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endo > cleaning and shaping > Flashcards

cleaning and shaping Flashcards

1
Q

SHAPING: PRINCIPLES
1. shape?
2. Curves of canal?
3. Retention of the “apical constriction”
4. Enlargement of the canal system?
5. Adequate “deep space” ?

A
  1. A constantly 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 filings (adequate cleaning)
  5. Adequate “deep space” for proper obturation
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2
Q

Native American and some Asian man molar roots

A

-L lower first molars (3rd root)

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3
Q

can roots be straight and canals differ?

A

yes

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4
Q

what curves are seen with radiographs

A

M/D

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5
Q

what is not seen on typical PAs
alt radio?
look for?

A
  • Facial and lingual curves will NOT generally be seen:
    – Try angled radiographs (SLOB)
    – Look for “bulls eye” radiograph (root tip
    turns to F or L)
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6
Q

If your initial #10 SS scouting file bends what may be present

A

canal curvature

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7
Q

what is indicated with F/L root curves

A

refer/CBCT

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8
Q

creating Ledges and Blockages

A
  • When we place a straight SS hand file in a curved canal:
  • Physics dictates it must track the OUTSIDE (convex) wall of the canal at some point. What does this do?
  • Tends to gouge and lean against the outside wall of the canal creating the a Ledge, which can be the first step to Blockage or Transportation
  • If we keep Pushing & Grinding on the file, we can eventually force it through the root to create a Perforation
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9
Q

As our shaping proceeded to the larger sizes of SS hand files above #15 what increases and decreases

A
  • Increase in Stiffness*
  • Decrease in Flexibility
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10
Q

Transportation, etc. is one of
the MAIN REASONS that we:

A

selected the current technique in which hand files used are generally no larger than #15

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11
Q

what is transposition

A

canal no longer follows normal anatomy, zip is formed

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12
Q

zip

A

result of apex

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13
Q

apical strip perforation

A

If the Zip occurs the through apex to the exterior of the root We have an apical strip perforation

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14
Q

transporation/zips effect on RCT outcome

A

poor/ no healing occurs

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15
Q

The Curved File is to be oriented
correctly to coincide or slightly exceed what?

A

The Curved File is to be oriented correctly to coincide or slightly exceed the curvature of the canal ,

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16
Q

introduction motion of curved file?
what motion with a negotiated canal?
if done carefully?

A

introduced in a gentle watch-winding motion and then flexed in a rasping pull motion with circumferential filing after the path is negotiated.

If done carefully, many canals may be safely enlarged to a reasonable MAF

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17
Q

Loose Resistance to Apical Advancement, what to do?

A

*You are encountering a ledge or a possibly
abrupt bend or curve:
* Do Not Force File: Instead STOP Irrigate, and
Bend the Tip
* The most apical flutes of the file must be
bent & rotated to track the inside wall of the canal.
*Gently enter canal rotate and advance the file a little at a time through the full 360 degrees until you fall into a TIGHT area. This is the canal and the file can now often advance & BYPASS the obstruction/ ledge to join the TRUE canal.

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18
Q

when can transposition occur

A

If there is a severe curve in the canal – especially if the curve occurs in the apical 1/3 and a very smooth glide path was not perfected and the operator tries to PUSH or Force the Wave One Gold file to WL
* By allowing the Vortex Blue finishing files to rotate at or slightly short of WL for more than 1 moment

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19
Q

preventing vortex blue transportations

A
  • KEEP THE VORTEX BLUE FILE MOVING using a smooth in-out motion in the canal while flexing it on the out stroke to smooth and further flare the walls.
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20
Q

Strip –Perforation
common location/instrument

A
  • Occurs when files used are either too large or too aggressively used for a small or thin walled canal.
  • Commonly the distal of the mesial root of lower molars, MF of upper molars , 2 canal max. PM
    often when the 25/12 is used too deep in canal
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21
Q
A

strip perforation

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22
Q
A

strip perforation

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23
Q

The 9 STEP PREP
(following proper access)

A
  1. Scouting
  2. Patency
  3. Working Length
  4. Glide Path
  5. Shaping of coronal 1/3 of canal
  6. Shaping of middle 1/3 of cana
  7. Perfecting Straight-Line-Access to mid-root
  8. Shaping of apical 1/3 of canal
  9. Final Shaping Objective Vortex Blue or
    Serial Step Back (SSB) using HAND FILES if MAF >#50
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24
Q

scouting instrument

A

10 hand file

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25
Q

patency instrument

A

10 hand file

26
Q

WL instrument

A

15 hand file, TIGHT

27
Q

glide path instrument

A

15 handfile, Loose file and ONLY hand files to this point

28
Q

shaping coronal third instrument

A

wave one gold

29
Q

shaping mid third instrument

A

wave one gold

30
Q

perfecting straight line mid root access tool

A

25/12 carefully

31
Q

shaping apical third tool

A

wave one gold

32
Q

final shaping tool

A

vortex blue or SSB with hand files if MAF >50

33
Q

obtaining patency
when obtained?
measure how in lab/clinic? clogging?
size?

A
  • The canal is “PATENT” when a #10 file goes slightly beyond the canal exit (.5 mm.) = Long = into the Periodontal Ligament. The Apex Locator will help us locate the canal exit clinically.
  • In lab, measure BEFORE you mount
    This tiny passageway can clog easily as
    soon as we start C&S, resulting in blockage
    = loss of patency. We want to keep a small
    hole out the end of the root (#10 file is ideal
    – no larger)
    Patency is maintained by “Recapitulation” (irrigating and revisiting patency after Wave One with the patency file #10 only)
34
Q

If it is TIGHT RESISTANCE to apical advancement:

A

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

35
Q

If it is LOOSE RESISTANCE to apical advancement:

A

If it is LOOSE RESISTANCE to apical advancement, you have encountered a canal curvature and you must bend the terminal flute of your file and search for the path to negotiate the curve.

36
Q

Working Length (WL)

A
  • ALL Shaping is done @ WL = 1mm. short of the Canal Exit
37
Q

confirming WL

A

Working length confirmed radiographically
Accurate WL is CRITICAL to RCT success

38
Q

WL reference points

A
  • Reference point: Anteriors: Incisal edge
  • Posteriors: Cusp for which canal is named, flatten cusp when possible
39
Q

creating glide path purposes

A

– To smooth curves & 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.

40
Q

how to make a glide path
tools?

A

The Glide Path is created using hand files (pre-curved to match or slightly exceed the curvature of the canal) using watch-wind entry followed by pull strokes directed in a circumferential manner to enlarge the canal to a size #15 at the WL. (#15 File should end up SLOPPY LOOSE)
– Always take each working file to WL. Never file SHORT of WL (prevent Blockage & Ledging)
– Irrigate following each active instrument (revisit patency 2-3 times during cleaning and shaping)

41
Q

How do you TELL if canals converge or are simply 2 canals in close proximity?

A

The “2 File Technique”
* Establish working length of “each canal” separately.
* Attempt to place 2 files to WL in ea. Canal @ same time
– If both go to WL = 2 canals
– If one goes & the other is short – reverse the placement sequence. If still one is short =
converging Class II canals

42
Q

shaping canals choice of file/tool

A

You will choose the size of Wave One file to be used based on the diameter of the canal you are treating:
1. If a 10 K-file was very resistant to movement, use Wave One Gold Small file.
2. If a 10 K-file moves to length easily, is loose or very loose, use Wave One Gold Primary file. (85%)
3. If a 20 hand file or larger goes to length, use WaveOne Gold Large file

43
Q

Once the WL is confirmed and the Glide Path
(#15) is smooth and unobstructed, you may?

A

You are ready to select the first machine
driven file to begin canal shaping

44
Q

setting for shaping with wave-one

A

You will set the Promark electric motor
to Wave One Reciprocal Motion and
insert the proper size Wave One file

45
Q

wave ne file lengths?

A

Wave One files come in lengths of 21, 25.
and 31 mm. Select the appropriate length for
your tooth.

46
Q

dividing canal for shaping

A

Think of the canal as comprised of 3 distinct
sections to consider in shaping with the Wave
One File. 3-5mm segements
We will be shaping the canal 1/3 at a time:
-coronal (13-15mm)
-middle (16-20mm)
apical (19-25mm)

47
Q

Wave One Gold Reciprocal Files sizes

A

Small: .20 mm. @ tip
.07 overall taper
Maximum Flute Diameter .8 mm.

Primary: .25 mm. at tip
.07 overall taper
MFD = .8 mm.

Large: .45 mm. at tip
.05 overall taper
MFD = .8 mm.

48
Q

Wave One Gold files are used only with the Dentsply motor on:

A

wave one setting

49
Q

wave one motion of use? why?

A

The operator action is a light “pecking”
motion. It is important to note that one must be vigilant as the Wave One action tends to push debris ahead of the file so stop
action at 1/3 and 2/3 of the operation approaching the apex to clean the file and to irrigate thoroughly at these stages of shaping

50
Q

when is striaght line access perfected?

A

after mid thrid of RCS is shaped, allows access to apical

51
Q

Perfecting STA (Straight-Line Access) to mid-root (Following 2nd 1/3 (Wave One shaping)

A

Place a .25/.12 Vortex Orifice opener in the Pro-Mark motor and adjust the action to Vortex and leave the speed at 500 rpm. MFD is 1.20mm
Allow the 25/.12 to mill to the depth of mid root ONLY . Any lateral motion should be AWAY FROM the furcal area (ex. In max/mand. MB canal pull toward the mesial & buccal only).
* RECAPULATE: IRRIGATE

52
Q

Shaping the apical 1/3 of Canal
* Set the Wave One Gold file at? Pro-Mark motor action? and guide it to advance to?
* Confirm? smooth? tool? continue? irrigate?

A
  • Set the Wave One Gold file at the confirmed WL (Working Length) and reset the Pro-Mark motor to reciprocal action and guide it to advance to the WL.
  • Confirm patency & smooth glide path with #15 hand file & then irrigate and continue to WL with Wave One.
  • IRRIGATE
53
Q

MAF scales

A

Small Roots about #30-35 MAF
Medium Roots about #40-45 MAF
Large Roots are #45-50 MAF or more

54
Q

Teeth with moderate to severecurvature require what MAF and why?

A

Teeth with moderate to severe curvature require smaller MAF to avoid transportation of canal.

55
Q

Younger teeth will have larger
canals & require what MAF to clean

A

larger

56
Q

Small MAF teeth

A

Mand. Incisors, 2 canal Premolars, M. canals of Mand. molars, B. canals of Max. Molars

57
Q

Medium MAF teeth

A

Medium = Palatal canals of Max. Molars, Single Distal canals of Mand. Molars

58
Q

Large MAF teeth

A

Max. Anteriors, M/M Cuspids, Single canal M/M Premolars

59
Q

files for final shaping

A

■ We will be using Vortex Blue Files for the final shaping and smoothing of the canal. Sizes .30/.04 through .50/04 available.

60
Q

how to use vortex blue files

A

■ Each Vortex Blue file should be KEPT MOVING and go completely to WL on each of 10 strokes. They should be flexed whilerotating & being drawn out to increase the flare of the canal in an appropriate direction - away from furca or toward the greater dimension of the canal. Shaping is complete when dentinal filings are on apical 1/3 of the instrument

61
Q

what to do after each active file

A

irrigate

62
Q

serial step back

A

used to produce a greater apical taper in control zone, when canal req larger diameter than the 45/04 vortex blue file
use of SS hand files

endo (22 decks)

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