Esthetic and physiologic considerations in metallic framework design.

The metal framework is the essential precursor to a successful porcelain fused to metal fixed partial denture. The framework should be rigid not by bulkiness, but by design. Pontics must be supported to span the edentulous space and replace the missing dentition while providing adequate space for a 1-mm porcelain veneer. The combined thickness of the metal and porcelain must be sufficient to achieve the desired color and vitality without producing a prosthesis that is morphologically overcontoured. To develop a framework that meets all the requirements of physiology, esthetics, and strength, a diagnostic waxup directs the positioning of connectors and allows planning of both form and support. A properly designed and positioned connector area should allow separation of the units by permitting the development of natural appearing labial embrasures. At the same time, the connector must, by engineered design, provide adequate structural strength to support the porcelain. Designing and fabricating the metallic framework for a fixed partial denture requires planning and an understanding of what is desired in the final form. An outline has been presented that details the connector form and placement and a technique has been suggested for developing a framework that provides optimal strength while allowing space for placement of esthetically contoured porcelain.