Capturing an exquisite final impression is our goal every time. Getting this result can be one of the most challenging things we do in dentistry. In addition to being masterful in taking an impression and handling the materials, we also must manage the oral environment properly.

Improving the Gingival Tissue Prior to the Impression Appointment

For crown and bridge impressions this process has to begin with optimal tissue management, and tissue management always begins before tooth preparation. Old restorations with poor margins often compromise hygiene with resultant irritated and inflamed gingival tissues. If the tissue is inflamed at the time, we recommend the tooth be crowned, we apply chlorhexidine varnish (Cervitec Plus – Ivoclar Vivadent). When the patient returns for impressions, tissue health is vastly improved.

Managing the Gingival Tissue for Tooth Preparation

Tooth preparation itself can result in difficulty managing the tissue. My preference is always to leave margins supragingival if that is clinically appropriate. My second choice is equigingival, where the margins are right at the crest of the tissue. If the margins are to be placed subgingival, I want to avoid cutting the tissue and then having to manage bleeding. If my initial margin placement is equigingival, I place a primary cord to move the tissue out of the way. This allows me to now drop the margin subgingival with minimal trauma to the tissue.

Retraction of the Gingival Tissue for the Impression

Once tooth preparation is complete, retraction creates a space for the impression material to go past the margin apically so that we can create the proper emergence profile of the restoration. There are many ways to retract prior to an impression. I personally use a second or top cord with a larger diameter than the primary cord I placed to move the tissue for subgingival preparation. If the tissue is bleeding after the placement of the top cord, I place 3M’s “Retraction paste” as a hemostatic agent. This allows for optimal control of bleeding without worry of negatively impacting the set of my impression materials or staining the prep or gingival tissues.

Taking the Final Impression

The final impression is taken with Flexitime impression material (Kulzer). I have my assistant load the tray with heavy body material. I first wet the top cord, so I do not cause bleeding upon removal. The area is now thoroughly dried to allow for proper contact of the impression material to the tooth and tissue surfaces. I inject Flexitime CorrectFlow (Kulzer) and then seat the impression tray. I hold the tray for the full intra-oral set time and do not allow patients to close or bite on the tray, as movement can negatively impact the accuracy of the impression.

Is the impression perfect?

Once removed I inspect the impression using magnification to assess that I have adequate flash beyond the margins of the light body, no pulls, voids, drags or evidence that the impression moved. There is no way to correct an impression for errors. If errors occur, we repeat the process from the beginning to take a new impression.

Check out some of my short videos about impressions on Restorative Nation at https://restorativenation.com/?s=impression.

One of the challenges we face today in dentistry is managing tissue health during the time period our patients are in provisonal restorations. This has become even more critical as we have incorporated more resin bonding techniques to seat indirect restorations. Isolation is critical to the long term success and can be challenging after multiple weeks in a bisacryl provisional.

We all stress oral hygiene to our patients during this time period, but let’s be honest there are barriers to optimal tissue health at the seat appointment. One barrier is often patients are fearful that their hygiene procedures will displace the provisional. This fear has them brush less vigorously, floss less or not at all, and even sometimes avoid that part of their mouths completely. Even when patients are undeterred int heir hygiene the provisional itself is often a barrier. Contacts can be less then optimal and increase interproximal food impaction. The Bisacryl itself, tends to hold and attract plaque due to a different surface texture even when finely polished.

Given the barriers and the goal of super healthy tissue, Chlorhexidine varnish (Cervitec Plus by Ivoclar) has become one of my favorite products. We are all familiar with the incredible anti-microbial effects of chlorhexidine, and also the reasons we dislike it. Cervitec does not have a bad taste, does not cause the typical brown staining, does not effect the patients taste buds, and they don’t have to remember to use it. Cervitec plus is a clear liquid applied with a micro-brush. At the end of any appointment where we have placed a provisional my assistants will coat the gingival margin with Cervitec as the last step before the patient leaves.

I have been using this as a critical step in my restorative procedures for over 5 years now, and I swear by it. I see almost perfect tissue health at seat appointments, and it is rare for me to struggle with isolation due to poor tissue management.