Dr. Len Boksman DDS, BSC, FADI, FICD

	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.”

 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 prosthesis

 as mentioned by Loos, Boyarsky and Quiring (2001).

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, 

, 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.

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 

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)

 also reported that polycarboxylate temporary luting cements present low post-operative sensitivity, adequate retention, and easy clean-up and they mentioned 

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 (

 Patient presented to the office with a lower first molar which was endodontically treated and restored with a 

Zircules Zirconium Nano-Filled Core Material (

]. Before preparation for an all-ceramic crown, a disposable and customizable metallic tray (

Clinician’s Choice) was loaded with a PVS matrix material (T

). 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 

. Due to its mechanical properties, the tray and matrix can be easily reinserted without distortions, thereby producing a provisional with virtually no flash. 

 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 

The Template matrix was reseated onto the preparation (

) and a provisional with no voids and minimal flash was produced (

). 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 (

The temporary restoration was cemented with 

 polycarboxylate temporary luting cement and the excess was easily removed (

), due to the cement’s mechanical properties and due to the smoothness of the final surface obtained by the use of 

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 

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 

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.

Articles

 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. 

How to prepare a strong, reliable temporary

	Separation rings can be used as a predictable method to place Class II composite resins and obtain tight, well-contoured, interproximal restorations.

	Use of a separating ring, such as the Garrison Composi-Tight 3D system, when restoring Class II composite restorations has a greater influence on the obtained proximal contact tightness compared to the influence of the consistency of the composite resin.

 Ceramic inserts or pre-polymerized resin particles have been used, which can wedge contacts interproximally as well as decrease the overall amount of composite used, thereby reducing overall shrinkage.

	The Garrison Composi-Tight 3D sectional matrix system has a Soft-Face (Fig. 1). The circular ring is made of polished stainless steel, with the bow section encased in plastic that stiffens the ring (Fig. 2). The hard and soft plastic combination of the tine area creates separating pressure while entering the interproximal area to minimize flash and enhance the grip on the contoured matrix band, which comes in a number of sizes and shapes. The U-shaped gingival contour of the soft face allows the ring to be placed over the wedge.

	The system has the option of using regular contoured bands or the new Slick bands (Fig. 3), which are designed to minimize adhesion to the matrix band. The Garrison Fender Wedge (Figs. 4 & 5) is an excellent way to protect the rubber dam, interproximal gingival tissues, and the tooth surface adjacent to the preparation.

	Clinical predictability is assured using the following protocol.

	A 20-year-old patient presented with four quadrants of failing composites due to open contacts, interproximal and occlusal decay and pain on chewing (Figs. 6 & 7). Tooth No. 15 had carious pulp exposure and required endodontic therapy. Rubber dam was applied to the lower left quadrant after anesthesia, interproximal wooden wedges were placed to begin the “pre-wedging” process and were advanced during the procedure.

After removing the old restorations and caries in tooth Nos. 19 and 20, a BlueView Pinch Matrix (Garrison Dental Solutions) was applied to tooth No. 19 (Fig. 8) and new wedges inserted to stabilize the band, adapt it gingivally to minimize the chance for composite overhang, and to create interproximal pressure.

To facilitate easy access, and because tooth Nos. 18 and 20 were going to be prepared and restored, no auxiliary separation was applied. Tooth No. 19 was etched with Ultra-Etch 35% phosphoric acid solution (Ultradent) by applying it to the enamel margins first, followed by placement within the cavity preparation, and washed and gently dried after 15 seconds, leaving a slightly moist surface.

G5 desensitizer (Clinician’s Choice) a mixture of 5% Gluteraldehyde, 35% HEMA and water was carefully applied, and the excess removed by suction. By coagulating plasma proteins in the tubules, the G5 acts as a pre-primer and has residual antimicrobial effects.

MPa (Clinician’s Choice), a fifth generation bonding agent, was placed in a single layer, air-thinned with the solvent evaporated and light cured with a Valo broad spectrum curing light (Ultradent) for 10 seconds.

A thin layer of DeMark, a hyper-opaque, flowable hybrid lining composite (Cosmedent) was teased into the base of the proximal box, into the deeper carious excavation areas and lightly teased over the pulpal floor (Fig. 9), followed by light curing for 10 seconds. Its radiopacity can be seen clearly on the radiograph (Fig. 10), which minimizes the chance for erroneous diagnosis of caries under the composite due to radiolucent lining materials. Placement of a flowable liner also creates an “elastic cavity wall”

 interface which minimizes the effect of C-factor shrinkage.

An incremental insertion technique was used to restore the tooth with Cosmedent Nano A2 (Cosmedent), with each layer no more than 2 mm, laterally placed to reduce the C-Factor and light cured for 10 seconds. The restoration was shaped on the occlusal with a 7803 multi-fluted bur, and the mesial interproximal shaped with a 7901.

On tooth No. 20 the Garrison contoured matrix was placed, followed by a G Wedge, and the Composi-Tight 3D ring applied to separate the teeth, and minimize interproximal flash (Fig. 11). After each placement of the contoured matrix band, a ball burnisher should be used to verify contact with the adjacent tooth.

The DO restoration was placed following the previously described protocol.

A final excellent contour and contact can be routinely achieved with this system (Fig. 12). Because of a tear in the rubber dam, a new dam was placed to adequately isolate tooth No. 18 and “pre-wedging” initiated.

Even with the rubber dam clamp on the same tooth, if well-placed apically, Figure 11 shows the application of the Garrison contoured matrix and the Composi-Tight ring over the rubber dam clamp. The easy 90° direct access allowed by the shape and design of the Valo curing light allows maximum curing penetration (Fig. 13).

After restoring tooth No. 18 as previously described and polishing the restorations with an occlusal diamond impregnated Groovy bristle brush (Clinician’s Choice), a post-operative photo was taken (Fig. 14).

Dr. Leendert (Len) Boksman DDS, BSc, FADI, FICD, is a part-time consultant to Clinical Research Dental acting as Director of Clinical Affairs, an Adjunct Clinical Professor at the Schulich School of Medicine and Dentistry and is in private practice in London, Ontario. He can be reached at 

. This article is a portion of one previously published in Oral Health November 2010.

 Separation rings can be used as a predictable method to place Class II composite resins and obtain tight, well-contoured, interproximal restorations.