DENT204, UNC School of Dentistry PROVISIONAL RESTORATIONS DENT204, UNC School of Dentistry Stephen C. Bayne and Jeffrey Y. Thompson Department of Operative Dentistry School of Dentistry University of North Carolina Chapel Hill, NC 27599-7450 Temporary restorations are used in dentistry either (1) for repair of a fractured or compromised restoration or tooth structure, or (2) as a substitute restoration while a permanent restoration is being fabricated in a dental laboratory.  2004, Bayne and Thompson, UNC School of Dentistry.

Temporary = Provisional = Non-Permanent = 2-26 weeks INTRODUCTION Definitions Temporary = Provisional = Non-Permanent = 2-26 weeks 10 20 30 40 50 weeks TEMPORARY Short- Term Long- Term Temporary System = RESTORATION + CEMENT In the case of being a substitute restoration, [CLICK] it is more appropriate to think in terms of a “temporary system” (i.e., restoration and cement). [CLICK] While the term “provisional” may be more technically correct, the term “temporary” is most commonly employed. Temporary systems may only be needed for a short time such as 2-6 weeks [CLICK] (i.e., short-term temporary), or [CLICK] might be used for a much longer time such up to 26 weeks (i.e., long-term temporary). There are even more extraordinary circumstances where a temporary might have to serve for 1-2 years. This is much more typical in the armed services where soldiers are stationed overseas or away from dental care units for very long times. The origin of a famous temporary material called “IRM” (Intermediate Restorative Material) is that is was developed under a research contract for the US Armed Services during the 1950s as a temporary for soldiers who were deployed to Korea. [CLICK] Temporary restorations can be constructed of a variety of materials, as will be seen shortly. They can be produced in vivo (i.e., direct temporaries) or ex vivo chair-side or in a dental laboratory (i.e., indirect temporaries). [CLICK] Direct temporaries only require about 12-15 minutes and this sequence is illustrated above. EXAMPLES: Temporary crown fabrication procedures: a. DIRECT -- intraoral fabrication (and intraoral/extraoral curing) b. INDIRECT -- extraoral or laboratory fabrication 0s = mix and add to pre-impression; 45s = insert in mouth; 1m = initial set; 2m = remove; 6m= trim; 7m =contour and polish; 12m =cement in mouth.

Preparation of Temporary Bridge INTRODUCTION Preparation of Temporary Bridge Mix. Add to pre-impression. Insert in mouth. Initial set. Trim. Light cure in mouth. Light cure in hand. The chairside procedure for an indirect temporary bridge, made from composite material, is illustrated above. A pre-impression is required before tooth preparation so that the anatomic contours of the original tissues can be captured. [CLICK] Material for the temporary restoration is dispensed and mixed. Then it is [CLICK] loaded into the pre-impression and [CLICK] inserted into the mouth over the prepared tooth surfaces. Then it is [CLICK] allowed to set and then is removed. The temporary bridge is trimmed to remove flash and excesses, and then light-cured [CLICK] to complete the set. Finally, [CLICK] it is carefully trimmed, polished, [CLICK], and then [CLICK] cemented in place. Trim and polish Cement.

Goals and Desirable Properties INTRODUCTION Goals and Desirable Properties 1. MANIPULATION GOALS: a. Clinical concerns: ease-of-use; versatility; low cost; easy to repair b. Reaction: Fast; low polymerization exotherm; high percent conversion c. Minimal surface reactions: O2 inhibition on curing; no interactions with impression material (e.g., PVS) causing surface inhibition 2. PHYSIOLOGIC GOALS: a. Protection of hard and soft tissues; stabilization of tooth; functional for chewing; b. Therapeutic (indirect pulpal medication); patient comfort 3. MATERIALS PERFORMANCE GOALS: a. Good esthetics: good color matching; stain resistance (to coffee and tea) b. Good fracture and wear resistance c. Good biocompatibility -- no sensitivity reactions 4. POST-TEMPORIZATION GOALS: no interference with cements for permanent restoration There are several requirements for success of provisional restorations. Obviously, the longer the materials are in service, the more complicated it is to succeed at all of these. These can be divided into (1) manipulation goals, (2) physiologic goals, and (3) materials performance goals, and (4) post-temporization goals, as listed above. Manipulation concerns involve ease-of-use. There should be no problems arising manipulation. It is important for the reaction to occur efficiently with little exothermic heat. At the same time, the final surfaces should be completely reacted. Oxygen inhibition often leaves a sticky outside surface that must be wiped away before finishing and polishing. Obviously it is important that the provisional crown be as functional as possible so that the patient feels comfortable. The major materials performance expectations are that the restoration be esthetic, fracture resistant, and wear resistant. If the provisional cement is adequate then there will be good retention as well. Fracture resistance is related to strength and toughness. Wear resistance is related to filler level and extent of small filler loading. Finally, the provisional materials (cement and restoration) should do nothing to interfere with the permanent restoration. It is possible that some of the provisional materials could contaminate the surfaces of the preparation and cause problems for permanent cementation.

Provisional Restorations and Cements CLASSIFICATION Provisional Restorations and Cements 1. Provisional restorations a. Intracoronal Restorations: (1) ZOE-based and/or ZONE-based temporaries b. Preformed Provisional Shell Crowns (and Cements): (1) Polycarbonate Crowns (2) Metal Alloy Crowns (Al, Anodized Al, Sn-Ag, Stainless Steel, Ni-Cr) c. Custom-Fabricated Provisional Crowns: (1) MMA-like products – self-cure (MMA/PMMA, IBMA/PBMA, EMA/PEMA) (2) Epimine-imine products – self-cure (3) Bis-acryl, bis-methacryl, Bis-GMA-like – self-cure, dual cure, VLC (a) Resins (b) Composites Provisional restorations for crowns and bridges are much more demanding than for intra-coronal restorations. [CLICK] Extra-coronal restorations can employ preformed shell crowns of polycarbonate plastic or different metal alloys. They are adapted to the tooth structure by trimming the margins. Then, they are filled with provisional cements and placed over the preparations. Of course, they fit poorly at best and rely on the skill of the clinician to make them a proper geometry and size. Custom-fabricated provisional crowns are molded by filling the original impression and gently pressing it back over the preparation. Materials can be set in the mouth or out of the mouth. The latter is preferable because of the setting exotherm. Current systems employ either (1) denture base monomer systems of MMA/PMMA (or similar monomers) or else they use (2) composite-like acrylic monomers which are highly filled. These are so called bis-arcryl or bis-methacryl monomers. These latter systems are very similar to Bis-GMA and can be self-cured, dual cured, or visible-light cured. These systems also are called resin provisionals but composite is the more correct term. To lute or bond these to the tooth preparations, provisional cements are utilized. [CLICK] These cements do not need to have much retentive strength or adhesion, since they need to be removed later and be cleaned off the tooth structure. Often vaseline or petroleum jelly will be intentionally added to permanent cements to destroy any potential for adhesion. 2. Provisional (Temporary) cements: a. ZOE-based or ZNOE-based cements: b. Calcium hydroxide cements c. "Admix cements" (Cements mixed with vaseline or petroleum jelly) d. Composite cements (without bonding systems)

Provisional Restorative Materials PRODUCTS Provisional Restorative Materials A wide range of current provisional restorations are available on the current market. A sampling is shown above in the table. The most popular systems are Bis-Acryl or Bis-Methacryl (composite resin) [CLICK] ones shown at the bottom of the table. Many of these different competitor’s products are licensed from the dental company, DMG Ltd in Germany. Thye are actually the same formulation under different brand names.

PRODUCTS Temporary Cements Provisional or temporary cements are quite varied as well. Examples are shown above. Quite often a provisional composite is supplied with a provisional cement.

POPULARITY 1999 Provisional Materials Market Share (~$20 Million) Self-Cure Composite Resins 84% Methyl & Ethyl Methacrylates 12% Dual-Cure Composite Resins 4% DMG/Zenith Luxatemp 25% Caulk Integrity 15% ESPE Protemp 32% Kerr Temphase 8% Parkell Snap 5% Bosworth Trim Other All Types 10% Personal Communication: Dr. Ed Shellard-Kerr Corporation The information reported above has been provided by Dr. Ed Shellard of Kerr Corporation about the relative use of provisional materials. In the top left-hand diagram, note that most provisional restorations [CLICK] are now made from self-curing composite. The diagram [CLICK] at the bottom right-hand portion of the slide shows the market share for the most popular products. Kerr Temphase, Caulk Integrity, ESPE Protemp, and DMG/Zenith Luxatemp [CLICK] are popular self-cure composites and dominate the market with about an 80% share. Snap and Trim (total 10% share) [CLICK] are MMA/PMMA types that are not as strong, but work well, as long as the provisional restoration is neither very complex or large.

Examples of Chemical, Physical, and Mechanical Properties Iso-Temp (3M) Luxatemp AutoMix (DMG) Prodigy Composite (Kerr) Z100 Type Temporary Permanent Cure CC DC VLC Cure Time 6-7 m % Shrinkage DT 38 C CS (MPa) 220 263 324 DTS (MPa) 36 41 57 FS (MPa) 80 124 105 BFS (MPa) 104 128 183 190 Provisional restorative materials are resistant to chemical degradation in the mouth (e.g., good chemical properties). They are thermal and electrical “insulators” (e.g., good physical properties). But, they do not have quite as good mechanical properties as commercial composites. For the sake of comparison, the chart of compressive strengths demonstrates that MMA/PMMA materials are much weaker than Bis-Acryl/Bis-Methacryl composites. [CLICK] A similar trend is noted with flexural strengths as well. [CLICK] In the table above are examples of just a few of the properties of two examples of provisional restoration materials (LEFT) [CLICK] compared to two examples of standard composite materials (RIGHT). Note that Luxatemp (provisional material) [CLICK] is not quite as strong as Prodigy composite.

Bis-Acryl and Bis-Methacryl Materials EXAMPLES Bis-Acryl and Bis-Methacryl Materials Temphase™ Temphase temporary crown and bridge material is a two-component (catalyst and base) material dispensed and mixed by a cartridge/static mixing tip combination. Temphase is intended for use in both short- and long-term crown and bridge temporaries. The material is compatible with light-cured composites for repair and characterization. Temphase contains methacrylate components and is radiopaque for easy radiographic identification. Available in two set times. Examples of 3 bis-acryl-based temporary materials are shown above. If you click on the individual samples, then you will be connected to the individual websites to look at more details of the materials. NEXT SLIDE

EXAMPLES MMA/PMMA Materials NEXT SLIDE Examples of 2 MMA/PMMA-based temporary materials are shown above from Bosworth. If you click on the individual samples, then you will be connected to the individual websites to look at more details of the materials. NEXT SLIDE

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