Provisionalization

The next step that is critical for reducing hypersensitivity is the fabrication of the provisional crown or fixed partial denture. The provisional will serve to protect the tooth for a period of several weeks while the crown or prosthesis is being fabricated. During this time it is common for many of the provisional cements to wash away from the crown margins. There are many provisional materials available. They all have in common the characteristic of shrinkage after polymerization.

Initial polymerization can lead to open margins around the tooth preparation (fig.4). A second mix of the provisional material should be placed on the margin of the restoration prior to resealing it on the prepared tooth to provide a more accurate margin. The second mix of material is much smaller and will experience less shrinkage (fig. 5). A clearly defined margin on the provisional restoration facilitates accurate margin trimming. This enhances the adaptation of the provisional restoration to ensure a seal around the margin, and minimize the potential for leakage under the crown.


Figure 4: Provisional crown margin after initial polymerization.


Figure 5: Additional provisional material being added to crown margin.

Microleakage is a common cause of hypersensitivity in prepared teeth. This can occur quickly around a margin that is ill fitting, particularly around a porous provisional crown margin. A well-designed margin will also enhance the recovery of the gingival tissues and minimize inflammation around the provisional margins while the definitive restoration is being fabricated (fig. 6).


Figure 6: All ceramic crown preparations three weeks after initial preparation and impression procedures.

It is important to evaluate the occlusion of the provisional prior to the patient leaving the office to ensure that it is not in hyper-occlusion. Hyper-occlusion can lead to extreme hypersensitivity. This can be easily checked and adjusted prior to cementation of the provisional restoration. Centric relation or maximum intercuspation contacts, as well as lateral and protrusive contacts, need to be evaluated for each provisional restoration. Following cementation, the occlusion should be re-evaluated and adjusted if necessary.

The author has found it beneficial to provide the patient with a syringe of chlorhexidine gluconate and have them apply it with a small brush tip to free gingival margin around the prepared teeth for a period of one week.