Endodontic BDS4 Summary Flashcards
What is the main aim of root canal treatment? 2
To eliminate INFECTION
remove root canal contents
What do we assess for endodontics?
Tooth colour
Soft tissue - any swellings
Palpate the soft tissue
sinus presence
TTP?
Sensibility testing
Radiographs
Prev restoration?
How is pain transmitted?
Via CNV and its three branches
What are A delta fibres?
The A-delta fibers are somatic, myelinated fibers that have primary connections to the cortical regions of the brain. These fibers convey sharp, lancinating, easily localized pain signals; this pain sensation usually quickly passes
What are C fibres?
C fibers respond to stimuli which have stronger intensities and are the ones to account for the slow, lasting and spread out second pain. These fibers are virtually unmyelinated and their conduction velocity is, as a result, much slower which is why they presumably conduct a slower sensation of pain
What are the types of sensibility tests?
Ethyl chloride
EPT
test adjacent sound teeth first so pt knows what to expect
What do sensibility tests assume?
That tooth having a nerve supply correlates to mean it has a vital blood supply
What does EPT do?
This is where we apply conducting medium such as toothpaste to tooth and pt holds to complete circuit and it generates AP in A delta fibres (short sharp pain) and when pt feels pain breaks circuit
What does Ethyl chloride do?
Cold stimulus applied that stimulates A delta fibres
SIs for endo?
Sensibility testing
Radiographs
Tooth sleuth
Selective anaesthetisa
What are the types of pulpal diagnosis?
Normal pulp
Reversible pulpitis
Asymptomatic Irreversible pulpitis
Symptomatic irreversible pulpitis
Pulpal necrosis
What is a normal pulp?
This is where the pulp is symptom free, normal response to testing
Mild/transient response to cold testing which lasts 1/2 seconds following removal
What is reversible pulpits?
Inflammation of the pulp that is capable of healing following management of cause
Tooth experiences discomfort to cold stimulus/sweet stimulus when applied but assess after few seconds of removal
not spontaneous
common in carious or prev restored tooth
What is symptomatic Irreversible pulpitis?
This is where pulp is inflamed and incapable of healing and RCT is indicated
Radiogaphuically - may be winding of PDL or loss of LD and only if chronic will be PA radiolucency
spontaneous, lingering pain, hard to localise, hot and cold, awake at night, OTC analgesia not effective
What is asymptomatic irreversible pulpitis?
This is where pulp inflamed, not capable of healing but tooth is asymptomatic - hard to dx
may have widened PDL or loss of LD
What is pulpal necrosis?
This is where pulp is no longer vital - has died
may prev have been symptomaitic but now asymptomatic and pulp has liquefied
if long standing can get PA radiolucency
What are the PA diasnoses?
Symptomatic apical periodontitis
Asymptomatic apical periodontitis
Chronic apical abscess
Acute apical Abscess
Condensing osteitis
What is Symptomatic apical periodontitis?
This is where there is inflammation of the apical periodontium, widening of the PDL, loss of LD, tooth is TTP, sporadic pain, RCT indicated
What is asymptomatic apical periodontitis?
This is where there is inflammation of apical periodontium, widening of PDL, loss of LD but tooth is not symptomatic - often small bony swelling present
What is an acute apical abscess?
This is where there is an inflammatory rxn to pulpal infection and necrosis - rapid onset, spontaneous pain, TTP, pus, swelling, often no radiographic changes
systemic malaise
What is a chronic apical abscess
Longstanding response to pulpal infection/necrosis
pt often has bad taste and may have sinus tract with discharging pus nbut little to no symptoms
PA radiolucneyc
What is condensing osteitis?
This is where there is a diffuse radiopaque lesion as a result of low grade inflammatory response (infection)
What are the tx options in Endo?
No intervention with review
Orthograde RCT
Re-RCT
Retrograde surgical RCT
How do we carry out endo?
Front surface mirror
Good light
Magnification
If pulp is NV and cause is endo what is tx?
RCT
If pulp is NV and cause is perio and endo what is tx
RCT then 7-10 days later perio tx
If pulp is vital and cause is endo what is tx?
RCT
or if pulpitis reversible then caries removal
What causes endodontic infection?
It is causes by microorganisms which invade the root canal space and proliferate and develop biofilms which adhere to dentine and make eradication difficult
Wha are the design objects of chemomechanical disinfection? 3
Maintain apical foramen position
Maintain size of apical foramen (keep as small as possible)
Create a continuously tapering funnel shape
What are the aims of cleaning and shaping the canals? 4
Remove the infected hard and soft tissue
create space for delivery of irrigants to disinfect canal system
create space for obturation
maintain structural integrity of apical periodontium
What are the stages in root canal?
LA, Dam
Access cavity
Straight line access with DG16 and 10k file to 2/3rds EWL
Negotiate canals
Create coronal flare
Det WL
Apical prep
What are ideal quality of irritant?
Removes smear layer
disrupts biofilm
kills microorganisms
non allergenic
low cost
non toxic to peri-radicualr tissues
What irritants do we use in endo?
Sodium hypochlorite (Parcan 3%)
EDTA 17% to disrupt the smear layer
CHX - 0.2%
What is sodium hypochlorite?
Irrigant used that has anti-microbial activity that kills MOs and disrupts the biofilm and any pulp remnants and dissolves necrotic and vital tissue
Conc of 0.5-6%
What factors affect sodium hypochlorite?
Concentration
Time
Volume
Contact
Why is conc of sodium hypochlorite important?
At high conc higher risk of extrusion and higher conc more active against organic tissue
Why is time in sodium hypochlorite important?
It needs to be in root canal space to dissolve the biofilm - needs appropriate time
Why is volume of sodium hypochlorite important?
volume as it inactivates quickly in canal so need to replenish with sufficient volume to disrupt the biofilm and kill micro-organisms
Why is contact relevant in sodium hypochlorite?
Needs to contact all of canal coronally to apically to disrupt biofilm and kill MOs
How do we begin all endodontic procedures regardless of the technique used?
LA and create access cavity (with or without dam)
Then use of dam
identification of canal orifices with GD16 probe and can also use 10k file to 2/3rds EWL for Canal negotiation
Glide path to EWL with 10k file
What are the types of endodontic techniques we use in RCT?
Modified double flare technique
Protaper Hand Files
Protaper Gold (rotary system)
Reciproc
Reciproc Blue
Describe the process of root canal treatment using modified double flare technique
Create access cavity (confirm witth DG16 and K files)
Irrigate - sodium hypochlorite
Coronal flaring - using Gates Glidden burs
- start using GG4 to 2/3rds of EWL with light apical pressure and brushing movement then irrigate, recapitulate, then GG3 to 2/3rds EWL to drop prep more apically, irrigate, recapitulate, GG2 to 2/3rds EWL
- now we can establish CWL with apex locator using size 10K file
- after coronal flare we do apical prep - use a size 15k file to CWL with watch winding motion (30, 60)- IAR, then size 20k file to CWL with balanced force technique (1/4 forwards, 1/2 back) , IAR, then size 25K file IAR, then once we find file binding we want to go up two more sizes to create an apical stop and this is our master apical file
- now we want to join coronal flare and apical prep - we do this by using step back technique - take one larger than master apical file and go to CWL - 1mm and then repeat with MAF 2 sizes bigger - 2mm until joined
- irrigate protocol
- dry
- obturate
What is balanced force technique?
Quarter turn clockwise
Half turn anticlockwise
What is watch winding technique
30 degree
60 degree
What is the steps involved in pro taper hand files?
Access cavity
Straight line access DG16 and K files to 2/3rd EWL
Then we want to establish CWL with 10k files and apex locator
Then use of ISO 10 file to CWL
Then use of ISO 15 file to CWL
Protaper S1 for coronal third prep
Irrigate and recapitulate
Protaper S2 for mid third prep
Irrigate and recapitulate
Then Protpaer F1 for apical prep 1/3rd (ISO20)
PROTAPER F2 FOR APUCAL PREP (ISO25) - if master apical file is 25k stop here but if larger canal may need F3, F4 F5
IRRIGATE AND RECAPITUALTE AND ESNRUE TUG BACK
CHECK WIH ISO25K FILE
IRRIGATION PROTOCOL
DRY
OBTURATE
What is proper gold?
This is a rotary instrument similar to pro taper hand files expect its done with motor system
initially exposure with 10K files to 2/3rds, then S1 to 2/3rds EWL, calculate CWL, then use S1 to CWl and then S2
then F1 F2
How do we use reciproc for RCT?
Make assessment first for R25 R40 or R50
if canal is narrow or not visible on X-ray then use of R25
If canal if medium/wide test with 30K file –> if it reaches EWL then R50 as wide canal
if it doesn’t reach EWL then use a size 20k file and then R40
What are the steps of reciproc?
Access cavity
Straight line access as above
Irrigation and get glide path and apical patency with size 10k file
R25 to 2/3rds EWL - irrigate and recapitulate - 3 pecks and ensure in movement until fully out canal and continue until get to 2/3rds EWL
then CWL with apex locator
Irrigate and recapitulate
then R25 to CWL - 3 pecks and irrigate and recapitulate
then check with ewuaivalnt K file (25K file) that we are at CWL and apical tug back - we have apical control
irrigate
dry
obturate
What is the process of obdurating?
Remove any inter canal medicaments and confirm CWL and tug back to ensure apical control
Dry canal using paper points (ensure final irrigation protocol has been carried out)
Then try in master GP cone and check for tug back
Mix root canal sealer (epoxy resin, GIC, RMGIC)
Lightly butter GP cone and place into canal
Use of finger spreader (a or B) and leave in position for 20 seconds then remove and place accessory cone into canal
Heat excess GP with endo alpha or heated plugger and condense GP in orifice to level of ACJ
seal with RMGIC to prevent coronal leakage
What are common symptoms of sodium hypochlorite extrusion?
Pain
Swelling
Bruising
Profuse bleeding into root canal system
Airway obstruction
Where doe bruising follow in sodium hypochlorite extrusion?
Along superficial venous vasculature
What are risk factors for sodium hypochlorite extrusion?
Loss of CWL/EWL - either through movement of rubber stop or not confirmed with radiograph or apex locator
Excessive pressure whilst irrigating - use of thumb instead of index finger
needle locked within Canal
Large apical constriction (immature teeth, root resorption)
Close proximity to maxillary sinus
Delivery of irrigant to fast (1ml/15 seconds)
Why does inc pressure cause sodium hypochlorite accident?
Inc pressure means that delivery is increased pressure which exceeds venous pressure in neck
How do we manage sodium hypochlorite accident? 10
STOP TX
Keep pt calm and reassure - we will take immediate management steps
if pain –> LA (block)
if profuse bleeding - allow bleeding into canal until HA
irrigate with saline
steroid containing medicament such as ledermix into canal (no obdurating at this visit)
seal coronal access
analgesia advice
review in 24hrs
ABX is case specific
What are the types of inter canal medicaments?
Ledermix (corticosteroid and antibiotic)
Non setting calcium hydroxide (antibacterial)
What is ledermix?
This is a inter canal medicament that contains corticosteroid and antibiotic that is antimcibrobial and used when pulp is hyperaemic or inflamed to reduce inflammation
What is non setting calcium hydroxide?
This is used when pulp is inflammed and is alkaline pH and is used as inter canal medicament and helps remove tissue debris
What are the 3 criteria before obturating?
Pt is symptoms free
Canal is able to be dried
Canal has undergone full biomehcanical cleaning process (irrigation and shaping)
No signs of infection.
What is the function of a sealer?
Fill the space between GP and root canal
provide fluid tight sesl
Examples of RC sealer?
Epoxy resin
GIC
ZOE
Why do we instrument the canal?
TO CREATE SPACE FOR OBTURATION
REMOVAL OF HARD AND SOFTI TISSUE THAT IS INFECTED
TO CREATE SPACE FOR CHEMOMECHANICAL PREP - MEDICAMENTS, IRRIFARION
RETAIN THE INTEGRITY OF PERI RADICULAR STRUCTURES
What is a watch winding movement?
30 degrees
60 degrees
binds to dentine to break it
good for small files
What is a balanced force technique?
1/4 turn clockwise
1/2 turn anti clockwise
breaks dentine
larger files
What is a barbed broach?
Instrument used to extirpate the pulp - not meant to bind in th ecanall
What are K files made of?
Stainless steel - have 2% taper
What are the advantages of Ni Ti file?
Shape memory
inc cutting effiencecy
increased flexibility in larger sizes and tapers
more user friendly
How do we prevent instrument fracture?
Ensure clinical is trained in method utilising - knowns technique
crown down technique
constant motion with gentle pressure - no forcing into canal
create a glide path
avoid rotary files in curved canals
Why may a file separate?
Cyclic fatigue due to flexural stress
torsional stressl
What is cyclic fatigue?
This is where instrument is freely rotating in the canal and generates a tension compression cycle which leads to work hardening and eventually fatigue and frcture
What is torsional stress?
This is where instrument binds to canal wall and encounters excessive friction and can lock into canal
What are the canal identification laws?
- pulp chamber darker than canal walls
2.. LAWS OF SYMMETRY
EXCEPT FOR MAXILLARY MOLARS THE CANAL ORIFICES ARE EQUIDISTANT FROM MD LINE THROUGH THE TOOTH AND ORIFICES LIE PERPENDICULAR ON MD LINE
