Cleaning & Shaping/ Irrigation in Endodontics Flashcards
What is the most important part of endodontics?
Cleaning and shaping
What is shaping?
Preparation of the canal system to allow for adequate disinfection and obturation
What is Cleaning?
removal of infected dentin and the disinfection of the canal space
What are the 4 desing objectives of cleaning and shaping the canals?
1) continously tapering funnel from apex to coronal access
2) root canal preparation should reflect that of the original anatomy
3) apical foramen should remain in the same location
4) apical foramen should remain as small as feasible
What are the 4 biologic objectives in cleaning and shaping?
1) confinement of instrumentation to within the root canal system
2) minimum extrusion of debris
3) removal of all tissue from the root canal system
4) creation of space for irrigaiton and medication
3 types of canal instrumentation?
1) manual/hand file
2) Rotary instrumentation
3) ultrasonic instrumentation
What are the 2 methods of manual/hand file instrumentation?
1) Step back
2) Crown down
What is the crown down technique?
start with large insturment sizes in coronal and sequentially using smaller hand files as you progress apically
Explain the step back instrumentation?
measure of the first binding file
- stepback 0.5-1 mm increase size by one increment
- proceed to stepback a total of 5 times
- handfile to smooth out the canal
- remeasure the apex
What is the first binding file?
the first file that slightly binds at WL after straight line access
What is the first binding file a guage of?
guage of original size
What is the master apical file?
What is this a guage of?
Final file that lightly binds at WL before obturation/after cleaning and shaping
Final apical size
What type of files are the most commonly used hand instruments in endo?
K files
What is the order of sizes of files (with colors)?
.06 - pink
.08- grey
.10- purple
.15- White
.20 - yellow
.25 - red
.30- blue
- 35 - green
- 40 - black
ETC… once it gets to 0.6, it increases by .10!!!
What is reaming?
Widening
What methods are used for k-files in reaming?
watch winding/rotational
What is more aggressive k-files or hedstrom files?
Hedstrom
What type of file is useful in retrieving of materials?
Hedstrom files
What are the 3 lengths of K files?
21mm, 25mm, 31mm
What do we do when reaming?
clockwise rotational motion
What do we do when filing?
vertical push-pull strokes
What is circumferential filing?
circular movement in a filing motion to ensure the entire circumference is being engaged
What is anticurvature filing?
At what anatomical areas would we typically do anticurvature filing?
lateral filing AWAY from thinner areas of dentin
root concavities and furcations
What % of the RCT is sterilized mechanically vs. chemically?
mechanically - 65% of cleaning
chemically - 35% of cleaning
Why has apical enlargement decreased since over time?
Emphasis on conservation of tooth structure
What is the difference between the first binding final and final instrumentation apically?
1 - 2 sizes
What are 4 reasons why we irrigate canals?
1) lubricate the canal to ease instrumentation
2) remove debris generated
3) dissolve tissue that exists in atypical anatomical variations
4) kill bacteria inhabiting the canals
What is the minimum time of irrigation of canals?
30 minutes
What is the limited time of action of sodium hypochlorite?
15 minutes
Describe the microorganism effects of sodium hypochlorite?
anti-bacterial, anti-fungal, effective at biofilm disruption
What irrigant dissolves organic debris?
What irrigant does not dissolve organic debris?
sodium hypochlorite
chlorhexidine
What irrignats are lubricating and non-lubricating?
sodium hypochlorite - lubricating
chlorhexidine - non-lubricating
What is concentraiton of irrigation fluid (chlorhexidine type)
0.2%
What irrigation fluid has a decreased effectiveness towards gram negative bacteria?
chlorhexidine
Is chlorhexidine anti-bacterial and anti-fungal?
YES
What are the 3 indications of using chlorhexidine as an irrigation fluid?
1) open apex at tooth (decrease toxicity)
2) large resportion defects
3) persistent/secondary infections
Why would we want to be cautious mixing chlorhexidine and sodium hypochlorite?
Forms a percipitate PCA (parachloroanaline)
- interfere with seal
- increase discoloration
- highly irritatnt to tissues and IS CARCINOGENIC