P rovisional restorations play an essential role when performing indirect restorative procedures. An accurate-fitting temporary seals the margins of the preparation, thereby reducing microleakage and sensitivity. It also helps to support the contours of the surrounding gingival tissues, ensuring that they can be easily cleaned and remain healthy. Occlusally, the provisional restoration helps to maintain the position of the prepared tooth and adjacent teeth by providing stable interproximal and occlusal contacts. All of these factors combined will significantly impact the seating of the definitive restoration by maintaining gingival health and tooth position.

Three main factors are involved in fabricating provisional restorations that achieve all of the aforementioned goals. These factors are the type of provisional material, the fabrication technique, and the amount of time spent fabricating the provisional restoration. Currently, there are more provisional restorative materials on the market than ever before. The two main categories of materials are the powder/liquid acrylics (methyl-methacrylates, ethyl-methacrylates) and the composite-based resins (Bis-acryl composites, light-cured composites). Although the chemical make-up and handling characteristics of these materials may be different, all of these provisional materials can be used successfully. So, if all of the materials can be used clinically to accomplish the goals of provisionalization, what is the limiting factor? The amount of time spent in fabrication of the provisionals and/or the technique. Typically, the amount of time spent fabricating the provisional is directly proportional to the amount of time remaining in the appointment before the next patient. With this in mind, the ideal provisional material and technique for single units would be one that is both time-efficient and user-friendly. The Protemp™ Crown (3M ESPE, St. Paul, MN) can be used to accomplish both (Figure 1).

PROTEMP CROWN TEMPORIZATION MATERIAL
The Protemp Crown combines the advantages of a composite-based resin temporization material (customized fit, esthetics) with the advantages of a prefabricated crown (no matrix required, efficient). What is unique about the Protemp Crown is that the material itself is malleable and hence does not need to be relined with any other material. In its uncured state the Protemp Crown handles like clay, which allows the crown to be easily customized and adapted (Figure 2A and Figure 2B). The malleable nature of the material not only provides an intimate fit to the prepared tooth structure and margins, ut also accurately captures the proximal and occlusal contact by having the patient bite together. Once the contours have been established, the restoration can be tack-cured to reduce the possibility of distortion upon removal. After the provisional is removed from the mouth, it can be fully light-cured before finishing and polishing. Currently, Protemp™ Crown Temporization Material (3M ESPE) is available for maxillary and mandibular molars, premolars, and canines in one universal shade. The physical properties of Protemp Crown Temporization Material show both a high flexural strength and fracture toughness with a wear rate that is similar to direct composite. The material is also radiopaque.

TECHNIQUE 
Upon completion of the preparation, the first step is to determine the proper Protemp Crown size. Given their malleability, Protemp Crowns come in only two sizes (small and large), with the main difference being the mesialdistal width. To obtain the appropriate size, the mesial-distal width of the space needs to be measured (proximal contact  proximal contact) (Figure 3). The provisional kit comes with a crown-size tool to help measure the mesialdistal width; however, the space can just as easily be measured with a periodontal probe or calipers. To better customize the crown before trying it in, the crown height of the adjacent teeth also needs to be measured. Once the appropriate crown size is chosen (according the mesial-distal width), the crown height measurement is used as a guide to determine the amount of excess to be trimmed off the gingival cuff (Figure 4).

With the excess trimmed from the gingival margin, the crown can be seated over the preparation to begin the adaptation process (Figure 5A). It is advisable to apply a light coat of petroleum jelly to the preparation to help prevent the crown from adhering and to make the removal process easier. Once the crown is in the mouth, adapt the buccal and lingual contours with your fingers to begin establishing the contour of the axial surfaces and to help establish the interproximal contacts (Figure 5B). Next, have the patient close into maximum intercuspation to help establish the occlusion. While the patient is still closed, adapt the provisional to the buccal margin using a plastic instrument or finger (Figure 6A). The plastic instrument can also be reoriented and used to start contouring the interproximal areas.

With the patient in maximum intercuspation and the buccal margin adapted, tack-cure the buccal surface for 2 to 3 seconds (Figure 6B). Care should be taken not to over-cure the material as this may cause the provisional to lock onto the preparation. The next area to be adapted is the lingual margin. With the patient open, adapt the lingual margin with a plastic instrument or finger while maintaining finger pressure on the buccal surface to help prevent movement or dislodgment of the crown (Figure 7A). Once completed, tack-cure the lingual surface for 2 to 3 seconds and then the occlusal surface for 2 to 3 seconds (Figure 7B and Figure 7C). After the tack-cure, carefully remove the provisional crown and light-cure for an additional 60 seconds outside the mouth, making sure to expose all of the surfaces to the light (Figure 8A through Figure 8C). Conventional finishing of the provisional crown can be accomplished with carbide burs, rubber wheels, and/or finishing discs. The final polish is completed in two steps. The first uses a wet rag wheel and pumice followed by a high shine using a dry rag wheel and polishing paste. Once the polishing is completed, the restoration can be tried in the mouth to verify the fit and occlusion, and conventionally cemented with temporary cement (Figure 9A and Figure 9B).

CONCLUSION
The Protemp Crown is a preformed, light-cured, tooth-colored composite crown designed for full-coverage provisional restoration of molars, premolars, and canines. The uniqueness of the material can be attributed to the fact that it is malleable and does not need to be relined with any other material. The Protemp Crown creates single-unit provisional restorations that are not only customized and esthetic, but also easily fabricated in minimal time.