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					Provisional Restorations

       Wael Al-Omari.
     BDS, MDentSci, PhD
Functions of Provisional Restorations
 Comfort/tooth     vitality
   Occlusion and positional stability
   Function
   Gingival health and contour
   Aesthetics
   Diagnosis
   Other practical uses
Assessment of Aesthetic Changes
 Assess appearance of intended
 restorations
 Make directly or use a matrix made
 from the wax-up.
 Ensure patient’s acceptance

 Record the temporary crowns and
 instruct technician to copy their form
 ad shape into the final restoration
 Provisional crown can be used to
assess axial and occlusal reduction
                 Occlusal Changes
   Prevent unwanted tooth movement by maintaining occlusal
    and interproximal contacts
   Evaluate patient’s tolerance to change in anterior guidance
    or increased occlusal vertical dimension:
   Cement temporary crowns made from diagnostic wax up
    and review for aesthetics, guidance, drifting, mobility,
    decementation, and comfort
 Copy the provisional crowns guidance by a custom
  guidance table, to transfer to definitive restorations.
 It is recommended to assess tolerance to change in vertical
  dimension by a reversible method such as splint.
        Periodontal Changes
   Allow for resolution of inflammation
   Improve gingival healing and stabilization
    of gingival margin position
   Used after surgical crown lengthening
    during the healing period before definitive
    preparation and impression
Preoperative                      Polycarbonate provisional
                                      crown cemented




          Gingival healing after 2 months
          Change in Tooth Shape
    Accurately copy a satisfactory and successful
     provisional restoration to:
1.    Avoid minor or major changes in tooth shape.
2.    Avoid disrupting fine mouth movements and
      lip/tooth contact
3.    Avoid incorporating wide cervical embrasure to
      prevent air leakage
    Provisional Restorations
           Materials
 Preformed crowns
 Plastic shells: polycarbonate or acrylic. Used for

  anterior and premolar teeth.
 Metal Shells: aluminum, stainless steel or nickel

 chromium.
 Self or light cured resins
Aluminum
provisional crown
    Self or light cured resins
 Polymethyl methacrylate
 Polyethyl methacrylate (Snap, Trim)

 Bis acryl composite (Protemp)

 Urethane dimethacrylate (light cured).

 Restorative composite
A- Polymethyl methacrylate
B- Bis-acryl composite
            Cast Metal
 Nickel chromium, silver and scrap gold.
 Durable

 Can be made with external retention beads to
retain acrylic or composite
 Rarely used
    Provisional Cements
  Creamy mix of zinc oxide eugenol
 Most practitioners use proprietary cements such as Temp

   Bond
 Available with modifier to soften the cement

 Non-eugenol Tem Bond is available and used to:

1.   Cement temporary restorations for preparations for
    definitive adhesive restorations (eg All ceramic, veneers)
    to avoid interference with bonding of resin cements.
 If eugenol containing cement used, eugenol residues
    should be removed with pumice and water
Provisional Cement (Temp Bond)
Direct Provisional Restorations Techniques
   Proprietary Shells
  Plastic Shells: Polycarbonate relined with resin,
 trimmed, polished and cemented.
  Metal shells:

 1. Aluminum shells: relined with resin (short term).
     Soft and galvanize with opposing amalgam
 2. Stainless steel and nickel chromium: used with
     bruxist patients.
  Custom shells: beaded acrylic and Mill crowns
     Matrices for Provisional Restorations
 Impressions:
 Alginate: absorbs resin exotherm

 Elastomers: reusable

Advantages: simple, quick, inexpensive.
 Vacuum formed thermoplastic:

 clear vinyl sheet on stone duplicate of the wax up.

 used only in presence of number of adjacent
locating teeth
 could be used with light cured resins.

 Proprietary celluloid crown form
A- Alginate impression as a matrix
B- Provisionals with an excess material
A preoperative silicone
 sectional impression



                          The resin material in injected
                              into the impression
               Techniques
 Direct Syringing: polyethyl methacrylate.
 Indirect Provisionals:

 Used for long term provisionals.

 Strong heat cured materials can be used

 Aesthetics and occlusion made on articulated wax up.

 Indicated or multiple restorations and for an

   increased vertical dimension.
 Alginate impression of the preparations, cast in fast
set stone, and fabricate provisionals.
A- Stone duplicate of the wax up
B- Vacuum formed matrix
A- preparation          B-Excess film of material
                        attached to provisional
                        crown




C-Trimming the excess    D- Cemented provisional
                         crown
    Provisionals of Adhesive Restorations

No temporary coverage
 Simple coat of zinc phosphate cement

 Composite resin bonded to a spot

  etched on the preparation
 Composite bonded to opposing tooth
       Problem Solving
 Insufficient bulk of material: Inadequate
reduction, or make it bulkier by relieving the matrix
(impression).
 Gross occlusal errors, air blows and voids: trim
away suspected areas (interpoximal), an educe
hydrostatic pressure by cutting escape vent.
 Locking in of provisional restorations: material
engaging the adjacent tooth proximal undercut.
 Marginal discrepancy: polymerization shrinkage,
distortion on removal, reline with resin around the
margins
The inside of the alginate is trimmed
  to increase the thickness of the
             provisional
          Problem Solving
 Multiple crowns: joined restorations prevent drifting,
  gingival embrasures should be opened to access brushing.
 Premature decementation: Ensure harmony with

  occlusion, use stronger cement
 Partial denture abutment: fabricate with the denture fully

  seated.
 Eugenol containing cements: do not use if the underlying

  core is composite.
 Removing temporary cement: use modifier.

 Removal of excess cement: apply petroleum jelly to

  outside of the restorations
Pre-operative view




                     Linked temporary Crowns made
                      at chairside using preoperative
                        clear thermoplastic matrix

				
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