Large nodule due to air trapped during investing

Multiple random nodules caused by inadequate vacuum during mixing

Black, rough casting due to breakdown of investment from excessive heat

Random porosity caused by excessive casting force

Working cast-Die preparation-Investing-Wax pattern-Casting

Impression-Die preparation-Working cast-Investing-Wax pattern-Casting

Die preparation-Wax pattern-Working cast-Investing-Casting

Working cast-Die preparation-Wax pattern-Investing-Casting

must provide sufficient strength to withstand the heat of burnout

must reproduce precisely the detailed form of wax pattern

must not expand to duplicate the actual casting of the molten metal

must expand sufficiently to compensate for the shrinkage of the alloy

Retention can be improved by providing the correct taper

Resistance form is improved by increased height as long as diameter is constant

Protection from fracture and wear

Preparation features that increase the resistance to rotation is not needed

Will lead to tooth discolouration

Is indicated in extruded teeth

Is contraindicated in patient with high caries index

The preparation of buccal and lingual walls are converge occlusally

The buccal reduction is extending 2.0 mm in depth with shoulder margin

Bevels are placed at the occlusal and gingival cavosurface margins to provide frictional retention

The cavity width is kept at ¼ th the intercuspal distance

Subgingival extension of gingival seat is acceptable if indicated

Internal line angles are rounded

1°

4°

7°

10°

When there is adjacent or opposing teeth have dissimilar metallic restorations, cast gold onlay should be avoided in order to prevent galvanism

When there are other gold castings present in the mouth

In situation where the proximal margins extend subgingivally

Gold inlays are not used as an abutment for a fixed or removable prosthesis

fabricated by indirect technique and able to accurately reproduce precise details of occlusal, axial contours and contacts.

cheaper than amalgam or composite resin restorations

esthetically acceptable in facial surfaces of posterior teeth.

less occurrence of microleakage since it is cemented with luting cements.