How do you make a plaster tooth cast?

Making a dental impression using a plaster alginate mixture involves selecting an impression tray, mixing the plaster, placing the mixture in the tray, seating the tray onto the teeth of the patient and then taking out the tray. Orthodontists use a separate technique for the upper and lower teeth. Taking dental impressions goes back to the 1700s when Philipp Pfaff, dentist to Frederick the Great of Prussia, described a technique for taking dental impressions using wax and plaster of Paris, according to GlidewellDental.com.

The following shows an example of the steps involved in making dental impressions, as stated on DentalHygeine411.com.

1. Select a tray

Select a tray that will contain the alginate mix. It should be slightly larger than the lower or upper arch of teeth.

2. Mix the alginate

The alginate mixture may be blended using an electronic mixer or by hand. Two scoops are usually needed for full arch impressions.

3. Pour the mixture into the tray

Place the alginate mixture evenly on the tray. Keep track of the time when the impression material was mixed, as it usually takes two to three minutes for the material to set.

4. Seat the tray onto the teeth

Using separate techniques for the upper and lower teeth, seat the tray with the alginate mixture onto the teeth of the patient. Hold the tray until the material has set.

5. Remove the impression

Once the impression material has set, remove the tray. This is usually done by pulling on the cheeks. Protect the other set of teeth while snapping off the tray.