. The purpose of a glide path is to create a canal diameter that’s the same size or larger than the first rotary instrument that’s used.
Patency
The maintenance of a clear canal, especially the apical portion, to prevent debris from building up. Patency is important because it prevents blockage and short obturation. A small file is maintained near or slightly beyond the apical foramen throughout the procedure.
