The steps of Custom Tray Impression are followed as below:

First, draw the border outlines of the proposed custom tray on the diagnostic cast and gives other design directions. For example: The maxillary denture is limited by the labial sulcus, buccal sulcus, pterygomaxillary notches and vibrating line. And mandibular denture is determined by the labial sulcus ,buccal sulcus, lingual sulcus and posterior extent of the retromylohyoid space and retromolar pads.

Second, the liquid to powder ratio is absolutely critical, please carefully follow the manufacturer’s direction. In this Lab class, I usually measure 7ml or 10 ml of Acrylic liquid and one spoon of powder (Tray Acrylic). Put the liquid first, then add the powder into a small rubber bowl. BTW,Acrylic is monomer and polymer of the autopolymerizing resin.When I make Acrylic(liquid and powder), I put my finger and feel no sticky. And then I pour them out into the cold water and keep them by moisture.

Third, cover the undercut with wax;

Forth, Ensure that the mold ( the diagnostic cast) is coated with Vaseline( petrolatum) before I place the resin into the stone mold. Cover the resin and roll out the resin to match the mold’s shape and thickness.

Fifth, cut away any excess dough and lift the acrylic resin blank from the mold. I store excess acrylic in a cold water to use later for fabricating a tray handle. I shape the resin to the borders .

Sixth, Attach a handle to the tray. Ensure the handle is strong enough to withstand considerable force and its shape is formed into an “L”.

Seventh, Cut through the excess bulk and sharp edges away with an abor band and burs to the cast and prevent the frenums not being cut, it means trim any excess acrylic resin to the outline border on the cast and make it round and smooth the borders of the tray. Get attention to the bulk of the tongue space and do spacer modification. Check if the space between the tray and the tissue is filled with a very accurate.

Eighth,I am sure to clean away all traces of resin that Acrylic that might be present on the tissue surface of the tray. Then I make disinfect again before going back to the dentist office.