What is a Dental Impression Rod?



An impression rod is a dental tool used during an implant impression.

In an implant impression, one distinguishes between two techniques:  The pickup and reposition technique. For each technique there are different impression rods, there is the two-part rod used in the pickup technique and the one-part rod used in the reposition technique. The pickup technique is the more exact of the two but requires more time on the dentist’s part. This short video "Impression Posts" is intended to show you the differences between the two techniques.

In the video you see a female patient after implantation. During an accident, the patient’s front teeth and parts of her jawbone were knocked out. She did not want jawbone reconstruction and the red-white aesthetics was not as important to her due to her low laugh line. Nevertheless, the gums were supported through connective tissue implants in order to compensate somewhat for the loss of jawbone. The provisional solution is being removed and one can see the gum formers, also called gingiva formers. These support caps enhance the healing process of the gums after implantation. The gingiva formers have to be untied before the impression is taken.

Now you will first see the pickup technique. The impression rods are placed on the implant and then get tightened with an instrument known as a chimney screw. The position of the impression rod has to be checked.  An imprecise fit will undoubtedly result in the dental technician creating an incorrect crown. The impression spoon is being adjusted; a little opening for the chimney screw is milled into the spoon. In this case, two holes are drilled to enable the opening of the chimney screws and subsequent removal of the impression rod from the implant after the conclusion of the hardening process.

This is the only way to remove the impression and the impression rod simultaneously from the implant. Therefore, during removal of the impression spoon from the patient’s mouth, the impression rod remains with the impression. This is the most important difference in comparison to the reposition technique.

You now see how the impression spoon is filled with impression material. Additionally, impression material is distributed with a syringe around the impression rods. This is done so that the rods are firmly settled in the impression and do not move around. After the hardening of the impression compound, the chimney screws are loosened and the impression, including the rods, are removed from the patient‘s mouth. Therefore, when using the pickup technique, the impression rods remain with the impression spoon. This is different with the reposition technique.

Please pay attention to the following short animation. A one part impression rod is placed on the implant and screwed on for the reposition technique. The impression spoon does not have to be customized for each individual patient because the rod remains in the patient‘s mouth when the impression is removed. It is only unscrewed from the implant after the removal of the impression. Only now is the impression rod repositioned into the impression, thus the name “reposition imprint.” However, these readjustments can lead to shifts in the impression. This technique results in less work for the dentist but it has more potential for flaws in the impression.

Click here to see the video: Impression Posts

This post is also available in: German

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