(11/7) Cleaning and Shaping I

T/F: C/S is chemo-mechanical preparation

T

chemo-mechanical preparation purpose (3)

1. remove necrotic debris & infected canal walls

2. disinfect root canal system

3. shape main canal space for appropriate obturation

chemo-mechanical preparation:

chemical =

mechanical =

irrigation solutions

hand files or rotary files

irrigation solution purpose (5)

1. flush out debris

2. lubricate canal

3. dissolve organic & inorganic tissues

4. prevent/remove smear layer

5. antimicrobial

what is the purpose of C/S?

to significantly REDUCE the irritants

T/F: the purpose of C/S to totally eliminate irritants

F

C/S is [disinfection/ sterilization]

disinfection

estimated WL

Radiographic length (RL) - 1.0 mm

corrected WL

EAL & radiographs

first file to bind at the estimated WL

initial apical file (IAF)

largest file that went to the corrected WL

master apical file (MAF)

apical enlargement shape/taper

round with rotary files

mean apical diameter (1, 2, or 5 mm from the root apex) shape

oval

what number file should be used for apical enlargement for maxillary central incisors, canines, and PMs

at least #30 or #35

or 3 sizes larger than the 1st file bind at estimated WL

if a #30 is the first file to bind slightly at WL, what file would be 3 sizes larger?

#45

principles of shaping with flaring (4)

1. facilitate cleaning

2. provide space for placing obturating materials

3. preserve root structures (prevent VRT)

4. establish apical stop/apical seat for obturation

continuous taper _________ from canal orifice to the apex reduces procedure errors

funnel

lateral condensation:

finger spreader reaches ____-____mm of corrected working length

1-2 mm

vertical compaction:

plugger within ____-____mm of working length

3-5 mm

preserving root structures → prevents

vertical root fracture

preserving root structures:

when shaping preserve __________ & ___________ dentin as much as possible

cervical

radicular

shaping instrument movements (4)

1. watch-winding

2. reaming

3. filing

4. rotary

Back and forth CW /CCW 90-180º rotation of the file with light apical pressure to move file apically

watch-winding

watch-winding:

Back and forth CW /CCW ____-____º rotation of the file with light ________ pressure to move file apically

90-180º

apical

File binding the walls and rotate clockwise 180-360º to plan walls and enlarge the canal space

reaming

reaming:

File binding the walls and rotate clockwise ____-____º to _______ walls and enlarge the canal space

180-360º

plan

Pressing file laterally against the wall while withdrawing along the path of insertion to plane the wall

filing

filing:

Pressing file laterally against the _______ while _____________ along the path of insertion to plane the wall

wall

withdrawing

continuous or reciprocal rotation with motor

rotary

rotary instrument movement must be used after #______ hand file to establish a

#20

glide path

filing motion on all sides of the canal walls

circumferential filing

small file to working length to loosen debris with a reaming motion & flushing it with 1-2 mL irrigant between files

recapitulation

recapitulation:

small file to working length to loosen debris with a ___________ motion & flushing it with 1-2 mL irrigant between files

reaming

anticurvature filing:

________ _________ using G-G drills, NiTi orifice shaper or hand files

selectively removing dentin away from the _________ zone

staying away from _________ wall

coronal flaring

danger zone

furcal

recapitulation purpose

to loosen accumulated debris so the debris can be flushed out with irrigant

recapitulation should be done between each successive enlarging instrument with a ________ size file

small (#10 or #15)

what type of motion should you use with recapitulation

reaming

the purpose of recapitulation is not to __________ or ___________ the canal walls

enlarge

plane

circumferential filing indications (3)

1. large canals and/or not round in cross section

2. C/S by removing/ enlarging canal walls

3. in step-back technique to smooth the walls

circumferential filing method:

___________ motion in a directional manner against all sides of canal walls

filing

circumferential filing method:

the flutes need to be cleaned of debris after each insertion with

alcohol-soaked gauze

circumferential filing method:

use a #____ to WL file with a filing motion AFTER

#15

apical flaring

circumferential filing method:

use a #____ to WL file with a filing motion AFTER apical flaring to remove the

steps

the first largest file that binds slightly at estimated WL after coronal flaring (SLA)

initial apical file (IAF)

ideally is the file used for WL radiograph

initial apical file (IAF)

Estimated measurement or confirmation of the terminal diameter or shape of a canal after initial crown-down shaping

apical gauging

the largest file used to the correct WL of a completely prepared root canal

master apical file (MAF)

MAF minimum = #_____ for undergraduate cases

#30

ideal termination of NSRCT

apical constriction (minor foramen)

2 methods of determining WL

1. radiographic determination

2. electronic apex locator (EAL)

what is the minimum sized k-file used radiographically to confirm WL

15

what sized files are used to determine MAF

at least #30 or 3 sizes > IAF

reference point used to maintain working length should be

flat reference point and reference point on the external portion of the tooth which is easy to visualize

what should you not use to maintain working length

an internal reference point

Electric resistance between an instrument in the canal and an electrode on the oral mucous membrane (~PDL)

EAL

3rd generation EAL

ratio methods of 2 frequencies and self-calibrating

3rd generation EAL has > 90% accuracy within _____ mm of apical foramen or CDJ

0.5 mm

3rd generation EAL has 100% accuracy within _____ mm of apical foramen or CDJ

1.0 mm

EAL problems (5)

1. affected by irrigants

2. vital tissues or blood

2. metallic restoration or material

3. canal patency

4. size of apical foramen

4. size of apical foramen:

< #___ = accurate

but > #____ = short of apical foramen

#20

#20

4. size of apical foramen

Blunderbuss apices

short reading because the instrument is not touching the apical dentin walls

WL is confirmed with ___________ in both Sim Lab and in clinic

radiographs

maintain WL by (5)

1. recheck WL frequently with EAL

2. recapitulation

- always maintain patency

3. irrigate frequently

4. avoid "screwing in" of hand files

5. be patient & gentle

WL can ___________ as curved canals are shaped & ultimately ___________

shorten

straighten

a small K file (#10 or #15) passively inserted just through the apical foramen (or to radiographic length at RL)

patency file

patency file:

a small K file (#10 or #15) passively inserted just through the

apical foramen or RL

A technique where the apical portion of the canal is maintained free of debris by recapitulation with a small file through the apical foramen

apical patency

to secure an open pathway to the canal terminus before using engine-driven rotary files (↓ rotary file fracture)

glide path

glide path:

to secure an open pathway to the canal terminus _________ using engine-driven rotary files (↓ rotary file fracture)

before

glide path:

created by #_____ → #_____ → #_____ K-file with what type of motion?

#10 → #15 → #20

watch-winding (balanced force)

glide path:

should use at least #____ file before using rotary files

#20

glide path:

____________ & ____________ in and out the canal to WL without resistance

passively & smoothly

instrumental goal - cervical 1/3:

prepare with what drill?

goal?

gates-glidden

canal is enlarged to allow SLA to apical portion of the canal

cervical constriction is usually on the ___________ wall of the anterior teeth

lingual

dentinal bulge is on the ________ & ________ walls of the pulp chamber of molars

mesial & distal

step-down approach (2)

1. coronal & mid 1/3 =

2. shaping apical 1/3 =

GG beginning with small size

hand instrument

shaping apical 1/3 with hand instrument:

passively inserting a file → rotate _____º to engage dentin

keep the file with adequate _________ pressure & rotate _______ 180-270º

advancing further ________ to WL

a final _________ rotation to evacuate the debris

90º

apical

CCW

apically

CW

instrumentation - mid-root 1/3:

prepared with either rotary files or hand files using what method?

crown-down method

instrumentation - mid-root 1/3:

goal

mid-root portion blends or tapers smoothly with the cervical portion and no ledge present

instrumentation - mid-root 1/3:

substandard

mid-root portion does not blend smoothly and ledge present but will not prevent canal obturation

the mid-root portion is transported

instrumentation - mid-root 1/3:

deficient

mid-root portion is perforation and/or grossly ledged that will prevent canal obturation

instrumentation - apical 1/3:

goal #1

Length

- the apical portion is instrumented to 1 mm coronal to the root apex

instrumentation - apical 1/3:

goal #2

Taper

- allow a finger spreader #30 to reach within 2 mm of WL with a Master Cone present

step-back technique steps (3)

1. coronal flaring with G-G drills

2. WL determination with 1st file to bind at estimated WL

3. Subsequent enlargement of apical to WL, up to MAF

step-back technique method:

one file size _________ than MAF will instrument to WL-1 mm to created a _____% taper

larger

5%

step-back technique method:

the succeeding ______ files are shortened by 0.5 mm to 1mm increments from the previous file length

larger files

step-back technique method:

at least ____-____ sizes larger than MAF

3-5

step-back technique for apical flaring:

1. MAF #45

2. step back with larger sized file _______ mm shorter than previous file (10% taper)

3. ________________ #10

4. ________________ filing with #15 to smoothly plane the walls

5. MAF #______ to WL

0.5 mm

recapitulate

circumferential

#45

step-back technique for apical flaring:

recapitulate with file size #______

#10

step-back technique for apical flaring:

circumferential filing with file size #_____

#15

MUSC technique:

what file is used to establish glide path

#20

MUSC technique:

step back with larger sized file ______ shorter than previous file (10% taper)

0.5 mm

SIM lab:

step back with larger sized file ______ shorter than previous file (_____% taper)

1 mm

5%

MUSC technique:

recapitulate with #_____

#10

MUSC technique:

last circumferential filing with #____ MAF to smooth walls

#45

how to determine if you have an apical stop/seat

tap on MAF while in the canal

the file should NOT move apically

how to ensure apical patency

after each rotary file, irrigate and maintain patency with a #10 file at RL

how to check canal tapering/flaring

with master cone in place to WL and finger spreader (#30) with 2 mm of WL