Endo Flashcards
Wha are the clinical objectives of RCT
Removing canal contents
Eliminating infection
What special tests can you carry out for a tooth that many have endo problems
Sensinility testing
-Cold sensibility with Ethyl Chloride
-Heat test with hot gutta percha (use vaseline)
-Electris pulp test (Primarily A-delta fast conducting fibres)
How do carry out a EPT
Dry teeth and isolate
Probe place on incisal edge or cusp tip )pulp horn proximity)
Conducting medium used
Circuit completed
Current slowly increases until response
What does a EPT not show
No indication of reversibility of inflammation
No correlation between threshold and pulp condition
EPT of teeth with open apices unreliable
What happens in reversible pulpitis
Inflammation should resolve following appropriate management of the aetiology
Discomfort is experienced when a stimulus applied only lasting a few seconds
Exposed dentin (dentinal sensitivity), caries or deep restorations
No significant radiographic changes in the periapical region of the suspect tooth and the pain experienced is not spontaneous
Follow-up required to determine whether the “reversible pulpitis” has returned to a normal status
Although dentinal sensitivity per say is not an inflammatory process, all of the symptoms of this entity mimic those of a reversible pulpitis
What happens in symptomatic irreversible pulpitis
Vital inflamed pulp is incapable of healing and that root canal treatment is indicated
Characteristics may include sharp pain upon thermal stimulus, lingering pain (often 30 seconds or longer after stimulus removal), spontaneity (unprovoked pain) and referred pain
Pain may be accentuated by postural changes such as lying down or bending over
OTC analgesics typically ineffective
Common aetiologies may include deep caries, extensive restorations, or fractures exposing the pulpal tissues
Teeth with symptomatic irreversible pulpitis may be difficult to diagnose because the inflammation has not yet reached the periapical tissues, thus resulting in no pain or discomfort to percussion
Dental history and thermal testing are the primary tools for assessing pulpal status
What happens in asympomatic irreversible pulpitis
Vital inflamed pulp is incapable of healing and that root canal treatment is indicated
No clinical symptoms and usually respond normally to thermal testing but may have had trauma or deep caries that would likely result in exposure following removal
What fibres in the pulp cause what type of pain
Alpha- Sharp pain
C fibres- Dull/aching pain
What are the differences between reversible and irreversible pulpitis
Reversible pulpitis:
-Pain to cold, lasts a short time
-Hydrodynamic expression- microleakage (A-fibres)
-No change in pulp blood flow
Irreversible pulpitis:
-Spontaneous pain, intermittent, sleep disturbance
-Negative to cold, pain to hot (e.g. tea/ coffee) (C-fibres)
-Increase in pulpal blood flow
What are the different reatment options for necorsis of the pulp in mature teeth and teeth with open apex’s
Mature teeth (closed apices):
-Root canal treatment
-Extraction
Immature teeth with open apices
-Pulpotomy
-Pulpectomy then full RCT
-Extraction
What are the design objectives of endo
Create a continuously tapering funnel shape
Maintain apical foramen in original position
Keep apical opening as small as possible
Why use sodium hypochlorite as the irrrigant
Potent antimicrobial activity
Dissolves pulp remnants and collagen
Only root canal irrigant that dissolves necrotic and vital tissue
Helps disrupt smear layer by acting on organic component
What factors are important for sodium hypochlorite function
Concentration
Volume
Contact
Mechanical agitation
Exchange
What naOCL conc. is best
3%
What are problems with NaOCL
Possible effect on dentine properties
Inability to remove smear layer by itself
Effect on organic material
What can be used with NaOCL to remove smear layer
17% EDTA
10% Citric Acid
MTAD
What is the objective of RCT
To provide an environment that allows healing of periradicular tissues so that the tooth is retained as a functional unit in the dental arch
What are the design principles for chemomechanical disinfection described by Herbert Schilder in 1974 for root canal shaping
Maintaining the original position and shape of the canal: This involves preserving the natural curvature of the root canal while shaping it to create a continuously tapering funnel from the coronal to the apical end
Creating a continuously tapering funnel shape from the coronal to the apical end: This involves shaping the canal in a way that ensures that all areas of the root canal are thoroughly cleaned and disinfected
Using a minimum of three instruments to achieve this shape: This involves using multiple instruments of increasing size to shape the canal and remove any remaining debris
What are the clinical objectives of RCt
Remove canal contents and eliminate infection
What is the endo-restorative interface
To provide an enviroment that allows healing of periradicular tissues so that the tooth is retained in the dental arch as a functional unit
What contraindications are there for RCT
Myocardinal infarction within 6months
Prognosis of RCT worst in diabetes so carefully monitor
Pregnancy, RCT in first trimester emergency only
What type of mirrors used in endo
Front surface
What is the prognosis of orthograde endodontics in irreversible pulpitis and necrotic teeth
up to 90% over 10 yrs for IP
up to 80% for NT
What form is there that helps with case selection of endo and what categories is there and when would a toth be in the other categories
AAE endodontic difficulty form
minimal= preop conditions indicate routine complexity and predictable outcomes
moderate= preop condition is complicated and at least 1 or more Tx factors listed in moderate difficulty
High= preop conditions exceptionally complicated expresssing several factors in moderate difficulty or at least 1 high factor
What is the plexus of raschow and where does it origonate and what does it do
A network of nerves below the odontoblast layer in the pulpodentinal border zone of pulp
Originates from inf/sup alveolar nerves and innervate OD layer
What seperates the plexus of raschow from the odontoblast layer
Cell free zone of Weil
What happens to dentile tubules nearer the pulp and what about this is important for caries
Increase in number and diameter so the deeper the cavity the greater the dentine permability and thus the pulp getting buggered
What nerves are in the dental pulp
Alpha fibres which give a sharp pain and stimulated by the EPT
C-fibres which give a dull ache
What is vital pulp therapy
Protection of the pulp frpm bacteria, products and toxic setting materials
What are materials used in vital pulp therapy and what must they be
Theu must adhere to dentine, Be thin, not dissolve and bacteria tight seal
ZOE
CaOH
Tricalcium phosphate
RMGI
Bioceramics e.g. MTA
What does the mechanical preperation of a tooth in endodontics do
Creates space to allow irrigating solutions and medicants to move effectively to eliminate micro-organisms from RC
What is NaOCL extrusion
It is when it is extruded beyond the RC into periradicular tissues
What does NaOCL extrusion lead to
pain
swelling
Ecchymosis
Nerological complications
Airway obstruction
What are the risk factors for NaOCl extrusion
Excessive pressure during irrigation
Needle locked within canal
Loss of control of working length
Larger apical diameters/constriction
-Root resorption
-Immature teeth
-Developmental anomalies
Anatomical factors/proximity to sinus
How can excessive pressure lead to NaOCL extrusion and how is it prevented
Pressure generated by positive-pressure irrigation delivery systems at the periapex have to exceed the venous pressure in the superficial veins of the neck
Flow rate of 1mL/15 secs and use a Luer-Lok 27g needele to a 3ml syringe and use index finger
Why are intra-canal medicants used
Between RC appt to destroy any remaining micro-organisms and prevent reinfection
What intra canal medicants are there and describe them
Anti-microbial paste e.g. odontopaste
-Contains corticosteroid and tetracycline
-During ‘hot pulps’ to reduce pulpal inflammation
-effective 5 to 7 days
Non-setting CaOH
-pH 12.5 for antimicrobial activity
-Hyrdolysis of lipposaccharide reducing inf. potentional
-Removes tissue debris and effective with NaOCl
-7 days
-Palced via injection, Ultracal optident
What is the aim of the instrumentation of a canal
Remove inf. soft and hard tissue
Give disinf. irrigants access to apical canal space
Create space for delivery of medicants and subsequent obturation
Retain integrity of radicular structures
What is meant by chemomechanical preperation
Shaping of the canal mechanically to allow obturation and to allow delivery of NaOCL to working length
What is the master apical file
The filer largest in diameter taken to calculated working length
Whast types of motionss are there in canal instrumentation
Filing
Reming
Watchwinding
Balanced force
Envelope of motion
Once shaping is complete of the roots what should you do
EDTA 17% for 1 min then NaOCL for 10mins
What is the watch winding motion and what is it used with
Smaller instruments
Light apical pressure and oscillation of 30-60 clockwise and anti-clockwise
What is balanced force and what is it used with
Bigger files to allow you to cut dentine with larger instruments and maintain safety of the instrument
Clockwise 90 with apical pressure and then anticlockwise >90
What is meant by the glide path and when is it performed
Explore RC with small kfile to EWL
Is required to allow easier instrumentation of canal with larger diameters/tper instruments
Not performed until coronal flair established
Initial exploration with a 10kfile then a 15kfile using watch winding motion and then ensure at EWL on radiograph
What is coronal falre
Created with gate glidden burs with each size advancing slightly more but make sure not more than 2/3 of RC
Use largest first then move down
What is used to gague depth of access cavity and to identif canals
DG-16 probe
What is the modified double flare technique and what does it do
Its a way to instrument the canal
Allows production of a continuesly tapering funnel shape prep and involves te development of a initial coronal flare and then a apical flare jined together
What is meant by reciproc
Follows reciprocating movement of file with 2 differt angles of rotation to create a step wise rotary motion
What are te angles of reciprocation
150 CCW 30CW
Is it necessary to have a coronal flare with reciproc
no
How do you select what drill to use in reciproc
Is the full canal fully visible on radiograph?
NO- R25
Yes- does a size 30 instrument inserted passively reach WL?
Yes- R50
No- does a size 20 instrument passively reach WL
yes-R40
no-R25
What does filling of the RC do
Prevents passage of micro-organism and fluid along the RC
Blocks apical formina as well as dentinal tunules and accessory canals
What must obturation materials be
Biocompatible
Dimensionally stable
Able to seal
Insoluble
Non-supportive of bacterial growth
Radiopaque
Removeable
What is GP and what is it made out of
trans-isomer of polyisoprene
20% GP
65% zinc oxide
10% radiopacifier
5% plastisiser
What operative factors contribute to success of a RCT
Filling extending to within 2mm of radiographic apex
Well condense and no voids
Good quality coronal restoration
What are the laws of symmetry
- Except from maxiallry molars orifices of canals are equdistant from a line drawn in a mesial-distal direction through pulp chambers floor
- Except from MM orifices of canals lie on a line perpindicular to a line drawn in a MD direction across centre of pulp floor
What are the laws of orifice
Orifices of RC’s are always located at junction of the walls and floor
Orifices of RC’s are located at angles in the floor wall junction
They are locatewd at the terminus of root developmental fusion lines
When removing GP what could you use
Hand files and eucalptus oil if well condensed
If poorly condensed can use Hedstroem files
Protaper D’s
What protaper D’s are used for GP removal
D1 for coronal filling removal
D2 for mid-root
d£ for apical
What complications are there from endo
Blockages
Ledges
Apical damage e.g. zipping, transportation
Perforation
Fractures instrument
