My blog on removing the air inhibited layer that occurs when resin sets, created a number of questions regarding a technique called immediate dentin sealing. This technique, which is more prevalent in Europe then the US, can be incorporated as part of every indirect restorative procedure. The concept is to seal all of the freshly cut dentin as soon as you have the preparation complete. This sealing of the dentin prevents continued bacterial contamination or chemical intrusion from the temporary cement into the dentinal tubules. In addition formation of a hybrid layer and bond strengths are more effective prior to the dentin being contaminated, or the collagen matrix collapses as part of the impression process. Additionally, immediately sealing the dentin decreases the incidence of post operative sensitivity between the prep and cementation appointments. The theory behind immediate dentin sealing is to increase patient comfort by minimizing post op sensitivity, decrease the risk of post operative pulpal inflammation and death by minimizing contamination into the tubules, and increase bond strengths by creating the hybrid layer on freshly cut dentin.
Prepare the teeth as you would for any indirect restoration. If you need to place a core do so, and then refine and finish the prep. At this point you will follow the steps for your dentin adhesive, etching, priming and applying the resin. This process can be done with either total etch or self etch adhesives. Cure the dentin adhesive completely. The enamel margins need to be free of adhesive, so after curing, go back and refine and finish the margins. The entire prep will have a thin layer of uncured resin, the air inhibited layer, present. If left it can prevent the set of certain impression materials, and also cause bisacryl provisionals made directly in the mouth to bond to the adhesive layer. Remove this air inhibited layer with rubbing alcohol. Now impress and provisionalize as you normally would.
Impressions should be taken in this technique after the dentin is sealed, both so that the film thickness of the resin will not alter the fit of the restoration, and the physical effect of the impression hasn’t altered the dentin. When the patient returns for placement of the final restoration, remove the temporary and thoroughly clean the prep. This can be done with a prophy cup and pumice or a very light application of air abrasion with 50 micron aluminum oxide. Once the prep is clean follow your regular process for bonding or cementation.