BDS2 Endodontics

Question 1

Provide a brief sequence of endodontic disease.

Answer 1

Bacteria invades the enamel of the tooth surface which then spreads into dentinal caries which allows the bacteria to leak into the pulpal chamber causing inflammatory changes in the pulp.
If the caries are removed at the early stages, this inflammation can be reversed
If it not removed, then the inflammatory process cannot be reversed and necrosis of the pulp tissue occurs.
These inflammatory changes then occur all down the root canal and we see destruction of PDL and loss of bone.

Question 2

What is the purpose of obturation?

Answer 2

Filling of the root canal space to prevent ingress of bacteria and persistent bacteria

Question 3

What fibres are stimulated by an Electric Pulp Test (EPT)?

Answer 3

Alpha fibres

Question 4

What fibres are affected if the patient complains of a sharp pain?

Answer 4

Alpha fibres

Question 5

What fibres are affected if the patient complains of a dull/aching pain?

Answer 5

C fibres

Question 6

What can a grey discoloured tooth indicate?

Answer 6

Blood breakdown products within the tooth

Question 7

What can a pink discoloured tooth indicate?

Answer 7

Resorptive process that is occurring within the tooth

Question 8

What is the purpose of cavity liners?
Name 3 examples

Answer 8

Thermal protection of the pulp and to prevent bacteria from entering
Examples
-Calcium hydroxide - dycal
-Resin modified glass ionomers (RMGI)- vitrebond
-Zinc oxide eugenol (ZOE)

Question 9

What is the effect of calcium hydroxide?

Answer 9

Bacteriocidal
High pH- stimulated fibroblasts (reparative dentine formation)
Stimulated recalficiation of demineralised dentine
Neutralises low pH from acidic restorative materials

Question 10

What are the options for treating pulp damage?

Answer 10

Indirect pulp cap
Direct pulp cap
Partial pulpal removal- pulpotomy
Full pulpal removal- pulpectomy (progress to RCT)

Question 11

What is tertiary dentine?

Answer 11

Formed in reaction to external stimuli (e.g. bacterial toxins, trauma, attrition)
It is deposited in proximity to the site of injury
Can be sub-categorised as reactionary dentine and reparative dentine

Question 12

What is reactionary dentine?

Answer 12

Formed when the insult to the odontoblast is not severe and the odontoblastic layer survives

Question 13

What is reparative dentine?

Answer 13

Formed when the insult is more severe with excessive damage to the odontoblastic layer
Pulpal stem cells are recruited and differentiate into odontoblast-like cells
Dentinal tubules are usually not present or continuous with those from secondary or reactionary dentine

Question 14

What are the signs and symptoms of extrusion of sodium hypochlorite through the root apex?

Answer 14

Intense pain and marked swelling of the area, with bleeding into the root canal from periradicular tissues

Question 15

How can extrusion of sodium hypochlorite through the root apex occur?
Why?

Answer 15

High pressure injection during irrigation
Injecting the irrigation too deep in the canal
Locking the syringe in the canal
Acute inflammatory reaction-which can be oedematous and/or haemorrhagic- leads to significant tissue necrosis

Question 16

What is your immediate action if the sodium hypochlorite has perforated through the root apex?

Answer 16

Local anaesthesia for pain relief
Canals irrigated with saline
Reassure patient
Dress tooth with non-setting calcium hydroxide

Question 17

How can you prevent sodium hypochlorite from perforating through the apex of a tooth?

Answer 17

Careful pre-operative radiograph assessment- ensure no open apices
Provide bib and eyewear
Rubber dam
Use chlorhexidine to test rubber dam seal
Ensure all syringes are labelled correctly
Do not wedge needle in canal
Stopped on the needle 2mm before working length
Fill syringe less- easier to handle

Question 18

What 3 criteria must have been fulfilled before you obturate a tooth?

Answer 18

Asymptomatic
Canal must be dried
Full chemomechanical disinfection carried out

Question 19

What is the function of a sealer in obturation?

Answer 19

To fill the space between the GP and the root canal wall & provide a tight seal

Question 20

How do you assess obturation on a radiograph?

Answer 20

Correct length
Well compacted
All canals filled
No GP in the pulp chamber

Question 21

What are the 3 Herbst-Schiller principles of endodontics?

Answer 21

Continuously tapering funnel shape
Keep apical constriction as small as possible
Maintain apical foramen position

Question 22

Give 4 reasons for irrigation during endodontic treatment.

Answer 22

Chemomechanical disinfection
Removes smear layer
Organic and inorganic content is dissolved
Flushes out debris
Lubrication- reduces friction between instrument and dentine

Question 23

What is ledermix?

Answer 23

Medicament that can be placed in canals or the pulp chamber
Antibiotic and anti-inflammatory properties

Question 24

What are the clinical objectives of endodontic therapy?

Answer 24

Removing canal contents
Eliminating infection

Question 25

What is the purpose of mechanical preparation?

Answer 25

Creates space to allow irrigating solution and medicaments to more effectively eliminate micro-organisms from the root canal

Question 26

What are the stages in mechanical preparation?

Answer 26

Preparation of tooth
Access cavity preparation
Creating straight line access
Initial negotiation
Coronal flaring
Working length determination
Apical preparation

Question 27

Why is sodium hypochlorite a good irrigant?

Answer 27

Potent antimicrobial activity
Dissolves pulp remnants and collagen
Dissolves necrotic and vital tissue
Helps disrupt smear layer by acting on organic component

Question 28

Name 6 ideal properties of an irrigant.

Answer 28

Low cost
Reduction of friction
Non-Toxic
Non-Allergic
Killing of biofilm microbes
Dissolution of organic and inorganic matter
Does not react with other dental materials