Root Camp Lecture 6 - Shaping and Cleaning

Question 1

Cleaning and shaping can have no greater
precision than the _________ ________

Answer 1

working length

Question 2

Establishes apical extent of instrumentation and apical level of root canal filling

Answer 2

WL

Question 3

T/F: Apical foramen does not always exit at the
exact apex of the root

Answer 3

True

Question 4

You want to treat to the _______ __________, which is 1 mm short of the radiographic apex

Answer 4

apical constriction

Question 5

In cases where apical root resorption has
occurred, the WL may be _____ - ______ mm short of the radiographic apex

Answer 5

1.5 - 2 mm

Question 6

Twisted file that has a cross section which is rhomboid or diamond-shaped

Answer 6

K-flex file

Question 7

This file has high flutes that provide the cutting edges and low flutes that provide more area for increased debris removal

Answer 7

K-flex file

Question 8

More flexible than the traditional K-type file; can be used in a filing or reaming motion

Answer 8

K-flex file

Question 9

Space beside this file in canal reduces chance of forcing debris out apex

Answer 9

K-flex file

Question 10

Round, tapered stainless steel file; flutes are cut into shaft

Answer 10

Hedstrom file

Question 11

This file is NOT for reaming or drilling (wood screw)

Answer 11

Hedstrom file

Question 12

This file cuts on retraction, very efficient

Answer 12

Hedstrom file

Question 13

This file’s primary purpose is body-shaping flaring canals; it cuts more rapidly than a K-type file; more aggressive instrument

Answer 13

Hedstrom file

Question 14

Which file is used for canal exploration?

Answer 14

Curved #10 pathfinder file

Question 15

Which file should you use a watch-winding finger action with probing, poking, twisting, and turning?

Answer 15

Curved #10 pathfinder file

(for canal exploration)

Question 16

How do you get a more accurate reference point for WL?

Answer 16

Flatten cusps

Question 17

When determining WL, which cusp is used for the stop?

Answer 17

Cusp next to canal being treated

Question 18

When determining WL, make sure the stop is on the file correctly and not tilted. Stoppers must be new and ______ on the files.

Answer 18

tight

Question 19

When determining WL in multi-canal teeth, it is important to separate the canals on X-Rays using the __________ technique

Answer 19

SLOB

Question 20

To achieve the SLOB technique, take an X-Ray straight on and then angled from the ________

Answer 20

mesial

Question 21

When taking an X-Ray angled from the mesial, which canal will move distally?

Answer 21

buccal

Question 22

If radiograph shows file tip to be > _____ mm short/long of desired length, then adjust file accordingly and re-take image

Answer 22

1

Question 23

If file is within _____ mm of desired length, make necessary adjustment in length, write down the working length for that canal and you are ready to begin instrumentation

Answer 23

1

Question 24

Determines canal length by “reading” when PDL has been reached by file tip at apical foramen

Answer 24

Electronic apex locator

Question 25

When shaping, you are trying to achieve specific shaping of the root canal to receive a specific type of _________

Answer 25

filling

Question 26

When cleaning, you are trying to achieve a thorough ______________ of the root canal system

Answer 26

debridement

Question 27

Which part of instrumentation? Clean + sanitize root canal system

Answer 27

Cleaning

Question 28

Which part of instrumentation? Similar to removing carious dentin in restorative

Answer 28

Cleaning

Question 29

Which part of instrumentation? Removal of dentin wall to eliminate necrotic debris, bacteria, etc

Answer 29

Cleaning

Question 30

Which part of instrumentation? Removes all contents of the root canal system - infected material, organic substrates, microflora, bacterial byproducts, tissue remnants, contaminated canal filling materials

Answer 30

Cleaning

Question 31

Which part of instrumentation? Mechanical removal, irrigating systems to flush away substances, and chemicals to dissolve contents of canal

Answer 31

Cleaning

Question 32

Which part of instrumentation? Establishes specific cavity form to receive filling material

Answer 32

Shaping

Question 33

Which part of instrumentation? Permits obturation instruments to fit freely within the canal; facilitates 3-D cleaning by providing direct access for files, etc

Answer 33

Shaping

Question 34

Which part of instrumentation? Mechanical process accomplished with various instruments

Answer 34

Shaping

Question 35

Root canal therapy is the only dental procedure that relies almost entirely on _______. Use “________ touch” and delicately manipulate instruments for a better result

Answer 35

feel; light

Question 36

Leave nature’s apical foramen alone, clean canal so that it is _________ and obturate it

Answer 36

patent

Question 37

_____________ weakens the root _____________ leaves debris, bacteria, etc

Answer 37

Overshaping Undershaping

Question 38

Continuously tapering shape that is appropriate for external root structure

Answer 38

Body shape

Question 39

Design feature that adds strength to file and keeps instrument centered in fine curved canals

Answer 39

Radial land of instruments

Question 40

Noncutting may guide file through the curve rather than cutting into outer wall of curve

Answer 40

Tip design of instruments

Question 41

Clockwise rotation of instrument

Answer 41

Reaming

Question 42

Instrument is basically screwing into canal, can be risky

Answer 42

Reaming

Question 43

If instrument unwinds, separation can occur

Answer 43

Reaming

Question 44

Push-pull motion

Answer 44

Filing

Question 45

Canal walls can be damaged quickly with this motion if used without “touch"

Answer 45

Filing

Question 46

Very effective with Hedstrom files for flaring canal

Answer 46

Filing

Question 47

Combination of reaming and filing

Answer 47

Quarter turn and pull

Question 48

This method an create ledge if not careful, particularly in curved canals

Answer 48

Quarter turn and pull

Question 49

Back and forth rotation of a file (30 degrees right and 30 degrees left) as it is advanced into canal

Answer 49

Watch-winding

Question 50

Motion that is very effective with all K-type files and small files

Answer 50

Watch-winding

Question 51

Which file? Negotiate canal openings Move around ledges + calcifications Avoid sharp kinks

Answer 51

Precurved file

Question 52

Which rotary file material? Super-elastic behavior means that on unloading it returns to original shape before deformation

Answer 52

NiTi

Question 53

Which rotary file material? Greater strength and lower modulus of elasticity than stainless steel

Answer 53

NiTi

Question 54

Which rotary file material? Possible advantage during preparation of curved root canals because not as easily permanently deformed

Answer 54

NiTi

Question 55

Which rotary file material? 55% Nickel 45% Titanium

Answer 55

NiTi

Question 56

Which rotary file material? Angular deflection 900° (compared to 540° for stainless steel)

Answer 56

NiTi

Question 57

Which rotary file material? Shape memory

Answer 57

NiTi

Question 58

What are the 2 ways NiTis can break?

Answer 58

Torsional fracture Flexural fracture (cyclic fatigue)

Question 59

Which fracture of Niti? Instrument tip locks in canal while shank continues to rotate

Answer 59

Torsional

Question 60

Which fracture of Niti? Contact area is important. Crown-down reduces torsional loads by preventing a large portion of the tapered rotating instrument from engaging root dentin; use light touch

Answer 60

Torsional

Question 61

Which fracture of Niti? Limited # of rotations before fracture

Answer 61

Flexural

Question 62

Which instrument preflares the coronal part of the canal? (smaller to larger)

Answer 62

Orifice openers

Question 63

Meant to be inserted beyond the canal orifice to the approximate depth of 2/3 their cutting flutes – no deeper

Answer 63

Orifice openers

Question 64

What should you use on all rotary files?

Answer 64

Lubricant

Question 65

___________ copiously the access opening making sure to leave a few drops of irrigant in the pulp chamber during cleaning and shaping

Answer 65

Irrigate

Question 66

Determine the working length using a #____ or _____ hand file (or if the canal is larger, the smallest size that reaches your tentative working length and binds enough in the canal so that is not displaced during the radiograph)

Answer 66

10 or 15

Question 67

Instrument the canal to working length with hand files to a size #____ and then to a size #____. Lightly coat each file tip with canal lubricant

Answer 67

15; 20

Question 68

If the canal is curved, _________ your stainless steel hand files

Answer 68

precurve

Question 69

The portal of exit of canal has been cleared of any debris in its path

Answer 69

Patency

Question 70

Which technique ends up with more debris in the apical foramen?

Answer 70

Step back (crown down doesn't cause as much debris)

Question 71

Keeps debris from plugging apical foramen

Answer 71

Patency

Question 72

Should only be maintained with #10 or 15 file; set at 1 mm longer than WL

Answer 72

Patency

Question 73

Larger patency files would lead to ___________

Answer 73

overfilling

Question 74

How is patency maintained? (5)

Answer 74

Curved SS files Lubrication Cleaning debris from used instruments Irrigation Reapitulation w/ a small file to patency (using a size 10 or 15 file 1 mm beyond WL)

Question 75

How do you know when you are done cleaning and shaping a canal? (3)

Answer 75

Canal has smooth tapered walls Selected spreader or plugger passes to within 2-3 mm of working length Canal has definite apical stop

Question 76

Minimal instrumentation at any appointment is to size ______

Answer 76

25

Question 77

Minimal size to fit gutta-percha is size _____

Answer 77

30

Question 78

Instrument 3 sizes larger than the first file that binds at working length

Answer 78

MAF

Question 79

What does NaOCl and CHX do?

Answer 79

Reduce microbes

Question 80

What causes the dissolution of soft tissues during irrigation?

Answer 80

Proteolytic effect

Question 81

Name 5 benefits of irrigation

Answer 81

Gross debridement Lubrication Reduce microbes Dissolution of soft tissues Remove smear layer

Question 82

Which benefit of irrigation? Similar to Washing of Open Wound Frequency and volume are important 1-2 mL each time Patency file greatly improves irrigation in fine canals

Answer 82

Gross debridement

Question 83

What are the irrigants we use?

Answer 83

NaOCl CHX EDTA

Question 84

Which irrigant? Proteolytic, disinfectant

Answer 84

NaOCl

Question 85

Which irrigant? Disinfectant, substantivity

Answer 85

CHX

Question 86

Which irrigant? Chelating agent to help remove dentinal debris (removes smear layer; softens obstructing dentin)

Answer 86

EDTA

Question 87

Which irrigant? No recognized tissue damage No chemical destruction of bacteria No tissue dissolution

Answer 87

Sterile saline

Question 88

Which irrigant? Most common irrigant Accomplishes tissue dissolution and antibacterial properties 1% and 2.5% solutions most commonly recommended

Answer 88

NaOCl

Question 89

Vital tissue takes __________ to dissolve than necrotic

Answer 89

longer

Question 90

Which irrigant? Effective in removing vital pulp tissue from dentin walls

Answer 90

NaOCl

Question 91

Cleaning and shaping root canal walls produces a _________ _________ on the instrumented walls

Answer 91

smear layer

Question 92

Contains inorganic and organic substances (odontoblast processes, microorganisms, and necrotic materials)

Answer 92

Smear layer

Question 93

What removes the smear layer?

Answer 93

NaOCl + EDTA

Question 94

Facilitate instrument movement in canal; eliminate soft tissue blockage

Answer 94

Lubricants

Question 95

___________ gauge needles allow better penetration in canal and more effective irrigation

Answer 95

Smaller

Question 96

Irrigant needle should be_________ in canal with slow gentle pressure on syringe plunger

Answer 96

passive

Question 97

Do NOT lock needle in the canal! Extrusion out apex results in excruciating pain, swelling, periapical tissue bleeding

Question 98

Recapitulate with patency file before _________ with size 10 or 15 file. This loosens debris compacted at apex and moves irrigant into apical 1/3

Answer 98

irrigation

Question 99

For irrigation, more is better and warmer is better