Cleaning, Shaping, and Obturation

Question 1

Schilder’s Five Principles

Answer 1

1. Continuously tapering funnel
2. canal narrower apically
3. Prepare in multiple planes (flow concept)
4. Maintain original position of apical foramen
5. Apical foramen as small as practical

Question 2

biological objectives of endodontic tx?

Answer 2

To completely debride the pulp space of

1. pulpal tissue
2. Bacteria and microorganisms
3. endotoxins

Question 3

definition of glide path

Answer 3

the negotiation followed by the preparation of a smooth paved reproducible pathway of endodontic files to the apical foramen

Question 4

describe process of creating a gliding path

Answer 4

1. use 50% NaOCl and 50% water
2. always work in a wet canal
3. prepare using a PRE-CURVED #10 followed by 12.5 and 15
4. set the rubber stopper on each file to the estimated WL

Question 5

reasons to use a pre-curved file

Answer 5

1. most teeth have some degree of apical curvature
2. using a straight file could result in
   a. apical perforation
   b. ledge formation
   c. apical blockage

Question 6

type of motion used when creating a gliding path

Answer 6

watch-winding and starting with a pre-curved #10 file with a well lubricated canal

Question 7

what does watch-winding and pre-curve allow for?

Answer 7

allows the file to

1. be deflected away from the canal walls irregularities
2. negotiate apical curvature

Question 8

when do you switch to a filing motion?

Answer 8

once the estimated WL is reached
- then continue with 10 file in a filing motion by moving .5-1mm in amplitude, moving in and out of canal until the instrument fits freely

Question 9

after you create a glide path with a 12.5 file what is next step?

Answer 9

go patent with a #10 file

then proceed with a number 15 file

Question 10

file number refers to diameter where?

Answer 10

at the tip

Question 11

taper of all hand files?

Answer 11

.02

Question 12

increase in diameter in a file ever 1mm is?

Answer 12

.02

example - if 15 file 2 mm from apex it is .19 there

(.15 +.04 = .19)

Question 13

ideal elargment of a canal prep?

Answer 13

6 taper?

Question 14

if you are unable to negotiate the #10 file to estimated WL what is the next step?

Answer 14

do not use force

• switch to a SMALLER file like #08 or #06
• then proceed to the next larger file

Question 15

if cannot get the #06 file to WL what should you do?

Answer 15

File in the coronal area - perform coronal flaring as it may be constricted there and acting as a ‘bottleneck effect’

Question 16

what is coronal flaring?

Answer 16

enlarging the coronal 1/3 of the canal
can be done multiple different ways
1. gates glidden drills sizes 2,3,and 4
- on slow spees

Question 17

how do you use a glates glidden?

Answer 17

on slow speed and BRUSHING MOTION AWAY FROM THE FURCATION

in the sequence of 2–3–4

Question 18

Foramen Locater/ Root ZX? AKA?

how to use?

Answer 18

electronic method of establishing WL

uses frequency to determine if patent or not so can only work if you are patent

there is a sudden change in frequency at tip of file when you get out the bottom

have to have already established good access and have a dry canal and use a file that has a snug fit

AFTER REGIDTER AN APEX READING – PULL BACK .5mm

Question 19

after electronic WL then what?

Answer 19

confirm it radio graphically with an x-ray with file at the established WL from the electronic method

Question 20

the main way you get actual WL?

Answer 20

with radiograph of file in the tooth at said WL with a number 15 file

Question 21

apical preparation is done when?

Answer 21

After you have determined and confirmed actual WL

Question 22

Master apical file (MAF) should be at least what size?

Answer 22

30 file

Question 23

concept of apical gauging?

Answer 23

finding the file that FITS SNUGGLY IN THE CANAL at the appropriate WL

• need to go to atleast a 30

Question 24

concept of step back

Answer 24

cleaning and shaping of the apical 1/3 of the canal

• instrumentation of the root canal system starting from the apex towards the crown
• smaller instruments are taken to the WL, then each larger instrument is used subsequently worked to a 1 mm (or .5mm) SHORTER DISTANCE THAN THE PREVIOUS INSTRUMENT
• If do rotary – this step is basically by-passed

Question 25

if have #25 file as the MAF and doing a .5mm step back what is the subsequent files and lengths?

Answer 25

30 to .5mm short of WL

and so on until #55 is 3mm short of WL

make sure to go patent in between these

Question 26

when can you use rotary?

Answer 26

Once glide path is formed with a #20

Question 27

crown down vs. step back

Answer 27

crown down = opposite of step back technique
enlarge from the orifice end then go down

step back you enlarge from foramen towards orifice

Question 28

function of the pro-taper rotary files?
characteristics?

Answer 28

blend the shape between the coronal, middle, and apical thirds

smooth canal walls

produce percise shape

• made of Nickel titanium
• flexibility and memory
• collects debris between flutes

Question 29

size of rotary you use first?

Answer 29

larger rotaries are used firs followed by smaller sizes

Question 30

sequence of files in rotary system

Answer 30

SIX files

1. shaping X file (SX)
2. shaping 1 file (S1)
3. shaping 2 file (S2)
4. finishing 1 file (F1)
5. finishing 2 file (F2)
6. Finishing 3 file (F3)

Question 31

Describe SX file

Answer 31

first shaping file

at tip has a diameter of .19 and a 5% taper

Question 32

diameter of S1, S2, F1, F2, F3

Answer 32

S1- .17
S2- .20
F1- .20
F2-.25
F3- .30

Question 33

size of F1, 2, and 3 in regards to hand files

Answer 33

F1- size 20
F2- size 25
F3 - size 30

Question 34

rotary is ONLY ALLOWED IF?

Answer 34

if used HAND INSTRUMENTS FIRST