Access/ Instrumentation

Question 1

What is the MBD rule?

Answer 1

When the X-ray tube moves medially the buccal canal moves distal

Question 2

What should be included in clinical exam prior to tx?

Answer 2

Any caries/ suboptimal resotrations
Structural durability - cracks
Rotating/ tilting
Mobility
Periodontal pocket
TTP
Vitality

Question 3

What other rule can be used to determine canal position during x-ray?

Answer 3

SLOB

Same lingual, opposite buccal

Question 4

How does SLOB rule relate to endo?

Answer 4

Xray tube moves mesial so lingual (or palatal) canal moves in same direction (mesial) and buccal canal moves opposite (distal)

Question 5

Do furcal lesions change prognosis?

Answer 5

If large PA lesion between roots have guarded prognosis

Question 6

What preliminary tx should be provided?

Answer 6

Tooth adequately restored

Dismantle any coronal restorations

Question 7

What instrument should always be used to remove crown?

Answer 7

Flat plastic

Question 8

Where should bur lines be placed when removing crown?

Answer 8

Buccal
Then occlusal
Then palatal

Question 9

What features should aim for in access preparation?

Answer 9

No undercut
All orifices visible
Smooth axial wall
Straight line access for instrument

Question 10

When should curves of canals be straightened if possible?

Answer 10

Allow more accurate WL determination

Question 11

How many canals does lower incisor have?

Answer 11

2 canals

Question 12

What can mistakes in orientation or depth gauge result in?

Answer 12

Perforation including between furcation

Question 13

How avoid perforation at furcation?

Answer 13

Measure distance from occlusal aspect to furcation

Question 14

How many canals does upper premolar have?

Answer 14

2 canals

Second premolar may only have one

Question 15

What is a feature to be aware of with upper premolars

Answer 15

Have deep pulp chambers - can be half working length

Question 16

What is a risk of upper premolars?

Answer 16

Access cavity not deep enough to remove all root of chamber - instrument chamber > canals

Question 17

How many canals do lower premolars have?

Answer 17

Often 1

Question 18

What % of lower premolars have two canals?

Answer 18

30%

Question 19

Which canal is missed if a lower premolar has tow canals

Answer 19

Often lingual canal - often due to access

Ensure no dentine shelf

Question 20

How to test for additional lingual canal in lower premolar?

Answer 20

Drag file down lingual aspect of canal - may feel catch

Question 21

How many canals do upper molars have?

Answer 21

6s - 4 canals

7s - 3 canals

Question 22

What canals are present in upper moalrs

Answer 22

MB1 (MB2 poss)
DB
P

Question 23

What is shape of access for premolar?

Answer 23

Ovoid - centre of tooth w/ bucco-lingual expansion

Question 24

How access upper molar?

Answer 24

Access shifted mesial - distorted triangle

Question 25

What canal is largest in upper molar?

Answer 25

Palatal canal

Question 26

How to find MB2 if have palatal and MB1?

Answer 26

Draw line MB1 to palatal - MB2 usually 1-2mm mesial and 2-3mm palatal from MB1

Question 27

What differs to access in upper second molar compared first?

Answer 27

MB2 less common | Canal entrance may be closer together

Question 28

How many canals does lower first molar have?

Answer 28

3 | 2 mesial: ML, MB and one big distal

Question 29

What are basic equipment needed to help with visualisation and access?

Answer 29

DG16 probe Long-shanked burs Goose neck bur

Question 30

Why are goose neck bur helpful but what is the disadvantage of this?

Answer 30

Thin shank helps with visualisation | Prone to breakage

Question 31

What are basic steps of access?

Answer 31

Access with appropriate bur - use LN to improve visibility De-roof pulp chamber - endo-Z Smooth sides access w/ endo-z Prepare coronal canal prep

Question 32

What should multi-rooted tooth have?

Answer 32

Own reference point on occlusal surface and WL

Question 33

How to reduce chance of strip perforation?

Answer 33

Preferential filing away from high risk area

Question 34

What is a strip perforation?

Answer 34

Long/narrow perforation down the canal - hard to repair

Question 35

What is a Hedstrom file?

Answer 35

Flute shaped file

Question 36

When is a Hedstrom file advantageous?

Answer 36

When have sclerosed canal

Question 37

What to bear in mind with curved canals?

Answer 37

As become straighter working length shortens