- Cast precise models
- Make a tension-free wax-up
- Sprue-up correctly
- Invest bubble-free
- Inclusion-free casting
- Deflask it with a hammer
The hammer
Bent clasps, cracked acrylics, broken-off acrylic dentures, warped bridges, and much more – all these damages result from using of a hammer. The uncontrolled percussive waves destroy the homogeneous structure.
Even more dangerous is hitting the metal object on the sprue former, thus damaging the object intentionally. Compared with the effort put into preparation before, this is crude treatment indeed.
The tongs
The tongs enforce a pincer-effect on the investment or plaster. This cleaves the material apart and transfers the force to the cast object, thus causing tension and warpage. An acrylic denture, for example, can easily break under such pressure. There is permanent danger of teeth breaking off.
Conclusion:
Both methods effect not only the investment but, in the same way, the cast object. Hard-to-reach areas are left out completely.
A pneumatic chisel is much more favourable as it in fact only effects the investment material.
