How to prepare a strong, reliable temporary

The old saying that “no chain is stronger than its weakest link” is certainly true in dentistry. When working with crown and bridge, one of the primary complaints from dentists to dental technicians is that “the occlusion was high and it took a long time to adjust it clinically.”¹ The restorative process for an indirect restoration includes many steps that, when not carefully executed, can contribute to this problem. 

One of the most important steps is the provisional restoration, and it plays a crucial role in avoiding sensitivity, infection, and maintaining a stable position of the tooth by maintaining opposing and adjacent contacts, and thereby avoiding tooth movement. At this temporization stage, an adverse outcome could mean an emergency visit to your office, or a problematic appointment during the placement of the final prosthesis² as mentioned by Loos, Boyarsky and Quiring (2001).¹

Currently amongst the provisional materials categories, bis-acrylic provisional material is the product of choice due to its low shrinkage, easy handling and esthetic properties. This year, Clinician’s Choice introduced INSPIRE Esthetic Provisional Composite, which demonstrates a dramatic improvement in its mechanical and esthetic properties.

This material has an excellent flexural strength (105 MPa) and impact strength (76 MPa). These properties combined with its diametral tensile strength (62 MPa) which is similar to restorative composites, imparts to this material the ability to withstand the challenges that the oral environment imposes on our temporary restorations. Such strong provisionals will reduce the risk of breakage, especially at the margins, where most provisionals fail if the amount of reduction it is not adequate.³

Wear/cement concerns

Clinicians should keep in mind that wear of the proximal contacts of the provisional restoration is the main reason why the final restoration does not seat properly on the prepared tooth. Every dentist knows how frustrating it is when you have to adjust the proximal contacts of your crown and the final result is a mesial or distal open contact. Also, occlusal wear of the provisional, with resultant tooth movement, is main reason for “high” contacts. Preventing this from occurring is why INSPIRE represents a leap in its category.

You should also keep in mind that, at the provisional stage, not only does the temporary restoration play an important role, but the selection of the temporary cement is also crucial. An ideal temporary cement should present the following characteristics: easy removal of excess cement from around the margins; good marginal seal to help minimize sensitivity; good retention but easy removal of the temporary prosthesis; low solubility in oral fluids; and compatibility with provisional resin restorations, resin core materials, bonding agents and permanent cements. Polycarboxylate cements are the easiest to clean, and Santos & Santos (2012)⁴ also reported that polycarboxylate temporary luting cements present low post-operative sensitivity, adequate retention, and easy clean-up and they mentioned Cling² Resin Optimized Cement (Clinician’s Choice) as example of this category. 

In the following clinical case, we will explore a predictable technique for preparing a strong and reliable temporary restoration where we combined these two products (INSPIRE and Cling²) in order to achieve optimal results.

Clinical Case

Step 1: Patient presented to the office with a lower first molar which was endodontically treated and restored with a MacroLock Illusion X-RO Post, Fibercones (RTD St. Egreve France) and Zircules Zirconium Nano-Filled Core Material (Clinician’s Choice) [Fig. 1]. Before preparation for an all-ceramic crown, a disposable and customizable metallic tray (TempTray, Clinician’s Choice) was loaded with a PVS matrix material (Template Ultra Quick Matrix Material, Clinician’s Choice) and an initial impression was taken (Figs. 2-3). Template is a PVS matrix material designed specifically for this step; it sets in only 30 seconds, saving time for the clinician when compared to traditional “putty” matrixes, which can take up to 6 minutes to set. Template also flows into the embrasure areas well, and will release maintaining its form as shown in Fig. 3. Due to its mechanical properties, the tray and matrix can be easily reinserted without distortions, thereby producing a provisional with virtually no flash. 

Step 2: Fig.  4 shows the molar prepared for a full coverage ceramic restoration and, since the preparation margins were quite sub-gingival, a double cord technique was used with a #000 and #00 Re-Cord (Clinician’s Choice) retraction cord.

After the final impression was taken, a provisional restoration was fabricated using INSPIRE (Fig. 5).

Step 3: The Template matrix was reseated onto the preparation (Fig. 6) and a provisional with no voids and minimal flash was produced (Figs. 7- 8). INSPIRE is easy to remove from the impression and requires little or no polishing due to its minimal surface oxygen inhibition layer. It produces a smooth, high luster, nonporous surface that will resist biofilm and plaque build-up. For this case, the clinician decided to polish the provisional and apply a final layer of a light-cured glazing material (Glisten, Clinician’s Choice) [Fig. 9].

Step 4: The temporary restoration was cemented with Cling² polycarboxylate temporary luting cement and the excess was easily removed (Figs. 10-11), due to the cement’s mechanical properties and due to the smoothness of the final surface obtained by the use of INSPIRE combined with Glisten. 

Step 5: At the final appointment, the provisional was easily removed followed by manual clean up of the preparation. The combination of the smooth surface of temporary material and the bacteriostatic properties of the temporary cement results in a healthy gingival tissue as can be seen in Fig. 12.

Conclusion

The significant amount of frustration and wasted time that is experienced by the clinician when a final restoration needs significant adjustment can be avoided by the use of a provisional restorative material that not only resists premature fracture, but also resists wear which results in tooth movement. The above combination of INSPIRE Esthetic Provisional Composite and Cling² Provisional Cement will minimize this clinical challenge. 

References

1. Loos LG, Boyarsky HP,Quiring DJ. Procedure for occlusal refinement of mounted definitive cast to reduce clinical time required for adjustment of occlusion. J Prosthet Dent 2001;81:246-51.

2. Ramp MH, Dixon DL, Ramp LC, Breeding LC, Barber LL. Tensile bond strengths of provisional luting agents used with an implant system. J Prosthet Dent 1999;81:510-4.

3. Lind SD. INSPIRE. Strong, fracture-resistant material for temporaries. Dental Product Shopper. Nov 2013;128.

4. Santos MJMC, Santos Jr GC . Selecting a Temporary Cement: A Case report. Dentistry Today: 31(3): 96-99, Mar 2012.