Disease; Working Length; Canal Preparation

Question 1

2 branches of endo disease

Answer 1

1. of the pulp 2. of the periapical tissues

Question 2

example of periapical disease and classification types

Answer 2

Apical Periodontitis. translucent area on x-ray. acute/chronic/abscess etc.

Question 3

abscess vs granuloma

Answer 3

abscess: presence of puss
granuloma: chronic inflammation of tissue

Question 4

two types of pulpal disease

Answer 4

reversible + irreversible pulpitis

Question 5

overall cause of pulpitis

Answer 5

bacteria (fungi may cause APICAL periodontitis)

Question 6

effect of trauma to pulp i.e. drilling partly through it in A STERILE ENVIRONMENT

Answer 6

will not cause pulpitis; bacteria needs be present; thus need for IPC & complete caries removal in endo

Question 7

“itis” =

Answer 7

“inflammation of”

Question 8

“ectomy” =

Answer 8

“removal”

Question 9

what is common to both pulpal and periapical disease

Answer 9

the aetiological factors (irreversible pulpitis –> necrosis –> apical periodontitis)

Question 10

3 categories of aetiological factors for endodontic disease

Answer 10

Microbial
Chemical (can only irritate pulp in absence of bacteria)
Mechanical (can only irritate pulp in absence of bacteria)

Question 11

x2 microbial factors

Answer 11

caries.

leakage around restorations.

Question 12

x2 chemical factors

Answer 12

dental materials - irritants (composite resins are cytotoxic; eugenol may kill a pulp, but it’s only chemical capable of this).
bleaching - (Hydrogen Peroxide = irritant)
*microbial biofilm also required for these to cause irreversible pulpitis)

Question 13

x3 mechanical factors

Answer 13

operative dentistry.
dentine exposure.
trauma.
*microbial biofilm also required for these to cause irreversible pulpitis

Question 14

the presiding aetiologic factor for irrevers pulpitis

Answer 14

microbial infection

Question 15

3 categories of endodontic procedures & one thing to note.

Answer 15

Vital Pulp treatment.
Non-surgical endodontics.
Surgical endodontics.
*sometimes more than one may be required

Question 16

meaning of Vital Pulp Treatment

Answer 16

pulp capping

Question 17

another term for pulp capping

Answer 17

Pulpotomy

Question 18

meaning of Non-surgical endodontics

Answer 18

root canal treatment/retreatment

Question 19

types of Surgical endodontics

Answer 19

Apicectomy (root end surgical removal & substitution w a biocompatible material).
Hemisection (removal of one un-treatable root in a multirooted tooth)

Question 20

Non-surgical Root Canal Treatment - Pulpectomy

Answer 20

removal of the pulp. aka “first stage RCT”

Question 21

indications for pulpECTOMY

Answer 21

irreversible pulpitis OR

pulp necrosis.

Question 22

pulpECTOMY scenarios

Answer 22

• deep decay
• deep restoration (shallow doesn’t count)
• cracked tooth
• constant pain
• swelling
• Apical periodontitis may be present.

Question 23

6 stages of RCT

Answer 23

1. Assessment, restorABILITY and Tx plan
2. Access
3. Chemo-mechanical prep
4. Obturation
5. Restoration
6. Follow up

Question 24

q’s to ask in 1. Assessment

Answer 24

tooth saveable? pt’s desire to keep or extract? enough structure remaining?

Question 25

working length

Answer 25

Distance (mm) between a coronal reference point (incisal edge OR cusp) and point at which canal prep and obturation should terminate.
*

Question 26

working length consideration

Answer 26

multi-rooted tooth: multiple working lengths

Question 27

if working length shorter than reality

Answer 27

canal not cleaned sufficiently. –> bacteria left behind –> higher chance of failure

Question 28

if working length longer than reality

Answer 28

tooth anatomy gets destroyed = hard to clean and obturate –> higher chance of failure

Question 29

working length apical end point

Answer 29

close as possible to Apical Constriction

Question 30

location of apical constriction

Answer 30

0.5mm - 2mm from the radiographic apex

Question 31

Apical Constriction?

Answer 31

narrowest portion of the canal

Question 32

apical constriction variables

Answer 32

Anatomical variation.
Age - increased cemental deposition.
Inflammation - Apical periodontitis: apical infection resorbs root = no apical constriction at all eventually

Question 33

Dummer et al 1984

Answer 33

Apical constriction varies in ALL people

Question 34

working length determination (x5)

Answer 34

1.tactile feel
2.bleeding point method
3.pt response
4.radiographs
5.electronic apex locators
RECOMMENDED by ESE: radiog & electr apex locators COMBINED

Question 35

electronic apex locators: indications

Answer 35

v. accurate
pulp chamber must be dry (canals not critical)
initial learning curve, but v useful later

Question 36

electronic apex locators: contra-indications

Answer 36

1. meaningless if canal is blocked

Question 37

electronic apex locators: principle

Answer 37

principle of electrical resistance. constant reading between LIP and PDL.
the circuit is complete when file touches PDL

Question 38

electronic apex locators: clinical procedure

Answer 38

a. preop periapical
b. measure file against radiogr. “estimated working length”
c. access tooth
d. shape coronal portion of canal
e. use apex locator to obtain length & introduce files
f. confirm by another periapical*
* if file on radiograph is >3mm away from radiographic apex, another radiograph must be taken

Question 39

minimum file size & reason

Answer 39

size 20, smaller not clearly visible on radiograph

Question 40

approx. no of x-rays needed for a non-surgical endo tx

Answer 40

4-5 radiographs

Question 41

what to do w working lengths and reference points BEFORE exposing radiograph AND after processing?

Answer 41

record them accurately