In a simple case where only one or two teeth are going to be restored indirectly and the tooth form is not badly broken down, I’ll often fabricate the provisionals directly. Usually this is a predictable procedure but it can become complicated and frustrating in the event that the provisional becomes damaged or lost.
Here’s a simple technique that involves using an inexpensive, disposable triple tray and a fast-setting bite registration silicone that has helped me to maximize efficiency during the provisionalization period.
Step 1: Evaluate the tooth or teeth to be prepared and modify contour if necessary. If a cusp has fractured, putty composite can be temporarily added to recreate a more favorable tooth shape.
Step 2: Inject fast setting, flexible bite registration silicone onto only the side of the triple tray facing the preparation site. Insert the tray and have the patient close and hold in intercuspation position (ICP). Just enough silicone should penetrate through the fabric to index the opposing teeth but not so much that it will require trimming or restrict the patient’s ability to close back into the matrix.
Step 3: Remove the tray after the silicone has polymerized and evaluate. Trim the material as necessary. When the preoperative condition is sufficiently captured, prep away feeling content that you have a reliable matrix for fabricating the provisionals!
Step 4: When ready for fabrication, simply inject bisacryl into the impression, reseat the impression in the mouth and ask the patient to bite lightly in ICP. Be sure to remove the matrix before the bisacryl has reached its final set in order to prevent locking the provisional in.
Step 5: Carefully tease the provisional from the matrix. Then trim, finish and cement as usual. Bisacryls exhibit some polymerization shrinkage so I do recommend relining the provisional with a wash of bisacryl in order to maximize marginal integrity. Finally, be sure to check the occlusion both in ICP and in excursions. The result should be a well-fitting provisional and an undamaged matrix. One huge advantage to this technique is that following the procedure, the silicone matrix can be disinfected and stored with the patient’s name, date and tooth number/numbers until the definitive restorations are delivered without any discernable distortion. In the event that the provisional is damaged or lost, the matrix is ready to go and fabrication of another provisional can be accomplished with minimal disruption to the schedule. Remember to dispose of the matrix following insertion of the case.
Darin M. Dichter, DMD,