Provisional restorations

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  • WOW.. slide 2 is a copy from an article in BDJ 2002
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Provisional restorations

  1. 1. Provisional Restorations Wael Al-Omari. BDS, MDentSci, PhD
  2. 2. Functions of Provisional Restorations Comfort/tooth vitality Occlusion and positional stability Function Gingival health and contour Aesthetics Diagnosis Other practical uses
  3. 3. 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
  4. 4. Provisional crown can be used toassess axial and occlusal reduction
  5. 5. 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.
  6. 6. 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
  7. 7. Preoperative Polycarbonate provisional crown cemented Gingival healing after 2 months
  8. 8. 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 contact3. Avoid incorporating wide cervical embrasure to prevent air leakage
  9. 9. 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
  10. 10. Aluminumprovisional crown
  11. 11. Self or light cured resins Polymethyl methacrylate Polyethyl methacrylate (Snap, Trim) Bis acryl composite (Protemp) Urethane dimethacrylate (light cured). Restorative composite
  12. 12. A- Polymethyl methacrylateB- Bis-acryl composite
  13. 13. Cast Metal Nickel chromium, silver and scrap gold. Durable Can be made with external retention beads toretain acrylic or composite Rarely used
  14. 14. 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
  15. 15. Provisional Cement (Temp Bond)
  16. 16. 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
  17. 17. Matrices for Provisional Restorations Impressions: Alginate: absorbs resin exotherm Elastomers: reusableAdvantages: simple, quick, inexpensive. Vacuum formed thermoplastic: clear vinyl sheet on stone duplicate of the wax up. used only in presence of number of adjacentlocating teeth could be used with light cured resins. Proprietary celluloid crown form
  18. 18. A- Alginate impression as a matrixB- Provisionals with an excess material
  19. 19. A preoperative silicone sectional impression The resin material in injected into the impression
  20. 20. 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 fastset stone, and fabricate provisionals.
  21. 21. A- Stone duplicate of the wax upB- Vacuum formed matrix
  22. 22. A- preparation B-Excess film of material attached to provisional crownC-Trimming the excess D- Cemented provisional crown
  23. 23. 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
  24. 24. Problem Solving Insufficient bulk of material: Inadequatereduction, or make it bulkier by relieving the matrix(impression). Gross occlusal errors, air blows and voids: trimaway suspected areas (interpoximal), an educehydrostatic pressure by cutting escape vent. Locking in of provisional restorations: materialengaging the adjacent tooth proximal undercut. Marginal discrepancy: polymerization shrinkage,distortion on removal, reline with resin around themargins
  25. 25. The inside of the alginate is trimmed to increase the thickness of the provisional
  26. 26. 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
  27. 27. Pre-operative view Linked temporary Crowns made at chairside using preoperative clear thermoplastic matrix

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