NiTi

Question 1

Features of traditional file?

Answer 1

Stainless steel
Standard shape (ISO)
Set taper 2%

Question 2

What is taper?

Answer 2

Diameter of instrument increases from fit to handle

Question 3

What does set taper 2% mean?

Answer 3

Each mm from tip increase 0.02mm

Question 4

Smallest and largest K file?

Answer 4

Small = 06
Large = 140

Question 5

How long is traditional file?

Answer 5

16mm

Question 6

3 main types of file?

Answer 6

K file
Flexible K file
Hedstrom file

Question 7

What is K file?

Answer 7

Created twisting wire produce cutting flute

Square or triangle in cross section

Question 8

What is flexible K file?

Answer 8

Similar K file but flexible

Can be made NiTi or SS

Question 9

What is Hedstrome file?

Answer 9

Grinding of tapered blank

Round in cross section

Question 10

Issue Hedstrom file?

Answer 10

Agressive

Not fine apical prep/narrow canal

Question 11

What are techniques to use hand files?

Answer 11

Watch winding
Balanced force
Circumferential filing

Question 12

What is watch winding?

Answer 12

30 degree watch wind each way following by pulling

Question 13

What is balanced force?

Answer 13

60 degree clockwise and 120 degree anticlockwise

Question 14

Disadv traditional files?

Answer 14

Narrow canal shapes - poor irrigation
Inflexible in larger size 
Prone fracture 
Can create ledge 
Push debris into canal
Takes more time

Question 15

What is NiTI?

Answer 15

Super elastic metal alloy - flexibility and shape memory

Question 16

How are NiTi designed to be used?

Answer 16

W/ continuous motion

Question 17

Why NiTi more expensive?

Answer 17

Can’t be twisted to shape - have to be machined

Question 18

Why do NiTi remain centred in canal?

Answer 18

Have non-cutting tip

Question 19

What should NiTi not be used for?

Answer 19

Canal negotiation - only be used for enlargement

Question 20

Example NiTi system?

Answer 20

ProTaper

Question 21

How to use NiTi system?

Answer 21

Crown down technique
Hand files create glide path - ideally 20K file 2/3 WL
Shapers are used 2/3 WL
Establish WL
Establish glide path WL
Finishing files
Apical gauge determine final finishing

Question 22

What files are used in ProTaper

Answer 22

3 shapes - SX,S1,S2

3 finishers - F1,F2,F3

Question 23

Features ProTaper?

Answer 23

Triangular cross section
Active cutting blade
Blunt tip = remain centred

Question 24

Use of shaping vs finishing files?

Answer 24

Shaping - coronal and middle third

Finishing - apical third prep

Question 25

Adv NiTI?

Answer 25

``` Less canal transportation Flexible - good curved canal Less debris extrusion Faster technique Fewer files ```

Question 26

Disadv NiTI?

Answer 26

Torsional failure - unwinding | Flexural fatigue over-curved canal

Question 27

Tips for NiTI?

Answer 27

Always have glide path Use light force/pecking motion Don't engage tight canal Discard if sign of stress

Question 28

When are rotary files contraindicated?

Answer 28

``` Tight/ scelorised canal Curved canal S shaped canal Apical hook No glide path ```

Question 29

Safety feature of machine used w/ rotary file?

Answer 29

Torque - amount of resistance before machine cuts out