Predictable Techniques for Successful Provisional Restorations
Providing the natural-looking, long-lasting provisionals patients want
Patient expectations of provisional restorations have increased dramatically with the advent of improved materials. Patients want a natural-looking, comfortable provisional restoration and often will not accept one that is not esthetic, rough, or ill-fitting. With the increase of elective cosmetic procedures, patients demand to leave the office looking as good as or better than when they walked in, even if they do not receive the finished restoration(s) at that appointment. In addition, making suitable provisionals takes the pressure off the dentist and laboratory to rush to complete the final case. Crowns can be seated when all are completely satisfied, regardless of the number of appointments necessary.
Patients lead busy lives and want to be assured that their provisional restorations will not come loose, particularly if they need to travel. Several years ago, for example, a patient presented to the author’s office to have all of her maxillary crowns replaced. Although the teeth had all been prepared, impressions had not yet been taken when she was unexpectedly called back to Europe. During the 4 months she was there, none of the provisionals needed to be re-cemented. Upon her return, the provisionals were removed and impressions were made. The crowns were fabricated and seated at the following appointment.
Functions of Provisional Restorations
Cemented removable provisional restorations serve many purposes and must satisfy many requirements.1 They help to cover tooth structure that has been prepared and would be sensitive if left exposed.2 They impede the migration of gingival tissue coronally over the margins of the tooth preparation.3 Provisional restorations help to prevent teeth from shifting, migrating, or erupting until a definitive restoration can be fabricated.4 They serve as a template or a guide for the desired shape, size, and color of an indirect restoration.5
Improvements of Provisional Materials
The change from polymethyl methacrylate provisionals to bis-acryl composite provisionals was a major improvement.6 The new materials were easier to mix, set faster, and did not give off as much heat. Shrinkage was significantly reduced. They were not as porous and did not stain or absorb odors as readily. They were more translucent and esthetic than the acrylic resins. Adjustments were easier and more precise because a high-speed handpiece could be more readily used to shape the provisional. Smells from setting material were not as strong. Finally, the material polished better and felt smoother to the patient.7-10
The selection of cements to use with provisionals has also expanded. The color, opacity, chemical makeup, adhesive properties, and noxious stimulating properties are all important factors when deciding on an appropriate cement. The ease of cleanup of excess cement around the margins is also important. Eugenol-containing cements are generally discouraged for use with teeth that have been prepared for restorations that will be bonded into place with resin cements because it inhibits resin polymerization.11 The newer composite provisional materials are more translucent; therefore, their final color is influenced by the color and opacity of the underlying cement. If the clinician chooses not to anesthetize the patient at the seating appointment, a cement that selectively adheres to the provisional rather than the tooth structure is preferable with vital teeth. Cements that are less acidic can reduce postoperative sensitivity.12 Use of cements that set quickly upon light activation and can be cleaned up immediately may be advantageous in the busy dental office.
The balance between ease of removal and adhesion can be perplexing. A cement that does not come off readily outside the office is desirable, yet having to cut off the provisional is also extra work. Dentists need to determine the desired level of adhesion for the provisional cements they use. Dentists who are frequently out of town or do not wish to return to the office on weekends to re-cement provisionals may elect to use cements that adhere better. The dual-cured resin cements are more translucent, adhere readily to the provisional when removed, readily set upon light curing, and are easy to clean up.13 Telio® CS (Ivoclar Vivadent, www.ivoclarvivadent.us) is a cement that fulfills all these requirements.
The only downside of using the new provisional materials with the resin cements is that patients may fail to return to the office to have their definitive restorations placed. This may be due to financial reasons, lack of compliance, or that they do not fully understand that the restoration was only a temporary solution. Recently, a patient who presented to the author’s office for a problem with another tooth was still wearing a provisional restoration that had been fabricated 2 years earlier (Figure 1). The provisional was removed and no decay was observed. The crown was subsequently tried in, adjusted, and seated.
Posterior Provisional Restoration Protocol
The expanded use of provisionals has elevated their importance in the office. Proper use of these materials improves the final outcomes for patients, as is demonstrated here.
For the single-unit indirect restoration, an alginate impression is made and poured in stone when the patient first enters the operatory. Once set, the cast is separated, trimmed, and any voids or desired buildup from the original shape are added using flowable and conventional composite. A piece of 0.020 ethylene vinyl copolymer (Temporary Splint Material .020, Henry Schein, www.henryschein.com) is heated in the vacuum former until it begins to sag (Figure 2). The heated sheet is drawn down over the model and the vacuum is turned on. The stint is trimmed and tried in the mouth to assure that it fits. Once the preparation is complete and acceptable impressions are made, a self-cure automix bis-acryl material (Luxatemp Ultra, DMG America, www.dmg-america.com) is mixed and placed into the stint, which has a black mark placed to indicate which tooth is being restored (Figure 3). Some of the material is also syringed along the margins of the preparation to ensure that the material extends completely to the margins. The material is allowed to set for 1 minute, and a scaler (#204, Karl Schumacher, www.karlschumacher.com) is used to slightly pierce the stint away from the restoration and then lift them both away from the tooth. These are set aside for 1 minute to allow further setting. The provisional is removed from the stint by bending the stint in a manner that does not warp the provisional.
Gross shaping is accomplished using a course diamond (56-018, Piranha®, www.sswhitedental.com) in a high-speed handpiece with water spray. The interproximal wings are reduced so that excess pressure is not exerted upon the adjacent teeth, which would cause the teeth to be further separated and cause the interproximal contacts to be open when trying in the final restorations. A carbide bur (#56, SSWhite) is inserted into the handpiece, and fine shaping and removal of the diamond scratches is performed. Trimming with magnification is employed to assure that the provisional ends exactly at the finish line. The interproximal areas are refined, and the zones around the contact area are blended in. The area below the contact is thinned and contoured to mimic the final restoration. The area above the contact is rounded and the marginal ridge made level with the adjacent teeth. If there are any voids or accidental over-shaping occurs, flowable composite can be added. Open margins can also be closed with the provisional placed on the tooth and pushed down while flowable is added and cured. The intaglio surface of the crown is actively scraped with the small spoon excavator to remove the soft oxygen-inhibited layer, which may prevent the crown from completely seating.
The provisional is placed over the tooth and the occlusion is marked and adjusted. When the occlusion is closer to being correct, the #56 carbide bur is used to re-establish the anatomical form of the grooves into the occlusal surface. The buccal surface is viewed from the front, looking backward to ascertain that it visually blends with the others; it is then adjusted while in the mouth. The non-centric cusp tips are evaluated to verify that they are in line with the others and that they do not interfere with excursive movements.
Finally, the provisional is polished using composite finishing points (Jazz® Supreme Point, SS White). Gluma® desensitizer (Heraeus Kulzer, www.heraeus-kulzer-us.com) is placed over the tooth if vital, and then the provisional is seated with a dual-cure resin cement (Telio CS, Ivoclar Vivadent, www.ivoclarvivadent.us). After the patient bites down on the provisional, a cotton roll is inserted for the patient to bite. The cement is light cured for 10 seconds from each surface (Figure 4). The excess cement is removed with the #204 scaler and explorer, the interproximals are flossed with knotted floss, and the provisional is once again thoroughly cured (Figure 5).
At their seating appointment, patients are asked if they experienced any sensitivity and if they want to be anesthetized. Most conventionally cemented crowns are seated without anesthesia. Patients receiving crowns that will be bonded to vital teeth with a separate bonding agent and resin cements are anesthetized. The chart is reviewed to see if a large core or post had been placed, and if so, the crown is sectioned for removal to prevent dislodging the buildup. Otherwise, two small pilot holes are drilled into the buccal and lingual surfaces of the crown (Figure 6). Pointed crown-removal forceps are seated into the holes, and the provisional is rocked slightly buccal/ lingually until the crown is loosened (Baade Crown/Band Removing Plier, American Dental, www.amerdental.com) (Figure 7). If the resin cement was used, it remains attached to the provisional, leaving a clean tooth surface. The crown is tried in, adjusted, and seated with resin cement (eCEMENT™, BISCO, www.bisco.com) (Figure 8).
Clinical Uses of Anterior Provisional Restorations
A patient presented with a periodontal abscess at the apex of the upper left central incisor. There was drainage on the buccal gingiva. The tooth was deemed to be un-restorable. Potential treatments presented included an implant, an implant and three crowns, or a bridge and three crowns. The patient felt that a bridge and a crown was the simplest, fastest, and most economical way to achieve the esthetic changes he desired. Photographs were taken and impressions made at the first appointment (Figure 9). A mock-up of the desired shape was made on a model (Figure 10). A vacuum-formed stint was made prior to the preparation appointment (Figure 11). The patient had the tooth extracted by the periodontist, and the socket was preserved with a bone graft and resorbable membrane (Figure 12). Teeth No. 7, No. 8, and No. 10 were prepared, and a provisional crown for the right maxillary lateral incisor (No. 7) was made, adjusted, and seated, as was a provisional bridge for the prepared right central incisor and left lateral incisor (No. 8, No. 9, and No. 10) (Figure 13). The area was allowed to heal for 4 months. The patient returned, and the teeth were reshaped and impressions were made. Three weeks later, the prostheses were tried in and seated (Figure 14).
The fabrication of anterior provisional restorations often draws upon all the technical and artistic elements of dentistry, as is demonstrated in the following case example. A patient who had performed tooth whitening presented with two anterior crowns that were darker than her other teeth. Digital photographs were taken and viewed by the dentist and patient on a monitor (Figure 15). It was recommended that the crowns be replaced on No. 8 and No. 9 and that either crowns or porcelain laminate veneers be placed on No. 7 and No. 10. The patient declined to have treatment on the lateral incisors for financial reasons. The patient returned, and preliminary maxillary and mandibular alginate impressions were made. A vacuum-formed stint was made on the maxillary cast. The old crowns were removed, the teeth were reshaped, and final impressions were made (Figure 16). The provisional material was placed in the stint with extra material syringed around the margins and then removed after 1 minute. Two central incisors were left connected together to avoid the challenges of shaping the ideal midline and contact area. The interproximal area at the gingiva was carefully shaped so that the material did not impinge. The facial extent of the provisionals should approach the margins but not be bulbous or over-contoured to avoid apical migration of the gingiva while the crowns are being fabricated in the laboratory. Once the provisional material was set, the preliminary contours were shaped. A laminate veneer type of preparation was performed on the facial surfaces of the provisionals. Composite was added to more accurately mimic the polychromatic nature of the natural teeth. Darker composites were underlaid with caramel-shaded modifiers placed along the cervical. “Maverick” colors, such as caramel, white, and blue, are often placed in the mid-body of the tooth. Blue/gray tints and incisal shades of composite were placed in the incisal areas. The provisionals were seated with an opaque white shade of resin provisional cement (Figure 17). A complete set of preoperative prepared teeth, stump shades, and custom shade guides were sent to the laboratory. The patient returned in 3 weeks and the crowns were tried in, adjusted, and seated (Figure 18).
Conclusion
Provisional restorations serve many important functions. Discerning patients demand comfortable and esthetic results. Developments have improved the physical and esthetic properties of these materials. Dentists who develop their skills and abilities will be able to provide natural-looking, long-lasting provisional restorations for their patients. Practice and attention to detail should lead to the fabrication of provisionals that dentists are proud to show to patients and colleagues alike.
Acknowledgements
The author would like to acknowledge the excellent crowns fabricated by Valley Dental Arts in Stillwater, Minnesota. The surgical extraction and socket preservation was performed by Dr. Mark Klabunde in Worthington, Ohio.
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About the Author
Daniel H. Ward, DDS
Private Practice
Columbus, Ohio
