Clinical endodontics II Flashcards
what is the purpose fo root canal treatment
Maintain asepsis of root canal system or to disinfect it adequately
how do we do the root canal treatment
Undertake chemo mechanical prep of root canal system, obturate it and restore it
Shape root canals, clean root canals , fill root canals , then tooth
what is chemo mechanical preparation of root canal
- Historically Filing away infected root dentine
- Use chemical irrigants to decontaminate the canal
what are the difficulties of root canal
- Sheer Complexity of root canal treatment
- Curvature of root canals prevent us from shaping them and leading to procedural eros
- Difficulties in getting the irrigants to all parts of the root canal system
what do we consider in radiographic assessment of RCT
- Are roots curved
- How many canals are there
- Is the canal obvious or is it sclerosis
- Is the apex damaged or open
do we need good moisture control for root canal treatment
yes
why is rubber canal needed for RCT
- good isolation of tooth
- protects airway
- prevents contamination by saliva
- prevents irritants form being swallowed
- can use oraseal if required for a tight seal
what happens when accessing the root canals
- Once the tooth is situated, remove all caries and restorative material and assess restorability
- Rule of thumb, if you can’t clamp it, you can’t fill it
- If restoratabel, build back up to facilitate RCT
what is done to figure out access strategy
- use measuring tool on digital systems or old school wet film
- place bur against wet film to measure how deep its got to go in
- estimate distance to roof of pulp chamber and floor of pulp chamber
what do we need to remember when accessing tooth
- crown and root is not always aligned
where would you access on lower molar
distal canal - palatal canal
describe the access strategy
- go through the roof of the pulp chamber and move to safe ended burs - ENDO BURS
- remove all pulp chamber root until you can see all fo the pulp chamber floor
what outlines does a upper central incisor have
how would you access upper central incisor
after accessing the upper central incisor - what do we do
what do we do when the pulp chamber is found
for accessing canals what 4 things do we need
- good isolation
- good magnification
- good pre operative assessment
- knowledge of the anatomy
when accessing a restored tooth what do we do
- Remove restoration to check restorability
- Build back up to created a 4 walled access cavity- improve to irrigate tooth
- Aim for the largest canal - distal in lower molar , palatal in upper molar
- Break through the roof of the pulp chamber
- Remove the roof of the pulp chamber using a safe ended bur
- Ensure that you can see all of the pulp chamber floor
- Remember how many canals you are looking for
what are we after after removing roof of pulp and pulp chamber
- Ensure the tooth is restorable
- Minimal removal of dentine to see the whole of the pulp chamber floor - maintain structure integrity
- Minimal removal of dentine to enable files to reach the root apex without being beyond their limits
what does root canal preparation consist off
- creating a shape that has smooth continuous taper tot he apex
- facilities irrigation and obturation of the root canal
- ## preserves dentine where possible
what is chemo mechanical preparation
- chemically irrigate- flush out debris
mehcncially file the root - remove debris
what does canal shaping do
- remove infected dentine but create shape we can clean
continuous taper
describe this image
1- coronal promotion of tooth undertaking coronal flare
2- Then open up root canal and move to middle portion of root canal and flare tha part
3- only once the coronal and middle parts prepared then we go to apical
what are mistakes made form coronal flaring
- get file to go straight to apex without undertaking sufficient coronal flaring
-this increases risk fo file fracture and carry debris down apical portion
prepare root canal form CROWN DOWN
what hand instrumentation is used
hand fiels
- hedstorm
- k files
- stain less steel
GG- gates glide burs - safe ended
what is the most common technique for RCT
what is the stem winding motion
- file twisted and engaged walls and apical pressure maintained on canal and fuel is pulled out
describe K files
- made from stainless steel
- made by twisting blank wire to create small flutes
- variety of motions, balanced and step filling
describe hedstrom fiels
more aggressive cutting flutes
- more procedural problems if not used right
- used in hand filling motion - in and out
label this
cross sectional shape
label this
handle
stop
file length
file tip
what does 35 mean in this file
tip of the file is 0.35 mm in diameter
what 3 lengths do file come in
21
25
35
which file length is most common
25
what does the cross sectional shape tell about the file
- square blank
- K file
what does a 2% Taper mean
- for every 1mm back from the tip the diameter increases by 0.02mm
what does the silicon stop on file do
measuring device
what is typically the file length
21 or 25mm
size 10 - tip 0.1 mm diameter
what would a 6% taper mean
for every 1mm back the diameter would increase by 0.06mm
who described the step-down preparations
Goerig 1982
- variations exist
describe the step-down
describe what the number fo bands indicate on a GG bur
what does the long shank of GG bur allow it to do
which GG bur is most common and why
most common - 2,3,4
GG 1- prone to fracture
5 and 6 - big and remove too much dentine
what is the size of GG2 bur same as
size 70 file
what is size of GG3 and GG4 same as
size 90 file
size 110 file
how do we use the GG bur
- brushing motion
- cutting on the outstroke
- brush away from furcation
- bruhs away to area with most dentine
- and take it further down
what’s impotent when preparing teeth
TO IRRIGATE
- flush out debris
how do we determine the working length
- once the coronal flare completed
- will already have idea from pre op
label this
how do we determine the working length
how do we take a working length radiograph
what else can we use for working length estimation
- place file in tooth after estimating the working length
- using stoppers to ensure accurate measurement
- take radiograph
- indicate where tip of file is relative to radiographic apex
what is the problems with radiographs when finding working length
- anatomy is not always what you think
- point to establish is not visible radiographically
describe how Electronic apex locator work
describe how this works
- when the file is out of the end of tooth = red light
- wind file back when transition between red and green occurs
how do we use clinical procedure to establish working length
what do we do once working length determined
-file to length and work until loose apically
what happens if the next file doesn’t go as easily to within 2mm of working elgnht
- go back to previous file and work looser
- irrigate between each file
- as files get bigger in size , they get stiffer so need to be more careful manipulation
what appends once master apical file is reached
how do we create 5% taper or 10% taper
when do we keep stepping back until
what are the root canal preparation aims consist of
- continuously tapering funnel form apex to access cavity
- cross sectional diameter should be narrower at every point apically
- the root canal prep should flow with shape of original canal
- apical foramen should remain in. original position
- apical opening should be kept as small as practical
