Provisional restorations

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 ChangesAssess 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 contact3. 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 methacrylateB- 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: reusableAdvantages: 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 matrixB- 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 upB- 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