Past paper questions

Question 1

What is the Herbert Schilders endo principles?

Answer 1

• Continuously tapering funnel shape
• Maintain apical foramen in original position and as small as poss
• Use correct irrigant and antimicrobial disinfectant to remove debris

Question 2

Why is irrigant useful?

Answer 2

• Disinfect root canal
• Dissolution of inorganic and organic pulpal material
• Lubricate root canal instruments
• Remove endodontic smear layer
• Flush out debris

Question 3

What is the best irrigant it’s ideal strength?

Answer 3

• Sodium hypochlorite 3%

Question 4

Caution to take into account when using irrigant?

Answer 4

• Ensure extreme care to prevent sodium hypochlorite from touching soft tissues
• Allergic reactions
• Discolouration of fabric
• Opthalmic injuries due to eye contact
• Apical extrusion leading to soft tissue necrosis

Question 5

What is working length?

Answer 5

• CWL measured from fixed reference point which will remain unchanged throughout treatment within clinicians view to the apical foramen
• Ideally measured from tip of cusps
• Can be done by radiographs/electric pulp locator/paper point length

Question 6

What radiographs used for endo?

Answer 6

• PA green

Question 7

During instrumentation of canal where is considered the ideal end point of shaping/obturation?

Answer 7

• Correct working length
• Should be 1mmfrom radiographic apex
• Check for tug back from apical constriction

Question 8

What is the term for maintaining communication between pulpal space and peri-radicular tissues?

Answer 8

• Patency

Question 9

Potential causes of corrected working length changing during course of endodontic shaping?

Answer 9

• Debris accumulation in apical region of canal
• Ledge formation
• Perforation

Question 10

What are some common intra-operative radiographs can be utilised during endodontic treatment to aid working length determination?

Answer 10

• Master cone radiograph
• Corrected working length radiograph

Question 11

Why is non setting calcium hydroxide an ideal inter appointment medicament?

Answer 11

• Antimicrobial properties
• Anti endotoxin properties
• Promotes tooth remineralisation

Question 12

Reason for obturating

Answer 12

• Promote haematic healing of periapical tissue
• Seal canals laterally and apically to prevent ingress of microorganisms and fluids into canal system
• Prevent bacteria from entering canal and periapical tissue and to prevent perio-endodontic lesions from occurring

Question 13

Components of GP

Answer 13

• 20% Gutta Percha
• 66% Zinc oxide
• 10-15% radiopacifier
• 5% plasticizer

Question 14

Why use sealer during cold lateral compaction?

Answer 14

• Promotes haematic seal as has antimicrobial properties
• Fills voids and irregularities between GP cone tips and walls
• Seals space between walls and cone to create homogenous seal
• lubricate during obturation

Question 15

What is Patency?

Answer 15

• Ability of file or instrument to pass through full length of root canal system without encountering any obstructions of blockages
• Important to allow release of PA pressure and maintain cleanliness of canal system
• Achieved by regularly irrigating and using small flexible files with 3 pick motion