There are many ways, and many means, to fabricate provisional restorations. Most of us use some form of direct technique. This may involve a traditional powder-liquid formula, or a light cured cartridge based material. Some may have our laboratories fabricate provisional shells, which we then reline in the mouth. All of these techniques have their pros and cons. This article’s purpose is simply to describe another means of “getting it done”.
I use this technique when I am working on multiple units only. I like to bring this patient in on a Friday morning, when they will be the only patient I see that day. Time spent is not an issue, and the patient is made to feel very comfortable, unhurried and not at all worked on. The technique allows for many patient breaks, which allows the patient to read, rest, have a juice, go to the bathroom, etc. It is how I would like to feel if I was committing to such an undertaking. As a note, there are two cases used in the article. The purpose is only to show the technique for the provisionals, not the treatment plan or treatment outcome.
Once the patient commits to the treatment to correct the esthetic problem (Fig. 1) the initial wax-up is done of the proposed treatment (Fig. 2). An index is made using ruthinium, a very hard polyvinylsiloxane material (Fig. 3). I usually make two indices, one for the provisionals and one as a prep guide (Fig. 4). This is very useful for cases when the size and contours of the finished restoration vary greatly from the starting situation, and the amount of preparation needed is difficult to visualize (Fig. 5). It can be sliced away to reveal the amount of clearance for each tooth as it is prepared. I find this to be more accurate than a “suck down” which is too flexible in the mouth and can be deceiving when looking in three dimensions for the correct amount of reduction.
Once the teeth have been prepared (Fig. 6), an alginate impression is made and immediately poured in Snap-Stone (Whip Mix). This material sets very quickly. While this sets, I may go back to the mouth and do an occlusal equilibration, if necessary. When restoring so much of the mouth, I like to be sure I equilibrate to centric relation. I do it after the teeth have been prepared, since that means there are fewer to equilibrate. Once the stone has hardened, it is removed, and prepared for the acrylic. I place Rubber Sep on the occlusal 1/2 to 2/3. This acts as a spacer to prevent the acrylic from locking in to the model. I let the Rubber Sep dry and then place liquid foil over the entire cast (Figs. 7 & 8). This will allow easy separation of the acrylic from the stone model. Acrylic is then placed in the index. There are many types of acrylic you can use for this. I like the Palavit 55 VS by Jelenko (Fig. 9). I have found that this material sets up a bit darker than its stated shade, so I have learned to use the lightest shade and stain the provisionals if necessary. The index is placed over the appropriate model and pressed to place. Numerous rubber bands are place to help hold the index to the model (Fig. 10).
The models are then placed into the AquaPres unit (Fig. 11). The unit is filled to overflowing with hot water and the top screwed to place until the pressure indicator reaches 30. This unit requires no air source like a pressure pot. It is more compact, and more versatile. The models are left in the unit for 20 minutes. During this time I am taking the impressions.
When the models are uncovered, the acrylic will be left on the models. A Buffalo knife placed under any terminal abutment margin, will release the provisional from the model with just a flick of the wrist. You are then left with a very hard provisional and very brittle, and thin flash (Fig. 12).
Most of the flash will quickly flick off right to the margin. The provisionals are then trimmed and polished as any provisional would be. If necessary, I will relign the provisionals directly in the mouth with any direct acrylic, preferably a fast set material. These provisionals are much harder than any direct provisional and therefore are very suitable for long term temporization where the patient may need to have periodontal surgery or some other treatment done prior to final placement.
Once the finishing of the provisionals is complete, the finalization of the provisionals is accomplished by staining and glazing the provisionals. I use the TempArt LC staining kit from Sultan Chemists (Fig. 13). I will paint it on directly in the mouth and light cure. You can mix the stains to achieve many shades. All are preferable to the homogeneity of “acrylic out of the bottle.” I then remove the provisionals from the mouth and have my assistant paint on and light cure the Gloss Cote. This will give a durable luster and shine to the provisional. The first photo is the provisional on the date of preparation (Fig. 14). The second photo is the provisional six months later at the beginning of the final phase of treatment (Fig. 15).
This is a simple way to enhance the provisionals that we do in the office. It does not require a lot of extra time, and can be done by a staff member, if one is available. The cost of the equipment necessary is very reasonable, and the patient is not subjected to very much intraoral work in this phase of the treatment.
Mark Pasternak graduated from McGill University in 1989. C.E. highlights include Dawson Institute for Advanced Dental Studies, Misch Institute. He currently practices in Etobicoke.
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