Trimming the Master Cast

The casts have to be trimmed before mounting on the articulator. This is especially true of the maxillary cast because you will lose your facebow record if the cast is trimmed after mounting. If your model doesn't fit the processing flask the lab tech will trim your cast, wiping out your notches you made to re-index the master cast on to the articulator.

Make the base of the cast about a half inch thick. It is also a good idea to trim the base parallel to the residual ridge.

Leave 2-3mm (width) of land area. The land area should be just high enough above the depth of the fold so that you can see the width of the fold.

Students alter the width of the fold especially on the lingual. Do not change the shape of the master cast without guidance from your instructor.

There are two sizes of processing flasks, regular and large. If possible try to get the model to fit the regular size. If you can't get it to fit the regular size flask then write on your prescription, "large flask."

Trim and notch the casts before you come to the clinic.
12. Notches only
Do not make any additional grooves on the master cast because it will make it more difficult to reseat the cast on the index.

Always put the cast in a safe place. Always place it with the base down. Never leave the cast in the center of the bracket table. Never work directly over a cast. You can drop something on it. If I carry a cast it will be held close to my body so it won't get knocked out of my hand.

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1999 by Julius Rosen, D.D.S.