Cleaning & Shaping/ Irrigation in Endodontics

Question 1

What is the most important part of endodontics?

Answer 1

Cleaning and shaping

Question 2

What is shaping?

Answer 2

Preparation of the canal system to allow for adequate disinfection and obturation

Question 3

What is Cleaning?

Answer 3

removal of infected dentin and the disinfection of the canal space

Question 4

What are the 4 desing objectives of cleaning and shaping the canals?

Answer 4

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

Question 5

What are the 4 biologic objectives in cleaning and shaping?

Answer 5

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

Question 6

3 types of canal instrumentation?

Answer 6

1) manual/hand file
2) Rotary instrumentation
3) ultrasonic instrumentation

Question 7

What are the 2 methods of manual/hand file instrumentation?

Answer 7

1) Step back
2) Crown down

Question 8

What is the crown down technique?

Answer 8

start with large insturment sizes in coronal and sequentially using smaller hand files as you progress apically

Question 9

Explain the step back instrumentation?

Answer 9

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

Question 10

What is the first binding file?

Answer 10

the first file that slightly binds at WL after straight line access

Question 11

What is the first binding file a guage of?

Answer 11

guage of original size

Question 12

What is the master apical file?

What is this a guage of?

Answer 12

Final file that lightly binds at WL before obturation/after cleaning and shaping

Final apical size

Question 13

What type of files are the most commonly used hand instruments in endo?

Answer 13

K files

Question 14

What is the order of sizes of files (with colors)?

Answer 14

.06 - pink

.08- grey

.10- purple

.15- White

.20 - yellow

.25 - red

.30- blue

0. 35 - green
1. 40 - black

ETC… once it gets to 0.6, it increases by .10!!!

Question 15

What is reaming?

Answer 15

Widening

Question 16

What methods are used for k-files in reaming?

Answer 16

watch winding/rotational

Question 17

What is more aggressive k-files or hedstrom files?

Answer 17

Hedstrom

Question 18

What type of file is useful in retrieving of materials?

Answer 18

Hedstrom files

Question 19

What are the 3 lengths of K files?

Answer 19

21mm, 25mm, 31mm

Question 20

What do we do when reaming?

Answer 20

clockwise rotational motion

Question 21

What do we do when filing?

Answer 21

vertical push-pull strokes

Question 22

What is circumferential filing?

Answer 22

circular movement in a filing motion to ensure the entire circumference is being engaged

Question 23

What is anticurvature filing?

At what anatomical areas would we typically do anticurvature filing?

Answer 23

lateral filing AWAY from thinner areas of dentin

root concavities and furcations

Question 24

What % of the RCT is sterilized mechanically vs. chemically?

Answer 24

mechanically - 65% of cleaning

chemically - 35% of cleaning

Question 25

Why has apical enlargement decreased since over time?

Answer 25

Emphasis on conservation of tooth structure

Question 26

What is the difference between the first binding final and final instrumentation **apically?**

Answer 26

1 - 2 sizes

Question 27

What are 4 reasons why we irrigate canals?

Answer 27

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

Question 28

What is the minimum time of irrigation of canals?

Answer 28

30 minutes

Question 29

What is the limited time of action of sodium hypochlorite?

Answer 29

15 minutes

Question 30

Describe the microorganism effects of sodium hypochlorite?

Answer 30

anti-bacterial, anti-fungal, effective at biofilm disruption

Question 31

What irrigant dissolves organic debris? What irrigant does not dissolve organic debris?

Answer 31

sodium hypochlorite chlorhexidine

Question 32

What irrignats are lubricating and non-lubricating?

Answer 32

sodium hypochlorite - lubricating chlorhexidine - non-lubricating

Question 33

What is concentraiton of irrigation fluid (chlorhexidine type)

Answer 33

0.2%

Question 34

What irrigation fluid has a decreased effectiveness towards gram negative bacteria?

Answer 34

chlorhexidine

Question 35

Is chlorhexidine anti-bacterial and anti-fungal?

Answer 35

YES

Question 36

What are the 3 indications of using chlorhexidine as an irrigation fluid?

Answer 36

1) open apex at tooth (decrease toxicity) 2) large resportion defects 3) **persistent/secondary infections**

Question 37

Why would we want to be cautious mixing chlorhexidine and sodium hypochlorite?

Answer 37

Forms a percipitate PCA (parachloroanaline) - interfere with seal - increase discoloration - **highly irritatnt to tissues and IS CARCINOGENIC**