Explain, with the use of diagrams,how to sprue porcelain crowns forpressable ceramic materials

Explain, with the use of diagrams,how to sprue porcelain crowns forpressable ceramic materials

1. Sprues are attached to the wax veneer or crown patterns and invested using a special refractory investment to produce a mould, capable of being injected with the E.Max Lithium Disilicate ceramic ingots.

2. Sprue to the incisal edge using the sprue ring provided. If more than one investing, place restorations opposite each other on the ring.

3. The Sprue should be at the correct angle, ensure your restoration follows the same angle. This should then be between 45-60̊ to the base.

4. sprue diameter- 2.5- 3mm

   • Attachment point- thickest part of wax up (generally cusps)
     • Sprue angle- axial
       • Design of attachment points- rounded and slightly tapered, no sharp angles or edges