lecture 1: policies, access and working length

Question 1

access procedure outline

Answer 1

• draw on the tooth
• create outline form through enamel
• bur is somewhat perpendicular to lingual surface of tooth
• stay shallow at this point just want <1mm

Question 2

access procedure penetration

Answer 2

• penetrate pulp chamber roof with bur angled approaching parallel to long axis of root in center of outline form
• reach pulp by 7mm
• confirm pulp canal entry with endodontic explorer

Question 3

do you look for a canal with a bur

Answer 3

NO only with an explorer

endodontic explorer = DG16: PUSH

Question 4

access procedure refining

Answer 4

• refine access prep with safe ended diamond bur or endo-Z

- want a straight-line access to mid root (mostly in molars)

Question 5

endo-Z bur

Answer 5

a side cutting instrument only

Question 6

working length determination

**

Answer 6

correct WL is 1mm SHORT of the CANAL EXIT

**

Question 7

what will happen if you don’t get the WL right

Answer 7

you get a poor outcome

Question 8

how to find the canal exit

Answer 8

• @hand: measure before you mount tooth
• @mouth: start with average length
• chart, apex locator and xrays

Question 9

can you take xrays with a #10 file

Answer 9

no.. it is too thin and will not be seen in xrays

use a #15.

Question 10

average root length of maxillary incisors

Answer 10

CI: 22.5
LI: 22

Question 11

average root length of mand incisors

Answer 11

CI: 20.7
LI: 21.1

Question 12

average root length of max and mand canine

Answer 12

max: 26.5 and mand: 25.6

Question 13

average root length of max pm

Answer 13

1pm: 20.6
2pm: 21.5

Question 14

average root length of mand pm

Answer 14

1pm: 21.6
2pm: 22.3

Question 15

average root length of max molars

Answer 15

1M and 2M 20

1M = 20.8

Question 16

average root length of mand molars

Answer 16

1m: 21
2m: 19.8

Question 17

what hand file do you use when using the apex locator

Answer 17

15 hand file. used to estimate the canal length

Question 18

between patency and WL.

Answer 18

1mm between the two

WL is critical

Question 19

patency

Answer 19

where canal exits the root. 1mm short is the constriction and what your WL is.

Question 20

what is a “blow out” and how does it happen

Answer 20

• when it is too long and a blow out guarantees incomplete compaction at the apex and an explosion of sealer in the PA tissue.

Question 21

you must have a reliable reference point… where are good locations to have a solid, reproducible location on the tooth

Answer 21

• tip of incisal edge (ant)

- tip of cusp for which the canal is name (molar)

Question 22

usual # of roots and root canals for max incisors

Answer 22

roots: 1

root canals: 1

Question 23

usual # of roots and root canals for max C

Answer 23

roots: 1

root canals: 1

Question 24

usual # of roots and root canals for max pm

Answer 24

1pm root: 2
1 pm root canals: 2

2pm root: 1, maybe 2
2pm root canals: 1, maybe 2

Question 25

usual # of roots and root canals for max M

Answer 25

roots: 3 | root canals: 3, maybe 4 or more

Question 26

usual # of roots and root canals for mand I

Answer 26

root: 1 | root canal: 1, maybe 2

Question 27

usual # of roots and root canals for mand C

Answer 27

root: 1 | root canal: 1

Question 28

usual # of roots and root canals for mand pm

Answer 28

root:1 | root canal: 1, maybe 2

Question 29

usual # of roots and root canals for mand m

Answer 29

root: 2 | root canals: 3, maybe 4 or more

Question 30

definition of access

Answer 30

drilling a hole through coronal structure to gain entrance into the pulp chamber

Question 31

3 steps of access

Answer 31

1. outline form 2. coronal access 3. radicular access

Question 32

requirements of access (4)

Answer 32

1. visibility of pulp chamber and all canal orifices from a single vantage point 2. straight-line access to mid-root for instrument placement 3. complete removal of pulpal roof and pulp horns 4. avoidance of unnecessary weakening of tooth

Question 33

wall of the coronal access should be ____ to the occlual

Answer 33

diverge

Question 34

why do you diverge the coronal access (3)

Answer 34

1. better light 2. better visualization 3. helps with leak and contamination

Question 35

access shape of max CI

Answer 35

triangular access, with base at the incisal. m and d marginal ridges are not invaded or weakened

Question 36

access shape of max LI

Answer 36

triangular/oval access *the most difficult of max ant teeth

Question 37

access shape of max C

Answer 37

triangular/oval access

Question 38

access shape of mand I

Answer 38

oval access - very narrow M-D, easy to perforate so be careful.

Question 39

canals of mand I

Answer 39

40% 2 canals (type II) | 60% 1 canal

Question 40

access shape of mand C

Answer 40

oval access

Question 41

canals of mand C

Answer 41

78% 1 canal | 22% 2 canals

Question 42

access of max 1 PM

Answer 42

thin oval access | - access is always gained through the O approach on all post teeth

Question 43

canals of max 1 PM

Answer 43

- 85% 2 canals - 9% one canal - 6% three canals

Question 44

access shape of max 2PM

Answer 44

thin oval

Question 45

canals of max 2PM

Answer 45

most often type I 1 root, 1 canal (75-85%) - 15-25% two roots - 3 roots is really rare

Question 46

access of mand 1PM

Answer 46

thin oval

Question 47

canals of mand 1PM

Answer 47

usually 1 root, 1 canal 73.5% | - type IV is 24%

Question 48

access of mand 2PM

Answer 48

thin oval

Question 49

canals of mand 2PM

Answer 49

- one root, one canal type I 85.5% | - type III 11.5%

Question 50

access max 1 M

Answer 50

triangle | apex to palatal should not cross the oblique ridge

Question 51

canals of the max 1M

Answer 51

4 canals the majority of the time

Question 52

access of max 2M

Answer 52

similar to the first molar but more compressed MD (triangle apex to palatal should not cross the oblique ridge )

Question 53

access mand 1M

Answer 53

trapezoid preferred

Question 54

canals of mand 1M

Answer 54

- 4 canals 64% | 3 canals 29%

Question 55

access of mand 2M

Answer 55

- trapezoid/triangle similar to first (trapezoid preferred )

Question 56

canals of mand 2M

Answer 56

81% 3 canals | 11% 4 canals