The use of hollow pontics is highly recommended to reduce stress in the porcelain.
Bridge pattern should be designed for complete porcelain coverage.
Connector size should be adequate size and shape to minimize distortion; 2mm x 3mm incisal/gingival x facial/lingual suggested.
Indirect spruing is recommended. Small bridges may use an 8 gz. runner bar, hevier bridges a 6 ga. runner bar.
Invest using gypsum or phosphate bonded investment. Divest very carefully as rough handling could result in distortion.
Prepare alloy surface by lightly grinding the entire porcelain-bearing surface with crosscut carbide burs. Do not sand-blast.
Oxidize by heating from 1100°F(593°C) to 1800°F (982°C),no vacuum, 5 minute hold. Do not remove oxide.
Use a 50% powder opaque: 50% dentine mixture to fill the hollow pontic. Cut into the center of the hole with a sharp blade to allow for shrinkage. Apply a wash of opaque to the rest of the framework.
Apply first masking opaque to framework and fill in voids in the pontic.
Additional opaque applications may be necessary to fill in all shrinkage voides.
The first buildup should utilize interproximal cuts down to the opaque to lessen the potential for distortion of the framework due to shrinkage of the porcelain.
A second porcelain application will fill in interproximal openings. Contour, stain and glaze normally.