Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Yr 3 Restorative - Endodontics > Modified Step Back technique (canal filing) > Flashcards

Modified Step Back technique (canal filing) Flashcards

1
Q

What is the stepback technique?

A

Instrumentation of the canal commences at the terminus and works backwards towards the coronal aspect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the modified stepback (or double flare) tecnique?

A

The coronal aspect is operned up first before creating a terminal stop and flaring backwards to the origional flare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the crown down technique?

A

the canal is instrumented from the coronal apect towards the terminus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What si the main use of the modified step back technique?

A
  1. Large canals
  2. Most often = anterior teeth (maxillary incisor and canines & both upper and lower premolars -> single rooted)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why do we file canals?

A

To shape the canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the ideal shape for a prepared canal?

A

= ideal configuration to receive the root filling material

  • narrowest part apically
  • widest part coronally
  • gradual outward flare
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What type of instrument is this?

A

Headstrom file

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are headstrom files made?

A

Machined from a round tapered blank by cutting a spiral groove into the shank = sharp cutting blade = aggressive cutting action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an alternative instrument for opening canal orifices?

A

Gates glidden burs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the properties of a gates glidden bur that make it good for opening canal orifices?

A
  • Long shank
  • Blunt tip (only cuts on withdrawal)
  • Thinner part near handpiece end of shank = snaps here if jammed
  • Aggressive (readily perforates side of tooth)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do you calculate the diameter of a gates glidden bur?

A

20 (GG+1) + 10

(e.g. Size 3 = 20(3+1) + 10 = 90)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the name of this instrument?

A

K file

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How are K files made?

A

Start as a tapered square = twisted out by machines at a 90 degree angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the tips of modern files (k and headstrom) like?

A

They’ve been blunted by removing the cutting surface at the leading edge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the benefit of having blunted tips?

A

Prevets the file gouging into dentne of canal wall so that it will follow along the path of the canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is ISO?

A

International standards apploed to endodontic files

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the ISO standardized sizing relate to?

A

The diameter 1mm from tip of instrument (colour coded handles)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do the ISO standards cover?

A

Sizing, length of working part of instrument and taper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the standardized taper?

A

2% taper (therefore each 1mm is 2% wider than the last)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 3 lengths of files?

A

21 mm (short canals, further back in the mouht)

25 mm (standard)

31 mm (i.e. maxillary canine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is file size measured in?

A

1/100ths of a mm (the diameter 1mm from the tip)

e.g. Size 25 is 0.25 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 3 stages if the modified stepback technique?

A
  • Orifice enlargement (first flare)
  • Apical stop
  • Stepback (second flare)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does orifice enlargement achieve?

A
  • Removes heavily infected material
  • Improves access to apical third of canal
  • Improves irrigateion
  • Reduces effective curvature

n.b. we only do this for the straight bit of the canal (or half of the length)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do we have to avoid the creation of in orifice enlargement?

A

Avoid creation of a fin (so use the files from 9 o clock to 3 o clock if curved canal - if straight canal use files all the way around)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do we use the file to enlarge the orifice?

A

Push it towards the side of the canal we want to file = curves the file

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How do we create an apical stop?

A

= use successively larger instruments (must use in particular manner to avoid blockage and damage to root

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which two filing techniques do we use to produce and apical stop?

A
  • Balanced force
  • Anticurvature filing
28
Q

How many instrument changes are required to produce an apical stop?

A

9

29
Q

Which damage can we cause to the rooth while creating an apical stop?

A
  • Apical zip
  • Hour glass shape
  • Elbow
30
Q

What technique do we use for the more flexible 10 and 15 k files?

A

Watch winding (minimal movement = no more than 1/4 turn)

31
Q

What is the balanced force-power phase?

A
  1. Place file until it binds
  2. POWER = Advance file clockwise by 60 degrees (engagement)
  3. CONTROL = Apply apical pressire and rotate the file 120 degrees in anticlockwise direction (cutting)
32
Q

What are the advantages of the balance force technique?

A
  • Superior shaping
  • File remains central within the canal
  • Less debris push apically
33
Q

Which cautions are there when using the modified stepback technique?

A
  • Flute cleaning
  • Copious irrigation
  • Discard damaged isntruments
34
Q

After using a size 15 file what should you do?

A

Recapitulate using a size 10 file to maintain patency

35
Q

After any file size changes in the balance force technique what should be done?

A

Recapitualte with the size belows file to maintain patency

36
Q

Which size file do you go up to when creating an apical stop?

A
  • Work up 2 sizes above the first file that binds the canal
37
Q

What is the stepback procedure?

A

Stepback at 1mm intervals with each successive larger file and recapitulate with MAF (the last one you made the apical stop with)

38
Q

Which errors are related to canal preparation?

A
  • Incomplete debridement
  • Lateral perforations (including stripping of furcal walls)
  • Apical perforations
  • Blockage of canals
  • Ledging
  • Apical zipping (inappropriate rotation of instruments)
  • Elbow formation (hour glass shape) = inappropriate pre-curving of instruments
39
Q

What is the technique of filing we use with the headstrom files?

A

Longitudinal circumfrential filing = push and pull in and out of the canal

40
Q

When is longitudinal circumfrential filing used for step back?

A
  • large irregular shaped canals at the step back stage (balanced force is inappropriate as files would be loose in canal
41
Q

Why is longitudinal circumfrential filing in a curved canal dangerous?

A

Risk of perforation because one side will be closer to the furcal area than the other wall = risk of strip perfortion

42
Q

What are the benefits of using rubber dam?

A
  • Protection of airway
  • Protection of tissues
  • Increases operating efficiency (fingers dont get wet by saliva)
  • Prevents contamination of canal system
43
Q

Why do we irrigate the root canals?

A

” what is removed from the root canals is more important than what is placed in them

44
Q

What are the ideal properties of an irrigant?

A
  • Non irritant
  • Bactericidal
  • Dissolve organic material (pulp tissue)
  • Remove inorganic material (calcified debris)
  • Non staining to dentine
  • Lubrication of instruments
45
Q

What are root canals like?

A

Thin and grooves along the canal (not straight and round = bacteria and pulpal tissue in them

46
Q

Which irrigants are used in root canal therapy?

A
  • Sterile saline (not bacteriacidal or dissolve organic material)
  • Local anaesthetic solution
  • Sodium hypochlorite (low concentration only = non-irritant)
  • Chlorohexidine (low concentration = non irritant but ownt dissolve organic material)
47
Q

Which irrigant is the best?

A

Soidium hypochlorite (Miltons) 1% solution

NaOCl

48
Q

What are the properties of sodium hypochlorite?

A

0.5%-5% solution

  • Antibacterial
  • Dissolves organic debris
  • Non-irritant to vital tissues (at low concentrations BUT CARE NEEDED)
49
Q

How much irrigation should be used and when?

A

Copious amounts THROUGHOUT instrumentation

= between every instrument use

= must take great care not to spill bleach

50
Q

What are the two types of irrigating needles?

A

Side delivery or End delivery

(both are blunted but mustnt let it bind to sides when irrigating otherwise it will force its way out of the apical foramen)

51
Q

Whats the benefit of side delivery irrigation needles?

A

Avoids the danger of solution extrusion (forcing the irritnt through the apex of the tooth)

52
Q

What do chelating agents do?

A

Chelates calcium ions = softens dentine

= breaks down inorhsnic debris & lubricant (REMOVES THE SMEAR LAYER)

e.g. Ethylene Diamine Tetra Acetic Acid (EDTA) 15-17%

53
Q

What is Ethylene Diamine Tetra Acetic Acid (EDTA)?

A

A chelating agent (conponent of lubricant pastes)

54
Q

What is an alternative chelating agent to EDTA?

A

Citric acid solution (applied at the end of the procedure)

55
Q

Name some lubricating pastes?

A

E.g. Canal +, Fileze, Glyde

56
Q

Why do we use lubricating pastes for filing?

A

It greatly improves the lubrication and efficiency of filing

57
Q

What are the components of Lubricating pastes?

A
  • 15% EDTA
  • 10% Urea peroxide
  • Water soluble base
58
Q

What action does urea peroxide have?

A

It reacts with sodium hypochlorite - Nitrogen, oxygen and hydrigen bubbles produced - helps kill off root canal bacteria (assists with canal cleansing even in those parts of the canal system not instrumented)

59
Q

How do we apply lubricating pastes to the canal?

A

We run the file through the material to coat it before instrumentation

60
Q

In which formulation can chlorhexidine be used as a lubricant?

A

as “hibiscrub” formulation

61
Q

What makes chlorhexidine makes it a potentially good canal mediciment?

A
  • Low toxicitity
  • Relitively broad spectrum of actvity
  • Substantivity (binds to tooth surface = prolongs the effect)

Remains a more popular material in periodontics

62
Q

What are the stages of shaping a root canal using the modified stepback technique?

A
  • Access
  • Estimate working length (radiograph/apex locator)
  • Check patency with #10 K file
  • Orifice enlargement (headstrom files)
  • Corrected working length radiograph
  • Create stop at corrected working length (K file 2 sizes above the first one to bind = MAF, watch wind with #10 & #15, balance force with #20 + = use irrigation and recapitulation)
  • Stepback (set each file 1mm less than previous, increasing diameter of file, recapitulate with MAF)
63
Q

After irrigating with sodium hypochlorite (and EDTA chelating gel) what needs to happen to the canal?

A

Must be thoroughly irrigated with sterile water or saline

64
Q

How do we dry the canal?

A
  1. First use an empty syringe to draw up an excess liquid in the cavity
  2. Use sterile paper points (in sterile blister packs and ISO sized), use until the last point used is dry on removal
65
Q

What do we put into the canal after drying?

A

A Gutta Percha point (transisomer of rubber = produced from the latex of tropical trees)

66
Q

How do we select a size for the Gutta Percher (GP) point?

A

Needs to be a snug fit and go to the full length of the canal that has been prepared

= SHOULD TAKE A RADIOGRAPH AFTER PLACEMENT TO CONFIRM THE CORRECT LENGTH AND QUALITY OF THE CANAL SHAPING

  • Initially we use the one that matches your master file to the apical stop (make sure mark a clear reference point)
  • Ideally should have snug fit with slight resistance to removal “tugback”

Yr 3 Restorative - Endodontics (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions