COMPLETE DENTURES



12. MAKING THE MASTER CAST
Beading

The purpose of beading is to provide the master cast with a land area (which should outline and preserve the peripheral roll). The land area serves to delineate the useful limits of the impression. This is done by incorporating a right angle (which does not exist in the mouth) in the master cast. The beading wax is made perpendicular to the impression, which results in a little shelf completely around the impression.

Apply a thin layer of sticky wax where you will add the utility wax. The sticky wax should not be visible above the utility wax. Carefully lute some utility wax strips completely around the periphery of both the maxillary and mandibular impressions. The wax strips must follow the borders (3mm below the height of contour) of the impression, dipping with the muscle attachments and rising with the mucobuccal and mucolingual folds.

It is this horizontal component of the wax strip that is visible when viewing from the tissue surface of the impression that will form the land area. If you can't see all the beading wax without rotating the impression then you will be missing part of the land area. Your ultimate purpose is to capture the shape of the muco-buccal and muco-lingual folds in the model.

The beading wax should act as a spacer between the impression and the boxing wax.

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©1999 by Julius Rosen, D.D.S.