S2 - Root canal anatomy

Question 1

Mx central incisor (overall length, no. of canals)

Answer 1

23.6mm

1

Question 2

Dr Rodrigo’s strategy for mx central RCT

Answer 2

WL 0.5-1mm from patency length

very end filled with sealer

vertical condensation not lateral condensation

Question 3

Mx lateral incisor (overall L, canals, morphology and implication)

Answer 3

22.5mm

1 (3% have 2)

DP curvature (not straight root) -> must bend SS files* or may get ledge or perforation

*dont need to for NiTi

Question 4

Mx canine

Answer 4

26(can be longer)

1 canal

DP curvature

Question 5

Good tools for access cavity

Answer 5

burs: Endo-Z (best- to smooth walls and provide correct inclination), Tungsten carbide flat fissure bur, round burs

ultrasound tips: used to remove calcification in pulp floor and smooth walls, then use endo explorer to stab/find canals (DO NOT use burs in pulp floor)

*when ‘drop’ into pulp chamber felt, don’t keep drilling with burs, use Endo Z or other non-cutting tip bur and remove pulp roof

Question 6

Access cavity for Mx centrals

Answer 6

1. place bur perpendicular to palatal surface, drill 2-3mm
2. change inclination along long axis of tooth until pulp chamber reached

need correct shape and be conservative

incisors = elongated triangle, canine = more oval

Question 7

Mx 1st PM

Answer 7

21.5mm

mostly 2 root 2 canals - B and P (85%)
1 (8%)
3 (7%- like molar roots -2B, 1P)

Question 8

Mx 2nd PM

Answer 8

21mm
1 (50%), 2 (50%)

1 root but 1-2 canals
(merge?)

Question 9

Access cavity for PMs

Answer 9

start at middle between B and P cusps and make oval access cavity slowly, once you feel the drop, use a bur with non-cutting tip to smooth the walls (otherwise may drill into furcation)

Question 10

Mx 1st molar

Answer 10

20mm

3 canals (30-40%) - 3 roots MB, DB, P
4 (60-80%) - MB2 (closer to P, most often MB2 and 1 merge but not always)

Question 11

Issue with mx 1st molar

Answer 11

MB2 not always visible, must explore for it

Question 12

Which is usually a bigger issue. Missing a MB2 that merges with MB1 or independent?

Answer 12

independent, some degree of disinfection of MB2 when merge at end (but bacteria still left in upper part) whereas if independent MB2 missed its a bigger issue

Question 13

Mx 2nd molar

Answer 13

20mm

3 (75%), 2 (15%), 1 (10%), 4 (0.7% - difficult, narrow canal but need to look for it, use ultrasound tip and explorer)

Question 14

Access cavity for mx molars

Answer 14

2B roots, 1P
-> triangle shaped access (base is B, apex P)

Question 15

Md central and lateral

Answer 15

central 20.8mm

1 (73%), 2 (27% - B and L)

lateal 22mm
1(85%), 2 (15%)

(flattened canal - need to use Hedstroem file in circumferential filing motion at end to touch all the walls w canal flooded w NaOCl)

Question 16

Common reason for failure in md incisors

Answer 16

small teeth, significant chances of having 2 canals

Question 17

Access cavity for md incisors

Answer 17

same as mx, first perpendicular to lingual surface for 2-3mm, then go down long axis of tooth to reach pulp chamber

elongated triangle shape

Question 18

Md canine

Answer 18

26mm

1 (88%), 2 (11%)

Question 19

Access cavity for md canine

Answer 19

oval shape
following same technique, usually some roof remaining, need to remove this all of roof to have straight access

Question 20

What must be achieved in ALL access cavities

Answer 20

remove/smooth all of pulp roof, to get straight access

Question 21

Md 1st PM

Answer 21

22mm

1 (66%), 2 (31% - 1B, 1L)

Question 22

Importance of taking 2 radiographs of different angulations

Answer 22

assess possibility of 2 canals

Question 23

Md 2nd PM

Answer 23

22mm
1(90%), 2 (10%)

Question 24

What is an uncommon anatomy for md premolar

Answer 24

C - shaped premolar
-> need to do CMP all the way around

Question 25

Access cavity for md PM

Answer 25

oval shape between B and L cusps

Question 26

Md 1st molar

Answer 26

21mm

3 (56%), 4 (36%), 2 (8%)

3- MB, ML, D canal usually centered in D root.
4- MB, ML, DB, DL. If u find 3 and they arent in a triangle, look for the DB/DL

Question 27

2 rare variations you may find in Md 1st molar

Answer 27

1. MM canal (mesial middle): fortunately it usually merges with MB or ML, problem if independent
2. Radix entomolaris: extra L root - you will have MB, ML, D and something L

Question 28

Summary of how many canals usually in teeth.

Answer 28

Mx central - 1
Mx lateral - 1
Mx canine - 1
1st PM - 2, 1, 3
2nd PM - 1 or 2, 50%/50%
1st molar -** 4**, 3
2nd molar - 3, 2, 1,4

Md central - 1, 2
Md lateral - 1, 2
Md canine -** 1,** 2
1st PM - ** 1,** 2
2nd PM - ** 1,** 2
1st molar -** 3,** 4, 2
2nd molar - **3, 2, 4

bold is most common, others are possible and listed from most common to

Question 29

Md 2nd molar

Answer 29

21mm

3 (73%), 2 (16%), 4 (11%)

Question 30

Rare variation of md 2nd molar

Answer 30

C shaped canals

Question 31

Access cavity for md molar

Answer 31

triangle