Canal Shaping, Errors in Canal Cleaning and Shaping

step-back technique

canal shaping technique that involves the preparation of the apical third initially, followed by middle and coronal third of the canal using subsequently larger instruments

reaming motion

motion of coronal instrumentation for step-back technique

circumferential filing

motion of apical instrumentation for step-back technique

2% SS files

specific instruments used in step-back technique

step-back technique

canal shaping technique that is ideal for a proper apical stop and gradual taper

extrusion of debris into periapex

the main limitation of step-back technique of canal shaping

crown down

canal shaping technique that involves the preparation of the two-thirds of the canal first followed by the middle and apical third of the canal

reaming motion

motion of instrumentation for crown down technique

false

true or false: both crown down and step back technique use rotary instruments

true

true or false: shaping is easier using the crown down technique

false

true or false: step back technique has better penetration/holds greater volume of irrigants thus enhances cleaning

false

true or false: step back technique reduces pressure and minimizes debris extrusion

true

true or false: crown down technique removes dentin mud and improves identification of the foramen

gouging

main limitation of crown down technique is ______________ of the apical third

hybrid technique

canal shaping technique that involves combination of crown down and step-back technique

Clem and Weine

who developed the step-back technique of canal preparation?

step-back technique

canal shaping technique that uses successively smaller to larger size of instruments to prepare the canal at millimeter increments progressing from the apical preparation to coronal

patency files

file sizes 6, 8, and 10 are called ____________

patency files

these files are used to check the opening of the apical foramen, if it is blocked by debris, and is also used in very fine canals

initial apical file

the first file that enters the correct working length with a snug fit feeling

master apical file

the file three sizes larger than the initial apical file at the correct working length

size 40

if the initial apical file is size 25, what would be the size of the master apical file?

size 30

if the initial apical file is size 15, what would be the size of the master apical file?

serial filing

phase I of step-back technique is also known as?

serial filing

identify if serial filing or step-back preparation: recapitulation using the previous file used

recapitulation

re-instrumentation with a smaller instrument following each filing and irrigation

recapitulation

done to remove debris produced during instrumentation and prevents apical plug formation and zipping

step-back preparation

identify if serial filing or step-back preparation: uses three file sizes larger than the master apical file

serial filing

identify if serial filing or step-back preparation: uses the same working length with each file

step-back preparation

identify if serial filing or step-back preparation: uses a 1mm shorter working length file after every file

step-back preparation

identify if serial filing or step-back preparation: recapitulation using the Master apical file after every file

size 30

if the IAF is size 15, what would be the last file used after serial filing?

size 45

if the IAF is size 15, what would be the last file used after step-back preparation?

tapering cone shaped

shape of a properly shaped canal

false

true or false: a properly shaped canal should be the same width as the original canal

filing motion

up and down movement of the files

absence of resistance

during filing, this determines when you should move to the next file

circumferential filing

this instrument motion enhances preparation by moving towards all directions and prevents a keyhole type of preparation

reaming motion

clockwise rotation of the instrument used commonly for reamers

false

true or false: reaming motion may be employed using K-files

false

true or false: to remove a stuck reamer from the canal, simply pull it out of the canal

turn and pull motion

a quarter turn to the right followed by a straight outward pull

watch winding motion

a back and forth oscillation of the file 30 to 60 degrees right and 30 to 60 degrees left as the instrument is pushed forward into the canal

clockwise

in the watch winding motion, what rotation pushes the file tip and working edges into the canal?

counter clockwise

in the watch winding motion, what rotation partially cuts away the engaged dentin?

true

true or false: watch winding motion is less aggressive than quarter turn and pull

balanced force technique

1/4 turn clockwise then 3/4 turn counterclockwise with apical pressure

crown down technique

canal shaping technique used for very fine canals

true

true or false: crown down technique does not require recapitulation

protaper gold

rotary instrument used in crown down technique that is malleable and readily available

glide path

the ability of the instrument to go inside the canal

WaveOne Gold

a specific crown down canal shaping technique that only uses one file

strain or metal fatigue

sign that the instrument is near breakage

precurve

when using stainless steel files, always _________ before insertion

ledges

deviation from the canal anatomy: makes it difficult for files to reach the apical portion/working length due to a small concavity created during instrumentation receiving the tip of the file

zips

deviation from the canal anatomy: ledge that usually occur at the apical extent of the canal which enlarges the apical foramen

false canal

deviation from the canal anatomy: a man made canal due to perforation

strip perforation

deviation from the canal anatomy: lateral walls of the tooth are perforated

transportation

deviation from the canal anatomy: jagged or zigzag root canal walls

apicoectomy

last ditch solution for fractured instruments inside the canal

SS

which files can be removed using ultrasonic vibration?

NiTi

which files fragment when subjected to ultrasonic vibration

EDTA

can be used to dislodge pulp stones with the help of a small file

mineral trioxide aggregate

used for the repair of perforations and in surgical endodontics as a retrograde filling material

Spreader reach test

a test done to determine if canal shaping and widening is already sufficient before obturation

Spreader reach test

test done by using a spreader 2 sizes smaller than the master apical file at the same working length and inserting it to the canal in order to determine if canal shaping is sufficient already

Spreader reach test

test done by using a spreader 2 sizes larger than the master apical file at -2mm working length and inserting it to the canal in order to determine if canal shaping is sufficient already