Root canal anatomy

Question 1

Radiographic Hints of “Abnormal”

Answer 1

Things not normal size
Things not centered
Things that abruptly change
Things that look “off ”

Question 2

Weine Classification

Answer 2

I - 1 canal
II - 2 canals that become one at apex
III 2 canals that remain separate
IV - 1 canal that splits in the apical third

Question 3

Maxillary Anterior general anatomy considerations

Answer 3

Central incisor … broad M - D pulp horns
Lateral incisor … apical D curvature
Canine … canal broader in B - L dimension … apical F, B curvature
Lingual shelf

Question 4

Max 1st premolar canal stats

Answer 4

1 canal ………………………………..9%
2 canals (2/3 stay separate)…85%
3 canals ………………………………6%

Question 5

Max 2nd Premolar canal Stats

Answer 5

1 canal……………………………….48%
2 canals (1/2 stay separate)….51%
3 canals……………………………….1%

Question 6

Max 1st Molar MF root stats

Answer 6

1 Canal ...20%
2 Canals....77%
     Weine type II =>40%
    Weine type III => 60%
3 Canals....3%

Question 7

Max 2nd Molar MF root stats

Answer 7

1 Canal….63%

2 Canals …..37%

Question 8

Avg distance between MB1 and MB2 orifices

Answer 8

1.8mm

Question 9

Maxillary Molar DB canal generalities

Answer 9

Straightest canal

most conical

Question 10

Max Molar P canal generalities

Answer 10

Wider in M-D dimension
Often curves to B in apical third
Obturation may appear short
prone to perforation/ledging from large instruments

Question 11

Man Ant incisor canal stats

Answer 11

1 Canal ….57%
2 Canals ….43%

1 Foramen …99%

Question 12

Man Canine Canal Stats

Answer 12

2 Canals …22%

Question 13

Man Ant generalities

Answer 13

Broader B - L than M - D
Lingual shelf
Canine may have 2 roots
Incisors … ideal access through incisal edge

Question 14

Man 1st Premolar Canal Stats

Answer 14

1 Canal ….75%
2 Canals….24%
3 Canals…1%

Question 15

Man 2nd Premolar Canal Stats

Answer 15

1 Canal 97%

2 Canals 3%

Question 16

Man 1st Molar Canal Stats

Answer 16

2 Canals…7%
3 Canals….64%
4 Canals…29%

Question 17

Man 2nd Molar Canal Stats

Answer 17

2 canals…4%
3 Canals 81%
4 Canals 11%
C shaped 3%

Question 18

Man 1st Molar M root

Answer 18

93% have 2 canals
60% stay separate
40% join

Question 19

Man 1st Molar D root

Answer 19

29% have 2 Canals
40% stay separate
60% Join

Question 20

Middle Mesial in Man 1st Molar

Answer 20

2-13% but may be closer to 50%

usually join MF or ML (90%)

Question 21

C shaped canal

Answer 21

–Difficult to debride
	–Difficult to obturate
	–Radiographic hints:
		- Conical roots
		- Indistinct features

Question 22

Furcation, Lateral, & Accessory Canals

Answer 22

Breaks in root sheath
Can occur anywhere
Usually in apical third
Contact with pulp and PDL

Question 23

Accessory Canals

Answer 23

Incidence: 10 - 47 %
Debridement
Obturation
Surgical removal

Question 24

Furcation Canals

Answer 24

Incidence: 8 - 76 %
Patency
Isolated Furcal Defects
Necrotic Pulp
Medicaments
Ca(OH)2

Question 25

Anatomic Laws

Answer 25

``` Centricity Concentricity CEJ Symmetry Color Change Orifice Location ```

Question 26

Law of Centricity

Answer 26

Pulp chamber in center of tooth at level of CEJ

Question 27

Law of Concentricity

Answer 27

Chamber walls are concentric to external surface

Question 28

Law of CEJ

Answer 28

landmark for pulp chamber location (97% of time)

Question 29

Law of symmetry

Answer 29

Orifices are equidistant and perpendicular from MD line

Question 30

Law of Color Change

Answer 30

Pulpal floor is darker than walls

Question 31

Law of Orifice Location

Answer 31

at junction of floor and walls

Question 32

Lateral Canals

Answer 32

``` Incidence: 10 - 76 % Suspect with lateral lesion More in posterior teeth Seldom a factor for success Debridement and obturation Ultrasonics Calcium hydroxide Softened gutta-percha Sealer ```

Question 33

Root Concavities

Answer 33

``` DANGER ZONE Mesial root Man 1st molar Max premolars, especially on the mesial Max 1st molars, MB root Instrumentation moves canal towards the danger zone Watch for 2 PDL’s ```

Question 34

% of canals with curvature

Answer 34

97%

Question 35

Secondary canal curvature incidence

Answer 35

30%

Question 36

Concresence

Answer 36

union of two or more teeth via fusion of the cementum; most commonly see in max permanent molars

Question 37

Fusion

Answer 37

Union of 2 tooth germs during development

Question 38

Dens invaginatus

Answer 38

4 types .25-10% incidence most common in max laterals

Question 39

Dens Evaginatus

Answer 39

2.2% prevalence 84% of times occurs in Man premolars Asian Female

Question 40

Taurodontism

Answer 40

Increased pulp chamber size w/ or w/o pulp stones | shortened roots often with curvatures