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endo II > lecture 2: cleaning and shaping > Flashcards

lecture 2: cleaning and shaping Flashcards

(53 cards)

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1
Q

the 9 step prep

A
  1. scouting
  2. patency
  3. working lengths
  4. glide path
  5. shaping of coronal 1/3 of canal
  6. shaping of middle 1/3 of canal
  7. perfecting straight-line-access to mid-root
  8. shaping of apical 1/3 of canal
  9. final shaping objective
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2
Q

step 1: scouting file

A
  • locate and negotiate canals

- once pulpal access is achieved you locate canals using endo explorer

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3
Q

what do you look for with the endo explorer

A

you look for a ‘stick’ in the canals

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4
Q

what file do you use for step one

A

scouting file #10

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5
Q

if you don’t irrigate what will happen

A

if you don’t irrigate you will almost certainly block yourself out and never reach patency

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6
Q

what is watch winding

A

a gentle right and lock rocking motion which causes the instrument to cut while inward pressure

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7
Q

step 2: obtain patency

A

finding patency using the #10 file going slightly beyond the canal exit and use the apex locator.

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8
Q

how it patency maintained

A

by recapitulation (irrigating and revisiting patency occasionally with the patency file only)

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9
Q

if you have a tight resistance to apical advancement then

A

you probably have a small canal which must be enlarged carefully to reach patency

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10
Q

if you have a loose resistance to apical advancement then

A

you have encountered a canal curvature and you must ben the terminal flute of your file and search for the path to negotiate the curve

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11
Q

during recapitulation what is very important:

A

you need to irrigate the canal and revisit patency

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12
Q

step 3: working length

A

ALL shaping is done at WL which is 1mm short of the canal exit.

confirm with a #15 SS File

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13
Q

is WL critical to RCT success

A

yes

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14
Q

what are your reference points

A

ant: incisal edges
post: cusp for which canal is named, flatten cusp when possible

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15
Q

step 4: create a smooth “glide path”

A
  • its created using hand files (pre-curved to match or slightly exceed the curvature of the canal)
  • enlarge the canal to a size #15
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16
Q

the purposes of creating a smooth glide path

A
  • to smooth curves and make sure there are no canal obstructions
  • to create space for rotary instruments to be used safely without excessive torque requirements
  • to relieve stress on tip of rotary file to minimize fracture
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17
Q

step 5 to 8: shaping the canals by thirds

A
  • coronal, middle and apical

- use the machine driven file to begin canal shaping.

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18
Q

what lengths do wave one files come in

A

21, 25, and 31 mm.

select the appropriate length for your tooth

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19
Q

you choose the size of wave one file to be used based on the

A

diameter of the canal you are treating

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20
Q

a 10 K file was resistant to movement so you use

A

a wave one gold small file

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21
Q

if a 10 k-file moves to length easily, is loose or very loose, use

A

a wave one gold primary file

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22
Q

if a 20 hand file or larger goes to length, use

Study These Flashcards
A

a wave one gold large file

23
Q

you will be shaping the canal 1/3 at a time:

Study These Flashcards
A

you will shape around 3-5mm at a time for each section

24
Q

wave one gold reciprocal files sizes are

Study These Flashcards
A

small: 0.2mm at tip
primary: .25mm at tip
large: .45mm at tip

25
step 7: straight line access to mid root
- use a .25/.12 vortex orifice opener - mill to the depth of mid root only. - any lateral motion should be away from furcal area - recapulate: irrigate
26
step 8: shaping apical 1/3
- confirm patency and WL | - then irrigate
27
step 9: final shaping objective
- pick MAF at the WL | - each canal is different and allows for a certain cleaning and shaping
28
MAF =
master apical file
29
MAF for small, medium and large roots
small: #30-35 medium: #40-45 large: #45-50
30
final shaping objective
- using vortex blue file keep moving and go completely to WL. - they should be flexed while rotating and being drawn out to increase the flare fo the canal in an appropriate direction .
31
vortex blue files automatically give you a __ taper
0.06 taper
32
how long should the vortex blue be there when taken to WL
no longer than 1 sec at WL or short of WL
33
if you rotate the vortex blue file short of the WL what will it create
it will ALWAYS create a ledge
34
primary etiologies of pulpa and periapical ds
- caries or other injuries - infected dentin and soft tissue (pulp) - microorganisms and their toxins invade - substrate in canal system fuels micro-organisms - result is peri-radicular lesion
35
primary objectives of rct
- remove all caries - remove infected dentin and pulp - remove micro-organisms and toxins - remove substrate from the canal system - create a shape encouraging proper obturation - seal the root canal system and all portals
36
what are the 5 shaping principles
1. a constant tapering funnel from crown to WL 2. curves of canal respected w/o transportation 3. retention of the apical constriction 4. enlargement of the canal system to create clean white fillings (adequate cleaning) 5. adequate "deep space" for proper obturation
37
what shapes do we want:
- constantly tapering funnel - that is a better deep shape - and follows the natural shape of the canal
38
shaping techniques
shaping: the files do the shaping - removes of all caries and infected dentin - allows convenience form for effective irrigation - creates a resistance form to facilitate effective obturation - conserve tooth and root structure to minimize VRF
39
cleaning techniques
- irrigation cleans - 8.3% NaOCl and 17% EDTA - it dilutes and neutralizes toxins - dissolves and removes substrates - flushes out debri - edta removes the smear layer
40
what removes the smear layer
edta
41
results of early RCT attempts by students
- over-enlarging - strip-perf - transportation - inadequate flair
42
WL key points
- critical to success | - 1mm short of canal exit
43
how is the WL measured
at a reproducible reference point usually use the cusps for which the canal is named.
44
if the WL is too short what will it result in
a blockage
45
if the WL is too long what will it result in
a blow out
46
finding the WL: ETL
estimated total length if tooth in mount, ETL use the apex locator in clinic
47
what is a "serial step back"
- aka SSB - a process to create an apical resistance form when rotary instruments are not available due to very large canal diameter
48
is it difficult to blow out lots of sealer with a large apical foramen
NO, it is EASY especially with hydraulic obturation
49
when should SSB be used
- when a canal requires enlargement larger than a size #.50, it will be necessary to employ SSB - when a blow out has been created and you need to create a new and larger apical control zone and taper to contain the GP within the root
50
ACZ is
apical control zone
51
how does SSB work
- initial apical gauge = #50 file - take MAF to #60 hand file at ACZ to retain (GP) - SSB at 1mm to #70, #80, #90, #100, #110, creates a taper using essentially straight hand files - SSB creates a taper coronal to ACZ to facilitate obturation in the absence of appropriate tapered files - final apical gauging - now have a good shape for GP
52
what is final apical gauging
- using hand files for SSB | - it should show a #45 goes patent, after MAF, a #60 file binds to ACZ and a #70 binds 1mm short
53
what type of shape will you end up with in a SSB
- a "stepped" preparation

endo II (7 decks)

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