Provisional restorations play a critical role in the successful treatment of the prosthodontic patient. An interim restoration that meets the functional and aesthetic requirements of the patient can mean the difference between success and failure of a treatment plan. Clinicians have often made the mistake of regarding the provisional as being merely “temporary” and thus do not devote adequate time and effort to this phase of treatment. This may result in the fabrication and cementation of an interim restoration, which is inadequate functionally and/or morphologically. According to Shillingburg, besides from meeting the individual patient’s aesthetic desires, the restorations should also meet the following requirements:
1. Provide pulpal protection.
2. Provide positional stability.
3. Provide the patient with the proper occlusal function.
4. Be easily cleanable.
5. Be strong and retentive.
6. Be aesthetically pleasing.
7. Margins should not impinge upon the gingival tissues.
Campagni and Caponigro (2) accurately describe the requirements of a successful provisional as one that mimics the planned restoration(s) in occlusal and axial morphology as well as aesthetics, while fulfilling its requirements for maintaining tooth position and protecting the tooth structure during function.
Numerous techniques and materials for fabrication of single-unit or multiple-unit provisional restorations have been described in the literature to meet these requirements. This article seeks to provide the clinician with an overview of various techniques and materials which have proven to be useful and thus have endured over the years.
The Direct Technique
This technique utilizes a prefabricated stent or matrix filled with the practitioner’s choice of provisional material, which is placed directly onto the patient’s prepared teeth. After initial polymerization, the material/matrix assembly is removed from the mouth, trimmed, and polished.
Kaiser and Cavazos (3) describe the following technique:
1. On the patient’s diagnostic cast, wax in any missing teeth.
2. Duplicate the cast and fabricate a matrix from a material of the clinician’s choosing.
3. Prepare the teeth.
4. Lubricate the teeth.
5. Place autopolymerizing resin into the matrix and seat onto the prepared teeth. Use a pumping motion to ensure that the provisional restoration will not get locked into any undercuts.
6. After initial set, remove the matrix from the mouth and allow the provisional restoration to completely polymerize.
7. Trim, contour, and polish.
Nayyar and Edwards (4) also describe a direct technique for use with a single unit using a commercially available metal crown in which the crown is relined directly on the tooth with autopolymerizing resin :
1. Measure the mesial/distal width of the tooth to be prepared.
2. Pick out a corresponding commercially available metal provisional crown.
3. Seat the crown, trim any excess material below the margin to the proposed finish line.
4. After preparation, lubricate the prepared tooth and coat with cavity varnish.
5. Pour acrylic resin into the crown, seat it and have the patient bite into the centric occlusion.
6. After initial set, lift the crown 3 mm and reseat. Repeat this action three or four times.
7. Remove, trim, and contour after the acrylic resin reaches final set.
One of the disadvantages of using a commercially available metal provisional crown is that the patient may complain about metallic taste when chewing food. Polycarbonate crowns may also be used in the preparation of an anterior tooth for a single-unit restoration. However, the aesthetic demands of patients often prevent their use in this region of the mouth.
Christensen (5) describes another method for direct fabrication of a single-unit using wax as a stent:
1. Fabricate a baseplate wax impression of the tooth to be prepared plus one to two teeth mesial and distal.
2. Prepare the tooth.
3. Place acrylic resin in the wax impression and seat it onto the lubricated prepared tooth.
4. As polymerization occurs, pump the wax matrix up and down a few times.
5. After initial polymerization, remove the wax matrix from the mouth and allow it to completely polymerize extraorally.
6. Trim and polish.
Psichogios et al (6) describe a direct technique for provisionalizing multiple single-units and three- or four-unit fixed partial dentures:
1. Fabricate a diagnostic waxing.
2. Construct a dual arch custom impression tray.
3. Take an impression using an addition silicone.
4. Trim the impression material 3-4 mm apical to the gingival margins of the diagnostic waxing and only include cusp tips or incisal edges of the opposing arch.
5. Prepare the teeth and coat with a lubricant.
6. Use a BisGMA restorative material to fill the impression.
7. Have the patient close into the custom tray.
8. Remove the tray after two minutes.
9. Bench polymerize for another two minutes.
10. Trim and polish.
.
