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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
patency instrument
10 hand file
26
WL instrument
15 hand file, TIGHT
27
glide path instrument
15 handfile, Loose file and ONLY hand files to this point
28
shaping coronal third instrument
wave one gold
29
shaping mid third instrument
wave one gold
30
perfecting straight line mid root access tool
25/12 carefully
31
shaping apical third tool
wave one gold
32
final shaping tool
vortex blue or SSB with hand files if MAF >50
33
obtaining patency when obtained? measure how in lab/clinic? clogging? size?
* 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
If it is TIGHT RESISTANCE to apical advancement:
you probably have a small canal which must be enlarged carefully to reach patency
35
If it is LOOSE RESISTANCE to apical advancement:
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
Working Length (WL)
* ALL Shaping is done @ WL = 1mm. short of the Canal Exit
37
confirming WL
Working length confirmed radiographically Accurate WL is CRITICAL to RCT success
38
WL reference points
* Reference point: Anteriors: Incisal edge * Posteriors: Cusp for which canal is named, flatten cusp when possible
39
creating glide path purposes
– 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
how to make a glide path tools?
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
How do you TELL if canals converge or are simply 2 canals in close proximity?
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
shaping canals choice of file/tool
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
Once the WL is confirmed and the Glide Path (#15) is smooth and unobstructed, you may?
You are ready to select the first machine driven file to begin canal shaping
44
setting for shaping with wave-one
You will set the Promark electric motor to Wave One Reciprocal Motion and insert the proper size Wave One file
45
wave ne file lengths?
Wave One files come in lengths of 21, 25. and 31 mm. Select the appropriate length for your tooth.
46
dividing canal for shaping
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
Wave One Gold Reciprocal Files sizes
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
Wave One Gold files are used only with the Dentsply motor on:
wave one setting
49
wave one motion of use? why?
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
when is striaght line access perfected?
after mid thrid of RCS is shaped, allows access to apical
51
Perfecting STA (Straight-Line Access) to mid-root (Following 2nd 1/3 (Wave One shaping)
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
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?
* 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
MAF scales
Small Roots about #30-35 MAF Medium Roots about #40-45 MAF Large Roots are #45-50 MAF or more
54
Teeth with moderate to severecurvature require what MAF and why?
Teeth with moderate to severe curvature require smaller MAF to avoid transportation of canal.
55
Younger teeth will have larger canals & require what MAF to clean
larger
56
Small MAF teeth
Mand. Incisors, 2 canal Premolars, M. canals of Mand. molars, B. canals of Max. Molars
57
Medium MAF teeth
Medium = Palatal canals of Max. Molars, Single Distal canals of Mand. Molars
58
Large MAF teeth
Max. Anteriors, M/M Cuspids, Single canal M/M Premolars
59
files for final shaping
■ We will be using Vortex Blue Files for the final shaping and smoothing of the canal. Sizes .30/.04 through .50/04 available.
60
how to use vortex blue files
■ 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
what to do after each active file
irrigate
62
serial step back
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

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