Endodontics Flashcards
what are the three design objectives of RCT
create continuously tapering funnel
maintain apical foramen
keep apical opening as small as possible
what material are K files made from and why
stainless steel or nickel titanium
cross sectional shape allows greater flexibility
how is the watch winding motion for RCT used
backwards ossilation of 30
forwards ossilation of 60
light apical pressure
when is the watch winding technique for RCT useful
for passing small files through canals
what is the balanced force motion in RCT preparation
1/4 turn clockwise
1/2 turn anticlockwise
repeat 1-3 times, remove, clean and reintroduce
name an advantage of using reciprocation system for RCT
mimics manual movement
reduces risk associated with continuously rotating a file through canal curvatures
name two disadvantages of reciprocation system for RCT
decreased cutting efficiency
requires increased inward pressure
limited capacity to get debris out the canal
what is cyclic fatigue
it is the stress/ strain and deformation induced in a material from cyclic loading
what does the regressive taper on reciproc instreuments allow for
coronal shaping without unnecessary loss of tooth substance
what are the rotations of reicprocation instruments
150 anticlockwise then
30 clockwise
why should the three peck movement be used with reciproc instruments
the flutes will become blocked if not cleaned after 3 pecks and this would increase friction in the instrument which causes the instrument to not work as well in the canal
what size of hand instrument is used to determine working length
ISO size 10
what is reciproc blue
there is heat treatment on the traditional NiTi alloy
has higher flexibility
suitable for strongly curved canals
how many canals does a maxillary central incisor have
1
how many canals does a maxillary lateral incisor have
1 (distal curve)
how many canals does a maxillary canine have
1 (distal curve)
how many canals does a maxillary 1st premolar have
2-3
how many canals does a maxillary 2nd premolar have
1-3
how many canals does a maxillary 1st molar have
3
how many canals does a maxillary 2nd molar have
3
how many canals does a mandibular central incisor have
1
how many canals does a mandibular lateral incisor have
1
how many canals does a mandibular canine have
1
how many canals does a mandibular 1srt premolar have
1
how many canals does a mandibular 2nd premolar have
1
how many canals does a mandibular 1st molar have
2-3
how many canals does a mandibular 2nd molar have
2
name five reasons why biofilms cause resistance
antimicrobials fail to penetrate
antimicrobials get trapped/ destroyed
antimicrobials not active against non-growing microorganisms
expression of resistance genes
stress response to hostile environment
name 2 clinical objectives of RCT
removing canal contents
eliminating infections
what is reactionary dentine
tubular and irregular structure
formed by original odontoblasts
what is reparative dentine
atubular and characterised by dead tracts where odontoblastic layer has been eradicated
formed by odontoblast like cells
where is the dental-pulp complex derived from embryologically
neural crest derived ectomesenchyme
what is enamel derived from embryologically
ectoderm
what endodontic diseases can periapical radiolucency be associated with
reversible pulpitis, irreversible pulpitis and pulpal necrosis
what occurs in response to bacterial ingress in the pulp chamber
acute inflammation
vasodilation and increased pulpal blood flow
extravasation due to increased vascular permeability
describe the pulp
unmineralised tissue composed of soft connective tissue, vascular, lymphatic and nervous elements encased in hard tissue
what is (peri)apical periodontitis
acute or chronic inflammatory lesions around the apex of the tooth root caused by bacterial invasion of the pulp
what occurs when there is an inflamed ligament around the tooth
apical periodontitis - which progresses to bone loss round the apex of the tooth
what is an acute abscess
occurs quickly
accumulation of pus
what is a chronic abscess
occurs slowly
can lead to sinus formation
what warning signs should you look for when monitoring an abscess so it doesn’t turn into cellulitis
malaise
fever
cellulitis
lymphadenopathy
persistent swelling
what is a dental abscess
localised collection of pus that forms inside the teeth or gyms which essentially initiates from bacterial infection
what is a radicular cyst
arises from cell rests of mallassez, in the periodontal ligament in response to inflammation after pulp death
name three potential complications of endodontic infection
maxillary sinusitis
ludwig’s angina
cavernous sinus thrombosis
which tooth fibres supply a sharp pricking sensation/ early shooting pain when activated
a-delta fibres
which tooth fibres supply a dull aching or burning pain when activated
c fibres
what is referred pain usually provoked by
intense stimulation of C-fibres leading to intense slow, dull pain
where does referred pain always radiate to
same side
what should you examine clinically as part of an endodontic exam
extra and intra oral soft tissue exam
intra oral swellings
sinus tracts
palpation
percussion
mobility
periodontal exam
why are heat tests not always recommended for sensibility testing
they can cause irreversible pulpitis
what tooth fibres are stimulated when using the EPT
A-delta fast conducting fibres
when is the EPT considered unreliable
in teeth with open apices
what are the 5 AAE pulpal diagnoses
normal pulp
reversible pulpitis
symptomatic irreversible pulpitis
asymptomatic irreversible pulpitis
pulpal necrosis
name the 6 AAE apical diagnoses
normal apical tissues
symptomatic apical periodontitis
asymptomatic apical periodontitis
chronic apical abscess
acute apical abscess
condensing osteitis
what is symptomatic apical periodontitis
inflammation of the apical periodontium ‘
painful response to biting
severe pain on percussion and indicative of degenerating pulp
what is asymptomatic apical periodontitis
inflammation and destruction of the apical periodontium that is of pulpal origin
appears as apical radiolucency
no clinical symptoms
what is a chronic apical abscess
inflammatory reaction to pulpal infection
gradual onset
little/ no discomfort
discharge of pus through sinus tract
what is an acute apical abscess
inflammatory reaction to pulpal infection
rapid onset
spontaneous pain/ extreme TTP/ pus formation
what is condensing osteitis
abnormal bone growth (radiopaque lesion) resulting from inflammation or infection
usually seen at apex of the tooth
when is pregnancy maybe a contraindication to endo treatment
in first trimester only emergency intervention
what medical conditions are contraindications to endo treatment
myocardial infarction within past 6 months
cancer - radiotherapy and chemotherapy to head and neck can compromise healing
allergy to latex - GP not a risk as non-cross reactive
what restorative factors may deem a tooth to be un-root-treatable
sub-osseous caries
poor crown/ root ratio
misalignment of teeth
presence of pre-existing full coverage restorations
what type of mirrors are better for endodontic treatment
front surface mirrors
