Technical Flashcards
Why isolate
Prevent contamination ingestion of instrument / irrigant
What to consider when preparing the tooth
Sound tooth (no caries / leakage )
Remove pulp / debris
Shape for effective cleaning
Removal of bacteria
Why irrigate
Lubricate
Flush debris
Dissolve organic debris
Remove bacteria
Aim of rct
Remove bacteria / fluid
Block foremen / tubules / acc. Canals
Root filling material must be
Biocompatible
Dimensionally stable
Insoluble
Radiopaque
Seal / prevent bacterial ingress removable
What radiographs when performing rct and why
2 pre op to see additional canals
Cone fit and post op to assess taper width length
1 year to assess pa lesion
Cross section of k and headstrom files
K- Diamond non cutting tip
H- Circle
How do you get past a ledge
Pre bend file / up and down movement
USS
edta irrigation or gel
How do you get pap
It is a reaction to Infection within the tooth
Decreased blood supply decreases defence and no longer greater pressure inside and fluid not pushed out so bad can enter pulp space
What moves the canal laterally
Transportation
What does straight gp indicate
Perforation
Difference between ledging and zipping
Sudden stop as debris deflects tip vs large foremen with leakage
Prognosis for retx with ap and no ap?
70 and 90%
What reduces prognosis
Apical lesion
Sinus
No proximal contact / restorability
Quality of current rct
Bone levels
Biological width
What can reduce prognosis of rct by 25%
Uncontrolled diabetes
Which niti files have a reduced restoring force
Gold due to heat treatments
What virus can make root canal infection worse
Hpv
Define over extension vs over filled
Changing constriction (failure risk)
Constriction intact e.g sealer puff
Pros and cons of 1% hypochlorite
Need to use more to have similar anti bac effect
Less severe hypochlorite incident
Benefits if a smaller apical gauge
More conservative
Less fracture risk / more favourable fracture
Reduced extrusion
Matches continuous taper prep
BUT MORE DEBRIS
How to determine the MAF
tap on the end and it shouldn’t move
What creates a triangular cross section that remains central
Balanced force
How to remove a broken file
Braiding files
IRS
Stieglitz rorfepw
Etpr post removal
What fibres help localise
A beta (pdl propripceptive)
What can prevent gp reaching length
Binding coronallh as gp 1.2mm and file max 1mm
What can reduce rct outcomes - mh
Cancer
Thyroxine
Diabetes
Bisphosphonates
Blood thinners if surgical
What can cause file breakage
No Sla
Push and stay too long
Tip binds / apical pressure
Working dry
Wrong rpm/ torque
Prognosis of pulp capping is improved if
Younger than 40
Mta over dycal
Occlusal perf of pulp over axial
Less than 100 days without symptoms / loss of vitality
(Haemostasis in 6 min with naocl)
What is apexogensis
Pulpotemy to allow tooth to grow
What does edta do
Softens dentine (chelating agent)
Removes smear allowing for better cleaning of LC AND DT
No antibacterial effect
Name some reciprocating files
Reciproc
Wave one gold (degressive taper 1.2mm max)
One curve
Describe manual irrigation
Easier depth control 1mm deeper and volume control
Reduced flushing action
Weak flushing action (reduced biofilm disruption)
Increases vapour lock
Using gp for irrigation is called
Pros / cons
Manual dynamic
Sterilises gp and reduced vapour lock
Hydrodynamic effect
But increased risk of extrusion
Active / ultra sonic
Less extrusion removes smear activates irritant
Risk of fracture high
Reduced amplitude increased frequency
Sonic pros / cons
No damage no fracture (polymer tips)
Low frequency high amplitude
How to manage a hypochlorite accident
Irrigate with la or saline or water until bleeding stopped
Place caoh2 temp infraoccluded
24 hours cold After warm
Analgesics anti his abc amox and metro
Self limiting rv in 3 days
Swelling increases up to a week but resolves at 2
When looking for anatomical landmarks when locating canals
Level of cej
At floor wall junction angles
Colour changes
Dentine map
Tooth shape is pulp shape
Central
Distance from cej to pulp same
Equidistant and perpendicular
Pro and con of reciprocating file
Decreased fracture and transportation as good centering
Increased debris and extrusion apically
If paper points are bloody you should
Increase file size to improve taper
If your idb doesn’t work even with lip sign what % of success with supplemental la
Articaine infil 84
Repeat idb higher 32
Pdl 48
Repeated AI ONLY 2%
Why does inflam stop
La working
Change in ph
Nocioceptors change
Vasodilation reduces concentration
What does straw colour fluid indicate
Radicular cyst
What type of sealer is one fill
Bioceramic which bonds to dentine and releases caoh2 and increases ph for new tissue growth
Name 3 sealers which dissolve
Tubiseal
Sealapex
Ah plus bioceramic
How would you carry out an aseptic technique
Rubber dam
Sterile pp
Disinfect gp/files
Change gloves
When does access size increase not matter as much in terms of fracture
When a marginal ridge already lost
Bigger apical preparation size
Increased risk of iatrogenic damage (stiffer instruments)
Not good for thermoplastic ob
Increased irrigant to WL
Remove infected dentine / debris
Smaller taper file 04 has
Increased cyclic fatigue resistance
What is the smear layer
Inorganic dental debris
Organic pulp materials
Bacteria and byproducts
Blood saliva
Limitations of edta
Use for 1 minute to prevent erosion of tubules with longer exposure
Why 30/06 taper
Good irrigant exchange vs not destructive
What is a good irrigation protocol
Naocl throughout
MAF selected then manual agitation with gp cone
Smear layer removed with edta 17% for 1 minute (aspirate)
Final rinse with naocl (risk of erosion) so can leave
What is balanced force
90 clockwise
Maintain pressure
270 anti clockwise
Listen
X3
Clean flutes
What is recapitulation
Small file to working to prevent blockages
What is patency filing
Small file to +0.5 of working length
Do not rotate when through foremen
Why restore with a crown
found that teeth restored with crowns more than 4 months after root canal treatment were almost 3 times more likely to be extracted when compared with those restored within 4 months
