Morphology / Tooth Structure

Question 1

Why does the pulp chamber decrease in size with age

Answer 1

Secondary (path/physiological) or
Tertiary (reparative) dentine

Question 2

Greatest diameter of the root canal is located

Answer 2

At the orifice , it is broadest buccal - lingual /palatal

Question 3

Where is the apical constriction

Answer 3

0.5-1mm from the anatomical apex (secondary cementum may place the foremen up to 2mm away)

Question 4

Difference between lateral and accessory canals

Answer 4

L- communication between canal and pdl space at right angle to main canal
A - apical few mm forming an apical delta

Question 5

How many canals do upper incisors have

Answer 5

1

Question 6

How many canals for a canine
Does it appear shorter or longer on Rads

Answer 6

1 curving labially to appear shorter , sudden narrow often leads to over instrumentation

Question 7

Morphology of upper and lower 4s

Answer 7

U: 1-3 roots normally 2 curve sharply apical 1/3
L: 25% have 2 cabals and 2 foremen (hard due to ADelta)

Question 8

5s canal %

Answer 8

Uppers
1 root 1 canal 40%
2 canals 58%

Lowers 12% 2nd canal

Question 9

Upper 6s in mm
Lowers 6s -4 canals

Answer 9

Palatal 22 - curves buccal appears shorter on red
Mb/md 21
MB2 is common

Lowers 1/3 have 4 canals

Question 10

7s number of canals

Answer 10

3

Question 11

In molars how far can the apical construction move (distal) from the radiograph apex

Answer 11

Lower molars 0.1-3
Upper molars 0.1 - 3.7

Question 12

How can you increase the accuracy of an apex locator

Answer 12

Dry canal and chamber
No metal
No leaking restoration
No pulp
Bigger files / glyde

Question 13

What is the name of grey causing bacteria

Answer 13

Prevotellamelaninogenica

Question 14

What is created with a super loose size 10 file

Answer 14

Glide path

Question 15

How many lower incisors have 2 canals

Answer 15

40-50%

Question 16

Where is the end point for root canal

Answer 16

Apical constriction

Question 17

What do apex locators measure

Answer 17

Vertical dimension
Pdl- 0 reading
(Measures impedance)

Use with radiograph tactile sensation and knowledge paper points

Question 18

Average wl of upper 6

Answer 18

22.3

Or

(22 palatal , 21 mb/d)

If mb2 sep normally 3-4 mm shorter than mb1

Question 19

Number of canals upper 6

Answer 19

3 canals 38%
4 canals 62% (approx 37% have 3 foremen)

Likely to have 2 MB canals (50% ) and 30% join - don’t over prep
Hard to see due to dentinal shelf

Question 20

How to find mb2

Answer 20

Mb - P fusion line , 1/3 along
The closer to mb1 the more likely to merge
Perpendicular to md