endodontics Flashcards
what is the cause of endodontic disease
bugs fungi archaea
what do we need for a PA lesion
bugs aka bacteria
what are the three things needed for endodontic problems
microorganisms
host response
time
why do we study endodontic microbiology
We can identify which bacteria play a key role in progression of disease
Helps develop a treatment strategy in terms of microbial eradication – present/future
To see how the microbes interact (tackling biofilm is diff to planktonic)
what type of bacteria do we find in the apical region
lower oxygen
less number of species
less accessible to tx
nutrients form the peri radicular tissues
what type of bacteria do we find in the coronal region
higher oxygen count
nutrients from carbs in oral cavity
higher bacteria count
easier to treat
how does the root canal microflora act
in a biofilm or planktonic
what do we see in the biofilm
calcium in the protective layer that can denature the sodium hypochlorite and makes it difficult to remove
state some resistance of biofilms to eradication
physical barrier mechanical shape metabolism transfer
issues with diagnosing endo
We are reliant on the pt. description of symptoms which may be confusing
There is a poor correlation between symptoms & histological status of the pulp
SOCRATES always tends to help
Character is most important part of SOCRATES for endo
When a pt. describes character of pain THINK about it, don’t just write it down
Other tests are available to aid diagnosis such as speciality tests & radiographs
Unless cortical plate has been lost, lesion may not be visible with conventional radiograph
We may need to use CBCT imaging to take slices of the lesion
what do we need to consider with multi rooted teeth
Pt’s may have one dead tooth and other teeth are vital
A positive result will be seen with EPT & TTP but tooth is partly necrotic & needs RCT
what is the first stage of RCT
isolation
why is isolation so important
stress for their comfort and improve prognosis of tx
what are some key facts for chemo mechanical prep
Instruments shape, irrigants clean
We aim to achieve a shape that optimises irrigation & simplifies obturation
what does the canal look like in CS
narrower at every point apically
where do we find the apical foramen
emain in its original position & we clean as much as poss. up to there
The apical opening should be kept as small as possible
what are some hand instrumentation techniques
step back
modified double flare
balanced force
stem winding
what is the step back technique
Coronal flare, file all way down to apex and step back from there
describe modified double flare
Crown down first, step back from apex & blend coronal with apex
describe balanced force
60 degrees clockwise to engage dentine & 180 anticlockwise to cut it
describe stem winding
Simple rotation & pull , slower than balanced force but safer
define patency filing
taking a file K10/15 all the way to the apex to clear out any debris
define recapitulation
taking the MAP all the way to full working length to check
give some examples of rotary instruments
rotary files( pro taper gold) wave one
what type of instrument is the pro taper gold
it is a rotary instrument in one direction only
what type of instrument is a wave one
reciprocating- rotates in one direction and then in the other direction
what are automated instruments made form
Ni-TI
what is the advantages with Ni-Ti
less likely to cause procedural errors
what are some procedural errors we can get
dentine debris
transportation
ledge
perforation
what are some types of file fracture we can get
torsional failure
cyclic fatigue
what is an apical granuloma
formation of tissue that forms at root tip
what is periapical periodontist
disease you have when you have an apical granuloma
how do we measure success of endo
should be measured 1 year cost op and subsequently for a minimum of four years
what do we look for in cases where the rct has succeeded
no abscess no pain no swelling no loss of function no sinus tract involvement normal radiographic PDL space around the root
give some examples of definitions of outcome
the strict criteria -
the loose criteria
survival
failure
explain the strict criteria
The length of review should be for at least 4 years
Strict criteria we generally use for research purposes
explain the loose criteria
Tooth is functional, pain free, no signs of swelling, lesion has only reduce din size
explain the survival criteria
We do this as it’s easy to collect data on survival studies
Difficult to follow up a lesion but easy to follow up presence of a tooth
Allows for comparison between diff treatment options
explain failure
if fails- say the disease has persisted not that the tx has failed
what makes the difference in improving survival rates
Presence or absence of a lesion
Filling should extend to within 2mm of radiographic apex but not extrude
Well condensed filling with no voids
Good quality coronal restoration
what are some things that decrease survival rate of rct
Pre op presence of sinus Increases size of lesion Presence of a flare up Perforation Mixing CHX & NaOCl
what are some things that increase survival rate of rct
Getting canal patency
Final rinse is with EDTA in retreatment
what is tx planning
What you’re going to do & when you’re going to do it
what is planning tx
How are you going to execute this treatment
what do we consider looking at the radiographic assessment
Root length
Degree of canal sclerosis
Canal symmetry
Canal curvature
what is some distinctive features of Vertical root fracture
Sinus at mid root level
Go round tooth, suddenly the probe will drop 13/14 mm (narrow isolated defect)
Circumferential bone loss will be seen on both sides of tooth
what is the prognosis like with vertical root fracture
prognosis low if below the pulp chamber need extrac
what are some differential diagnosis options
reversible/ irreversible pulpits
periapical periodontitis
dentine hypersensitivity
what are some tx options for dentine hypersensitivity
fluoride varnish- 2x per year limit
what are some tx options for reversible pulpits
removal or caries removal
what are some tx options for irreversible pulpits
RCT / XLA
what do we need to consider with RCT
need informed consent as patient might just find it easier to remove the tooth
what do we need to check in reinfected teeth
remove the fillings to see what the leakage is like and how can we provide cuspal coverage for it
what are the four radiographs which need to be taken
pre op
working length
master point
post op
what assessments of root filled teeth do we need to do before tx
endo
periodontal
coronal tissue
what does the coronal tissue assessment include
quality of tooth position of tooth rests aesthetics occlusion
advantages of restoring immediately after endo
good coronal seal
protection from tooth fracture
places tooth back in function
disadvantages of restoring immediately
risk of tooth fracture
unsure of endodontic outcome
expensive restoration if we need to re endo
what is the disadvtnages of delayed restoration
risk of endo failure
may require revision
increased risk of loss of coronal seal and tooth frac
what is the advantages of delayed restoration
endodontic success confirmed
expense of new crown avoided
what are some restoration options to build up a tooth
standard plastic
Nayyar core
pre fabricated post
cast post and core
how do we do a standard plastic restoration
this involves cutting the GP back with hot excavator & plugging it down
The definitive restoration is placed over the top of this
Don’t forget to place an RMGIC lining over the GP to prevent coronal leakage
how do we carry out a Nayyar core
good option if a whole wall is broken down
remove 2-4 mm of the GP in the canal and line with RMGIC and fill will amalgam
advantages of Nayyar core
Can be placed immediately after endo Uses coronal tooth structure to improve retention Reduces stresses (compared to post placement) Usually easy to remove
what do we do if there is not enough tissue for a core
we need to use a post but this weakens the tooth
what is the principle of post design
Aims to maximise retention & minimise stresses within the root
what are some types of post
tapered
serrated
cast
what is the issue with tapered posts
as it acts like a wedge it can put pressure on the tooth and cause it to fracture
what is the issue with serrated posts
cuts into dentine and can break the tooth
what is the benefit of serrated posts
some just passively sit in the canal (most used)
what should the post length be
leave 5mm of apical Gp to stop contamination
should be greater than the crown of the tooth
what is the width of the post
not exceed 1/3rd of the width of the CEJ
where do we want the forces to be transmitted in the post
to the dentine then the PDL and bone to reduce the risk of root fracture
positives of fibre posts
Aesthetic
Bond with dual cure resins (LC & Chemical cure)
Flex properties close to dentine (slightly less) so when force occurs, it fracs before dentine
Can be removed for revision of endo treatment
Claimed to reinforce root but evidence doesn’t confirm this
main cause of failure of fibre posts
decementation
advantages of cast post and core
can go sub gingival
good in oval canals
disadvantages of cast post and core
extra clinical visit
temporisation is difficult
advantages of pre fab post and core
immediate coronal seal
crown prep on same visit
better aesthetics
reduces number of stages
disadvantages of pre fabricated post and core
core takes time to build
what is the ferrule effect
360 degrees wrap around of dentine which increases strength and success of RFT
what is the job of the ferrule
improves resistance ot dynamic loading
reduces potential for stress concentration
helps maintain integrity of the cement seal
how dow e protect the tooth from fracture
using an extra coronal restoration
what do we need to consider in regards to occlusion
eg if working on a canine we need to change to GF from canine guidance to put less stress on the tooth
what are the three main points to success
preverse and protect remaining tooth tissue
establish and maintain seal
restore aesthetics and function
what does healthy periapical tissue look like
healthy PDL space seen as a radiolucent white line
what does the radiolucent white line represent
the lamina dura
what is the bone pattern of the maxilla like
less tabular and lower density
what is the bone pattern of the mandible
horizontal trabecular pattern
what are some shadows we can see that are radiolucent
antrum
mental foramen
nasopalatine foramen
what are some radiopaque shadows we can see
mylohyoid ridge
zygoma
sclerotic bone
what does rarefying mean
radiolucent
what does oestitis mean
inflammation go the bone
why might we see hypercementosis on the x ray
Idiopathic cause
Stresses on the tooth
Certain systemic diseases
what is osseous dysplasia
Condition with unknown aetiology
radiolucencies on apical region of teeth
who do we see a increased prevalence of osseous dysplasia
ANTERIOR TEETH in afro carribean middle age females
stages of periapical rarefying osteitis
ill defined
well defined
corticated Radiolucency
increased in chronicity
early stages of periapical rarefying osteitis
Ill defined, symptomless, common to see pt.’s with grotty mouths and only 1 giving pain
Diagnosis of ill-defines rarefying osteitis & non-vital
This person has an abscess – pain, looks tight, shiny & pushing lip down
Clinically we can diagnose an abscess
Radiographically they have an ill-defined radiolucency associated with premolar
Diagnosis of ill-defined rarefying osteitis & non vital
how long does ti take for radiographic appearance to catch up with symptoms
10 days approx
if lesions are less than 1cm then it can be
2/3 are granuloma
if lesions are 1-1.5cm then it can be
50% granuloma
50% cysts
if lesions are greater than 1.5cm then it is a
2/3rd chance it is a radicular cysts
describe sclerosing osteitis
Even more chronic still
May be no radiolucent component
May be halo of sclerosing osteitis surrounding an area of rarefying osteitis
Often seen around roots of lower first molars
Also called condensing or focal sclerosing osteitis
