Shaping

Question 1

What are the design objectives?

Answer 1

1. Create continuously tapering canal
2. Maintain original position of apical foramen
3. Keep apical opening as small as possible

Question 2

What size file is IO colour white?

Answer 2

15, 45

Question 3

What size file is SIO colour yellow?

Answer 3

20, 50

Question 4

What size file is SIO colour red?

Answer 4

25, 55

Question 5

What size file is SIO colour blue?

Answer 5

30, 60

Question 6

What size file is SIO colour green?

Answer 6

35, 70

Question 7

What size file is SIO colour black?

Answer 7

40, 80

Question 8

What size file is SIO colour purple?

Answer 8

10

Question 9

What are the envelops of motions?

Answer 9

1. Filing
2. Reaming
3. Watch winding (small twists back and forth; good for passing through small canals)
4. Balanced forced motion (1/4 turn CW, 1/2 CCW)

Question 10

What are the reasons for early flaring of the coronal portion of a root canal?

Answer 10

1. Avoids hydrostatic pressure in canal
2. Early removal of heavily contaminated contents
3. Improved straight line access to apical 1/3

Question 11

How is the estimated working length determined?

Answer 11

Pre-op XR

Question 12

How is actual working length determined?

Answer 12

Peri-op XR

Apex locator

Question 13

What are the disadvantages with hand stainless steel preparation techniques?

Answer 13

• Mishaps (ledges, blockage, foramen zipping)
• Debris extrusion
• Time consuming
• Less predictable shapes in curved canals with inexperience

Question 14

What are the advantages of Nickel titanium files over SS?

Answer 14

• Superelasticity; less mishaps
• Increased cutting efficiency
• Safer
• More user firendly

Question 15

What is the sequence of shaping? (following access prep)

Answer 15

1. CORONAL NEGOTIATION (coronal 2/3)
   - ISO 10/ 15 file (watch winding) working up to size 20 with sodium hypochlorite irrigation in between
   - -> Working up to size 20 creates glide path
2. CORONAL FLARING (coronal 2/3)
   - Flared with SS hand files or NiTi hand (S1) or rotary files or Gates-Glidden drills
   - -> Copious irrigation with sodium hypochlorite and frequent recapitulation with 10 or 15 file (prevents blockage)
3. APICAL NEGOTIATION (apical 1/3)
   - Negotiation up to ISO size 20 to develop glide path along entire length of canal
4. AWL DETERMINATION
   - XR with file (size 15) with coronal silicone stop
   - Electronic Apex Locator
5. APICAL PREPARATION (apical 1/3)
   - Preparation to 1mm short of AWL and apical width; determined by passively inserting ISO file to AWL to gauge apex (generally apical prep at least size 20)
   - SS HAND FILES = creation of apical enlargement in ‘modified double-flare technique’
   - NiTi HAND OR ROTARY = Finishing files to do this (F files; finish on corresponding colour of apex gauging ISO file)
   - -> Copious irrigation with sodium hypochlorite and frequent recapitulation in between filing
6. SMEAR LAYER REMOVAL
   - Once shaping complete, final irrigation with EDTA –> dried –> NaOCl

Question 16

If carrying out a multi-visit RCT, what material should be used?

Answer 16

Inter-visit medicament = nsCaOH, iodine-containing pastes