Endodontics Flashcards
Normal pulp - define
pulp is symptom free and normally responsive to pulp testing
pulp may not be histologically normal
mild or transient response to thermal cold testing, lasting no more than 1 or 2 seconds after stimulus is removed
reversible pulpitis - define
discomfort experienced when stimulus (such as cold or sweet foods) applied
- goes away within a couple seconds following removal of stimulus
no significant radiographic changes in periapical region of suspect tooth
should return to normal following appropriate management of aetiology
reversible pulpitis - common causes
caries
deep restorations
exposed dentine (dentinal sensitivity)
symptomatic irreversible pulpitis - define
vital inflamed pulp
incapable of healing
sharp pain upon thermal stimulus
- lingering for 30 seconds or more
spontaneous pain
referred pain
pain may be accentuated by postural changed e.g. lying down or bending over
over the counter medications typically ineffective
symptomatic irreversible pulpitis - common causes
deep caries
extensive restorations
fractures exposing pulpal tissues
asymptomatic irreversible pulpitis - define
vital inflamed pulp
- incapable of healing
no clinical symptoms
usually normal response to thermal testing
pulp necrosis - define
death of dental pulp
pulp non responsive to pulp testing and is asymptomatic
previously treated - define
tooth has been endodontically treated and the canals are obdurated with various filling materials
- tooth does not respond to thermal or electric pulp testing
previously initiated therapy - define
tooth has been previously treated by partial endodontic therapy such as pulpotomy or pulpectomy
- may or may not respond to pulp testing
normal apical tissues - define
not sensitive to percussion or palpation
radiographically:
- lamina dura surrounding root is intact
- PDL space is uniform
symptomatic apical periodontitis - define
represents inflammation, usually of the apical periodontium
produces clinical symptoms
- painful response to biting and/or percussion or palpation
may or may not be accompanies by radiographic changes
asymptomatic apical periodontitis - define
inflammation and destruction of apical periodontium that is of pulpal origin
appears as apical radiolucency
does not present with clinical symptoms (no pain on percussion or palpation)c
chronic apical abscess - define
inflammatory reaction to pulpal infection and necrosis
characterised by:
- gradual onset
- little or no discomfort
- intermittent discharge of pus through associated sinus tract
typically radiographic signs of osseous destruction
how to identify the source of an associated sinus tract
place a gutta percha cone through the opening until it stops and take a radiograph
acute apical abscess - define
inflammatory reaction to pulpal infection and necrosis
characterised by
- rapid onset
- spontaneous pain
- extreme tenderness of the tooth to pressure
- pus formation
- swelling of associated tissues
may be no radiographic signs of destruction
patient often experiences malaise, fever and lymphadenopathy
condensing osteitis - define
diffuse radiopaque lesion representing a localised bony reaction to a low-grade inflammatory stimulus
You assess a root canal treatment after 1 year - what factors would constitute to a successful outcome?
absence of pain, swelling and other patient symptoms
no sinus tract
no loss of function
radiographic evidence of a normal PDL
possible complications that can occur while instrumenting a canal with handfiles
blockage
ledges
apical zipping/transportation
perforation
What causes blockage of a canal?
dentine debris getting packed into the apical portion of the root
attempts to remove a blockage in a canal can result in…
false canal being cut and possible perforation
what is a ledge, in reference to Endodontics? When does it occur?
internal transportation of the canal
occurs when working short of length
- can occur if curved canals are instrumented as if they were straight
How can a ledge be by-passed?
by placing a curve at the tip of a small file, with a rubber stop with marker to show direction of the curve
how does apical transportation occur?
occurs as a result of the tendency of the instrument to straighten inside a curved canal
apical transportation - consequences
transportation of apical foramen = fails to provide resistance for packing of gutta-percha
cases tend to be overextended and poorly filled
apical transportation - management
in minor cases
- canal can be reshaped to new level just above foramen
more severe cases:
- attempts to reshape can result in weakening or perforation of root
how to avoid apical transportation?
pre-curve the initial small sized hand instruments
do not skip instruments in the sequence
never rotate the instruments in curved canals
Perforation - how can it be diagnosed?
persistent bleeding into the canal
multiple radiographs
electronic apex locators
dental operating microscope
2 ways an orthodontic instrument can separate?
torsional fatigue
cyclic fatigue
how does torsional fatigue occur?
extensive instrument surface encounters excessive friction on canal walls
- instrument tip larger than canal section to be shaped
- tip may lock, torque exceeds critical level
reasons why an obturation might be too short
error in working length determination
error in preparation
- ledge formation
- incomplete preparation
error in obturation
how to avoid fractured files during endodontic treatment
know limits of instruments
use a recognised technique
pay attention to degrees of rotation
lubricate canals
what are the objectives of a RCT?
- to eliminate infection
- to remove the contents of the canal
How many roots do incisor teeth have?
1
how many roots do Canines typically have?
1
how many roots to maxillary first premolars usually have?
2
how many roots do maxillary second premolars usually have?
1
how many roots do mandibular premolars typically have?
1
how many roots do maxillary molars typically have?
3
how many roots do mandibular molars usually have?
2
Why is sodium hypochlorite used in endodontic treatment?
potent antimicrobial activity
dissolves pulp remnants and collagen
dissolves necrotic and vital tissue
downsides of sodium hypochlorite
Possible effect on dentine properties -may penetrate into it
inability to remove smear layer
effect on organic material
What is the smear layer and why does it need to be removed?
organic pulpal material and inorganic dentinal debris
- formed during preparation
must be removed due to:
- bacterial contamination
- interferes with disinfection
- prevents sealer penetration
Sodium hypochlorite complications
discolouration of fabrics
ophthalmic injuries due to eye contact
apical extrusion leading to tissue necrosis
allergic reaction
components of GP
gutta percha
zinc oxide
radiopacifiers
plasticisers
define working length
the distance from a coronal reference point to the point at which canal preparation and obturation should terminate
reasons for carrying out obturation
- prevent coronal leakage
- prevent ingress of nutrients from periapical tissue reaching inter canal bacteria
- prevent bacteria entering peri apical tissues via apical foramen
How could you restore an endodontically treated anterior tooth with intact marginal ridges?
- composite restoration
OR - veneer
How would you restore an endodontically treated tooth with destroyed marginal ridges?
- core build up with crown
OR - post crown
What is the function of a post and core
Core = retention for crown
Post = retains core
What are the features of an ideal post?
parallel sided:
- more retentive than tapered
- avoids wedging
non-threaded (Passive)
- smooth surface incorporates less stress to remaining tooth than treated (active)
cement retained
- less retentive than threaded post
BUT
- cement acts as buffer between masticatory forces and post/tooth
What materials can be used for posts?
- metal: gold, stainless steel, brass, titanium
- ceramics: alumina, zirconia
- fibre: glass, quartz, carbon
What are the downsides of metal posts?
- poor aesthetics
- corrosion
- vulnerable to root fracture
- nickel sensitivity
- radiopaque
What are the advantages of ceramic posts?
- favourable aesthetics
- high flexural strength
- high fracture toughness
what are the disadvantages of ceramic posts?
- difficult retrievability
- root fracture common
What are the advantages of fibre posts?
- flexible
- similar properties to dentine
- good aesthetics
- retrievable
- radiolucent on radiographs
What materials can be used for a core?
- composite
- amalgam
- glass ionomer
What is the most commonly used core material and why?
Composite
- tooth coloured - aesthetics
- bonds to tooth structure
- used with fibre posts
What are the potential probems with posts?
- perforation
- root fracture or crack
- core fracture
- post fracture
outline the procedure for using an electric pulp tester
dry tooth
isolate
conducting medium added to tip of EPT probe
probe placed on incisal edge or cusp tip adjacent to pulp horn
circuit completed (by patient holding handle of EPT)
current slowly increased
patient indicates when tingling/heat sensation is felt
give examples of materials that can be used for vital pulp therapy
zinc phosphate
zinc oxide eugenol
calcium hydroxide e.g. decal
tricalcium phosphate
resins
RMGI
bioceramics e.g MTA, biodentine
Calcium hydroxide - effects on pulp in vital pulp therapy
- bacteriostatic
- high pH (12.5) stimulates fibroblasts
- reparative dentine formation
- stimulates re-calcification of demineralised dentine
- neutralises low pH from acidic restorative materials
calcium hydroxide disadvantages
weak
very soluble if not protected
MTA properties
high pH
creates bacterial-tight seal
biocompatible
sets hard enough to act as a base for restorative material
difference between white and grey MTA
grey MTA contains iron
disadvantages of MTA
prolonged setting time (over an hour)
discolouration of crown
advantages of biodentine
similar to MTA but
- quicker setting
- no discolouration
CVEK pulpotomy steps (assume anaesthesia has already been achieved and dam has been placed)
1-2mm coronal pulp remove initially (with high speed)
additional pulp removed if bleeding excessive
stop once vital pulp reached
rinse with 5% sodium hypochlorite
place Calcium hydroxide, MTA or biodentine over pulp tissue
place sealing restoration e.g. GIC
place restoration e.g. composite
types of endodontic complications
complications with access
complications of instrumentation
post operative complications
Give 2 reasons why it is important the the roof of he pulp chamber is completely removed when carrying out RCT
allows you to gain access to all canals
provides a reservoir for irritants during instrumentation
What factors could affect the accuracy of an apex locator?
conductive material in the canal e.g. blood, irritagants
immature apex
root canal perforation
abscess or purulent discharge
how to determine working length
electric apex locator
pre-operative radiograph - subtract 0.5-1mm
combination
questions to ask patient prior to carrying out re-root treatment
when was initial RCT?
why was it required?
did treatment improve symptoms?
dental dam
hypochlorite use
procedural problems
Features of an endodontic examination
extra oral exam
intra oral exam
soft tissue exam
intra oral swelling
sinus tract
palpation
percussion
mobility
periodontal exam
other special tests in endo (other than radiographs)
bite test
- frac finder
- tooth sleuth
staining and transillumination
test cavity
selective anaesthesia
factors to consider before root canal retreatmnet
diagnosis
risk/benefit analysis
good reason to treat?
consent?
is tooth restorable?
endodontic re-treatmnet; features to asses in radiographic assessment
root filling
- length
- quality of obturation
- voids
unfilled/missed canals
shape of canal
potency
- posts
- sclerosis
bone support
crown to root ratio. (1:1.5)
pathology
- resorption
- periapical radiolucency
- perforation
principles for restoring root treated teeth
normally massive loss of coronal tooth structure
consider cuspal protection (onlay/crown)
- coronal seal
- prevention of fracture
what is a core build up?
restorative material used to replace the lost tooth tissue in the internal part of the tooth
- provides retention and resistance for definitive restorations
features of a Nayyar core
amalgam core extended into the pulp chamber and coronal third of root canal system
gutta percha removed - typically 2-4mm from orrifice
When preparing to fit a post, how much gutta percha should be left in the apical portion of the canal?
3-5mm
advantages of a fibre post
biocompatible
reduced risk of root fracture
- similar elastic modulus to dentine
aesthetics
- tooth coloured
improved bonding
corrosion resistance
stress distribution
easier procedure - reduced chair side time
disadvantages of fibre posts
hard in retreateatments
technique sensitive
can debond
