Provisional Restorations Flashcards
what is a provisional
a prosthesis designed to enhance esthetics, stabilization and/or function for a limited period of time after which it is to be replaced by a definitive prostheses
what is a provisonal used for
to assist in determination of the therapeutic effectiveness of a specific treatment plan or the form and function of the planned definitive prosthesis
what is the advantage of digital dentistry
provisionals are not needed when you can digital scan and mill in the office as the patient leaves the office with a cemented definitieve restoration
what are the functions of a provisional restoration
- prevent sensitivity
- prevent drifting
- allow tissues to heal
- return function to dentition
- esthetics
- diagnostic evaluations
what are the requirements of a quality provisional
- pulpal protection
- positional stability
- occlusal function
- ability to clean
- marginal integrity
- strength and retention
- esthetics and phonetics
how do provisional restorations protect the prepared teeht
- protect against plaque and saliva
- protect against irritating and painful stimuli such as temperature changes and chemicals/fluids
- protect against abrasion or breakage of prepared tooth
what provides positional stability of the provisionL
-proximal contacts
- occlusal contact
- inter-abutment stability with a bridge
a provisional will prevent _____ drifting of the prepared and/or adjacent eeth
lateral
a provisional with open contacts will allow:
food and debris to impact in between
what do open contacts lead to
short term discomfort and pain
- periodontal inflammation and possibility of too much bleeding to be able to seat the crown when patient returns
without appropriate contacts on your provisional:
there is a good chance the teeth will shift collapsing the vertical between your preparation and opposing
what does lack of occlusal contact result in
extrusion
what will happen when trying to seat definitive crown if provisional is too low
the crown will be high
- material can be thinned and weaker, anatomy destroyed and crown cant function appropriately in the occlusal scheme of the patient
if the temporary is too high:
there will be pain, possible loss of the temporary or a breakage of temporary
describe the ideal occlusal contacts
- ideal centric occlusal contacts
- lateral and protrusive guidance where appropriate (anterior teeth)
- no contact in lateral or protrusive on posterior teeth
describe the provisonal/peridontal interaction
- non- impinging margins
- physiologic contours, emergence profiles, embrasures, and proximal contacts
- smooth surface texture and finsih
- all these lead to optimum periodontal health and predictable crown delivery
describe provisional marginal integrity
- fit as close to the finish line of the tooth as possible
- shape the contour to make it smooth and undetectable with an explorer with a smooth surface finish
- seal the provisional at the margin to prevent pain, sensitivity or dislodgement
how should the emergence profile on the provisional look
flat or slightly concave not convexed or bulging
what does a rough margin lead to
plaque accumulation and gingival inflammation
what does bleeding gums pose a challenge to
impressions and crown seating
need adequate _______ for strength
thickness of material
what allows for adequate thickness of temporary
adequate tooth reduction
what is the #1 reason temporaries break
occlusion
describe bis-acryl
- easy to use and easy to trim and polish
- is a brittle material which can fracture if occlusal load is too strong and if material is too thin
describe provisional esthetics and phonetics
- maintain phonetics
- facial lip support
- proper tooth form and appearance
- tooth shade compatible with remaining teeth
- provisionals can be a preview of final restorations to enhance patient acceptance
how can phonetics be maintained with temporaries
-proper tooth length
- position
- contours
describe interim fabrication
- material is placed in a matrix while in a fluid state
- matrix is placed on tooth and allowed to solidify
- matrix is trimmed and polished while material continues to harden
- must continually place temporary on preparation or temporary will not fit
- most interim materials shrink as they solidify
describe direct interim fabrication
- create matrix prior to prep
- prepare tooth
- place temp material in matrix and seat in mouth
- remove, trim, and adjust
- cement
the _______ forms the external portions of the interim while the ______ forms the internal of the interim
matrix; preparation
what are the 2 types of interim restorations
-external surface forms
- directly on tooth versus indirectly on cast
what are the external surface forms
pre-fabricated (preformed) crowns (singles)
custom fabricated molds (multiple)
what are the temp prefabricated crowns
- aluminum or tin-silver
- stainless steel
- polycarbonate shells
- cellulose acetate shells
- VLC moldable crowns
describe pre-fabricated crown forms
- limited to single units
- must be lined with auto-polymerizing resin
- considerable modification needed for appropriate fit and contour
- best when patient in your office with crown off and lost or broken tooth with not enough tooth to make a traditional matrix form
describe custom molded interims
- less time consuming
- can be used for singles but required for multiple units
- improved contours and esthetics
- simulated planned restorations when used with diagnostic wax up
describe the direct technique
- convenient
- time required for fabrication - routine restorations
describe indirect technique
- patient comfort
- if presence of multiple undercuts, allows you to see this before it gets stuck in patient mouth
- great of long span bridges or multiple units
- can be fabricated ahead of time in advance of the tooth prep appointment
describe lab fabricated shell provisional
- typically used for multiple units or full arch provisionals
- shell is thin and will be relined in the mouth
- made prior to preparations
- saves time on big cases
- not cheat, can be several hundred dollars
- can also mill temporary shells in office with some systems
what are the currently used materials for provisionals and what brands of each
- acrylic resins: PMMA Jet acrylic, Powder/liquid formulations
- Bis-Acryl composite resins: Bis-GMA containing materials, chemically activated, light activated
what are the advantages and disadvntages of PMMA
- A: good marginal fit, good strength, good polishability, durability
- D: high exothermic heat increase, low abrasion resistance, free monomer toxic to pulp, high volumetric shrinkage
what are the advantages and disadvantages of Bis-acryl
- A: good marginal fit, low exothermic heat increase, good strength, low shrinkage, good surface hardness and abrasion resistance, good biocompatibility, color stability and patient acceptance, can light cure
-D: surface hardness, less stain resistance, limited shade selection, limited polishability, brittle, high cost, brittleness, no rubbery stage
describe PMMA (jet acrylic) temporary material
- chemical conversion of monomer to biologically inert polymer is through a chain reaction
- unreacted free monomer is toxic
- inadequate polymerization results in poor mechanical properties
- polymerization is exothermic and there is shrinkage upon polymerization and cooling
what properties are associated with monomer im PMMA
chemical or allergic reaction
what properties of set material for OMMA
- exothermic reaction
- volumetric shrinkage
- increased strength due to polymerization
what are the properties of polymer in the powder in PMMA
- with proper amount we have strength and handling
- too little poweder- loss of strength
- too much powder- poor handling and adaptation
what are the problems with interim restorations
- time to fabricate
- length of time temp is required in the mouth
- materials are good but not great
- managing deficiencies: relining or repairing
how should you treat fractured surfaces
- grind to expose a fresh surface
- roughed this fresh surface
- composite flowable resin to repair
describe Zinc oxide eugenol
- temp bond
- low strength
- eugenol is a sedative for tooth
- eugenol can inhibit resin polymerization
when would you not use eugenol
core buildup or anything with resin because it inhibits polyermization
what are the non-eugenol cements
- polycarboxylate cement (ultratemp)
- glass ionomer based cement (smart temp)
- resin cement (telio)
what are the types of cements
- eugenol
- non-eugenol
what is the only eugenol cement
zin oxide eugenol
describe ultratemp
low strength
describe smart temp
longer term temporary use
describe telio
translucent
what are the steps to cementation
mix equal parts of base and catalyst on mixing pad with spatula
when should you check the occlusion and why
after cementation because the cement thickness can inhibit full seating of the provisional
