Difficult Primary Impressions

There are some instances when you just can't seem to get a good primary impression. This is especially true in very deleted mandibles.

I have taken compound impressions and then relined them with zinc oxide and eugenol or rubber base for the primary impression.

I have loaded the patient's old denture with alginate, and used the denture as a tray for the primary impression. If needed, you can use alginate adhesive on the denture. Since the adhesive is difficult to wash off be sure to tell the patient that the old denture will stick to the gums better until the adhesive wears off.

You want to be careful pouring up the model, to make sure you can easily remove the old denture from the cast. It is safest to use plaster for this model.

There are occasions when the patient uses their tongue to prevent you from completely inserting the tray for the maxillary impression. You will eventually get the tray in the mouth and get the impression. Sometimes you will need two fingers to hold the tongue down. Practice inserting the empty tray.

It is important to remember when taking the secondary impression that this patient has a "fighting tongue." The patient will block your tray, lined with the impression material which will be setting while you try to force it passed the tongue. Be ready with two fingers to depress the tongue.

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©1999 by Julius Rosen, D.D.S.