PRELIMINARY CAST
Grade A	Casts are neat, clean, free of voids and/or defects, have sharp detail. Tongue area of mandibular cast trimmed flat and smooth. Casts reflect entire basal support area. The cast base is approximately 10-15mm thick in thinnest area and is trimmed approximately parallel to the ridge. No impingement of impression tray evident. Cast is labeled with patient name and date. Cast is smoothly trimmed with at least 2-3mm of vestibule present lateral to the deepest part of the vestibule labially and buccally. Cast edges are beveled and smooth. Land area of the cast is trimmed so no undercut is present. The sides of the cast and the edentulous ridges should be parallel and perpendicular to the base.
Grade B	Minor discrepancies from above which do not compromise the quality of the clinical treatment. Casts reflect correct extension, but minor, non-critical defects in areas of stone not covered by tray are present. Casts slightly thinner or thicker than ideal. Cast is not smoothly trimmed. Cast is not labeled.
Grade C	Cast extension adequate to make a clinically acceptable tray but marginal. Full vestibular depth missing in isolated areas. Cheek slightly captured in distobuccal areas of mandibular cast. Tissue surface of cast somewhat unclear and slightly scarred. Land area slightly interferes with correct tray construction. blockout wax remains on cast. Stone debris left on cast. Cast is not clean and neatly trimmed.
Grade E	Cast prevents construction of clinically acceptable impression tray. Border extension inadequate for correct tray construction. land areas poorly defined, missing, or so high they prevent proper tray construction. Tongue space not trimmed neatly and/or prevents access to lingual borders. Cast base excessively thick or thin (less than 5mm or greater than 20mm)