Cleaning, Shaping, and Obturation Flashcards
Schilder’s Five Principles
- Continuously tapering funnel
- canal narrower apically
- Prepare in multiple planes (flow concept)
- Maintain original position of apical foramen
- Apical foramen as small as practical
biological objectives of endodontic tx?
To completely debride the pulp space of
- pulpal tissue
- Bacteria and microorganisms
- endotoxins
definition of glide path
the negotiation followed by the preparation of a smooth paved reproducible pathway of endodontic files to the apical foramen
describe process of creating a gliding path
- use 50% NaOCl and 50% water
- always work in a wet canal
- prepare using a PRE-CURVED #10 followed by 12.5 and 15
- set the rubber stopper on each file to the estimated WL
reasons to use a pre-curved file
- most teeth have some degree of apical curvature
- using a straight file could result in
a. apical perforation
b. ledge formation
c. apical blockage
type of motion used when creating a gliding path
watch-winding and starting with a pre-curved #10 file with a well lubricated canal
what does watch-winding and pre-curve allow for?
allows the file to
- be deflected away from the canal walls irregularities
- negotiate apical curvature
when do you switch to a filing motion?
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
after you create a glide path with a 12.5 file what is next step?
go patent with a #10 file
then proceed with a number 15 file
file number refers to diameter where?
at the tip
taper of all hand files?
.02
increase in diameter in a file ever 1mm is?
.02
example - if 15 file 2 mm from apex it is .19 there
(.15 +.04 = .19)
ideal elargment of a canal prep?
6 taper?
if you are unable to negotiate the #10 file to estimated WL what is the next step?
do not use force
- switch to a SMALLER file like #08 or #06
- then proceed to the next larger file
if cannot get the #06 file to WL what should you do?
File in the coronal area - perform coronal flaring as it may be constricted there and acting as a ‘bottleneck effect’
what is coronal flaring?
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
how do you use a glates glidden?
on slow speed and BRUSHING MOTION AWAY FROM THE FURCATION
in the sequence of 2–3–4
Foramen Locater/ Root ZX? AKA?
how to use?
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
after electronic WL then what?
confirm it radio graphically with an x-ray with file at the established WL from the electronic method
the main way you get actual WL?
with radiograph of file in the tooth at said WL with a number 15 file
apical preparation is done when?
After you have determined and confirmed actual WL
Master apical file (MAF) should be at least what size?
30 file
concept of apical gauging?
finding the file that FITS SNUGGLY IN THE CANAL at the appropriate WL
- need to go to atleast a 30
concept of step back
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
if have #25 file as the MAF and doing a .5mm step back what is the subsequent files and lengths?
30 to .5mm short of WL
and so on until #55 is 3mm short of WL
make sure to go patent in between these
when can you use rotary?
Once glide path is formed with a #20
crown down vs. step back
crown down = opposite of step back technique
enlarge from the orifice end then go down
step back you enlarge from foramen towards orifice
function of the pro-taper rotary files? characteristics?
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
size of rotary you use first?
larger rotaries are used firs followed by smaller sizes
sequence of files in rotary system
SIX files
- shaping X file (SX)
- shaping 1 file (S1)
- shaping 2 file (S2)
- finishing 1 file (F1)
- finishing 2 file (F2)
- Finishing 3 file (F3)
Describe SX file
first shaping file
at tip has a diameter of .19 and a 5% taper
diameter of S1, S2, F1, F2, F3
S1- .17 S2- .20 F1- .20 F2-.25 F3- .30
size of F1, 2, and 3 in regards to hand files
F1- size 20
F2- size 25
F3 - size 30
rotary is ONLY ALLOWED IF?
if used HAND INSTRUMENTS FIRST
