Lec 10-11

Question 1

objectives for access

Answer 1

-gain visualization
-room for instruments
-obturation
-maintain strength of tooth
-preserve incisal edge, marginal ridge

Question 2

proper outline form for max anteriors

Answer 2

max CI: triangular with base towards incisal edge
max LI: same, narrower and less flared
max canine: more oval shaped

Question 3

pulp is usually located in center mass of root form

Answer 3

TRUE

Question 4

proper outline from for mandibular anteriors

Answer 4

very narrow M-D and have 2 canals 40% of time, easily perforated

-triangular to oval but narrow
-canines are oval

Question 5

should look for canals with the bur

Answer 5

FALSE
use endo explorer

Question 6

mark bur at what depth for reaching the pulp?

Answer 6

7 mm depth should reach the pulp

Question 7

if you are lost during access

Answer 7

stop and take radiograph and ask for help

Question 8

if your access is not proper form, too much removed, what could happen?

Answer 8

the tooth is weakened and more complications can occur like fractures

Question 9

max central access

Answer 9

-triangle shaped
-incisal edge and marginal ridges intact
-3 mm of tooth structure on all sides of access

Question 10

max lateral access

Answer 10

-use 2 round
-triangle shaped
-watch incisal compromise bc smaller

Question 11

max canine access

Answer 11

-use 2 or 4 round
-oval shaped
-single canal usually
-huge chamber

Question 12

mand incisor access

Answer 12

-use 2 round
-very small and narrow
-easily perforated
-2 canals 40-44% of the time
-mostly type II canals
-if fast break seen, then multiple canals

Question 13

mand canine access

Answer 13

-oval shaped

Question 14

Weines classification for premolar access

Answer 14

type I: one canal
type II: 2 canals join at apex
type III: 2 canals that don’t join
type IV: one canal divides into 2

type 2 and 4 most difficult

Question 15

max 1st premolar access

Answer 15

-2 canals 85% B-L
-thin oval access
-use 2 round bur. no wider than #4 bur
-most common error is not totally unroofed

Question 16

what is the color of the roof and floor of the pulp chamber

Answer 16

roof is more clear/yellow
floor is darker colored

Question 17

max 2nd premolar access

Answer 17

-one canal usually
-use 2 round
-thin oval access
-4 round width
-if canal not in center, then 2 canals probs (23%)

Question 18

what does it mean if you see a fast break in the root and a fuzzy canal, or 4 PDLS seen on a radiograph of mandibular 2nd premolar?

Answer 18

means that there are 2 canals (rare)

Question 19

mandibular premolar access

Answer 19

-thin oval access
-usually 1 root and 1 canal
-color of pulp chamber floor is darker than the roof

Question 20

what is the law of centrality?

Answer 20

pulp chamber is located in center of tooth

Question 21

what is the law of concentricity?

Answer 21

the pulp chamber walls are concentric to the external surface

Question 22

what is the law of the CEJ?

Answer 22

the CEJ is the most consistent landmark for locating the pulp chamber

Question 23

what is the worst access error?

Answer 23

perforation

Question 24

mand 1st molar access
and mand 2nd molar access

Answer 24

-3 or 4 canals
-trapezoidal shape, wider base on mesial
-may be 2nd distal canal (DL) that is often missed (30%)
-single distal canal will be in center of access shape

Question 25

what is the symmetry rule?

Answer 25

entrance of the canals is equidistant to line drawn mesial-distal

Question 26

Where do you find C shaped canals?

Answer 26

in mandibular 2nd molars
-very difficult, adv endo

Question 27

max 1st molar access

Answer 27

-4 canals usually
-MB2 canal most difficult, found 95% of the time
-MB 2 canal very small
-law of symmetry does not apply

Question 28

common variations: anteriors

Answer 28

max incisor: multiple canals rare

mand incisor:
-1 root, 1 canal = 60%
-1 root, 2 canals = 40%

max canine: multiple canals rare

mand canine:
-single canal = 68%
-2 canals = 22%

Question 29

common variations: premolars

Answer 29

max 1st:
-2 canals = 85%
-single canal = 9%
-3 canals = 6%
max 2nd:
-single = 50%
-2 canals = 50%

mand 1st:
-single = 74%
-2 canals = 25%
-3 canals = 1%
mand 2nd:
-single = 98%
-2 canals = 2%

Question 30

common variations: molars

Answer 30

max 1st:
-3 roots, 4 canals = 95% (MB2)
-3 roots, 3 canals = 5%
max 2nd:
-3 roots, 4 canals = 60%
-3 roots, 3 canals = 40%

mand 1st:
-2 roots
-2 mesial canals = 98%
-1 mesial canal = 2%
-1 distal canal = 70%
-2 distal canals = 30%
mand 2nd: C shaped
-2 roots, 3 canals = 81%
-2 roots, 2 canals = 15%
-1 root, 1 canal = 4%