Provisional Extra-coronal restorations Flashcards
Why should the provisional restoration be of high quality
otherwise failures occur
this leads to problems
What does the provisional play a role in the immediate and long term health of
the tooth
the supporting structures
the definitive restoration
What are the clinical stages of an indirect restoration
preparation
temporisation
impressions and registration
cementation
Why is provisional so important in terms of tooth preparation
tooth prep compromises aesthetics in smile line
degrades tooth function - occlusal reduction and destabilizes occlusion
What does occlusal and interproximal reduction do to the tooth
render a vital tooth sensitive as there is exposed dentine
compromise coronal seal of RCT’d teeth
What are features that a provisional should have
good marginal fit
be well contoured so there’s no overhangs
cleanable and maintainable by px
What does a poorly fitting and contoured provisional result in
px unable to clean resulting in caries and gingival inflammation
poor moisture control
gingival overgrowth
What must a provisional restoration do
establish and or maintain dental aesthetics mimicking either the original tooth or the definitive restoration
prevent sensitivity
allow ‘optimum home care’
prevent micro leakage/bacterial leakage
confirm that tooth prep is adequate
intra and extra coronal design characteristics
preserve or improve function
isolation for RCT
matrix for core build up
What are desirable characteristics of a provisional material
non irritant to pulp and periodontal tissues
low temp rise during setting
dimensional stability
adequate working tiem
adequate setting time
adequate strength and wear resistance
good aesthetics
What are the types of provisional restorations
custom formed
preformed
What is a custom formed provisional restoration
bespoke to individual situations
preferable
can be technically demanding
What is a performed provisional restoration
standard shapes and sizes
adjust to fit chair side
What material are custom resin provisionals made from
chemically cured bis acrylic composite resin
e.g protemp
How is custom resin provisional crowns customizable
fits tooth prep internally
reproduces contact points and occlusion externally
Why do we make them before the impression for the definitive restoration is taken
to help check that the tooth prep is satisfactory
check for udnercuts
check there’s sufficient reduction
What can we use to check there’s sufficient reduction
svensen gauge
Why are sectional impressions better for custom resin provisional crowns
a full arch one is unnecessary and difficult to reseat
What materials can you use for the sectional impression
additional cured silicone putty
alginate
softened modelling wax
What are the advantages of additional cured silicone putty
can be disinfected and kept by px or clinician
can be reused
resistant to tearing
What are the advantages and disadvantages of alginate
cheaper
cannot be reused or kept
What are the advantages and disadvantages of softened modeling wax
easy to adjust and smooth cheap unsuitable for deep undercuts distorts cannot be reused
What is the method for a custom resin provisional crown
- sectional impression
- prepare tooth for chosen resotration
- syringe bis-acrylic composite resin onto bracket table or mixing pad
- syringe material onto sectional impression of tooth that has been prepared
- relocate impression in the mouth (ensure fully seated and click over bulbosity of remaining teeth)
- remove before complete polymerization
- remove completely
- remove flash and ledges
- confirm tooth prep using svensen guage
- chem marginal fit and occlusion in situ
- check aesthetics
- cement using temp luting cement
If there is loss of original tooth form such as in wear cases what should be done
re establish tooth shape
pilot occlusion and aesthetics using provisional restorations
What should be done for guidance (anterior/incisaL
produce on crowns
diagnostic wax up
articulated study models
face bow reg required
Once the guidance and aesthetics are satisfactory are done what should be done
lab should duplicate the waxed up cast and construct a vacuum formed mould/stent//template
the next patient visit prepare the tooth and use the mould to produce a custom formed provisional restoration to thew new occlusion and appearance
What is the patient trial
they wear until happy with form and function
then you can adjust and alter and trim with a bur or add composite
once satifaoctry make an impression for the technician
How can provisionals help establish gingival contours
use provisional restorations to achieve satisfactory emergence profile for definitive restoration
What are the variations in provisional crowns
can be tooth colored or metal
What are the tooth colored preformed crowns
polycarbonate
clear plastic crown forms that are filled with composite
What are problems with preformed provisional crowns
unlikely to fit accurately - cervically, occlusally, interdentally
large bank of crowns needed to accommodate variation between px and this is costly
When are preformed provisional crowns useful
for situations where no impression is present prior to tooth prep or damage
e.g trauma
What is the method for preformed provisional crowns
- select shell slightly larger than prep
- trim back
- fill shell
- seat over tooth
- allow polymerization
- remove
- check fit
- trim/tidy if necessary
- cement
- cut off tag
With the preformed provisional crowns where do you trim back to
correct preparation dimension
seats fully over tooth preparation
not bedding into gingival
What are the advantages of clear plastic crowns
thin
easy to trim
What is the method for clear plastic crowns
- select and trim until fit
- pierce hole at cusp tip/canine tip/incisal angle
- fill with bis-acrylic composite resin
- seat over tooth
- allow setting
- remove from tooth
- remove plastic crown form
- check margins and occlusion
- cement with temporary cement
What are metal preformed crowns used for
used for posterior teeth
What are the materials for metal preformed crowns
aluminum
stainless steel
What are issues with the preformed metal crowns
ledges and sharp margins can cause soft tissue trauma
difficult to adjust, some provided with crimping device to help mould margins
If you are replacing an old crown what can you do
can use/modify original crown for temp
may need partially sectioned/reclined and preserve original crown as much as possible
What are the preformed malleable composite crowns
soft
easily moldable to tooth prep
What is the method for composite provisional restorations
moulded over tooth to desired shape partially lite cured remove then completely cure outside of mouth check fit adjust if necessayr cement
What are composite provisional restorations
they used in veneer cases
spot bonded
What are indirect provisional restorations
lab made
What are the advantages and disadvantages of indirect provisional restorations
Adv low shirnkage intra orally more accurate high strength used long term
disadv
time and cost consuming
What are examples of indirect provisional restorations
composite
acrylic
meta
What are provisional replacement of missing teeth
conventional bridge work temporization (diagnostic wax up)
acrylic removable partial denture
essix retainer with pontic
edentulous space and only provisional crowns on prepared teeth
resin bonded bridges and implants
What advice should be given to the px
brushing 2-3 x daily
interdentally cleaning 1-2x daily
caution with floss as may pull out the restoration
If patient doesn’t follow advice what can happen
increased GCF, bleeding, poor moisture control for definitive impressions
inadequate cement lute placement
