Endodontic Restorative Interface

Question 1

Give some reasons as to why a root treated tooth might give symptoms:

Answer 1

• PDL
• Bone
• Microorganisms
• Tooth not sterile
• Lateral / accessory canals

Question 2

What is involved in the clinical assessment of a root treated tooth?

Answer 2

• check integrity of coronal seal
• check ferrule
• assess restorability of tooth
• look for swelling/sinus/TTP/mobility
• look for pocketing

Question 3

What is involved in the radiographic assessment of a previously root treated tooth?

Answer 3

Assess:
- Root filling = length, quality of obturation [any voids]
- Unfilled/missed root canals
- Shape of canal
- Patency [fractured instruments, posts, sclerosis]
- Bone support
- Crown to root ratio [should be 1:1.5]
- Pathology

Question 4

What problems are associated with re-RCT of a tooth?

Answer 4

• amount of remaining tooth structure
• restoration type
• lack or no ferrule
• wide post holes
• endo complications eg fractured instruments, perforations, short/long root filling

Question 5

What is a core build-up?

Answer 5

Internal part of tooth is built-up with restorative material to replace the lost tooth tissue
- provides retention & resistance for definitive restorations

Question 6

What questions might you ask the patient at endodontic retreatment stage?

Answer 6

• when was initial RCT done?
• why was RCT required?
• did treatment improve symptoms?
• was dental dam used?
• was hypochlorite used?

Question 7

Why is AHplus difficult to remove?

Answer 7

Resin based material so it bonds to the tooth

Question 8

What is a tooth sleuth used for?

Answer 8

Helps to find fractured cusps
- isolate each cusp and place tooth sleuth on top
- get pt to bite down
- evaluate where pain is coming from

Question 9

State 5 ways that biofilms may be resistant to antimicrobials:

Answer 9

Antimicrobials may:
- fail to penetrate beyond surface layers of biofilm
- trapped and destroyed by enzymes
- not active against non-growing microorganisms

• expression of biofilm specific resistance fenes
• stress response to hostile environment conditions

Question 10

What is the purpose of an intra-canal medicament?

Answer 10

Placed inside root canal between treatment appts in an attempt to kill microorganisms and prevent re-infection
- reduce inflammation & exudate
- control of root resorption

Question 11

What is Odontopaste?

Answer 11

Paste containing corticosteroid and tetracycline
- aids in reduction of pulpal inflammation
- effective for 5-7 days

Question 12

What is the pH of non-setting CaOH? Why is this relevant?

Answer 12

12.5
- high pH contributes to antibacterial activity
- hydrolysis of lipopolysaccharide reducing its inflammatory potential

Question 13

What types of motion are involved in instrumentation of the canal system?

Answer 13

• filing
• reaming
• watch winding
• balanced force motion
• envelope of motion

Question 14

How can watch winding be described?

Answer 14

Back and forward oscillaion of 30-60 degrees
- light apical pressure
- effective with K files

Question 15

The shaping of the canal is complete, what is the follow up irrigation protocol?

Answer 15

• EDTA 17% for 1 minute
• Sodium Hypochlorite 3% for 10 mins

SLOW INJECTION DONT USE THUMB

Question 16

What is the function of a barbed broach file?

Answer 16

Used for extripating NOT shaping
- must not engage canal walls
- pulls the pulp out of canal

Question 17

Describe the process of canal shaping and cleansing (not obturation) using
ProTaper Universal instrumentation of root canals. Assume that straight
line access has been achieved and working length has been determined
with a size 10 stainless steel hand file. Your apical finishing size should be
0.25mm.

Answer 17

• ProTaper files used in either balanced force motion or in a reaming motion
• File S1 used to prepare coronal third of canal
• File S2 deepens shape to middle third of canal
• Finishing files used to prepare apical third of canal
  (these range from F1-F5)
• For an apical finishing size of 0.25mm an F2 file should be used

Question 18

List how you select the appropriate RECIPROC instrument to use:

Answer 18

• Size 30 hand file reaches WL = R50 used [large]
• Size 20 hand file reaches WL = R40 [medium]
• If Size 20 does not reach CWL PASSIVELY use R25

Question 19

Explain the procedural steps of canal shaping using the RECIPROC method:

Answer 19

• Length of canal is estimated with pre-op radiograph
• Stopped on RECIPROC instrument set to 2/3 of that length
• Use a 10/15 size K-file to CWL to ensure passive access
• the RECIPROC instrument is introduced to canal and pecking motion used 3x (3-4mm)
• Irrigation between each round of pecking motions and recapitulation with a 10 file
• RECIPROC used until reached 2/3 of canal and apex locator & radiograph taken
• RECIPROC used in same way until reaches CWL

Question 20

What rotary instrument can be used where there is a high risk of Cyclic Fatigue occuring?

Answer 20

RECIPROC blue

Question 21

Outline the steps of cold lateral compaction:

Answer 21

• Select master GP cone [will be same size as apical prep & should give sensation of tug back]
• Mix sealer [AHplus]
• Use a paper point to lightly coat canal walls with sealer
• Coat the master cone in sealer and insert slowly to CWL
• Use size A/B finger spreader in canal alongside master point & add accessory point if necessary
• Melt excess GP in pulp chamber with Super Endo Alpha and plug canal
• Seal with RMGIC

Question 22

How can removal of unsatisfactory GP filling be done at re-treatment stage?

Answer 22

• Access cavity as usual
• Remove pulp chamber contents with round burr
• Use Gates Glidden drills to remove majority
• Use K-files to remve apical portion