Provisional Materials: Advances Lead to Extensive Options for Clinicians
The progression of provisional materials to bis-acrylics has lead to such improvements as easier handling, improved compressive and tensile strength, less water sorption, and less shrinkage. The end-result is more options for clinicians for high-quality chairside provisional restorations. Newer provisional materials are easy to manipulate and bring increased comfort to the patient. This review of current products affirms that the choices of provisional materials available for the dental professional today are quite extensive and have advanced the quality of interim restorations.
The provisional or “temporary” crown has been an integral part of crown and bridge procedures in dentistry, and throughout the years there has been an evolution in the materials used for this purpose. Dentistry has progressed dramatically since the workhorse powder and liquid self-cured methacrylate-type materials used decades ago. The evolution of provisional materials to bis-acrylics, complete with auto-mixing, easier handling, improved compressive and tensile strength, less water sorption, and less shrinkage has lead to the creation of chairside provisional restorations that are better than ever. These self- or light-cured materials offer expanded color range possibilities and varying degrees of translucency/opacity.
Bis-acrylics are dimethacrylate materials and can be categorized into two groups: bisphenol A-glycidyl methacrylate (bis-GMA); and urethane dimethacrylate (UDMA).1,2 These materials are multi-functional methacrylate esters that are filled with glass and/or silica particles. They are very easy to manipulate with their availability in auto-mix cartridges, and they bring a good level of comfort to the patient because they produce minimal odor, heat, and shrinkage during the curing process.3,4
The basic procedure for producing a provisional crown is illustrated in Figure 1 through Figure 10. There are a number of provisional materials that are in widespread use today. This article will examine several provisional material products.
One brand of products (Luxatemp®, DMG America, www.dmg-america.com) consists of a family of self- and light-cured composite provisional materials that have a glass filler content of 44 wt %, with a working time of 45 seconds and setting time of 2 to 3 minutes, and complete cure of 6 to 7 minutes. The product is methyl methacrylate- and peroxide-free. The manufacturer instructions for use (IFU) for the product states that with its self-curing materials “the setting reaction has to be monitored intraorally (eg, with a scaler) as the temperature in the mouth has a significant influence on the setting time and the temporary can be removed only during the elastic phase.” This is a very important concept that clinicians should be mindful of for all self-curing provisional materials.
Several product variations in the Luxatemp line include: Luxatemp Fluorescence (which is aimed at achieving superior esthetics), Luxatemp Ultra (which incorporates proprietary nano technology to provide increased flexural strength), and Luxatemp Solar (a light-cured material). The light-cured Luxatemp Solar adds a new dimension to the arena of provisional materials in that the material has extended working time since it “sets on command” when cured with a light source. The manufacturer reports that it has high strength—with compressive strength being 250 MPa5—making it an ideal choice for long-span temporary bridges.
An important feature of bis-acryl materials is their ability to enhance, or add to, the provisional restoration using composites. Products specifically designed for this purpose include LuxaFlow™ and LuxaFlow™ Ultra. The LuxaFlow product is a composite formulated specifically for use as an add-on resin for any bis-acryl provisional material. The manufacturer reports that it is ideal for blocking out undercuts and helps create a seal at the gingival interfaces of the provisional being created.6 LuxaFlow Ultra adds a fluorescent property to LuxaFlow, which makes it well suited for provisional add-ons in the esthetic portions of the oral cavity.
LuxaGlaze® Light-Cured Varnish is a one-bottle light-cured varnish that provides a surface glaze for provisionals. It cures in as little as 10 seconds after application, making it a convenient way to add a superior esthetic sheen to a provisional restoration, and it can be used with any provisional bis-acryl material.
The latest in the Protemp™ (3M ESPE, www.3MESPE.com) line of provisional materials, Protemp Plus, is reported to be a highly fracture-resistant material with high gloss without polishing.7 It comes in five shades designed to match 3M ESPE Filtek™ Supreme Ultra Flowable Restorative materials. Like the previously described materials, it can be used for single- or multiple-unit provisional restorations. The manufacturer reports that Protemp Plus is a unique bis-acryl material that contains “a new generation of sophisticated (nanotechnology) fillers,” which makes it a strong and long-lasting provisional material with high esthetics through natural gloss and fluorescence that requires no polishing or glaze to bring out the sheen. A sheen is generated by simply using an alcohol gauze to wipe the provisional restoration with ethanol.
Working time for Protemp Plus is 40 seconds and it should be removed from the mouth between 1:40 to 2:50 minutes after start of the mix (the set should be monitored carefully). It is recommended to keep the provisional restoration in the matrix in which it is created for at least 5 minutes before removal and trimming in order to achieve optimum esthetic properties.
Another interesting addition to the Protemp line is the Protemp Crown Temporization Material. These preformed, malleable composite temporary crowns come in nine preformed sizes, can be custom fit for single-unit crowns that provide remarkable strength—with compressive strength of 395.6 MPa—and are light curable. Even so, they exhibit low intraoral heat during the fitting and curing process. The process of placing a Protemp Crown is rather easy. First, the crown size is determined using the manufacturer’s crown size tool, and the temporary crown is prepared by removing the film from the Protemp Crown. The height of the adjacent teeth is then measured to help determine the amount of excess material to remove from the gingival aspect of the crown, and that portion of the Protemp crown is removed and contoured. Then, the crown is placed on the prepared tooth, adapted, and shaped, and the interproximal contacts established to achieve a snug fit. The prepared tooth should be moist during this process.
Then the buccal and lingual surfaces of the Protemp crown should be gently closed and the occlusion established by the patient biting down. At this point it may be necessary to readapt the buccal and lingual margins again. Any last adjustments to the occlusion should be made, and the patient should bite gently again to check the buccal margin and tack-cure done for 2 to 3 seconds. Over-tack-curing should be avoided or it may become difficult to retrieve the crown. With the patient’s mouth open, the lingual margin should be checked for adaptation; then the patient should close and a seal made as appropriate, and the lingual surface tack-cured for 2 to 3 seconds. The occlusal surface is then done similarly.
Finally, the Protemp Crown is removed, and light-cure is done for 60 seconds to fully cure all exposed composite. The crown is trial fitted, and any minor adjustments needed to the occlusion and margins are made. Polishing with a dry muslin rag wheel or polishing brush is then done, and the provisional cemented to place, removing excess temporary cement as appropriate.
Another new bis-acryl provisional material (Integrity® Multi-Cure, DENTSPLY Caulk, www.caulk.com) is reported by the manufacturer to deliver durable results due to wear resistance and strength properties (compressive strength of 386 MPa to 394 MPa), minimal shrinkage, and fast procedure times (5-minute self-cure, 20- to 60-second light-cure). Available in five shades, Integrity Multi-Cure has added fluorescence for esthetics and can be polished to a natural luster. The material has a working time of 45 seconds, and is removed from the mouth after approximately 90 seconds. Once removed the material can either set for 5 minutes before removal from the matrix or can be light-cured for 20 seconds to enable faster trimming and polishing. This reduction in procedure time can certainly be important when time is of the essence in the procedure and for the patient.
Inspire™ (Clinician’s Choice, www.clinicianschoice.com) is another provisional material available to the profession. The manufacturer states that it has an elastic modulus of 3136 MPa,8 and it is reported to have high flexural and compressive strength, is designed to be easy to trim, and is resistant to fracture. Working time is 40 seconds with removal from the oral cavity between 1:20 and 2:30 minutes. Total cure occurs at 4:30 minutes. The manufacturer also states that it has one of the lowest exothermic reactions, coming in at 53°C. The product comes in four shades.
Perfectemp 10 (DenMat, www.denmat.com) is what the company calls, “the next generation of temporary material” that delivers fast, strong, esthetic temporaries. It has a 1:30 minute intraoral and 4:30 full cure set time. The material’s elastic modulus is reported at 3500 MPa, flexural strength 120 MPa, and volumetric shrinkage less than 3.4%.9 The flexural strength makes it “stiffer” than other materials. Perfectemp 10 is available in five shades.
The Structur® (VOCO America, Inc., www.voco.com) family of provisional materials consists of a variety of products, including Structur 3 and Structur Premium. Structur 3 is reported by the manufacturer to be a nanofilled material with high fracture resistance and compressive strength (more then 500 MPa), quick setting (45 seconds intraoral setting time), and strength.10 It features what the manufacturer calls “Wipe and Go” technology, which provides a natural gloss and tooth-like fluorescence that comes in eight shades. Again, this high sheen is achieved with the use of an alcohol wipe on the material after completion of trimming and polishing.
Structur Premium is a 1:1 cartridge mix like Structur 3 that the manufacturer reports as being a fast setting bis-acryl provisional material with ceramic-like esthetics, high fracture resistance ideal for long-span bridges, a brilliant gloss, natural fluorescence, and a lifelike incisal shade that also comes in eight shades with a fast intraoral setting time (30 to 45 seconds). The wide range of shades in the Structur products gives the clinician a broad array of shades to help match almost every possible tooth shade the patient presents with in a cost-effective manner, because the mixture is 1:1 versus the 10:1 base-to-catalyst auto-mix cartridges of other provisional materials.
Another material (Visalys® Temp, Kettenbach, www.kettenbach.us) is a self-cured fluorescent provisional material with high translucency that is based on a multifunctional acryl composite that uses no bisphenol A or bisphenol A precursors. The manufacturer reports it is an easy-to-use high fracture-resistant material (impact strength 12.5 kJ/mm2, flexural strength 132 MPa), can be precisely trimmed with minimal dust, and has a high luster without polishing by using an alcohol wipe.11 Like many of the other materials described, working time is 40 seconds, and the temporary crown and bridge material should be removed from the mouth from 1:20 to 2:20. Visalys Temp can be removed from the matrix at 2:20 and trimmed after 4 minutes. The material comes in six shades.
A diurethane dimethacrylate material (Tuff-Temp™ Plus, Pulpdent Corp., www.pulpdent.com) features a synthetic rubber molecule inserted into it to produce a tough, impact-resistant, dimensionally stable provisional material that the manufacturer calls a “rubberized urethane.” This material is reported to be a fluorescent, strong, impact-resistant provisional product that does not shrink or distort and grips the tooth tightly.12 It virtually eliminates fractures and debonding due to its rubberized-urethane chemistry.13 The material grinds and powders during trimming without softening or distorting, which makes refinement of the margins very easy for the operator. It comes in six shades that can be used in self-cure or light-cure modality. The working time of the material is similar to the previously discussed materials (45 seconds), and it is removed from the mouth 2:15 from the beginning of the mix. The oxygen layer is removed with an alcohol wipe, and then the material can be light-cured to accelerate the cure or can self-cure at 5 minutes after mix was initiated. The compressive strength is 200 MPa, Vickers Hardness is 514 MPa, and flexural strength is 75 MPa.12 This flexural strength indicates that the material is less brittle and, as such, has both fracture and impact resistance due to the rubberized urethane component as compared to traditional bis-acrylics.13
There is a shade-matching light-cured flowable resin available in Tuff-Temp with a matching rubberized-urethane chemistry to add to the provisional as needed to make alterations and create smile designs. A glaze (Tuff-Temp Provisional Glaze) can also be applied and then light-cured to create a highly glazed provisional.
Selecting a Material
Certainly, the choices of provisional materials available for the dental professional today are quite extensive. Any one of the aforementioned products, not to mention other products not covered in this report, can work very effectively depending on the clinician’s needs, which can vary greatly from case to case. Materials have diverse pros and cons. Only after thorough samplings of various products can a clinician determine which ones are best for his or her use.
During investigation for this article, it became clear to the author that finding detailed, in-depth data on the overall physical properties on a number of provisional materials was difficult or near impossible. Products where no specific data was found regarding the mechanisms used to make such general claims as “high strength” and “high shine” are not included in this article. While it would be beneficial for clinicians to compare materials and understand any ramifications of using one material versus another, this is not always possible. Therefore, often times clinicians must “test drive” products to see what works best in their hands. Cost, of course, is usually a consideration when selecting a material, however it should not be the focal point of a clinician’s decision. Factors such as ease of use, fracture resistance, the ability to function well and retain over the period of time that the provisional will be present, and how well the marginal integrity can be achieved should have the greatest weight in the decision-making process.
The author has no affiliation with any of the companies mentioned in this article.
About the Author
John C. Comisi, DDS, MAGD
Private Practice, Ithaca, New York
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