Operative techniques Flashcards
Hand piece safety
Check back cap
Check bur
Check coupling (ie attachment to machine)
Check resistance/ grainy
Check lateral movements of bur
Check for weird sound and water
Principles of cavity design and preparation
- Identify and remove carious enamel
- Identify maximal extent of lesion at the ADJ, smooth enamel margins
- Remove peripheral caries in dentine, circumferential deeper to avoid exposing pulp
- Outline form modification (ie shape)
- Internal design modification (smooth and rounded)
Line angle
Line angle = two linear surfaces meet
Point angle
Point angle = three linear surfaces meet
what angles can act as stress concentration points
sharp angles
what happens if we leave stress concentration points
stress and fracture or microleakage
when to restore a tooth
- lesion is cavitated
- patient can’t access lesion for prevention
- lesion into the dentine radiographically
- Lesion causing pulpitis or pain
whats LA and PA
LA = labial approach
PA = proximal approach
WHEN TO Pulp exposure
If necrotic material in pulp
Irreversible pulpitis
RCT
Sensitivity tests required
why keep Configuration factor low
reduce polymerisation contraction stress, ie less bonded surfaces, restoration involves minimal tooth structure
Configuration factor
ratio of bonded to unbounded surfaces, especially important for composite restoration
Polymerisation contraction stress
Polymerisation contraction shrinkage -> plastic deformation; composite pulls away from the bonded surface towards the direction of curing light
plastic deformation
Plasticity = non reversible change of shape in response to an applied force
Deformation = change in shape due to an applied force
Differential etch
Differential etch = 10 sec on enamel before moving the etch to dentine for another 10 seconds (total 20sec on enamel)
Injuries of pulp
- Caries
- Cavity prep
- Trauma
- Heat, vibrations, sharpness, strong force from high speed
- Chemicals from materials eg. Etch
- Tooth wear
- Periodontal health
- Ortho
- Dehydration of dentine
- Cutting odontoblastic processes, essentially damaging pulp
what risky substances can permeate into the pulp
- Bacteria
- Immune complexes
- Antibodies
- Microorganisms that cause pulpal disease
which fibres respond to an EPT
A fibres
what pain does C fibres detet
C fibres unmyelinated for dull pain, increased pulpal blood flow -> pressure -> pain
when looking at pulpal health what are the two broad categories of diagnosis
pulpal diagnosis and periapical diag
Reversible pulpitis vs Irreversible pulpitis
Can reverse to health
pain to cold
no change to pulpal blood flow
A fibres
vs
Still vital but inflammation cannot be healed
negative pain to cold
C fibres due to increase in pulpal blood flow
how to treat Reversible pulpitis and Irreversible pulpitis
o Vital pulp therapy
vs
o Pulpotomy -> vital pulp therapy
o Pulpectomy -> RCT
what is a necrotic pulp
o Non vital
o Can be partial or total necrosis
where do you find open apices?
Immature teeth
difference in treatment of open and closed apices
Closed apices
RCT or extraction
Open apices
Pulpotomy -> vital therapy
Pulpectomy -> RCT
Extraction
Open apices immature teeth have more recovery potential since more blood supply
dangers of rct on open apices
, rct can be dangerous because the materials used can be shoved through the open apex
c fibres stimulated is reversible or irreversible pulpitis
irreversible
5 types of periapical diagnosis
healthy
periapical periodontitis
acute apical abscess
chronic apical abscess
condensing osteitis
4 types of pulpal diagnosis
healthy
reversible pulpitis
irreversible pulpitis
necrotic pulp
how to diagnose healthy periapical
o Not sensitive to tapping or palpation
lamina dura intact
PDL space uniform
Periapical periodontitis
Pain when biting or palpation
Inflammation
wha is Acute apical abscess
o Inflammatory rxn to infection
symptoms of acute apical abscess
o Rapid onset
o Spontaneous pain
o Extreme tenderness
o Pus
o Swelling
o Fever or malaise
o Lymphadenopathy
difference between acute and Chronic apical abscess
both are Inflammatory rxn to infection
acute is rapid while chronic is Gradual onset
acute is very pain while chronic has little to no pain
another name for Chronic apical abscess
sinus
what is a gp cone used for
o Can use GP cone to tell you which tooth pulp is the source of infection
Condensing osteitis
Represents localised bony reaction to inflammation usually found at apex
No treatment usually because RCT doesn’t clear up this bone condition
How to tell if a tooth is vital or not?
- Discoloration
- Sinus
- Gross caries
- Large restoration
- PA Radiolucency
- Sensibility tests
RMB THAT SENSIBILITY TESTS DOES NOT MEAN THE SAME AS VITALITY TEST
Electric pulp tester which fibres stimulated
A delta fibres stimulated
- If current is high and patient still doesn’t feel anything prob necrotic
- EPT doesn’t tell you the condition of pulp
why EPT on young pulps and recently traumatised pulps are unreliable
the nerves may not be fully developed
the pulp may not have recovered from the trauma
Cold -> outward or inward flow of dentinal fluid?
Cold -> outward flow, nerves stretched, cold more sensitive than hot
Thermal tests work on the basis of?
Thermal tests work on the basis on dentinal fluid movement
what is used in hot test and what fibre does it stimuate
Hot test
- Hot gutta percha
- A and c fibres
- Too much heat can cause irreversible pulpitis be careful
what happens to pulp as we age
o less regenerative potential
o pulp becomes smaller, less blood vessels and nerves
o more fibrous content
o Less resistant to inflammation
what does insult to the pulp do to it
o Dentinal tubules occlude, tertiary dentine forms, pulp becomes smaller
reparative vs reactionary dentine
Reactionary is mild stimulus
Reparative is intense stimulus
treatment for an unexposed pulp
indirect pulp cap
stepwise excavation
seal caries in
stepwise excavation
- remove caries but leave someone over the pulpal floor if too close to the pulp
- temporary restoration
- Wait for tertiary dentine to form over the pulp
- Remove remaining caries and fully restore
seal caries in
- Leave caries there over the pulpal floor
- Seal well so that you cut off the sugar supply of bacteria
- Caries doesn’t progress
exposed pulp treatment options
direct pulp cap
partial pulpotomy + vital pulp therapy
complete pulpotomy
pulpectomy
RCT
pulpotomy vs pulpectomy
Partial pulpotomy – remove necrotic parts only
Complete pulpotomy – remove all but the root pulp
Pulpectomy – remove all and RCT
materilas used for vital pulp therapy
o Calcium hydroxide
o RMGIC
o Bioceramics ->Mineral trioxide aggregate MTA or Biodentine
what happens to dentine permeability as we get closer to the pulp?
it increases
how does CaOH work
kills bacteria-high pH
irritates pulp and stimulates tertiary dentine as a protective layer
stimulates recalcification of demineralized dentine
neutralizes pH from acidic restorative materials
how does MTA work
high pH to kills bacteria
bacteria tight seal
hard enough to act as a base
biocompatible
how does biodentine work
same as MTA but no discoloration
whats a complete pulpotomy
remove entire pulp from pulp chamber but leave the pulp in root canals
